No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Cryptosporidium infections in cats and dogs
Abstract
Cryptosporidiosis was recognized as an important zoonosis in the early 1980s. Early studies assumed that all infections in mammals, including humans, were caused by the parasite Cryptosporidium parvum. Recent studies using molecular biologic tools and host-specificity studies indicate that cats and dogs have their own unique species of Cryptosporidium (C. felis and C. canis, respectively). Surveys indicate that up to 38.5% of cats and up to 44.8% of dogs are infected with Cryptosporidium spp. Initial studies indicate that owning a cat or dog does not increase the risk of humans acquiring cryptosporidiosis, although human infections with C. felis and C. canis have been found in patients with AIDS, immunosuppressed patients, and children from impoverished areas. Clinical signs of cryptosporidiosis in cats and dogs vary from none to chronic or intermittent diarrhea. Fluids and other supportive measures should be used in animals with diarrhea, but there is no proven safe and effective treatment of cryptosporidiosis.
... Cryptosporidium parvum is known to have zoonotic infectious characteristics that cause diarrhea in various mammals including humans and ruminants . Although the association between C. parvum infection and diarrhea in dogs is unclear, it was reported that C. parvum oocysts were moderately infectious in dogs (Lindsay and Zajac, 2004). In addition, the presence of this species in dogs (Abe et al., 2002;Giangaspero et al., 2006;Li et al., 2021) suggest a risk of infection or transmission to humans. ...
... Studies conducted among dogs from many other countries via various techniques such as fecal-, molecular-and serological-based surveys revealed that up to 44.8% of dogs have been infected with Cryptosporidium spp. On the other hand, it has been indicated that up to 38.5% of cats examined have been exposed to or are excreting Cryptosporidium oocysts (Lindsay and Zajac 2004). The zoonotic po-tential of Cryptosporidium spp. is well known and domestic animals are the important reservoir of infection for humans (Robertson et al. 2000, Xiao et al. 2004, Fontanarrosa et al. 2006.To date, there are 16 different species of Cryptosporidium spp. ...
To estimate the current prevalence of gastrointestinal (GI) parasites in dogs and cats, a total of 105 fresh faecal samples were collected from rural areas in Peninsular Malaysia. Each faecal sample was examined for the presence of GI parasites by microscopic examination after formalin-ether concentration technique and for protozoa, trichrome and Ziehl-Neelsen staining were employed. The overall prevalence of GI parasitic infection was 88.6% (95% CI = 82.5-94.7) in which 88.3% of dogs and 89.3% of cats were infected with at least one parasites species, respectively. There were 14 different GI parasites species (nematodes, cestodes and protozoa) detected, including Ancylostoma spp. (62.9%), Toxocara spp. (32.4%), Trichuris vulpis (21.0%), Spirometra spp. (9.5%), Toxascaris leonina (5.7%), Dipylidium caninum (4.8%), Ascaris spp. (2.9%), Hymenolepis diminuta (1.0%) and others. General prevalence of GI parasites showed a significant difference between helminth (84.4%) and protozoa (34.3%) infections. Monoparasitism (38.1%) was less frequent than polyparasitism (46.7%). As several of these GI parasites are recognized as zoonotic agents, the results of this investigation revealed that local populations may be exposed to a broad spectrum of zoonotic agents by means of environmental contamination with dogs and cats faeces and this information should be used to mitigate public health risks. Prevention and control measures have to be taken in order to reduce the prevalence rates especially in socioeconomically disadvantaged communities where animals live in close proximity to people, poor levels of hygiene and overcrowding together with a lack in veterinary attention and zoonotic awareness.
... Rare reports of infection in immunosuppressed humans and one child whose house cat was shedding oocysts can be found in the literature, [14][15][16][17] but infection from other sources of contamination could not be excluded. Infection in cats may remain unnoticed [18][19][20][21] and is generally subclinical in cats infected by C felis but may lead to diarrhea when cats are infected by C parvum. 12,22 Young animals are more prone to Cryptosporidium species infection and although the relationship between human immune status and cryptosporidiosis has been defined and extrapolated to animals, an association between domestic cats immune status and disease course/signs still has to be established. ...
Cryptosporidium is a coccidian that can lead to diarrhea, especially in immunosuppressed individuals. Retroviruses are considered a primary cause of immunosuppression in cats. Fecal specimens and blood collected from the 60 cats were evaluated for the presence of acid-fast cryptosporidia in three consecutive stool samples and for feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibody by ELISA testing. Five animals (8.33%) shedding oocysts were found, one was both FIV- and FeLV-negative and four were FeLV-positive.
