No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Diversity of Cryptosporidium spp. in Apodemus spp. in Europe
... However, recorded occurrence values are highly variable within and between host genera. In Apodemus spp., Cryptosporidium occurrence ranged from 21% to 68% [19,77], in Microtus spp. and Myodes spp., it ranged from 2% to 73% [2,19,74,[78][79][80][81], in Mus spp., it ranged from 0% to 32%, in Rattus spp., it ranged from 14% to 45% and in shrews of the genus Sorex, it ranged from 14% to 44% [2,8,38,[82][83][84]. Thus, in this study, the overall occurrence of 1% and host-specific occurrence values are comparatively lower than in previous studies from Europe. ...
... Cryptosporidium muris was identified as the only Cryptosporidium species in two samples of Algerian mice and one sample of Cabrera's vole from geographically separated sampling units. As expected, the obtained SSU rRNA gene sequences shared 100% sequence identity with the reference strain C. muris RN66, the most frequently detected strain in Europe [63,77,[86][87][88]. In future studies, additional genetic markers, such as microsatellite markers, could be added to provide a more detailed understanding of the genetic variability in C. muris [89]. ...
... C. muris has been described in a variety of mammals and up to now, it has been identified in 17 rodent species worldwide [41]. In the European scenario, C. muris was identified in yellow-necked field mice, wood mice, house mice, Algerian mice, bank voles, black rats (Rattus rattus) and brown rats (Rattus norvegicus) [8,40,77,82,83] and Cabrera's voles in the present study. Moreover, C. muris is considered as a zoonotic species [85], since it has been reported in healthy children [90] and HIV-positive individuals [91][92][93][94] and also healthy adults were susceptible to experimental infection [95]. ...
Simple Summary
Wild small mammals can be a veterinary and public health concern, because they can act as reservoir hosts for numerous pathogens and potentially transmit them to humans, domestic animals and other wildlife species. This study represents the first investigation of the diarrhea-causing parasites Cryptosporidium spp. and Giardia spp. in wild rodents and shrews from Portugal. Cryptosporidium spp. was rarely and Giardia was frequently detected in the feces of the analyzed species, with the southwestern water voles (Arvicola sapidus) and Lusitanian pine voles (Microtus lusitanicus) showing the highest infection rates of Giardia spp. Genetic characterization based on common genomic marker sequences revealed the rodent-adapted Giardia microti and potentially zoonotic Cryptosporidium muris as the only circulating species. These findings suggest the limited role of wild rodents and shrews as natural sources of human infections in Portugal regarding the investigated parasites. Moreover, the host ranges of Giardia and Cryptosporidium spp. were extended and the obtained genetic sequences of Giardia microti are useful for future comparative studies. From the One-Heath perspective, this study helps to understand the epidemiology of Giardia spp. and Cryptosporidium spp. in wildlife.
Abstract
Cryptosporidium spp. and Giardia spp. are important diarrhea-causing protozoan parasites worldwide that exhibit broad host ranges. Wild small mammals can harbor host-adapted and potentially zoonotic species of both parasites. The aim of this study was to investigate Cryptosporidium spp. and Giardia spp. in wild rodents and shrews in Portugal, focusing on the protist’s occurrence and genetic diversity. Molecular screening by PCR at the small subunit (SSU) rRNA gene locus of 290 fecal samples from wood mice (Apodemus sylvaticus), southwestern water voles (Arvicola sapidus), Cabrera’s voles (Microtus cabrerae), Lusitanian pine voles (Microtus lusitanicus), Algerian mice (Mus spretus) and greater white-toothed shrews (Crocidura russula) in Northeast Portugal revealed the low occurrence of Cryptosporidium spp. (1%) and high occurrence of Giardia spp. (32.8%). The analysis revealed that “species” was the only significant factor associated with the increasing probability of Giardia spp. infection, with the highest prevalence reported in southwestern water voles and Lusitanian pine voles. Cryptosporidium and Giardia species determination at the SSU rRNA gene locus revealed C. muris and G. microti as the only circulating species, respectively. Subtyping of the glutamate dehydrogenase (gdh) and beta-giardin (bg) genes provided evidence of the high genetic diversity within the G. microti clade. This study suggests that rodent-adapted G. microti occurs to a large extent in cricetid hosts and supports the limited role of wild rodents and shrews as natural sources of human infections in Northeast Portugal regarding the investigated parasites. Moreover, this is the first record of G. microti in southwestern water voles, Lusitanian pine voles, Algerian mice, wood mice and Cabrera’s voles and C. muris in Cabrera’s voles. Finally, this study improves the database of sequences relevant for the sequence typing of G. microti strains and provides new insights about the epidemiology of Giardia spp. and Cryptosporidium spp. in wild rodents and shrews, two parasite genera of high importance for public and animal health.
... The parasite infects a broad range of hosts, including various bovids, camelids, equids, canids, non-human primates, and marine mammals [94]. C. parvum is the dominant species in rodents; at least 20 species of rodents such as rats, mice, voles, squirrels, Rhizomys sinensis, and Chinchilla lanigera are known to be positive for C. parvum [8,11,24,28,37,44,64,68,80,87]. C. parvum has been detected in wild rodents, pet rodents, and farm rodents in 14 countries [37,80,87,24,64]. ...
... C. parvum is the dominant species in rodents; at least 20 species of rodents such as rats, mice, voles, squirrels, Rhizomys sinensis, and Chinchilla lanigera are known to be positive for C. parvum [8,11,24,28,37,44,64,68,80,87]. C. parvum has been detected in wild rodents, pet rodents, and farm rodents in 14 countries [37,80,87,24,64]. Pet rodents and farm rodents have close contact with humans. ...
... Subtyping of C. parvum at the gp60 locus identified more than 20 subtype families. Several studies that identified C. parvum in rodents have conducted typing at the gp60 locus; a variety of C. parvum subtypes including IIaA15G2R1, IIaA16G2R1, IIaA17G2R1, IIaA18G1R1b, IIaA18G3R1, IIdA15G1, IIiA10, IIpA9, IIpA6, IIoA15G1, and IIoA13G1 have been reported from rodents [37,80,87,24,64]. The IIa, IId, IIi, and IIo subtypes were previously reported in humans [87]. ...
Cryptosporidium is one of the most important genera of intestinal zoonotic pathogens that cause diarrhea in both humans and animals. Rodents are common and important hosts or carriers of pathogens with public health importance, and rodents play an important role in the ecology of zoonotic transmission. The overall worldwide prevalence of Cryptosporidium spp. in rodents is 19.8% (4589/23142). Twenty-five known Cryptosporidium species and 43 genotypes have been identified, and C. parvum is the dominant species in rodents worldwide. Rodents transfer pathogens to humans by the direct route or by serving as intermediate hosts transmitting the pathogens to other animals. We review the epidemiology, diversity, and transmission routes of Cryptosporidium spp. in rodents. The main purpose of this review is to highlight Cryptosporidium infection in rodents and its transmission, associated risk factors, and prevention; in addition, we assess the public health and ecological significance of Cryptosporidium infections from the One Health perspective.
... Furthermore, previous studies have shown a prevalence of 13.7-31.8% in Apodemus spp. [7,26], 21.3-22.6% in voles [7,11] and 14.3% in shrews [7]. In a previous Finnish study using microscopic methods, wild voles were infected with Cryptosporidium spp. in 0.8% of Microtus agrestis, 2.4% of Myodes glareolus and none of the Alexandromys oeconomus [18]. ...
... Previous studies have reported C. parvum, and other zoonotic species, in many rodent species [26], especially in urban areas [7,9]. However, they have been quite an infrequent finding in rodents overall and it has been suggested that e.g., C. parvum infections, might be transient and short-term and occur following exposure to contaminated manure from ruminants [26]. ...
... Previous studies have reported C. parvum, and other zoonotic species, in many rodent species [26], especially in urban areas [7,9]. However, they have been quite an infrequent finding in rodents overall and it has been suggested that e.g., C. parvum infections, might be transient and short-term and occur following exposure to contaminated manure from ruminants [26]. Furthermore, it has been suggested that C. alticolis and C. microti, which are vole-species specific, might have been misidentified as C. parvum in studies merely based on microscopic evaluation [11]. ...
There has been a significant increase in the number of reported human cryptosporidiosis cases in recent years. The aim of this study is to estimate the prevalence of Cryptosporidium spp. in wild rodents and shrews, and investigate the species and genotype distribution to assess zoonotic risk. Partial 18S rRNA gene nested-PCR reveals that 36.8, 53.9 and 41.9% of mice, voles and shrews are infected with Cryptosporidium species. The highest prevalence occurred in the Microtus agrestis (field vole) and Myodes glareolus (bank vole). Interestingly, bank voles caught in fields were significantly more often Cryptosporidium-positive compared to those caught in forests. The proportion of infected animals increases from over-wintered (spring and summer) to juveniles (autumn) suggesting acquired immunity in older animals. Based on Sanger sequencing and phylogenetic analyses, Apodemus flavicollis (yellow-necked mouse) is commonly infected with zoonotic C. ditrichi. Voles carry multiple different Cryptosporidium sp. and genotypes, some of which are novel. C. andersoni, another zoonotic species, is identified in the Craseomys rufocanus (grey-sided vole). Shrews carry novel shrew genotypes. In conclusion, this study indicates that Cryptosporidium protozoan are present in mouse, vole and shrew populations around Finland and the highest zoonotic risk is associated with C. ditrichi in Apodemus flavicollis and C. andersoni in Craseomys rufocanus. C. parvum, the most common zoonotic species in human infections, was not detected.
... Previous studies of C. sciurinum n. sp. in Eurasian red squirrels have reported prevalences of 10.6% (13/123) and 21.5% (15/70) in Italy and 26.3% in China [13,16,17]. The prevalence range of Cryptosporidium is similar with that found in other wild rodents, such as 14% in Apodemus spp. in Europe, 27% in Apodemus speciosus in Japan, 16% in brown rats (Rattus norvegicus) in Czech Republic, 12% in muskrats (Ondatra zibethicus) in USA, 30% in Chinese bamboo rats (Rhizomys sinensis) in China, or 7-14% in voles in Europe [38][39][40][41][42]. Consistent with most reports describing natural infections with Cryptosporidium spp. in wild rodents [16,17,38,[42][43][44], Eurasian red squirrels infected with C. sciurinum n. sp. ...
... The prevalence range of Cryptosporidium is similar with that found in other wild rodents, such as 14% in Apodemus spp. in Europe, 27% in Apodemus speciosus in Japan, 16% in brown rats (Rattus norvegicus) in Czech Republic, 12% in muskrats (Ondatra zibethicus) in USA, 30% in Chinese bamboo rats (Rhizomys sinensis) in China, or 7-14% in voles in Europe [38][39][40][41][42]. Consistent with most reports describing natural infections with Cryptosporidium spp. in wild rodents [16,17,38,[42][43][44], Eurasian red squirrels infected with C. sciurinum n. sp. shed low numbers of oocysts, often below the detection limit of microscopy. ...
... Similarly, divergent types of SSU have been reported within, e.g., C. andersoni, C. apodemi, C. ditrichi, C. parvum, C. ubiquitum, Cryptosporidium sp. apodemus genotype I and II, or Cryptosporidium rat genotype II and III [15,42,43,55,56]. As inferring the evolutionary relationships of Cryptosporidium spp. ...
Cryptosporidium spp. are common protozoan pathogens in mammals. The diversity and biology of Cryptosporidium in tree squirrels are not well studied. A total of 258 Eurasian red squirrels (Sciurus vulgaris) from 25 and 15 locations in the Czech Republic and Slovakia, respectively, were examined for Cryptosporidium spp. oocysts and specific DNA at the SSU, actin, HSP70, TRAP-C1, COWP, and gp60 loci. Out of 26 positive animals, only juveniles (9/12) were microscopically positive (18,000 to 72,000 OPG), and molecular analyses revealed the presence of Cryptosporidium sp. ferret genotype in all specimens. Oocysts obtained from naturally-infected squirrels measured 5.54–5.22 μm and were not infectious for laboratory mice (BALB/c and SCID), Mongolian gerbils, Guinea pigs, Southern multimammate mice, chickens, or budgerigars. None of naturally infected squirrels showed clinical signs of disease. The frequency of occurrence of the ferret genotype in squirrels did not vary statistically based on host age, gender or country of capture. Phylogenetic analysis of sequences from six loci revealed that Cryptosporidium sp. ferret genotype is genetically distinct from the currently accepted Cryptosporidium species. Morphological and biological data from this and previous studies support the establishment of Cryptosporidium sp. ferret genotype as a new species, Cryptosporidium sciurinum n. sp.
... However, many species and genotypes of Cryptosporidium, particularly those infecting wild animals, do not cause clinical signs [3,4]. Genetic and biological studies have shown a high diversity within the genus Cryptosporidium, with much of this diversity observed in wildlife hosts [5][6][7][8][9][10]. To date, 47 valid species [11][12][13] and more than 100 genotypes, which are distinguished from valid species on the basis of molecular differences and probably represent separate species, have been described [2]. ...