Sunulan çalışmada Türkiye’nin çeşitli bölgelerine köpek yetiştiren Jandarma At ve Köpek Eğitim Merkezi Komutanlığı’ndaki yavru köpeklerde karşılaşılan ishallerde Cryptosporidium parvum varlığının belirlenmesi amaçlandı. Hayvan materyalini 100 adet farklı ırk (Pointer, Alman çoban köpeği, Belçika Malinois, Çatalburun, Labrador ve Golden Retriever), yaş (28 gün-9 aylık) ve cinsiyette ishalli köpek oluşturdu. Köpeklerden alınan dışkı örneklerinde natif, flotasyon ve karbol fuksin boyama yöntemi ile parazitolojik inceleme yapıldı. Ayrıca immunokromotografik hızlı test kitleri kullanılarak C. parvum’un varlığı araştırıldı. Çalışmaya dahil edilen köpeklerden 18’inde Toxocara canis (%18), 3’ünde Toxoscaris leonine (%3), 8’inde Giardia spp. (%8), 25’inde ise Cystoisospora spp. (%25) belirlenirken Cryptosporidium parvum tespit edilemedi. Cystoisospora spp. yüzdesi bakımından yaş ve ırk arasında anlamlı bir ilişki bulunurken (P0.05). Sonuç olarak; Cryptosporidium parvum için test edilen 100 köpeğin dışkı örnekleri, nativ, flotasyon ve karbol fuksin boyama yöntemleri ve immunokromatografik hızlı test kiti muayeneleriyle negatif bulundu.
A small type of Cryptosporidium oocysts was isolated from a naturally infected cat and its biological nature was investigated. In cats experimentally inoculated with Cryptosporidium oocysts, long-lasting shedding of the oocysts occurred after a prepatent period of 8-10 days, and a number of peaks of oocyst count appeared at intervals of several days to a few weeks, earlier in the infection course. Cryptosporidium infection in cats is likely to pass from an acute to a chronic stage. During the chronic stage, prednisolone injection into the cats gave rise to a recurrence of proliferation of the parasite along with a marked increase in the number of oocysts shed. None of the infected cats showed clinical symptoms. Infection experiments using Cryptosporidium oocysts were unsuccessful in several species of animals such as mice, rats, guinea pigs, dogs, suckling mice and mice previously injected with prednisolone or hydrocortisone.
From February, 1988 to February, 1989, an epidemiological survey for feline cryptosporidiosis was carried out on domestic cats that had been committed to the Tokyo Metropolitan Animal Protection Center by owners residing in the Tokyo Metropolitan District. Of a total of 608 cats, 23 (3.8%) were found to have Cryptosporidium oocysts. The percentage of cats positive for the infection ranged from 0 to 13.6% by month. The infection was found to be more common in "baby" and "young" cats than in "middle" and "old" ones. No significant difference in incidence was shown between the sexes. In each positive cat, no apparent clinical symptom such as diarrhea was found, and the size of the oocysts measured from 4.3 to 4.7 microns in diameter (small type).
Neospora caninum is a recently recognized protozoan parasite of animals, which until 1988 was misidentified as Toxoplasma gondii. Its life cycle is unknown. Transplacental transmission is the only recognized mode of transmission. It has a wide host range, but its zoonotic potential is unknown. Neosporosis is a major cause of abortion in cattle in many countries. It is also an important cause of neuromuscular paralysis in dogs. This paper reviews information on parasite structure, life cycle, biology, clinical signs, diagnosis, treatment and control.
The infectivity of three Cryptosporidium parvum isolates (Iowa [calf], UCP [calf], and TAMU [horse]) of the C genotype was investigated in healthy adults. After exposure,
volunteers recorded the number and form of stools passed and symptoms experienced. Oocyst excretion was assessed by immunofluorescence.
The ID50 differed among isolates: Iowa, 87 (SE, 19; 95% confidence interval [CI], 48.67–126); UCP, 1042 (SE, 1000; 95% CI, 0–3004);
and TAMU, 9 oocysts (SE, 2.34; 95% CI, 4.46–13.65); TAMU versus Iowa, P = .002 or UCP, P = .019. Isolates also differed significantly (P = .045) in attack rate between TAMU (86%) and Iowa (52%) or UCP (59%). A trend toward a longer duration of diarrhea was seen
for the TAMU (94.5 h) versus UCP (81.6 h) and Iowa (64.2 h) isolates. C. parvum isolates of the C genotype differ in their infectivity for humans.
The phylogenetic placement of gregarine parasites (Apicomplexa: Gregarinasina) within the Apicomplexa was derived by comparison of small-subunit ribosomal RNA gene sequences. Gregarine sequences were obtained from Gregarina niphandrodes Clopton, Percival, and Janovy, 1991, and Monocystis agilis Stein, 1848 (Eugregarinorida Léger 1900), as well as from Ophriocystis elektroscirrha McLaughlin and Myers, 1970 (Neogregarinorida Grassé 1953). The sequences were aligned with several other gregarine and apicomplexan sequences from GenBank and the resulting data matrix analyzed by parsimony and maximum-likelihood methods. The gregarines form a monophyletic clade that is a sister group to Cryptosporidium spp. The gregarine/ Cryptosporidium clade is separate from the other major apicomplexan clade containing the coccidia, adeleids, piroplasms, and haemosporinids. The trees indicate that the genus Cryptosporidium has a closer phylogenetic affinity with the gregarines than with the coccidia. These results do not support the present classification of the Cryptosporidiidae in the suborder Eimerioirina Léger, 1911.
Genetic and phylogenetic characterization ofCryptosporidium isolates at two loci (18S rRNA gene and heat shock gene) from both Australian and United States dogs demonstrated that dog-derived
Cryptosporidium isolates had a distinct genotype which is conserved across geographic areas. Phylogenetic analysis provided support for the
idea that the “dog” genotype is, in fact, a valid species.
The identification of Cryptosporidium oocysts in environmental samples is largely made by the use of an immunofluorescent assay. In this study, we have used a
small-subunit rRNA-based PCR-restriction fragment length polymorphism technique to identify species and sources of Cryptosporidium oocysts present in 29 storm water samples collected from a stream in New York. A total of 12 genotypes were found in 27 positive
samples; for 4 the species and probable origins were identified by sequence analysis, whereas the rest represent new genotypes
from wildlife. Thus, this technique provides an alternative method for the detection and differentiation of Cryptosporidium parasites in environmental samples.
Recent molecular characterizations of Cryptosporidiumparasites make it possible to differentiate the human-pathogenicCryptosporidium parasites from those that do not infect humans and to track the source of Cryptosporidium oocyst contamination in the environment. In this study, we used a small-subunit rRNA-based PCR-restriction fragment length
polymorphism (RFLP) technique to detect and characterize Cryptosporidiumoocysts in 55 samples of raw surface water collected from several areas in the United States and 49 samples of raw wastewater
collected from Milwaukee, Wis. Cryptosporidium parasites were detected in 25 surface water samples and 12 raw wastewater samples. C. parvum human and bovine genotypes were the dominantCryptosporidium parasites in the surface water samples from sites where there was potential contamination by humans and cattle, whereas C. andersoni was the most common parasite in wastewater. There may be geographic differences in the distribution ofCryptosporidium genotypes in surface water. The PCR-RFLP technique can be a useful alternative method for detection and differentiation of
Cryptosporidium parasites in water.
Cryptosporidium parvum is usually considered the agent of human cryptosporidiosis. However, only in the last few years, molecular biology-based
methods have allowed the identification ofCryptosporidium species and genotypes, and only a few data are available from France. In the present work, we collected samples of whole
feces from 57 patients from France (11 immunocompetent patients, 35 human immunodeficiency virus [HIV]-infected patients,
11 immunocompromised but non-HIV-infected patients) in whomCryptosporidium oocysts were recognized by clinical laboratories. A fragment of the Cryptosporidium 18S rRNA gene encompassing the hypervariable region was amplified by PCR and sequenced. The results revealed that the majority
of the patients were infected with cattle (29 of 57) or human (18 of 57) genotypes ofCryptosporidium parvum. However, a number of immunocompromised patients were infected with C. meleagridis (3 of 57), C. felis (6 of 57), or a new genotype of C. muris (1 of 57). This is the first report of the last three species of Cryptosporidium in humans in France. These results indicate that immunocompromised individuals are susceptible to a wide range ofCryptosporidium species and genotypes.
To determine whether infection with Tritrichomonas foetus causes diarrhea in specific-pathogen-free or Cryptosporidium coinfected cats.
4 cats with subclinical cryptosporidiosis (group 1) and 4 specific-pathogen-free cats (group 2).