... An earlier study reported C. parvum in nutrias based on oocyst morphology [15,20]. Given that C. parvum has a broad host specificity, is reported infrequently in wildlife species [5,6,[47][48][49][50], and was found in a single nutria in the present study, it is possible that Pavlásek and Kozakiewicz [20] correctly identified the species. In support, they found that oocysts from naturally infected nutria were infectious for four-day-old laboratory mice under experimental conditions, a characteristic of C. parvum but not C. myocastoris (as we have shown in the present study). ...
... The prepatent period (5-6 DPI) is consistent with other intestinal Cryptosporidium spp. that are specific for rodents, such as C. ratti (4)(5) in rats, C. alticolis in voles (3-4 DPI), C. tyzzeri in mice (4-7 DPI), or other mammals, such C. parvum in calves (2-7 DPI) and C. scrofarum in pigs (4-6 DPI) [6,12,63,66,71,72]. ...
Cryptosporidium spp., common parasites of vertebrates, remain poorly studied in wildlife. This study describes the novel Cryptosporidium species adapted to nutrias (Myocastor coypus). A total of 150 faecal samples of feral nutria were collected from locations in the Czech Republic and Slovakia and examined for Cryptosporidium spp. oocysts and specific DNA at the SSU, actin, HSP70, and gp60 loci. Molecular analyses revealed the presence of C. parvum (n = 1), C. ubiquitum subtype family XIId (n = 5) and Cryptosporidium myocastoris n. sp. XXIIa (n = 2), and XXIIb (n = 3). Only nutrias positive for C. myocastoris shed microscopically detectable oocysts, which measured 4.8–5.2 × 4.7–5.0 µm, and oocysts were infectious for experimentally infected nutrias with a prepatent period of 5–6 days, although not for mice, gerbils, or chickens. The infection was localised in jejunum and ileum without observable macroscopic changes. The microvilli adjacent to attached stages responded by elongating. Clinical signs were not observed in naturally or experimentally infected nutrias. Phylogenetic analyses at SSU, actin, and HSP70 loci demonstrated that C. myocastoris n. sp. is distinct from other valid Cryptosporidium species.
... Furthermore, recently some new species have been described in different rodent species, among them Cryptosporidium alticolis and Cryptosporidium microti in wild-caught common voles [21], Cryptosporidium ditrichi and Cryptosporidium apodemi in Apodemus spp. mice [22,23]. Among these recently discovered species, C. ditrichi has shown a certain zoonotic potential since it has been newly reported infecting three patients in Sweden [24]. ...
... mouse genotype I [47], mostly infects domestic mice and small rodents, and it has been found in several non-specific hosts such as the lesser panda, black leopards, voles, snakes and horses, among others [48][49][50][51]. Cryptosporidium tyzzeri has also been recently reported for the first time in Apodemus spp., suggesting this murine species as a minor host due to the low prevalence obtained [23]. In humans, a severe cryptosporidiosis caused by a coinfection of C. tyzzeri and C. parvum has been reported in healthy young individual, demonstrating that the transmission of Cryptosporidium spp. ...
... In different studies carried out worldwide, C. muris was reported in many rodent species [23,46,49,62], and also in humans [61,[63][64][65][66], bilbies [67], birds [68] and other mammals [45,49,51,[69][70][71][72]. Moreover, C. muris has been reported in children and HIV-positive individuals from developing countries; however, healthy adults are also susceptible to infection [73]. ...
Background:
Cryptosporidium spp. are worldwide protozoan parasites which include species that can lead to cryptosporidiosis in humans. Different animal species can serve as reservoirs and sources of dissemination of the disease, such as rodent species due their potential in transmitting zoonotic pathogens to humans and other animals. In the Canary Islands (Spain), Cryptosporidium parvum and Cryptosporidium hominis have been identified in patients with diarrhea. However, the occurrence of Cryptosporidium spp. in possible reservoirs in this archipelago remains unclear. Considering the zoonotic potential of these protozoans, the aim of the present study was to determine the presence of Cryptosporidium spp. in peridomestic wild rodents and the possible role of these mammals as a source of transmission of these protozoans in Canary Islands.
Methods:
A total of 179 rodents belonging to Rattus rattus and Mus musculus domesticus from four Canary Islands, La Palma, El Hierro, Tenerife and Lanzarote, were analyzed. Feces were screened for Cryptosporidium spp. by nested PCR of the 18S ribosomal RNA fragment and the sequences used for phylogenetic analyses.
Results:
Cryptosporidium spp. were found widely distributed with an overall prevalence of 12.30% in rodents (13.86% for R. rattus and 10.25% for M. m. domesticus). The overall prevalence by island was 19.60% for Tenerife, 7.14% for La Palma, 5.71% for El Hierro and 0% for Lanzarote. Cryptosporidium tyzzeri, Cryptosporidium meleagridis, Cryptosporidium muris and Cryptosporidium sp. rat genotype I and II/III were successfully identified, in addition to two unidentified Cryptosporidium genotypes.
Conclusions:
This study contributes to the knowledge of the biodiversity and distribution of Cryptosporidium spp. in wild rodents from the Canary Islands, highlighting the presence of three zoonotic species, C. tyzzeri, C. meleagridis and C. muris, being the first detection of these three species in wild rodents in the Canary Islands and the first report of C. meleagridis in R. rattus. Given the results obtained in our study, future studies in non-sampled areas are required to better understand the epidemiology of these protozoans in wild rodents in the archipelago.
... Recently a new rodent-specific Cryptosporidium species, Cryptosporidium ditrichi, was described from Apodemus flavicollis (yellow-necked mouse) (Condlova et al., 2018). The host range was later extended to include Apodemus sylvaticus (wood mouse) and Apodemus agrarius (striped field mouse) (Condlova et al., 2019) (Fig. 1). ...
... In 2018, C. ditrichi was formally described as a new species appearing in A. flavicollis (Condlova et al., 2018). A later study found C. ditrichi in A. sylvaticus and A. agrarius as well (Condlova et al., 2019). ...
... The only reported confirmed C. ditrichi infection in Apodemus spp. from the Nordic countries originated from Finland (Condlova et al., 2019). ...
Most human cases of cryptosporidiosis are caused by Cryptosporidium parvum or Cryptosporidium hominis. However, the number of recognised Cryptosporidium species, some of which are capable of infecting humans, is continuously increasing. Here we present three human cases infected with Cryptosporidium ditrichi, a recently described species in Apodemus spp. (striped field mouse, yellow-necked mouse, and wood mouse) from various European countries. All three patients were infected in Sweden, but in different years and in different parts of the country. Two patients, from whom clinical data were available, showed symptoms consistent with cryptosporidiosis. For one patient, epidemiological data indicated a possible close contact with mice. The obtained sequences at the small subunit rRNA, actin, and Cryptosporidium oocyst wall protein loci showed 100% identity to C. ditrichi isolates from Apodemus spp., while no 70 kDa heat shock protein gene sequences from C. ditrichi were available for comparison. This study shows the importance of including molecular typing in Cryptosporidium surveillance programmes, and it adds one more species to the plethora of Cryptosporidium spp. hitherto diagnosed in Swedish patients.
... Furthermore, recently some new species have been described in different rodent species, among them Cryptosporidium alticolis and Cryptosporidium microti in wild-caught common voles [21], Cryptosporidium ditrichi and Cryptosporidium apodemi in Apodemus spp. mice [22,23]. Among these recently discovered species, C. ditrichi has shown a certain zoonotic potential since it has been newly reported infecting three patients in Sweden [24]. ...
... mouse genotype I [47], mostly infects domestic mice and small rodents, and it has been found in several non-specific hosts such as the lesser panda, black leopards, voles, snakes and horses, among others [48][49][50][51]. Cryptosporidium tyzzeri has also been recently reported for the first time in Apodemus spp., suggesting this murine species as a minor host due to the low prevalence obtained [23]. In humans, a severe cryptosporidiosis caused by a coinfection of C. tyzzeri and C. parvum has been reported in healthy young individual, demonstrating that the transmission of Cryptosporidium spp. ...
... In different studies carried out worldwide, C. muris was reported in many rodent species [23,46,49,62], and also in humans [61,[63][64][65][66], bilbies [67], birds [68] and other mammals [45,49,51,[69][70][71][72]. Moreover, C. muris has been reported in children and HIV-positive individuals from developing countries; however, healthy adults are also susceptible to infection [73]. ...
... The vast majority of C. ditrichi sequences in the NCBI Database are from various species of Apodemus, typically, Apodemus flavicollis sampled all over Europe from Latvia and Finland to France and Spain [40,41] (Suppl. Table 1), and it was by far the most common species detected in murids and cricetids sampled in the wild in Denmark in a recent survey [42]. ...
... Table 1) but was not detected in a few dozens of murids and cricetids recently sampled in the wild in Denmark (Rotovnik et al., submitted). Most C. tyzzeri DNA sequences in the NCBI Database are from Mus musculus, but the parasite has also been detected in other rodents, including Apodemus flavicollis, Microtus arvalis, and Clethrionomys glareolus [46], other species of Apodemus [40], and rats [47]. ...
Cases of cryptosporidiosis in humans have been reported with strong indication of transmission from rodents. Here, we report seven new human cases of cryptosporidiosis involving rodent-adapted species (Cryptosporidium ditrichi [n = 1], Cryptosporidium mortiferum [n = 4; previously known as Cryptosporidium chipmunk genotype I], Cryptosporidium tyzzeri [n = 1], and Cryptosporidium viatorum [n = 1]) and review cases of human infection caused by these four species published to date. The seven new cases were detected in Denmark within a period of twelve months from 2022 to 2023. Only the C. tyzzeri and C. viatorum cases were associated with travel outside Denmark. The total number of human cases of cryptosporidiosis due to C. ditrichi and C. tyzzeri documented to date globally are still limited (4 and 7, respectively), whereas cases involving C. viatorum and C. mortiferum have been detected to a larger extent (43 and 63 cases, respectively). The four new cases of C. mortiferum were all of the XIVaA20G2T1 subtype, which is the only subtype identified so far in Scandinavia, and which is a subtype not yet found outside of Scandinavia. The new C. viatorum case was identified as the XVaA3g subtype. The C. tyzzeri case was subtyped as IXbA6. No subtype data were produced for C. ditrichi due to lack of a subtype assay. Review of existing data suggests the presence of C. ditrichi and C. mortiferum primarily in northern countries and C. tyzzeri and C. viatorum primarily in warmer climates. While our data may further support the role of Cryptosporidium as a cause of zoonotic disease, case descriptions should be obtained where possible to determine if Cryptosporidium species primarily adapted to rodents are the likely cause of symptoms or just an incidental finding.
... For example, moles are always infected with multiple intestinal Eimeria, while shrews usually harbour only a single species [52]. On the other hand, there is an interest in the screening of rodents and insectivores for Cryptosporidium spp., because they can be true reservoirs of C. parvum and C. muris [54,55]. A high prevalence of C. parvum, C. muris and C. tyzzeri has been reported in small mammals in Spain [54,56], with the former especially widespread in the north-eastern regions [54,57]. ...
... A high prevalence of C. parvum, C. muris and C. tyzzeri has been reported in small mammals in Spain [54,56], with the former especially widespread in the north-eastern regions [54,57]. These studies have suggested that small mammals, including insectivores, are important sources of transmission of Cryptosporidium between wild species even in the absence of farm animals or significant human activity [55]. However, the low prevalence and limited geographic distribution (two sites in Ambroz with only two positives in each site) suggest a very limited intraspecific transmission in desman populations, which is further hindered by the strong isolation between desman populations in Extremadura [1]. ...
Simple Summary
Until now, data on parasites or bacteria of the Iberian desman (Galemys pyrenaicus) was practically absent. We used non-invasive methods of sample collection and analysis to determine the health status of G. pyrenaicus. We detected four species of bacteria and three parasites using qPCR assays. Based on DNA sequence data, G. pyrenaicus in the study area harbors a likely new species of the previously monotypical genus Omphalometra.
Abstract
The Iberian desman (Galemys pyrenaicus) is a small semi-aquatic mammal that inhabits mountainous areas from the centre to the north of the Iberian Peninsula and the Pyrenees and is listed as endangered because it has suffered a serious decline. Since 1960, only three species of digeneans (Omphalometra flexuosa, Maritrema pyrenaica and Mathovius galemydis) and two nematodes (Aonchotheca galemydis and Paracuaria hispanica) have been reported from the desman, but no further information on health status and no data from Extremadura has been available. The aim of our study was to characterise the diversity and distribution of parasites and microbiomes of desmans in different areas of the Central System of Extremadura. Between 2019 and 2021 we collected 238 fecal samples and one tissue (intestine) sample that was obtained from a dead desman. DNA templates were processed by commercial or customised real-time PCR using TaqMan probes. Representative data were obtained for Cryptosporidium spp., Omphalometra spp., Eimeria spp., Salmonella spp., Staphylococcus spp. and Leptospira spp. Omphalometra spp. was studied using a newly developed PCR test. The screening of the dead desman allowed us to obtain, for the first time, a partial sequence of the 18SrDNA. This study is the most complete study of the desman, allowing us to identify parasites and the microbiome in populations of G. pyrenaicus using non-invasive sampling.
... Thus far, at least 15 known Cryptosporidium species (C. parvum, C. ubiquitum, C. viatorum, C. andersoni, C. muris, C. wrairi, C. homai, C. tyzzeri, C. apodemi, C. ditrichi, C. microti, C. alticolis, C. rubeyi, C. occultus, and C. rati) and 28 genotypes (rat genotypes II-V, ferret genotype, chipmunk genotypes I-V, bamboo rat genotypes I-III, hamster genotype, squirrel genotypes I-III, muskrat genotypes I-II, apodemus genotypes I-II, vole genotypes I-VII and Brandt's vole genotype I) have been identified [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Therefore, rodents are considered reservoirs of some zoonotic Cryptosporidium spp. ...
... It is one of the two most common Cryptosporidium species causing human cryptosporidiosis. Previously, at least 20 species of rodents, such as rats, mice, voles, and squirrels are known to be positive for C. parvum [9][10][11]19,23,26,[40][41][42][43][44][45][46][47][48]. In China, rodents are frequently infected with this species, and the prevailing subtype family IId in rodents is also commonly found in cattle and other livestock [49]. ...
Cryptosporidium spp. are common protozoan pathogens in mammals. With pet rodents being integrated into modern life, the potential roles of them in transmitting parasites to humans need assessments. In the present study, we examined the occurrence of Cryptosporidium spp. in pet rodents in Guangdong, south China. A total of 697 fecal samples were collected from 11 species of rodents in seven pet shops, one pet market and one farm. Cryptosporidium spp. were identified by PCR analysis of the small subunit rRNA gene. An overall infection rate of 36.9% (257/697) was obtained, with infection rates varying from 9.3% in chinchillas, 52.3% in guinea pigs, 57.1% in squirrels, to 68.4% in cricetid animals. Nine Cryptosporidium species and genotypes were identified, including C. wrairi (in 129 guinea pigs), C. andersoni (in 34 hamsters), C. homai (in 32 guinea pigs), Cryptosporidium hamster genotype (in 30 hamsters), C. ubiquitum (in 24 chinchillas and squirrels), C. parvum (in 2 chinchillas), Cryptosporidium ferret genotype (in 2 chipmunks), C. muris (in 1 hamster and 1 guinea pig), and Cryptosporidium chipmunk genotype V (in 1 chinchilla and 1 chipmunk). Sequence analysis of the 60 kDa glycoprotein gene identified three subtype families of C. ubiquitum, including family XIId in 15 chinchillas, XIIa in 5 chinchillas, and a new subtype family (XIIi) in 1 squirrel. The identification of C. parvum and C. ubiquitum in pet rodents suggests that these animals, especially chinchillas, could serve as reservoirs of human-pathogenic Cryptosporidium spp. Hygiene should be practiced in the rear and care of these animals, and One Health measures should be developed to reduce the occurrence of zoonotic Cryptosporidium infections due to contact with pet rodents.
... Depending on the species, parasites can either increase (Aivelo and Norberg, 2018;Popovic et al., 2024) or decrease (Midha et al., 2022) the diversity of bacteria in the gut. is relationship between intestinal parasites and bacteria is bidirectional (Reynolds et al., 2015); they in uence each other by either directly or indirectly by modulating host immunity. Zoonotic parasites, such as Cryptosporidium (Condlova et al., 2019) and Hymenolepis (Roble et al., 2012), are at risk of human and livestock infection, potentially causing health and economic damage, the prevalence of which needs to be clari ed. ...
The environment profoundly affects the gut microbiota of wild rodents, which are reservoirs of various infectious diseases. In the gut of wild rodents, parasites cohabitate and interact with the bacteria. Thus, monitoring the gut microbes is important for the prediction of future outbreaks of zoonosis, as well as the livestock infectious diseases. However, reports on the gut microbiome of wild rodents in Japan are limited. In the present study, we investigated the gut symbiosis of prokaryotes and eukaryotes in wild mice captured at the two sites around Lake Kahoku-gata in Ishikawa Prefecture, Japan. The diversity and composition of the microbiome differ between the locations around the same lake, highlighting the need to cover several sites, even in the same water system, for the precise prediction of possible zoonosis in the future.
... With the accumulation of epidemiologic data on Cryptosporidium spp., it was also found in humans and some other nonspecific animal hosts, such as pandas, black leopards, horses, and snakes [41]. Based on sequence analysis of the gp60 gene, to date, there have been five subtypes identified, and they belonged to three subtype families (IXa-IXc) in rodent-derived C. tyzzeri isolates, including IXaA6R1, IXaA6R2, IXaA8, IXbA6, and IXcA6 [6,10,24]. The present study identified two subtypes (IXaA6R1 and IXbA8) of C. tyzzeri. ...
Cryptosporidium species can infect humans and more than 260 animal species, including 54 rodent species. However, data on the occurrence and genetic characterizations of Cryptosporidium spp. in laboratory rodents are limited. The present study aimed to determine the occurrence rate and genetic characterizations of Cryptosporidium spp. in laboratory mice and rats. We collected 506 fresh combined fecal pellet specimens (457 from mice and 49 from rats) of more than 2,000 laboratory rodents in Heilongjiang Province and Shanghai City, China. Cryptosporidium spp. were identified and subtyped by DNA sequencing of the SSU rRNA and the gp60 genes, respectively. By sequence analysis of the SSU rRNA gene, the occurrence rate of Cryptosporidium spp. was 16.6% (84/506) in combined fecal specimens, with 18.2% (83/457) for mice and 2.0% (1/49) for rats. Cryptosporidium parvum (n = 39), C. tyzzeri (n = 33), and C. parvum + C. tyzzeri (n = 11) were identified in mice. Cryptosporidium parvum was only detected in one rat fecal specimen. At the gp60 locus, 71.4% (60/84) of the Cryptosporidium-positive specimens were successfully amplified, and they all came from mice. We identified five C. parvum subtypes (IIaA14G2R1, IIaA16G2R1, IIaA17G1R1, IIaA17G2R1, and IIaA18G2R1) and two C. tyzzeri subtypes (IXaA6R1 and IXbA8). Based on the identification in laboratory mice of C. parvum subtypes that have been reported previously in humans, the mice infected with this species may threaten human health, especially for people who have contact with the animals and their feces.
... However, pathogenicity of Cryptosporidium sp. apodemus genotype I is still unknown [69]. Bacteria and fungi identified with the Cryptosporidium nPCR were all potentially zoonotic, thus posing a particular risk for snake charmers and tourists. ...
The world-famous markets of Marrakech, also known in Arabic as souks, harbor a vast diversity of reptiles that are sold for medicinal/magic/pet purposes or used for snake charming. This unique epidemiological context has never been studied considering the interactions of humans, reptiles, and zoonotic pathogens. Thus, the aim of this study was to identify the parasites and pathogens present in blood and feces associated with handled reptiles in the markets of Marrakech to assess the risk of zoonotic transmission within the reptile-human interface. Privately owned reptiles (n = 118), coming from vendors or snake charmers, were examined and blood and feces sampled. DNA was extracted and molecular screening (cPCR, nPCR, qPCR, dqPCR) was performed aiming to identify potentially zoonotic pathogens (i.e., Anaplasma/Ehrlichia spp., Rickettsia spp., Borrelia burgdorferi sensu lato, Coxiella burnetii, Babesia/Theileria spp., Cryptosporidium spp., Giardia spp., Leishmania spp., Cestoda). Overall, 28.9% (34/118) of reptiles were positive for at least one pathogen. In blood, Anaplasma spp. were detected in four snakes, with two Montpellier snakes positive for Anaplasma phagocytophilum, while Rickettsia spp. were detected in one Mediterranean chameleon and four puff adders. Leishmania tarentolae was molecularly detected in a Mediterranean chameleon and a Montpellier snake. In feces, the cox1 gene generated a myriad of sequences for nematodes, cestodes, fungi and bacteria. Importantly, Proteus vulgaris was identified from a Mediterranean chameleon. Cryptosporidium spp. nPCR yielded a positive sample (i.e., Cryptosporidium sp. apodemus genotype I) from a Moroccan worm lizard, as well as for bacteria such as Pseudomonas aeruginosa in an Egyptian cobra, and Morganella morganii from a puff adder. Results from this study demonstrated the risk of zoonotic transmission of microorganisms and parasites present in blood and feces from reptiles that are brought to the souks in Marrakech, Morocco, to be sold for medicinal purposes or used for snake charming, being in direct and straight contact with humans.
... This is the first time that these parasite species have been observed in Mustelidae. Cryptosporidium ditrichi is characteristic for rodents of the genus Apodemus spp., as described in studies conducted on rodent populations from Central European countries [40,41]. ...
Cryptosporidium is an apicomplexan protozoan parasite that primarily infects the gastrointestinal epithelium in humans and domestic and wild animals. The majority of studies have been focused on human, livestock, and pet infections. Hence, Cryptosporidium spp. in wildlife, including wild carnivores, remained neglected. There are several studies reporting the occurrence of Cryptosporidium spp. in wild foxes, but these are only a few molecular surveys; no data is available concerning the occurrence of this parasite in raccoon dogs and martens in Europe, and to the best of our knowledge to date, only one study has reported Cryptosporidium from badgers in Spain. Therefore, we used molecular analyses to identify and genotype Cryptosporidium spp. in wild-living mesocarnivores in Poland. A total of 322 individual fecal samples from six carnivore species, i.e., raccoon, raccoon dog, red fox, European badger, pine, and beech martens were collected and then analyzed for the presence of Cryptosporidium spp. using the nested PCR method. The appearance of PCR products in the reaction with Cryptosporidium-specific primers against the 18S rRNA and actin genes demonstrated that Cryptosporidium spp. occurred in 23.0% of all examined species of animals. Performed sequence analyses showed the presence of the Cryptosporidium skunk genotype, Cryptosporidium vole genotype II, Cryptosporidium canis dog and fox genotypes, as well as Cryptosporidium erinacei, Cryptosporidium ditrichi, Cryptosporidium suis, and Cryptosporidium alticolis, in these hosts. Molecular data presented here indicate that examined mesocarnivores may be a significant reservoir of specific and non-specific Cryptosporidium species, including those with zoonotic potential. Most studies of carnivores have described the presence of non-specific Cryptosporidium spp. in carnivore hosts, and this is probably the result of the transfer of these parasites from prey species through the digestive tract or the transfer of the parasite from a contaminated environment.
... Typing of C. tyzzeri is at the gp60 locus has identified three subtype families; IXa, IXb and IXc [31,200], including subtype IXbA22R9 from a horse [195]. Cryptosporidium tyzzeri (subtype IXaA6R2) was identified from a child in Kuwait [43] and subtype family IXb has been detected in three human patients in New Zealand [54]. ...
The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and >120 genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and amplicon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.
... In 1907, Ernest Edward Tyzzer discovered a parasite in the gastric glands of laboratory mice and named it Cryptosporidium muris [7]. The parasite was able to infect a variety of mammals, including various rodent species [8,9], cats, dogs [10], crab-eating macaques [11], deer [12], horses [13], mountain goats, Bactrian camels and humans [14]. Studies conducted on the life-cycle of C. muris found that all stages were localized in the gastric glands of the stomach [15]. ...
Background
Cryptosporidium is an opportunistic pathogen that infects a wide variety of vertebrates. The aim of the present study was to characterize Cryptosporidium spp. isolates from Bactrian camels and to foster further understanding of the biological characteristics of the pathogen.
Methods
Fecal specimens were collected from two 4-year-old Bactrian camels resident at the Kaifeng City Zoo in China and examined for Cryptosporidium . Fecal specimens were screened using the floatation method, and then genomic DNA was extracted from the oocysts and identified by nested-PCR amplification of the small subunit ribosomal RNA (SSU rRNA) gene, the actin gene and the Cryptosporidium oocyst wall-protein (COWP) gene. Subtype analysis was performed based on four minisatellite (MS) loci (MS1, MS2, MS3 and MS16) that were aligned and phylogenetically analyzed to determine the species and subtype of Cryptosporidium . We then established a BALB/c mice infection model and further verified the results through clinical status, pattern of oocyst excretion and histological examination.
Results
Cryptosporidium oocyst isolates from the two Bactrian camels had an average (± standard deviation) size of 7.49 ± 0.13 × 5.70 ± 0.10 μm ( n = 50). The sequencing and phylogenetic analysis confirmed the species as C. muris . Multilocus sequence typing analysis indicated that the subtypes were M13, M4, M1 and M5. Following the inoculation of BALB/c mice, we found that the prepatent period and number of oocysts per gram increased with increasing infective dose. Oocysts were first detected in the feces of BALB/c mice at 7–8 days post-infection (dpi), with levels peaking twice thereafter, at 15–16 dpi and 19–20 dpi. Histology and scanning electron microscopy studies showed that the stomach contained gastric pits filled with Cryptosporidium that adhered to the surface of gastric mucosa gland epithelial cells, causing the latter to deform, swell and become disordered.
Conclusions
The findings of this study indicated that oocysts isolated from Bactrian camels were from C. muris . This is the first report of C. muris isolated from camels in China. More epidemiological data are needed to understand the prevalence and transmission of C. muris in camels in different geographic areas.