Cats were infected orogastrically with an axenic culture of T. foetus isolated from a kitten with diarrhea. Direct microscopy and protozoal culture of feces, fecal character, serial colonic mucosal biopsy specimens, and response to treatment with nitazoxanide (NTZ; group 1) or prednisolone (groups 1 and 2) were assessed.
Infection with T. foetus persisted in all cats for the entire 203-day study and resulted in diarrhea that resolved after 7 weeks. Group-1 cats had an earlier onset, more severe diarrhea, and increased number of trichomonads on direct fecal examination, compared with group-2 cats. Use of NTZ eliminated shedding of T. foetus and Cryptosporidium oocysts, but diarrhea consisting of trichomonad-containing feces recurred when treatment was discontinued. Prednisolone did not have an effect on infection with T. foetus but resulted in reappearance of Cryptosporidium oocysts in the feces of 2 of 4 cats. During necropsy, T. foetus was isolated from contents of the ileum, cecum, and colon. Tritrichomonas foetus organisms and antigen were detected on surface epithelia and within superficial detritus of the cecal and colonic mucosa.
After experimental inoculation in cats, T. foetus organisms colonize the ileum, cecum, and colon, reside in close contact with the epithelium, and are associated with transient diarrhea that is exacerbated by coexisting cryptosporidiosis but not treatment with prednisolone.
An 840-bp fragment of the 18S rRNA gene was used to identify Cryptosporidium spp. recovered from human immunodeficiency virus (HIV)-infected and -uninfected patients from Kenya, Malawi, Brazil, the
United Kingdom, and Vietnam. Initial identification was by Ziehl-Neelsen acid-fast staining. Confirmation was by nested PCR,
targeting the most polymorphic region of the 18S rRNA gene. Genotyping was by restriction endonuclease digestion of the PCR
product followed by nucleotide sequencing. Among 63 isolates analyzed, four genotypes of Cryptosporidium were identified; 75% of the isolates were of the C. parvum human genotype, while the potentially zoonotic species were of the C. parvum bovine genotype (21.7%), the C. meleagridis genotype (1.6% [one isolate]), and the C. muris genotype (1.6% [one case]). HIV-infected individuals were more likely to have zoonotic genotypes than the HIV-uninfected
individuals. Among the C. parvum group, strains clustered distinctly into either human or bovine genotypes regardless of the geographical origin, age, or
HIV status of the patients. The intragenotypic variation observed in the C. parvum human genotype was extensive compared to that within the C. parvum bovine genotype group. The variation within genotypes was conserved in all geographical regions regardless of the patients'
HIV status. The extensive diversity within genotypes at the 18S rRNA gene locus may limit its application to phylogenetic
analyses.
Persistent cryptosporidiosis and lymphocytic duodenitis were documented in an 18-month old Domestic Shorthair cat. Systemic immunosuppression or other concurrent diseases were not documented. Clinical signs of disease, Cryptosporidium parvum oocyst shedding, and lymphocytic duodenitis resolved following the administration of clindamycin hydrochloride and tylosin.
Cryptosporidium parvum is now recognised as being responsible for around 2% of gastroenteritis cases in the immunocompetent population in developed nations, as well as being a significant cause of morbidity in immunocompromised hosts with depressed T-cell function. The resistance of Cryptosporidium oocysts to chlorine-based disinfectants creates particular concerns for drinking water supplies, and numerous outbreaks of cryptosporidiosis have been recorded from both drinking water and recreational water sources in parts of Europe and North America. In Australia, there have been a number of swimming pool-associated outbreaks of cryptosporidiosis, and only one drinking water outbreak from a small private water supply has been documented. Two genotypes of Cryptosporidium parvum have been identified as the major cause of infections in immunocompetent humans. Genotype 1 (or H), appears to infect humans specifically, whereas genotype 2 (or C) may infect humans and a range of other mammals (including cattle, sheep and goats). Species other than C. parvum have been reported to be responsible for up to 20% of infections in immunocompromised hosts, and there is emerging evidence that such species are also responsible for a minority of infections in the immunocompetent human population. We carried out case-control studies of cryptosporidiosis in Melbourne (with high quality source water treated by chlorination only) and Adelaide (with poor quality source water treated by conventional flocculation, sedimentation, filtration and chlorination). The results indicated that drinking tap water was not a significant risk factor for cryptosporidiosis in either city, but that person-to-person transmission and public swimming pools were the main sources of public health risk. Cryptosporidium isolates from participants in the Adelaide case-control study were characterised genetically using single strand conformation polymorphism analysis of the small subunit gene (pSSU; ~300bp) and second internal transcribed spacer (pITS-2; 230bp) of nuclear ribosomal DNA. Of 26 isolates characterised to date, 15 (58%) were identified as C. parvum genotype 1, 9 (35%) were C. parvum genotype 2 and 2 (7.5%) were C. meleagridis. Neither of the people infected with C. meleagridis had reported any illness or condition affecting the immune system when interviewed for the case-control study. These results support observations from Europe that a small proportion of Cryptosporidium infections in immunocompetent people are caused by species other than C. parvum, in particular C. meleagridis. Acknowledgment: This work was funded by the CRC for Water Quality and Treatment, the Water Services Association of Australia, Melbourne Water Corporation, City West Water Ltd, South East Water Ltd and Yarra Valley Water Ltd.