Graphical abstract
... Research on Cryptosporidium spp. in wild animals has increased significantly in the last decade, expanding our knowledge of genetic diversity in the genus, but the biological properties of these parasites in wildlife remain poorly studied (Ren et al., 2012;Li et al., 2015;Kváč et al., 2018;Tan et al., 2019;Wei et al., 2019). Recent studies indicate that rodents, which represent about 40% of the mammalian diversity, are predominantly parasitized by host-specific Cryptosporidium spp. with unknown biology (Lv et al., 2009;Feng et al., 2011;Ng-Hublin et al., 2013;Stenger et al., 2017;Čondlová et al., 2019). Today, 45 valid Cryptosporidium species and a similar number of genotypes have been reported (Holubová et al., 2020). ...
The diversity and biology of Cryptosporidium that is specific for rats ( Rattus spp.) are not well studied. We examined the occurrence and genetic diversity of Cryptosporidium spp. in wild brown rats ( Rattus norvegicus ) by microscopy and polymerase chain reaction (PCR)/sequencing targeting the small subunit rDNA ( SSU ), actin and HSP 70 genes. Out of 343 faecal samples tested, none were positive by microscopy and 55 were positive by PCR. Sequence analysis of SSU gene revealed the presence of Cryptosporidium muris ( n = 4), C. andersoni ( n = 3), C. ryanae ( n = 1), C. occultus ( n = 3), Cryptosporidium rat genotype I ( n = 23), Cryptosporidium rat genotype IV ( n = 16) and novel Cryptosporidium rat genotype V ( n = 5). Spherical oocysts of Cryptosporidium rat genotype I obtained from naturally-infected rats, measuring 4.4–5.4 μ m × 4.3–5.1 μ m, were infectious to the laboratory rats, but not to the BALB/c mice ( Mus musculus ) nor Mongolian gerbils ( Meriones unguiculatus ). The prepatent period was 3 days post infection and the patent period was longer than 30 days. Naturally- and experimentally-infected rats showed no clinical signs of disease. Percentage of nucleotide similarities at the SSU , actin, HSP 70 loci between C. ratti n. sp. and the rat derived C. occultus and Cryptosporidium rat genotype II, III, IV, and V ranged from 91.0 to 98.1%. These genetic variations were similar or greater than that observed between closely related species, i.e. C. parvum and C. erinacei (93.2–99.5%). Our morphological, genetic and biological data support the establishment of Cryptosporidium rat genotype I as a new species, Cryptosporidium ratti n. sp.
Cryptosporidium infection is a common occurrence in rodents worldwide. In this study, 435 wild brown rats were captured from an animal feedlot in Xinjiang, China, with a fecal sample obtained directly from the rectal contents of each rat. The DNA extracted from these fecal samples was analyzed for Cryptosporidium spp. using PCR targeting the SSU rRNA gene. The prevalence of Cryptosporidium infection in brown rats was found to be 5.5% (24 out of 435). Interestingly, the infection rates varied among different animal enclosures, with rates of 0% in the chicken coop (0/51), cowshed (0/3), and varying rates in other areas including the sheepfold (6.1%, 6/98), the pigsty (7.6%, 10/132), the dovecote (7.0%, 5/71), and outdoor environments (3.8%, 3/80). The study identified three species and one genotype of Cryptosporidium, namely C. occultus (n = 10), C. parvum (n = 4), C. ditrichi (n = 1), and Cryptosporidium rat genotype IV (n = 9). Additionally, two of the C. parvum isolates were successfully subtyped as IIdA19G1 (n = 2) at the gp60 gene. These results offer valuable insights into the prevalence and genetic diversity of Cryptosporidium in brown rats within the region.
Cryptosporidium spp. infection is common in rodents worldwide. In this study, 435 wild brown rats were captured from an animal feedlot in Xinjiang, China, and a fecal sample was collected directly from the rectal contents of each rat. The extracted DNA from all fecal samples was examined for Cryptosporidium spp. by PCR at SSU rRNA gene. The prevalence of Cryptosporidium infection in brown rats was 5.5% (24/435). The infection rates varied across different animal enclosures. Specifically, infection rates were 0% (0/51) in chicken coop, 0% (0/3) in cowshed, 6.1% (6/98) in sheepfold, 7.6% (10/132) in pigsty, 7.0% (5/71) in dovecote, and 3.8% (3/80) in outdoor environments. The study identified three species and one genotype of Cryptosporidium , including C. occultus (n = 10), C. parvum (n = 4), C. ditrichi (n = 1), and Cryptosporidium Rat genotype IV (n = 9). Of the C. parvum isolates, two were successfully subtyped as IIdA19G1 (n = 2) at the gp60 gene. These findings present fundamental data on the prevalence and genetic evolution of Cryptosporidium in rodents.
Rodents represent the single largest group within mammals and host a diverse array of zoonotic pathogens. Urbanisation impacts wild mammals, including rodents, leading to habitat loss but also providing new resources. Urban-adapted (synanthropic) rodents, such as the brown rat (R. norvegicus), black rat (R. rattus), and house mouse (Mus musculus), have long successfully adapted to living close to humans and are known carriers of zoonotic pathogens. Two important enteric, zoonotic protozoan parasites, carried by rodents, include Cryptosporidium and Giardia. Their environmental stages (oocysts/cysts), released in faeces, can contaminate surface and wastewaters, are resistant to common drinking water disinfectants and can cause water-borne related gastritis outbreaks. At least 48 species of Cryptosporidium have been described, with C. hominis and C. parvum responsible for the majority of human infections, while Giardia duodenalis assemblages A and B are the main human-infectious assemblages. Molecular characterisation is crucial to assess the public health risk linked to rodent-related water contamination due to morphological overlap between species. This review explores the global molecular diversity of these parasites in rodents, with a focus on evaluating the zoonotic risk from contamination of water and wasterwater with Cryptosporidium and Giardia oocysts/cysts from synanthropic rodents. Analysis indicates that while zoonotic Cryptosporidium and Giardia are prevalent in farmed and pet rodents, host-specific Cryptosporidium and Giardia species dominate in urban adapted rodents, and therefore the risks posed by these rodents in the transmission of zoonotic Cryptosporidium and Giardia are relatively low. Many knowledge gaps remain however, and therefore understanding the intricate dynamics of these parasites in rodent populations is essential for managing their impact on human health and water quality. This knowledge can inform strategies to reduce disease transmission and ensure safe drinking water in urban and peri‑urban areas.
Rodents may serve as reservoirs of zoonotic species of Cryptosporidium; however, data from molecular surveys in support of this hypothesis are still scarce. In this study, we screened faeces and rectal content from murid and cricetid rodents (N = 58) caught around three farms in Zealand, Denmark, for Cryptosporidium spp. by amplicon-based next-generation sequencing (NGS) of ribosomal genes. Selected samples were further examined using nested conventional PCR targeting SSU rRNA, gp60, and actin genes. Cryptosporidium-specific DNA was identified in 40/58 (69%) samples, and in 12 (30%) of the 40 positive animals, mixed cryptosporidial infections were observed. Cryptosporidium ditrichi was the species most commonly identified, found in 28 (48%) of the animals. Cryptosporidium parvum was identified in 4 (7%) of the animals, all of which were co-infected with C. ditrichi. The present study is the first to utilize NGS-based screening for Cryptosporidium species in wild rodents. Moreover, it is the first study to provide molecular data on Cryptosporidium in rodents sampled in Denmark and to detect DNA of C. ditrichi in Mus musculus, Myodes glareolus, and Microtus agrestis. The NGS approach was successfully applied to yield new knowledge, and the results showed that zoonotic species of Cryptosporidium are common in murid and cricetid rodents in Zealand, Denmark.
Micromammals have historically been recognized as highly contentious species in terms of maintenance and transmission of zoonotic pathogens to humans. Limited information is currently available on the epidemiology and potential public health significance of intestinal eukaryotes in wild micromammals. We examined 490 faecal samples, grouped in 155 pools, obtained from 11 micromammal species captured in 11 Spanish provinces for the presence of DNA from Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. The presence of Leishmania spp. was investigated in individual spleen samples. All micromammal species investigated harboured infections by at least one eukaryotic parasite, except Apodemus flavicollis, Myodes glareolus, Sorex coronatus and Sciurus vulgaris, but sample size for these host species was very low. Cryptosporidium spp. was the most prevalent species found (3.7%, 95% CI: 2.2–5.7), followed by G. duodenalis (2.8%, 95% CI: 1.6–4.6) and E. bieneusi (2.6%, 95% CI: 1.4–4.3). All pooled faecal samples tested negative for Blastocystis sp. Leishmania infantum was identified in 0.41% (95% CI: 0.05–1.46) of the 490 individual spleen samples analysed. Sequences analyses allowed the identification of C. andersoni (5.9%), C. ditrichi (11.7%), C. muris (5.9%), C. parvum (5.9%), C. tyzzeri (5.9%), rat genotypes CR97 (5.9%) and W19 (5.9%), vole genotypes V (11.7%) and VII (5.9%) and Cryptosproridium spp. (35.3%) within Cryptosporidium (n = 17). Known genotypes C (66.7%) and Peru11 (25.0%), and a novel genotype (named MouseSpEb1, 8.3%) were detected within E. bieneusi (n = 12). None of the G. duodenalis‐positive samples could be genotyped at the assemblage level. Molecular data indicate that wild micromammals were primarily infected by rodent‐adapted species/genotypes of eukaryotic pathogens and thereby have a limited role as source of human infections. The presence of ruminant‐adapted species C. andersoni along with finding C. parvum is indicative of an overlap between domestic/peri‐domestic and sylvatic transmission cycles of these agents. This article is protected by copyright. All rights reserved
According to the World Health Organisation, cryptosporidiosis is a global diarrhoeal disease affecting millions of individuals; it is the second most common cause of infantile death in developing countries and is increasingly identified as an emerging cause of morbidity and mortality worldwide. The disease is also extremely severe in livestock, causing profuse diarrhoea and considerable economic losses in farmed young animals. Given the lack of effective treatment (absence of vaccines and effective drugs) and the limited understanding of the causative parasite, cryptosporidiosis represents a major challenge in the battle against global diarrhoeal diseases. Currently, there are 45 described Cryptosporidium species infecting a whole spectrum of animals. In this book chapter we will present an overview of the parasite, focusing on its taxonomic status, its morphology, its prevalence and transmission. We will review both cell biological and molecular techniques currently used to investigate the biology of this parasite and we will introduce the new state-of-the-art techniques that have been established by several laboratories in the field. With the development of these new technologies, we will be able to further understand the unique biology of Cryptosporidium and its role in health and disease of its host.
Cryptosporidium can cause severe diarrhea and morbidity, but many infections are asymptomatic. Here, we studied the immune response to a commensal strain of Cryptosporidium tyzzeri (Ct-STL) serendipitously discovered when conventional type 1 dendritic cell (cDC1)-deficient mice developed cryptosporidiosis. Ct-STL was vertically transmitted without negative health effects in wild-type mice. Yet, Ct-STL provoked profound changes in the intestinal immune system, including induction of an IFN-γ-producing Th1 response. TCR sequencing coupled with in vitro and in vivo analysis of common Th1 TCRs revealed that Ct-STL elicited a dominant antigen-specific Th1 response. In contrast, deficiency in cDC1s skewed the Ct-STL CD4 T cell response toward Th17 and regulatory T cells. Although Ct-STL predominantly colonized the small intestine, colon Th1 responses were enhanced and associated with protection against Citrobacter rodentium infection and exacerbation of dextran sodium sulfate and anti-IL10R-triggered colitis. Thus, Ct-STL represents a commensal pathobiont that elicits Th1-mediated intestinal homeostasis that may reflect asymptomatic human Cryptosporidium infection.
Fecal samples from wild-caught common voles ( n = 328) from 16 locations in the Czech Republic were screened for Cryptosporidium by microscopy and PCR/sequencing at loci coding small-subunit rRNA, Cryptosporidium oocyst wall protein, actin and 70 kDa heat shock protein. Cryptosporidium infections were detected in 74 voles (22.6%). Rates of infection did not differ between males and females nor between juveniles and adults. Phylogenetic analysis revealed the presence of eight Cryptosporidium species/genotypes including two new species, C. alticolis and C. microti . These species from wild-caught common voles were able to infect common and meadow voles under experimental conditions, with a prepatent period of 3–5 days post-infection (DPI), but they were not infectious for various other rodents or chickens. Meadow voles lost infection earlier than common voles (11–14 vs 13–16 DPI) and had significantly lower infection intensity. Cryptosporidium alticolis infects the anterior small intestine and has larger oocysts (5.4 × 4.9 µ m), whereas C. microti infects the large intestine and has smaller oocysts (4.3 × 4.1 µ m). None of the rodents developed clinical signs of infection. Genetic and biological data support the establishment of C. alticolis and C. microti as separate species of the genus Cryptosporidium .
Background. Rodents could act as reservoir for Cryptosporidium spp. specially C. parvum, a zoonotic agent responsible for human infections. Since there is no information about Cryptosporidium infection in rodents of Ahvaz city, southwest of Iran, hence, this survey was performed to determine the prevalence and molecular characterization of Cryptosporidium spp. in this region. Materials and Methods. One hundred rodents were trapped from different regions of Ahvaz city. Intestine contents and fecal specimens of rodents were studied using both microscopy examination to identify oocyst and nested-polymerase chain reaction (PCR) technique for 18s rRNA gene detection. Eventually restriction fragment length polymorphism (RFLP) method using SspI and VspI restriction enzymes was carried out to genotype the species and then obtained results were sequenced. Results. Three out of 100 samples were diagnosed as positive and overall prevalence of Cryptosporidium spp. was 3% using both modified Ziehl-Neelsen staining under light microscope and nested-PCR (830 bp) methods. Afterwards, PCR-RFLP was performed on positive samples and C. parvum pattern was identified. Finally PCR-RFLP findings were sequenced and presence of C. parvum was confirmed again. Conclusions. Our study showed rodents could be potential reservoir for C. parvum. So an integrated program for control and combat with them should be adopted and continued.
The morphological, biological, and molecular characteristics of Cryptosporidium avian genotype V are described, and the species name Cryptosporidium avium is proposed to reflect its specificity for birds under natural and experimental conditions. Oocysts of C. avium measured 5.30-6.90 μm (mean = 6.26 μm) × 4.30-5.50 μm (mean = 4.86 μm) with a length to width ratio of 1.29 (1.14-1.47). Oocysts of C. avium obtained from four naturally infected red-crowned parakeets (Cyanoramphus novaezealandiae) were infectious for 6-month-old budgerigars (Melopsittacus undulatus) and hens (Gallus gallus f. domestica). The prepatent periods in both susceptible bird species was 11 days postinfection (DPI). The infection intensity of C. avium in budgerigars and hens was low, with a maximum intensity of 5000 oocysts per gram of feces. Oocysts of C. avium were microscopically detected at only 12-16 DPI in hens and 12 DPI in budgerigars, while PCR analyses revealed the presence of specific DNA in fecal samples from 11 to 30 DPI (the conclusion of the experiment). Cryptosporidium avium was not infectious for 8-week-old SCID and BALB/c mice (Mus musculus). Naturally or experimentally infected birds showed no clinical signs of cryptosporidiosis, and no pathology was detected. Developmental stages of C. avium were detected in the ileum and cecum using scanning electron microscopy. Phylogenetic analyses based on small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. avium is genetically distinct from previously described Cryptosporidium species.
In order to examine the prevalence of Cryptosporidium infection in wild rodents and insectivores of South Korea and to assess their potential role as a source of human cryptosporidiosis, a total of 199 wild rodents and insectivore specimens were collected from 10 regions of South Korea and screened for Cryptosporidium infection over a period of 2 years (2012-2013). A nested-PCR amplification of Cryptosporidium oocyst wall protein (COWP) gene fragment revealed an overall prevalence of 34.2% (68/199). The sequence analysis of 18S rRNA gene locus of Cryptosporidium was performed from the fecal and cecum samples that tested positive by COWP amplification PCR. As a result, we identified 4 species/genotypes; chipmunk genotype I, cervine genotype I, C. muris, and a new genotype which is closely related to the bear genotype. The new genotype isolated from 12 Apodemus agrarius and 2 Apodemus chejuensis was not previously identified as known species or genotype, and therefore, it is supposed to be a novel genotype. In addition, the host spectrum of Cryptosporidium was extended to A. agrarius and Crosidura lasiura, which had not been reported before. In this study, we found that the Korean wild rodents and insectivores were infected with various Cryptosporidium spp. with large intra-genotypic variationa, indicating that they may function as potential reservoirs transmitting zoonotic Cryptosporidium to livestock and humans.
Previously we reported the unique Cryptosporidium sp. "c" genotype (e.g., Sbey03c, Sbey05c, Sbld05c, Sltl05c) from three species of Spermophilus ground squirrel (Spermophilus beecheyi, Spermophilus beldingi, Spermophilus lateralis) located throughout California, USA. This follow-up work characterizes the morphology and animal infectivity of this novel genotype as the final step in proposing it as a new species of Cryptosporidium. Analysis of sequences of 18S rRNA, actin, and HSP70 genes of additional Cryptosporidium isolates from recently sampled California ground squirrels (S. beecheyi) confirms the presence of the unique Sbey-c genotype in S. beecheyi. Phylogenetic and BLAST analysis indicates that the c-genotype in Spermophilus ground squirrels is distinct from Cryptosporidium species/genotypes from other host species currently available in GenBank. We propose to name this c-genotype found in Spermophilus ground squirrels as Cryptosporidium rubeyi n. sp. The mean size of C. rubeyi n. sp. oocysts is 4.67 (4.4-5.0) μm × 4.34 (4.0-5.0) μm, with a length/width index of 1.08 (n = 220). Oocysts of C. rubeyi n. sp. are not infectious to neonatal BALB/c mice and Holstein calves. GenBank accession numbers for C. rubeyi n. sp. are DQ295012, AY462233, and KM010224 for the 18S rRNA gene, KM010227 for the actin gene, and KM010229 for the HSP70 gene.
Cryptosporidiosis is one of the main protozoan infections in birds. It manifests as either a respiratory or a digestive illness, and it affects a very large number of avian species across several continents. The aim of this review is to report on the main results of studies on cryptosporidiosis among birds and the importance of these results to veterinary medicine and public health.
Cryptosporidium spp. and Giardia spp. have been detected in a range of host species, including rodents. The aim of this study was to determine the distribution of these pathogens and recognition of the reservoir role of rodents in the maintenance of these pathogens in south-western Poland. Additionally, preliminary molecular studies were conducted to elucidate the species and genotypes of Cryptosporidium and Giardia identified in this study. Stool samples (n=266) from A. agrarius, A. flavicollis and M. glareolus, were subjected for analyses. Values of prevalence were 61.7, 68.3 and 68.1%, respectively, for Cryptosporidium spp. and 41.7, 24.4 and 38.4%, respectively, for Giardia spp. There was a statistically significant correlation between host species and Giardia infection where A. agrarius was the species of the highest prevalence. Statistically significant differences were not found for comparisons made for study sites and occurrence of Giardia spp. and Cryptosporidium spp. Due to preliminary nested PCR results, specific amplifications of Cryptosporidium COWP and SSU rRNA genes were obtained for several isolates taken from rodent host species. One isolate recovered from A. agrarius (from a semi-aquatic, urban area) was identified as C. parvum and revealed 100% similarity with sequences obtained from humans. To the best of the knowledge of the authors, this is the first record of the C. parvum zoonotic species from the striped field mouse. Also recorded were the first findings of C. ubiquitum from three small rodent species.
Background
Infectious diseases represent the greatest threats to endangered species, and transmission from humans to wildlife under increased anthropogenic pressure has been always stated as a major risk of habituation.
Aims
To evaluate the impact of close contact with humans on the occurrence of potentially zoonotic protists in great apes, one hundred mountain gorillas (Gorilla beringei beringei) from seven groups habituated either for tourism or for research in Volcanoes National Park, Rwanda were screened for the presence of microsporidia, Cryptosporidium spp. and Giardia spp. using molecular diagnostics.
Results
The most frequently detected parasites were Enterocytozoon bieneusi found in 18 samples (including genotype EbpA, D, C, gorilla 2 and five novel genotypes gorilla 4–8) and Encephalitozoon cuniculi with genotype II being more prevalent (10 cases) compared to genotype I (1 case). Cryptosporidium muris (2 cases) and C. meleagridis (2 cases) were documented in great apes for the first time. Cryptosporidium sp. infections were identified only in research groups and occurrence of E. cuniculi in research groups was significantly higher in comparison to tourist groups. No difference in prevalence of E. bieneusi was observed between research and tourist groups.
Conclusion
Although our data showed the presence and diversity of important opportunistic protists in Volcanoes gorillas, the source and the routes of the circulation remain unknown. Repeated individual sampling, broad sampling of other hosts sharing the habitat with gorillas and quantification of studied protists would be necessary to acquire more complex data.
Unlabelled:
Murine cytomegalovirus (MCMV) is a betaherpesvirus of the house mouse, Mus musculus domesticus. It is a common infectious agent of wild mice and a highly studied pathogen of the laboratory mouse. Betaherpesviruses are specific to their hosts, and it is not known if other Mus taxa carry MCMV or if it is restricted to M. m. domesticus. We sampled mice over a 145-km transect of Bavaria-Bohemia crossing a hybrid zone between M. m. domesticus and Mus musculus musculus in order to investigate the occurrence of MCMV in two Mus subspecies and to test the limits of the specificity of the virus for its host. We hypothesized that if the two subspecies carry MCMV and if the virus is highly specific to its host, divergent MCMV lineages would have codiverged with their hosts and would have a geographical distribution constrained by the host genetic background. A total of 520 mice were tested by enzyme-linked immunosorbent assay (ELISA) and/or nested PCR targeting the M94 gene. Seropositive and PCR-positive individuals were found in both Mus subspecies. Seroprevalence was high, at 79.4%, but viral DNA was detected in only 41.7% of mice. Sequencing revealed 20 haplotypes clustering in 3 clades that match the host genetic structure in the hybrid zone, showing 1 and 2 MCMV lineages in M. m. domesticus and M. m. musculus, respectively. The estimated time to the most recent common ancestor (1.1 million years ago [Mya]) of the MCMVs matches that of their hosts. In conclusion, MCMV has coevolved with these hosts, suggesting that its diversity in nature may be underappreciated, since other members of the subgenus Mus likely carry different MCMVs.
Importance:
Murine cytomegalovirus (MCMV) is a betaherpesvirus of the house mouse, Mus musculus domesticus, an important lab model for human cytomegalovirus (HCMV) infection. The majority of lab studies are based on only two strains of MCMVs isolated from M. m. domesticus, Smith and K181, the latter derived from repeated passage of Smith in mouse submaxillary glands. The presence of MCMV in other members of the Mus subgenus had not even been investigated. By screening mouse samples collected in the European house mouse hybrid zone between M. m. domesticus and M. m. musculus, we show that MCMV is not restricted to the M. m. domesticus subspecies and that MCMVs likely codiverged with their Mus hosts. Thus, the diversity of MCMV in nature may be seriously underappreciated, since other members of the subgenus Mus likely carry their own MCMV lineages.
Cryptosporidium ubiquitum is an emerging zoonotic pathogen. In the past, it was not possible to identify an association between cases of human and animal infection. We conducted a genomic survey of the species, developed a subtyping tool targeting the 60-kDa glycoprotein (gp60) gene, and identified 6 subtype families (XIIa–XIIf) of C. ubiquitum. Host adaptation was apparent at the gp60 locus; subtype XIIa was found in ruminants worldwide, subtype families XIIb–XIId were found in rodents in the United States, and XIIe and XIIf were found in rodents in the Slovak Republic. Humans in the United States were infected with isolates of subtypes XIIb–XIId, whereas those in other areas were infected primarily with subtype XIIa isolates. In addition, subtype families XIIb and XIId were detected in drinking source water in the United States. Contact with C. ubiquitum–infected sheep and drinking water contaminated by infected wildlife could be sources of human infections.
Download MP3
Length: 1:40
SUMMARY Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence.
SUMMARY A total of 207 wild rodents were caught on nine pig farms, five chicken farms and five non-farm locations in Sweden and surveyed for a selection of bacteria, parasites and viruses. Lawsonia intracellularia and pathogenic Yersinia enterocolitica were only detected in rodents on pig farms (9% and 8% prevalence, respectively) which indicate that these agents are more likely to be transmitted to rodents from pigs or the environment on infected farms. Brachyspira hyodysenteriae (1%), Brachyspira intermedia (2%), Campylobacter jejuni (4%), Campylobacter upsaliensis (2%), leptospires (7%) and encephalomyocarditis virus (9%) were also detected from rodents not in contact with farm animals. Giardia and Cryptosporidium spp. were common, although no zoonotic types were verified, and Salmonella enterica was isolated from 1/11 mice on one farm but not detected by PCR from any of the rodents. Trichinella spp. and Toxoplasma gondii were not detected.
Cryptosporidium is an enteric parasite of public health significance that causes diarrhoeal illness through faecal oral contamination and via water. Zoonotic transmission is difficult to determine as most species of Cryptosporidium are morphologically identical and can only be differentiated by molecular means. Transmission dynamics of Cryptosporidium in rural populations were investigated through the collection of 196 faecal samples from diarrheic (scouring) calves on 20 farms and 63 faecal samples from humans on 14 of these farms. The overall prevalence of Cryptosporidium in cattle and humans by PCR and sequence analysis of the 18S rRNA was 73.5% (144/196) and 23.8% (15/63), respectively. Three species were identified in cattle; Cryptosporidium parvum, Cryptosporidium bovis and Cryptosporidium ryanae, and from humans, C. parvum and C. bovis. This is only the second report of C. bovis in humans. Subtype analysis at the gp60 locus identified C. parvum subtype IIaA18G3R1 as the most common subtype in calves. Of the seven human C. parvum isolates successfully subtyped, five were IIaA18G3R1, one was IIdA18G2 and one isolate had a mix of IIaA18G3R1 and IIdA19G2. These findings suggest that zoonotic transmission may have occurred but more studies involving extensive sampling of both calves and farm workers are needed for a better understanding of the sources of Cryptosporidium infections in humans from rural areas of Australia.