(C) 2003 Lippincott Williams & Wilkins, Inc.
Modified Ziehl-Neelsen (MZN), auramine-phenol (A-P) and fluorescein isothiocyanate-labelled (FITC-labelled) monoclonal antibody (MAb) techniques were compared for detection of Cryptosporidium parvum oocysts in cat faecal specimens inoculated with known numbers of C. parvum oocysts. Of the three techniques, the FITC-labelled MAb technique detected more oocysts than the MZN and A-P techniques (P < 0.05), but A-P was more efficient than MZN (P < 0.05). Comparison of sucrose flotation, zinc sulphate (ZnSO4) flotation and formol-ether (F-E) sedimentation techniques revealed that F-E was the most efficient of the three (P < 0.05) for concentration of C. parvum oocysts from cat faecal specimens. On average, the F-E technique recovered 37% of oocysts from the original sample, whereas the sucrose and ZnSO4 flotation techniques recovered 33% and 11%, respectively. The findings of this study suggest that MZN and A-P staining are both useful for screening C. parvum oocysts in cat faecal materials containing 10(6) oocysts or more, but FITC-labelled MAb should be used when the number of oocysts is low. Also, the F-E sedimentation technique is recommended for concentrating oocysts in cat faecal specimens.
A clinical and post mortem survey of domestic and feral cats in the Glasgow area revealed that 19 of 235 (8.1 per cent) were infected with Cryptosporidium species. More kittens than adults were infected (P less than 0.01), and of 51 of the cats which had diarrhoea, four also had cryptosporidium infection. Of seven domestic cats with cryptosporidium infection, two were also positive for feline immunodeficiency virus. There was no significant difference between the prevalence of cryptosporidium infection in domestic and feral cats. Cryptosporidium oocysts were detected in faecal and mucosal impression smears stained with auramine-phenol and modified Ziehl-Nielsen techniques. Endogenous developmental stages of cryptosporidium were found in the microvillus region of enterocytes of eight of 19 positive cats in sections stained with haematoxylin and eosin. The results suggest that cryptosporidium infection is common among young and newborn kittens, and that the disease is usually asymptomatic.
A case of intestinal cryptosporidiosis in an eight-year-old boy is presented. The patient became ill during a visit to a farm where diarrhoea in newborn calves is a recurrent problem. Furthermore, on that farm kittens periodically suffer from diarrhoea and failure to thrive. Oocysts of Cryptosporidium sp. were identified in the stool of the patient, and in the stool of the cat he had contact with. At that time the calves were not infected. The patient's gastrointestinal symptomatology consisted of severe diarrhoea, vomiting, colics and moderate dehydration, and was preceded by coughing.
Chronic intestinal cryptosporidiosis was diagnosed as the cause of chronic diarrhea and weight loss in an adult dog without obvious signs of immunosuppression. Results of tests for digestive function suggested that the dog had impaired intestinal absorption or bacterial overgrowth. The nutrient malabsorption might have resulted in or have been caused by the cryptosporidiosis. Temporary clinical improvement without reduction in fecal oocyst concentration was noticed following treatment with clindamycin. The dog was euthanatized. At necropsy, the dog was found to have chronic lymphoplasmacytic enteritis and cryptosporidiosis. A veterinary student that worked in the ward where the dog was kept developed cryptosporidal diarrhea.