Waste lagoons of swine operations are a source of Cryptosporidium oocysts. Few studies, however, have reported on oocyst concentrations in swine waste lagoons; none have reported on oocyst
viability status, nor has there been a systematic assessment of species/genotype distributions across different types of swine
facilities. Ten swine waste lagoons associated with farrowing, nursery, finishing, and gestation operations were each sampled
once a month for a year. Oocysts were extracted from triplicate 900-ml effluent samples, enumerated by microscopy, and assessed
for viability by dye exclusion/vital stain assay. DNA was extracted from processed samples, and 18S ribosomal DNA (rDNA) genes
were amplified by PCR and sequenced for species and genotype identification. Oocysts were observed at each sampling time at
each lagoon. Annual mean concentrations of total oocysts and viable oocysts ranged between 24 and 51 and between 0.6 and 12
oocysts ml−1 effluent, respectively. The species and genotype distributions were dominated (95 to 100%) by Cryptosporidium suis and Cryptosporidium pig genotype II, the latter of which was found at eight of the lagoons. The lagoon at the gestation facility was dominated
by Cryptosporidium muris (90%), and one farrowing facility showed a mix of pig genotypes, Cryptosporidium muris, and various genotypes of C. parvum. The zoonotic C. parvum bovine genotype was observed five times out of 407 18S rDNA sequences analyzed. Our results indicate that pigs can have mixed
Cryptosporidium infections, but infection with C. suis is likely to be dominant.
To understand the prevalence of Cryptosporidium infection in rodents in China and to assess the potential role of rodents as a source for human cryptosporidiosis, 723 specimens
from 18 rodent species were collected from four provinces of China and examined between August 2007 and December 2008 by microscopy
after using Sheather's sugar flotation and modified acid-fast staining. Cryptosporidium oocysts were detected in 83 specimens, with an overall prevalence of 11.5%. Phodopus sungorus, Phodopus campbelli, and Rattus tanezumi were new reported hosts of Cryptosporidium. The genotypes and subtypes of Cryptosporidium strains in microscopy-positive specimens were further identified by PCR and sequence analysis of the small subunit rRNA and
the 60-kDa glycoprotein (gp60) genes. In addition to Cryptosporidium parvum, C. muris, C. andersoni, C. wrairi, ferret genotype, and mouse genotype I, four new Cryptosporidium genotypes were identified, including the hamster genotype, chipmunk genotype III, and rat genotypes II and III. Mixed Cryptosporidium species/genotypes were found in 10.8% of Cryptosporidium-positive specimens. Sequence analysis of the gp60 gene showed that C. parvum strains in pet Siberian chipmunks and hamsters were all of the subtype IIdA15G1, which was found previously in a human isolate
in The Netherlands and lambs in Spain. The gp60 sequences of C. wrairi and the Cryptosporidium ferret genotype and mouse genotype I were also obtained. These findings suggest that pet rodents may be potential reservoirs
of zoonotic Cryptosporidium species and subtypes.
Biological data support the hypothesis that there are multiple species in the genus Cryptosporidium, but a recent analysis of the available genetic data suggested that there is insufficient evidence for species differentiation. In order to resolve the controversy in the taxonomy of this parasite genus, we characterized the small-subunit rRNA genes of Cryptosporidium parvum, Cryptosporidium baileyi, Cryptosporidium muris, and Cryptosporidium serpentis and performed a phylogenetic analysis of the genus Cryptosporidium. Our study revealed that the genus Cryptosporidium contains the phylogenetically distinct species C. parvum, C. muris, C. baileyi, and C. serpentis, which is consistent with the biological characteristics and host specificity data. The Cryptosporidium species formed two clades, with C. parvum and C. baileyi belonging to one clade and C. muris and C. serpentis belonging to the other clade. Within C. parvum, human genotype isolates and guinea pig isolates (known as Cryptosporidium wrairi) each differed from bovine genotype isolates by the nucleotide sequence in four regions. A C. muris isolate from cattle was also different from parasites isolated from a rock hyrax and a Bactrian camel. Minor differences were also detected between C. serpentis isolates from snakes and lizards. Based on the genetic information, a species- and strain-specific PCR-restriction fragment length polymorphism diagnostic tool was developed.
Rats (n = 73) were trapped from nine rural farms around Oxfordshire and faeces were examined using the auramine-phenol and the Modified Ziehl-Neelsen techniques. Cryptosporidium parvum oocysts were detected in the faeces from 46 (63%) rats. This suggests that wild rats represent a risk to human and livestock health through the carriage and transmission of this zoonotic protozoan.
Biological data support the hypothesis that there are multiple species in the genus Cryptosporidium, but a recent analysis of the available genetic data suggested that there is insufficient evidence for species differentiation. In order to resolve the controversy in the taxonomy of this parasite genus, we characterized the small-subunit rRNA genes of Cryptosporidium parvum, Cryptosporidium baileyi, Cryptosporidium muris, and Cryptosporidium serpentis and performed a phylogenetic analysis of the genus Cryptosporidium. Our study revealed that the genus Cryptosporidium contains the phylogenetically distinct species C. parvum, C. muris, C. baileyi, and C. serpentis, which is consistent with the biological characteristics and host specificity data. The Cryptosporidium species formed two clades, with C. parvum and C. baileyi belonging to one clade and C. muris and C. serpentis belonging to the other clade. Within C. parvum, human genotype isolates and guinea pig isolates (known as Cryptosporidium wrairi) each differed from bovine genotype isolates by the nucleotide sequence in four regions. A C. muris isolate from cattle was also different from parasites isolated from a rock hyrax and a Bactrian camel. Minor differences were also detected between C. serpentis isolates from snakes and lizards. Based on the genetic information, a species- and strain-specific PCR-restriction fragment length polymorphism diagnostic tool was developed.
Inconsistent data exist on the distribution of zoonotic Cryptosporidium species and subtypes in sheep and goats in European countries, and few such data are available from Greece. In this study, 280 fecal specimens were collected from 132 diarrheic lambs and 148 diarrheic goat kids aged 4 to 15 days on 15 farms in northern Greece, and examined for Cryptosporidium spp. using microscopy of Ziehl-Neelsen-stained fecal smears. Cryptosporidium spp. in 80 microscopy-positive fecal specimens (39 from lambs and 41 from goat kids) were genotyped by PCR-RFLP analysis of the small subunit rRNA gene and subtyped by sequence analysis the 60 kDa glycoprotein gene. Among the 33 specimens successfully genotyped, C. parvum was found in 32 and C. xiaoi in one. Seven subtypes belonging to two subtype families (IIa and IId) were identified among the 29 C. parvum specimens successfully subtyped, including IIaA14G2R1 (1/29), IIaA15G2R1 (6/29), IIaA20G1R1 (7/29), IIdA14G2 (1/29), IIdA15G1 (9/29), IIdA16G1 (3/29), and IIdA23G1 (2/29). Lambs were more commonly infected with C. parvum IIa subtypes, whereas goat kids were more with IId subtypes. The results illustrate that C. parvum is prevalent in diarrheic lambs and goat kids in northern Greece and these animals could potentially play a role in epidemiology of human cryptosporidiosis.
Faecal samples from striped field mice (n = 72) and yellow-necked mice (n = 246) were screened for Cryptosporidium by microscopy and PCR/sequencing. Phylogenetic analysis of small-subunit rRNA, Cryptosporidium oocyst wall protein and actin gene sequences revealed the presence of C. parvum, C. hominis, C. muris and two new species, C. apodemi and C. ditrichi. Oocysts of C. apodemi are smaller than C. ditrichi and both are experimentally infectious for yellow-necked mice but not for common voles. Additionally, infection by C. ditrichi was established in one of three BALB/c mice. The prepatent period was 7–9 and 5–6 days post infection for C. apodemi and C. ditrichi, respectively. The patent period was greater than 30 days for both species. Infection intensity of C. ditrichi ranged from 4000–50,000 oocyst per gram of faeces and developmental stages of C. ditrichi were detected in the jejunum and ileum. In contrast, neither oocysts nor endogenous developmental stages of C. apodemi were detected in faecal or tissue samples, although C. apodemi DNA was detected in contents from the small and large intestine. Morphological, genetic, and biological data support the establishment of C. apodemi and C. ditrichi as a separate species of the genus Cryptosporidium.
The present study was undertaken to describe Cryptosporidium spp. infection in tree squirrels from 17 locations in Northern Italy. A total of 357 squirrels were examined, including species native to Europe (Sciurus vulgaris; n=123), and species introduced from North America (Sciurus carolinensis; n=162) and Southeast Asia (Callosciurus erythraeus; n=72). Faecal samples of all squirrels were examined for the presence of Cryptosporidium infection by microscopy (flotation method) and PCR/sequence analysis of the Cryptosporidium 18S rRNA, actin, and gp60 genes. Despite the overlapping ranges of native and introduced tree squirrel species in the study area, they host different Cryptosporidium spp. Sciurus vulgaris were exclusively infected with Cryptosporidium ferret genotype (n=13) belonging to three novel gp60 subtypes, VIIIb-VIIId. Sciurus carolinensis hosted C. ubiquitum subtype XIIb (n=2), Cryptosporidium skunk genotype subtype XVIa (n=3), and chipmunk genotype I subtype XIVa (n=1). Cryptosporidium chipmunk genotype I subtype XIVa was also found in two C. erythraeus. Comparing data from this and previous studies, we propose that Cryptosporidium skunk genotype and possibly C. ubiquitum subtype XIIb were introduced to Europe with eastern grey squirrels. Cryptosporidium chipmunk genotype I and ferret genotype were associated with high intensity infections, but there was no association with diarrhoea.
Cryptosporidium spp. is an important causative agent of intestinal parasitoses-induced diarrhoea in humans and animals worldwide. Rodents (small mammals), the main reservoir of infections, are globally expanded and overpopulated, which increases the risk of transfer of human and zoonotic pathogens from the genus Cryptosporidium. In this study, Cryptosporidium was detected in wild immunocompetent asymptomatic small mammals. Altogether 262 faecal samples were collected from five areas in eastern Slovakia from four different rodent species (Myodes glareolus, Apodemus agrarius, Apodemus flavicollis, Rattus norvegicus), eight samples originated from two insectivore species (Sorex araneus, Crocidura suaveolens) and two sample from a carnivore Mustela nivalis. The samples were examined using a method modified in our laboratory, based on the use of specific primers on a small subunit rRNA (18S rRNA) gene for species identification, and amplification of GP60 gene coding 60-kDa glycoprotein for genotype determination. The following species were identified: Cryptosporidium parvum (n = 15), genotypes IIaA18G3R1 (n = 11; KU311673), IIaA10G1R1 (n = 1; KU311670), IIcA5G3a (n = 1; KU311669), IIiA10 (n = 2; KU311672); Cryptosporidium suis (n = 4; KU311671); Cryptosporidium scrofarum (n = 28); Cryptosporidium environment sp. (n = 12; KU311677); Cryptosporidium muskrat genotype I (n = 3; KU311675); Cryptosporidium muskrat genotype II (n = 3; KU311676). From one of the rodent, the species Cryptosporidium hominis genotype IbA10G2 (KU311668) was identified for the first time.
Associations between intensity and frequency of Cryptosporidium and Giardia shedding with growth, carcase weight and dressing % were investigated using a longitudinal study of 1182 lambs on eight Australian farms. Live weight was recorded and faecal samples were collected on three sampling occasions; weaning (approximately 12 weeks of age), post-weaning (approximately 19 weeks) and pre-slaughter (approximately 29 weeks). Hot standard carcase weight (HSCW) and dressing % were measured at slaughter. Faecal samples were screened for presence and concentration of Cryptosporidium, Giardia and Haemonchus oocysts using a quantitative PCR. Trichostrongylid eggs were quantified with modified McMaster faecal worm egg count (WEC). Protozoan shedding intensity was categorised as high (above median oocyst concentration in positive sheep), low (below median oocyst concentration in positive sheep) or not detected. Shedding was also categorised for shedding type (no shedding, single Giardia infection, single Cryptosporidium infection, concurrent Giardia and Cryptosporidium infection) and lambs were categorised for frequency of shedding (shedding identified on 0, 1, 2 or 3 occasions). Associations of parasite shedding intensity category, shedding type, shedding frequency, WEC and Haemonchus status (positive or negative) with lamb production were assessed using general linear models (HSCW and dressing %) and linear mixed effects models (live weight). High Cryptosporidium parvum shedding was associated with lower live weight, ranging 2.31–4.52 kg over the 3 sampling occasions. Cryptosporidium parvum shedding was associated with less HSCW in high (3.22 kg less) and low (3.22 kg less) shedding lambs post-weaning, and high (2.21 kg less) and low (2.60 kg less) shedding lambs pre-slaughter as well as lower dressing % (2.7% lower in high shedding lambs post-weaning). Cryptosporidium (all species) shedding pre-slaughter was associated with reduced dressing % in both high (1.25% lower) and low (1.21% lower) shedding lambs. Giardia shedding pre-slaughter was associated with 0.59 kg less HSCW in high shedding lambs. Increased frequency of C. parvum and Giardia shedding in a specific animal (repeated detection) were associated with reduced HSCW and dressing %. Concurrent Giardia and Cryptosporidium shedding pre-slaughter was associated with reduced dressing %. No statistically significant main effects for either WEC (P > 0.05) or Haemonchus status (P > 0.05) were identified for any of the sheep meat productivity measures (live weight, HSCW and dressing %). The findings suggest naturally acquired Cryptosporidium and Giardia infections in grazing sheep are associated with depressed growth, carcase weight and dressing efficiency beyond the neonatal period in sheep representing a range of genetic backgrounds and different sheep production environments.
Cryptosporidium parasites belong to the phylum Apicomplexa and possess features of both the coccidia and gregarines. Currently, 25 species of Cryptosporidium are recognized in fish, amphibians, reptiles, birds and mammals. All 25 species have been confirmed by morphological, biological, and molecular data. Cryptosporidium duismarci and C. scophthalmi lack sufficient biological and/or molecular data to be considered valid species. In addition to the named species, more than 40 genotypes from various vertebrate hosts have been described. For these genotypes to receive taxonomic status, sufficient morphological, biological, and molecular data are required and names must comply with the rules of the International Code for Zoological Nomenclature (ICZN). A different interpretation of the ICZN led to the proposal that Cryptosporidium parvum be renamed as Cryptosporidium pestis and that C. parvum be retained for C. tyzzeri. However, this proposal violates the guiding ICZN principle of maintaining taxonomic stability and avoiding confusion. In addition, C. pestis lacks a full taxonomic description and therefore is not a valid species. The taxonomic status of Cryptosporidium spp. is rapidly evolving and many genotypes are likely to be formally described as species in the future.
Although pigs are commonly infected with Cryptosporidium spp. and Giardia duodenalis,
including potentially zoonotic species or genotypes, little is known about age-related infection
levels, seasonal differences and genetic variation in naturally infected pigs raised in organic
management systems. Therefore, the current study was conducted to assess seasonal and agerelated
variations in prevalence and infection intensity of Cryptosporidium and Giardia,
evaluate zoonotic potential and uncover correlations between species/genotypes, infection
intensity and faecal consistency. Shedding of oocysts and cysts ((oo-)cysts) was monitored at
quarterly intervals (September 2011 to June 2012) in piglets (n=152), starter pigs (n=234),
fatteners (n=230) and sows (n=240) from three organic farms in Denmark. (Oo-)cysts were
quantified by immunofluorescence microscopy; and 56/75 subsamples from Cryptosporidium
infected pigs were successfully analysed by PCR amplification and partial sequencing of the
small subunit (SSU) 18S rRNA and hsp70 genes, while 13/67 Giardia subsamples were
successfully analysed by amplification and partial sequencing of the 18S rRNA and the gdh
genes. Altogether, Cryptosporidium or Giardia infections were observed in 40.9% (350/856)
and 14.0% (120/856) of the pigs, respectively, including 8.2% (70/856) infected with both
parasites. Prevalence, intensity of infections and presence of Cryptosporidium species varied
significantly between age-groups; 53.3% piglets, 72.2% starter pigs, 40.4% fatteners and 2.9%
sows were infected with Cryptosporidium, whereas 2.0% piglets, 27.4% starter pigs, 17.8%
fatteners and 5.0% sows were infected with Giardia. The overall prevalence was stable
throughout the year, except for dual-infections that were more prevalent in September and
3
December (p<0.05). The infection intensity was age-related for both parasites, and dualinfected
pigs tended to excrete lower levels of oocysts compared to pigs harbouring only
Cryptosporidium. Likewise, pigs infected with C. scrofarum excreted fewer oocysts (mean CPG:
54,848±194,508 CI: 9085–118,781) compared to pigs infected with C. suis (mean OPG:
351,035±351,035 CI: 67,953–634,117). No correlation between faecal consistency and (oo-
)cyst excretion levels was observed.
Of the successfully genotyped isolates, 38/56 (67.9%) were C. scrofarum and 18/56 (32.1%)
were C. suis, while the livestock specific G. duodenalis Assemblage E was detected in 11/13
(84.6%) isolates and the potentially zoonotic Assemblage A was identified in 2/13 (15.4%)
isolates. Piglets exclusively hosted C. suis, with one exception, while starter pigs and fatteners
predominantly hosted C. scrofarum. As organic pigs are partly reared outdoors, environmental
contamination with Cryptosporidium and Giardia is inevitable. Nevertheless, the present data
indicate that the potential public health risk associated with both of these parasites in Danish
organic pig production seems to be negligible.
Wildlife-associated Cryptosporidium are an emerging cause of cryptosporidiosis in humans. The present study was undertaken to determine the extent to which North American tree squirrels and ground squirrels host zoonotic Cryptosporidium species and genotypes. Fragments of the Cryptosporidium 18S rRNA and actin genes were amplified and sequenced from fecal samples obtained from three tree squirrel and three ground squirrel species. In tree squirrels, Cryptosporidium was identified in 40.5% (17/42) of American red squirrels (Tamiasciurus hudsonicus), 40.4% (55/136) of eastern gray squirrels (Sciurus carolinensis), and 28.6% (2/7) of fox squirrels (Sciurus niger). Human-pathogenic Cryptosporidium ubiquitum and Cryptosporidium skunk genotype were the most prevalent species/genotypes in tree squirrels. Because tree squirrels live in close proximity to humans and are frequently infected with potentially zoonotic Cryptosporidium species/genotypes, they may be a significant reservoir of infection in humans. In ground squirrels, Cryptosporidium was detected in 70.2% (33/47) of 13-lined ground squirrels (Ictidomys tridecemlineatus), 35.1% (27/77) of black-tailed prairie dogs (Cynomys ludovicianus), and the only golden-mantled ground squirrel (Callospermophilus lateralis) that was sampled. Cryptosporidium rubeyi and ground squirrel genotypes I, II, and III were identified in isolates from these ground squirrel species. In contrast to the Cryptosporidium infecting tree squirrels, these species/genotypes appear to be specific for ground squirrels and are not associated with human disease.
Gregarine 18S ribosomal DNA trees are hard to resolve because they exhibit the most disparate rates of rDNA evolution of any eukaryote group. As site-heterogeneous tree-reconstruction algorithms can give more accurate trees, especially for technically unusually challenging groups, I present the first site-heterogeneous rDNA trees for 122 gregarines and an extensive set of 452 appropriate outgroups. While some features remain poorly resolved, these trees fit morphological diversity better than most previous, evolutionarily less realistic, maximum likelihood trees. Gregarines are probably polyphyletic, with some ‘eugregarines’ and all ‘neogregarines’ (both abandoned as taxa) being more closely related to Cryptosporidia and Rhytidocystidae than to archigregarines. I establish a new subclass Orthogregarinia (new orders Vermigregarida, Arthrogregarida) for gregarines most closely related to Cryptosporidium and group Orthogregarinia, Cryptosporidiidae, and Rhytidocystidae as revised class Gregarinomorphea. Archigregarines are excluded from Gregarinomorphea and grouped with new orders Velocida (Urosporoidea superfam. n. and Veloxidium) and Stenophorida as a new sporozoan class Paragregarea. Platyproteum and Filipodium never group with Orthogregarinia or Paragregarea and are sufficiently different morphologically to merit a new order Squirmida. I revise gregarine higher-level classification generally in the light of site-heterogeneous-model trees, discuss their evolution, and also sporozoan cell structure and life-history evolution, correcting widespread misinterpretations.
Cryptosporidium has adapted to a broad range of hosts in all major vertebrate classes, and the species associated with humans and livestock represent a small fraction of the diversity in the genus. This review focuses on Cryptosporid-ium and cryptosporidiosis in terrestrial vertebrates other than humans and livestock. As the known host range of Cryptosporidium continues to expand, major orders of amphibians (Anura), reptiles (Squamata and Testudines), avians (17 out of 26 orders), and mammals (18 out of 29 orders) are now represented. The greatest Cryptosporidium diversity appears to be in mammals, which may be an Artifact of undersampling in other classes, but more likely reflects a different mechanism of Cryptosporidium diversification in mammals relative to other classes.
Cryptosporidium parvum from 73 dairy calves less than two months old from Buenos Aires province (Argentina) were molecularly characterized using sequence analysis of the GP60 gene. Seventy five sequences were obtained, and seven different subtypes were identified, all belonging to the IIa subtype family. The most common subtypes were IIaA20G1R1 (27/75), IIaA22G1R1 (16/75), and IIaA18G1R1 (13/75). Subtypes IIaA21G1R1, IIaA23G1R1, IIaA16G1R1 and IIaA19G1R1 were found sporadically. Two samples contained mixed infections with IIaA21G1R1 and IIaA22G1R1. A significant association was found between subtypes and geographic location, whereas there was no relation between subtypes and presence of diarrhea. Three of the subtypes found in this study (IIaA16G1R1, IIaA18G1R1, and IIaA19G1R1) were previously identified in humans. These findings suggest that cattle could play an important role in the transmission of cryptosporidiosis to humans in Buenos Aires province.
Two house mouse subspecies occur in Europe, eastern and northern Mus musculus musculus (Mmm) and western and southern Mus musculus domesticus (Mmd). A secondary hybrid zone occurs where their ranges meet, running from Scandinavia to the Black Sea. In this paper, we tested a hypothesis that the apicomplexan protozoan species Cryptosporidium tyzzeri has coevolved with the house mouse. More specifically, we assessed to what extent the evolution of this parasite mirrors divergence of the two subspecies. In order to test this hypothesis, we analysed sequence variation at five genes (ssrRNA, Cryptosporidium oocyst wall protein (COWP), thrombospondin-related adhesive protein of Cryptosporidium 1 (TRAP-C1), actin and gp60) in C. tyzzeri isolates from Mmd and Mmm sampled along a transect across the hybrid zone from the Czech Republic to Germany. Mmd samples were supplemented with mice from New Zealand. We found two distinct isolates of C. tyzzeri, each occurring exclusively in one of the mouse subspecies (C. tyzzeri-Mmm and C. tyzzeri-Mmd). In addition to genetic differentiation, oocysts of the C. tyzzeri-Mmd subtype (mean: 4.24×3.69μm) were significantly smaller than oocysts of C. tyzzeri-Mmm (mean: 4.49×3.90μm). Mmm and Mmd were susceptible to experimental infection with both C. tyzzeri subtypes; however, the subtypes were not infective for the rodent species Meriones unguiculatus, Mastomys coucha, Apodemus flavicollis or Cavia porcellus. Overall, our results support the hypothesis that C. tyzzeri is coevolving with Mmm and Mmd.
The genus Cryptosporidium, which is an obligate intracellular parasite, infects various vertebrates and causes a diarrheal disease known as cryptosporidiosis. Wild rodents are naturally infected with zoonotic Cryptosporidium; thus, they are potential reservoirs of the parasites. Mice are common rodents frequently found in agricultural areas and have many opportunities to contact other wild animals, livestock, and humans. Irrespective of the potential risk, there are few epidemiologic studies of Cryptosporidium in wild mice because of their low economic importance and the difficulty in conducting surveys. Hence, the species and genotypes of Cryptosporidium in wild mice living around various areas remain unclear. We investigated the species and genotype distribution and prevalence of Cryptosporidium in the large Japanese field mouse (Apodemus speciosus) in an agricultural site in Osaki, Miyagi Prefecture, Japan. In total, 15 mice were captured and examined in this study. By microscopic analysis, only one mouse (JFM 3) was determined to be Cryptosporidium-positive, while the parasite were detected in four mice (JFM 3, 6, 10, and 15) by a molecular approach using partial SSU rRNA gene sequences. Based on nucleotide sequence and phylogenetic analysis, the Cryptosporidium isolates were identified as C. ubiquitum (from JFM 10) and C. muris (from JFM 3 and 6). In contrast, the Cryptosporidium in JFM 15 was not identified as a known species or genotype and is therefore proposed as a novel genotype; the Naruko genotype. More molecular data are necessary to elucidate the taxonomic identity of this novel Cryptosporidium genotype. The C. muris Japanese field mouse genotypes showed marked divergence compared to that in a previous report. The large Japanese field mouse might thus represent a reservoir of multiple Cryptosporidium spp.
This study was undertaken to investigate the occurrence and public health significance of Cryptosporidium species/genotypes and subtypes in a newborn lambs. A total of 175 diarrheic fecal samples from lambs (younger than 21 days) were collected in seven sheep flocks located in western Romania, and were microscopically examined for the presence of Cryptosporidium oocysts after staining with modified Ziehl-Neelsen technique. Twenty-four (13.7%) fecal samples were tested Cryptosporidium positive by microscopy and were subjected for molecular characterization. All positive samples were successfully amplified through a nested polymerase chain reaction (PCR) of the small subunit (SSU) rRNA gene (18S). Cryptosporidium species were determined by restriction fragment length polymorphism (RFLP) analysis of the secondary PCR products using the conventional SspI and VspI restriction enzymes. The identified species were: Cryptosporidium parvum (20/24), C. ubiquitum (2/24) and C. xiaoi (2/24), respectively. PCR-RFLP results for C. ubiquitum and C. xiaoi isolates were confirmed by DNA sequencing. Subsequently, subtyping of seven randomly selected C. parvum isolates, based on sequence analysis of the GP60 gene, revealed the presence of five different subtypes (IIaA17G1R1, IIaA16G1R1, IIdA20G1, IIdA24G1 and IIdA22G2R1) belonging in two zoonotic subtype families (IIa and IId). These findings may suggest the potential role of the newborn lambs as a source for human cryptosporidiosis. This is the first published report about the presence of C. ubiquitum and C. xiaoi in lambs from Romania.
Three and 8 week old pigs were inoculated with Cryptosporidium muris HZ206 (Mus musculus musculus isolate), Cryptosporidium tyzerri CR2090 (M. m. musculus isolate) or C. tyzzeri CR4293 (isolate from a hybrid between Mus musculus domesticus and M. m. musculus) at a dose of 1 × 10(7) oocysts per animal. Inoculated pigs showed no detectable infection and no clinical symptoms of cryptosporidiosis during 30 days post infection (DPI), and no macroscopic changes were detected in the digestive tract following necropsy. Developmental stages were not detected in gastrointestinal tract tissue by histology or PCR throughout the duration of the experiment. The infectivity of isolates was verified on SCID mice, in which oocysts shedding started from 4 to 8 DPI. Based on our findings, it can be concluded that pigs are not susceptible to C. muris or C. tyzzeri infection.
The Cryptosporidium in the small intestine of domestic mice (Mus musculus) was initially described as Cryptosporidium parvum. Recent genetic and biologic characterization of Cryptosporidium isolates indicate that domestic mice are infected with several morphologically indistinguishable intestinal Cryptosporidium parasites with different host specificities, including C. parvum sensu stricto, mouse genotype I, and mouse genotype II. In this study, the morphological, biological, and genetic characteristics of the Cryptosporidium mouse genotype I are described. As a full re-description of C. parvum was made in 1985 for isolates from calves and humans and the name C. parvum has been widely used for the parasite that is infectious to both ruminants and humans, the mouse genotype I is named as Cryptosporidium tyzzeri. Oocysts of the new species (4.64±0.05 μm ×4.19±0.06 μm, with a mean shape index of 1.11±0.02; n=69) are slightly smaller than those of the re-described C. parvum. The prepatent period was six and seven days, and the patent period was 24-28 and 28-29 days in neonatal and adult mice, respectively. Oocysts were not infectious to lambs and calves. Light, transmission electron and scanning electron microscopy studies of the new species showed the presence of developmental stages in the microvillar brush border of the jejunum and ileum of experimentally infected mice, with the infection most intensive in the ileum. It had nucleotide sequences significantly different from C. parvum at the small subunit rRNA, 70 kDa heat shock protein, oocyst wall protein, actin, and the 60 kDa glycoprotein genes. Based on the morphological, genetic, and biological data and in compliance of established Cryptosporidium species naming criteria, this geographically widespread parasite is named as a new species in honor of Ernest Edward Tyzzer, who pioneered Cryptosporidium research.
Twenty-six experimentally infected calves were monitored daily for oocyst excretion. All began excreting oocysts 3-6 days p.i. Most calves (n = 23) excreted oocysts for 6-9 days, with a daily range from 4 x 10(2) to 4.15 x 10(7) oocysts g(-1) of faeces. Over half the calves excreted peak numbers of oocysts 6-8 days p.i. Diarrhoea, observed intermittently beginning as early as day 3 p.i., lasted 4-16 days and varied greatly in severity from calf to calf. In a second study, nine of 18 calves were orally inoculated with 5 x 10(6) oocysts between birth and 2 days of age and nine remained uninfected. Monoclonal antibodies for cell surface markers indicated substantial increases in CD4+ and CD8+ T cells in the intraepithelial lymphocyte population of the ilea of infected calves at 7-9 days of age. RT-PCR demonstrated increases in mRNA for interleukin-12 and interferon-gamma that correlated with increases in both CD4+ and CD8 + intraepithelial lymphocyte cells. Increased mRNA for interleukin-12 and interferon-gamma from lamina propria lymphocytes correlated with increased numbers of CD8+ cells. No changes were found in interleukin-2, interleukin-4 or interleukin-10 mRNA levels. However, interleukin-15 mRNA, possibly from epithelial cells contaminating intraepithelial lymphocytes, was decreased in infected calves and had a negative correlation with increases in CD4+ and CD8+ cells. No differences were detected in mRNA levels for cytokines from lymph node lymphocytes.
Faecal samples from 224 roe deer (Capreolus capreolus) and 381 wild boars (Sus scrofa) shot during the 2008-2009 hunting season (August-January) in Galicia (NW Spain) were examined to determine the presence and intensity of infection by Cryptosporidium and Giardia. Analysis of a single sample from each of the roe deer revealed that the prevalence of cryptosporidiosis and giardiosis was 1.3% and 5.3% respectively. The prevalence of Giardia infection was significantly higher in juvenile female roe deer than in adult females, but no other significant differences were found in relation to age and sex. In wild boars, the prevalence of cryptosporidiosis and giardiosis was 7.6% and 1.3% respectively. The prevalence of Cryptosporidium infection was significantly higher in juvenile male wild boars than in adult males, but no other significant differences were found in relation to age or sex. In both groups of wild animals, the number of Cryptosporidium oocysts per gram of faeces (OPG) ranged from 5 to 200 and the number of Giardia cysts per gram of faeces (CPG) was between 5 and 47; there were no significant differences between the two groups with respect to number of infections. This is the first large study of Cryptosporidium and Giardia in roe deer and wild boars in hunting areas in Spain and the results demonstrate a low, but widespread prevalence of Cryptosporidium and Giardia in these animals.
The infectivity of Cryptosporidium muris (strain RN 66), originally isolated from the house rat (Iseki 1986), to various laboratory animals was studied by transmission experiments. After oral inoculation with 1 x 10(6) oocysts, mice, guinea pigs, rabbits, dogs, and cats all discharged endogenously produced oocysts in their feces. Among these host species, mice and cats were highly susceptible to the parasite. The prepatent period for six 3-week-old specific pathogen-free (SPF) mice was 5 days postinoculation (PI), the patent periods varied between 34 and 75 days for each mouse, and the number of oocysts discharged per individual per day (OPD) was 11-46 x 10(6) at the maximum on days 16-26 PI. The total number of oocysts discharged per mouse during the patent period was estimated to be 170-560 x 10(6). Three inoculated cats (1-2 months old) also discharged a large number of oocysts for a long period. Guinea pigs, rabbits, and dogs showed low susceptibility to this strain; the OPD was extremely small and the patent periods were less than 3 weeks. The entire endogenous development of this parasite occurred in the stomach and not in the small and large intestines of these experimental animals. Because of this lack of host specificity, it is suspected that C. muris could be infective to humans, especially immunocompromised patients such as those with AIDS.
SYNOPSIS. Cryptosporidium wrairi sp. n. is described from the laboratory guinea pig Cavia porcellus. The life cycle is given insofar as it is known. Two schizogonous generations are described; the 1st with 8 merozoites, the 2nd with 4 merozoites. The latter generation was previously referred to as the sporulated oocyst, but evidence is presented to show that it is a schizont. Micro- and macrogametogony are also described. No oocysts were found. Cross-transmission to mice, chickens, turkeys and rabbits was unsuccessful. The generic character of oocysts with 4 naked sporozoites is discarded and the presence of endogenous stages in the striated border of epithelial cells is used as the emended generic character. A listing of valid and non-valid species is given.
Wild brown rats (Rattus norvegicus) from 11 rural UK farmsteads were found to carry 13 zoonotic and 10 non-zoonotic parasitic species, many of which (e.g. Cryptosporidium, Pasteurella, Listeria, Yersinia, Coxiella and Hantavirus) have rarely or never been previously investigated for wild rats. The study suggests that wild brown rats, serving as vectors of disease, represent a serious risk to the health of humans and domestic animals in the UK.
Three-week-old ICR SPF mice were orally inoculated with one of 5 doses ranging from 2 x 10(2) to 2 x 10(6) oocysts of Cryptosporidium muris (strain MCR) per mouse. Oocyst inoculation was directly proportional to the amount of oocysts shed and was inversely proportional to the period required for peak oocyst production and to the prepatent period. Peak oocyst production occurred between fifteen and thirty-one days with a patent period from 61 to 64 days. Three days after all mice stopped shedding oocysts, they were orally challenged with a single dose of 2 x 10(6) oocysts of the same species. Marked seroconversion for IgG antibody accompanied recovery from mice inoculated with 5 x 10(5) oocysts. Mice administered with carrageenan excreted a small number of oocysts for 49.0 days on the average after challenge inoculation (ACI) and control mice for 14.2 days in a dose-independent fashion. Just before challenge infection, phagocytic activity of peritoneal macrophages (M phi) and the number of peripheral M phi were dramatically decreased. Mild challenge infection implies that the immunogenicity of C. muris (strain MCR) is very strong, despite M phi blocker carrageenan administration.
A recent report suggested that an isolate of Cryptosporidium parvum had established infections in fish, amphibians, and reptiles and raises concern that animals other than mammals might be a potential source of waterborne Cryptosporidium oocysts. To test this possibility, viable C. parvum oocysts, infectious for neonatal BALB/c mice, were delivered by gastric intubation to bluegill sunfish, poison-dart frogs, African clawed frogs, bearded dragon lizards, and corn snakes. Histological sections of the stomach, jejunum, ileum, and cloaca prepared from tissues collected on days 7 and 14 postinoculation (PI) were negative for Cryptosporidium developmental stages. However, inoculum-derived oocysts were detectable by fluorescein-labeled monoclonal antibody in feces of inoculated animals from day 1 to day 12 PI in fish and frogs, and up to day 14 PI in lizards. Snakes did not defecate for 14 days PI. Impression smears taken at necropsy on days 7 and 14 PI revealed C. parvum oocysts in the lumen of the cloaca of 2 fish and 1 lizard on day 7 PI only. Because tissue stages of the pathogen were not found, it appears that C. parvum was not heterologously transmitted to lower vertebrates. Under certain circumstances, however, such as after the ingestion of C. parvum-infected prey, lower vertebrates may disseminate C. parvum oocysts in the environment.
Cryptosporidium wrairi was isolated from guinea pigs during a spontaneous outbreak of cryptosporidiosis. Despite the morphological and antigenic similarities to C. parvum, C. wrairi displayed a different host range and site of infection and may represent a separate species or sub-species. We used the polymerase chain reaction to clone two distinct 550 bp-long DNA fragments, Wc-I and Wc-II, of the gene encoding the Cryptosporidium oocyst wall protein (COWP) of C. wrairi, which showed 98% identity to the C. parvum homologue. Within Wc-I, polymorphic Rsal restriction sites were used to develop a polymerase chain reaction-restriction fragment length polymorphism method able to distinguish C. wrairi from C. parvum and to identify two groups of C. parvum isolates differentially associated with animal and human infections.
Wild mice and voles were tested for Cryptosporidium during a 2-year survey at an agricultural site in Warwickshire, United Kingdom. C. parvum and C. muris, the two cryptosporidial species known to infect mammals, were detected. Prevalence figures of 22%, 21% and 13% noted for C. parvum for Mus domesticus, Apodemus sylvaticus and Clethrionomys glareolus, respectively, were higher than those recorded for C. muris at 10%, 6% and 2%. C. parvum causes the sometimes severe diarrhoeal disease cryptosporidiosis in many hosts, but the wild rodents were asymptomatic. The discovery of C. muris in A. sylvaticus and C. glareolus confirms a wider distribution in wild rodents than has previously been reported. Rodents may represent a significant reservoir of Cryptosporidium with a high potential for infection of man and livestock due to cohabitation.
Six 2-week-old Cryptosporidium-free Peking ducklings (Anas platyrhynchos) each received 2.0 x 10(6) viable Cryptosporidium serpentis oocysts from 6 naturally infected captive snakes. Histological sections of digestive (stomach, jejunum, ileum, cloaca, and cecum) and respiratory tract tissues (larynx, trachea, and lungs) did not contain life-cycle stages of Cryptosporidium in any of the inoculated ducklings. Because ducklings were refractory to infection, C. serpentis transmission via a diet of Peking ducklings is improbable. Viable (per in vitro excystation assay) inoculum-derived oocysts were detected in duckling feces up to 7 days post-inoculation (PI); the number of intact oocysts excreted during the first 2 days PI was significantly higher than for the remaining 5 days PI (P < 0.01). The dynamics of oocyst shedding showed that overall the birds released a significantly higher number of intact oocysts than oocyst shells (P < 0.01). Retention of the viability of C. serpentis oocysts following intestinal passage through a refractory avian species may have epizootiological implications. Under certain circumstances such as after the ingestion of C. serpentis-infected prey, herpetivorous birds may disseminate C. serpentis oocysts in the environment.
Five rodent and two insectivore species were investigated for Cryptosporidium at seven sites in north-eastern Spain. Of the 442 animals studied, 82 Apodemus sylvaticus, 1 A. flavicollis, 5 Mus spretus, 1 Rattus rattus, 8 Clethrionomys glareolus and 13 Crocidura russula were infected with only C. parvum. Eleven A. sylvaticus and 2 C. glareolus were infected with only C. muris and 16 A. sylvaticus, 1 M. spretus and 2 C. glareolus showed mixed infections. Both cryptosporidial species were found in most study areas. No causal relationship was found between intrinsic host factors (age and sex) and the parasitic prevalence in the most captured host species (A. sylvaticus and C. russula). Extrinsic factors such as collection site of host, seasonality and covering vegetation exerted different influence on the prevalence of Cryptosporidium. Small mammals could become one of the most important sources of cryptosporidial oocysts in those areas where neither farm animals nor significant human activity are present. This is the first study to report the infection of M. spretus and C. russula by C. parvum and the first finding of C. muris in M. spretus.