Between January 12 and February 7, 1987, an outbreak of gastroenteritis affected an estimated 13,000 people in a county of 64,900 residents in western Georgia. Cryptosporidium oocysts were identified in the stools of 58 of 147 patients with gastroenteritis (39 percent) tested during the outbreak. Studies for bacterial, viral, and other parasitic pathogens failed to implicate any other agent. In a random telephone survey, 299 of 489 household members exposed to the public water supply (61 percent) reported gastrointestinal illness, as compared with 64 of 322 (20 percent) who were not exposed (relative risk, 3.1; 95 percent confidence interval, 2.4 to 3.9). The prevalence of IgG to cryptosporidium was significantly higher among exposed respondents to the survey who had become ill than among nonresident controls. Cryptosporidium oocysts were identified in samples of treated public water with use of a monoclonal-antibody test. Although the sand-filtered and chlorinated water system met all regulatory-agency quality standards, sub-optimal flocculation and filtration probably allowed the parasite to pass into the drinking-water supply. Low-level cryptosporidium infection in cattle in the watershed and a sewage overflow were considered as possible contributors to the contamination of the surface-water supply. We conclude that current standards for the treatment of public water supplies may not prevent the contamination of drinking water by cryptosporidium, with consequent outbreaks of cryptosporidiosis.
A 36-year-old man had chronic, debilitating diarrhea due to cryptosporidiosis. This patient had longstanding common variable hypogammaglobulinemia and recurrent bacterial infections. Immunologic evaluation after discovery of Cryptosporidium showed lymphopenia with persistently reduced numbers of helper/inducer cells (OKT-4), variable numbers of suppressor/cytotoxic cells (OKT-8), OKT-4/OKT-8 ratio of 0.09, and increased levels of serum alpha-interferon, all of which describe the acquired immunodeficiency syndrome. Oocysts of Cryptosporidium were found in feces from the patient's cat, thus identifying a possible source of his infection. The patient had disseminated candidiasis, cytomegalovirus pneumonia, and cryptosporidiosis when he died.
Infection with cryptosporidium occurred in 12 immunocompetent persons who had direct contact with the feces of infected calves during three unrelated outbreaks of calf cryptosporidiosis. Nine of the twelve subjects had diarrhea and abdominal cramps that lasted 1 to 10 days. Infections were diagnosed and monitored by detection of oocysts in feces, with a modified Sheather's flotation technique and phase-contrast microscopy. Oocysts of cryptosporidium were isolated from calves but not from other animals with which these subjects had been in contact. Oocysts of cryptosporidium were also detected during repeated examinations of feces from two immunodeficient patients with persistent cryptosporidiosis. An apparently identical infection was transmitted to calves and mice, using oocysts from infected calves and human beings. Oocysts from an immunodeficient person also produced infections in kittens, puppies, and goats. This study shows that cryptosporidium may produce a moderate self-limited illness in immunocompetent persons, which contrasts sharply with the prolonged severe diarrhea in immunocompromised patients who contract cryptosporidiosis. Calves with diarrhea should be considered a potential source of human infection, and immunocompromised persons should avoid contact with such animals.
Cryptosporidiosis has been reported in calves, lambs, man, pigs, and cats [l-91. In most species, they are associated with diarrhea. Transmission and scanning electron microscopy have demonstrated different stages of cryptosporidia free in the lumen and attached to the microvillus border of the intestinal epithelium [7]. This report describes an intestinal infection by cryptosporidium. A five-year-old male domestic longhair cat with clinical signs of anorexia, weight loss, and persistent diarrhea for 2% months was admitted for treatment. Clinical laboratory findings revealed packed cell volume 37.0%, serum alanine aminotransferase 47.7 IU/L, alkaline phosphatase 1.15 IU/L, serum aspartate aminotransferase 16.8 IU/L, lipase 0.93 U/ml, amylase 332 IU/L, and creatinine 1.3 mg/dl. The feline leukemia virus fluorescent antibody test on blood was negative. Examination of a Giemsa-stained blood smear did not reveal Haemobartonella organisms. Fecal flotation and direct microscopic examination of feces were negative for ova or parasites, and aerobic bacterial culture of a fecal sample was negative for known bacterial pathogens. The cat did not respond to treatment with Aziomycin (Schering Corporation, Kenilworth, N.J.), B- 12, B-plex, fluids, and lincocin. Exploratory surgery revealed enlarged mesenteric lymph nodes, dilatation, and marked thickening of the small intestine and cecum. The cat was euthanatized and necropsied immediately. Specimens for light microscopy were fixed in buffered neutral 10% formalin, sectioned at 6 pm, and stained with hematoxylin and eosin (HE). For transmission electron microscopy, appropriate tissue sections in paraffin blocks were deparaffinized, soaked in xylene, and rehydrated by passing through descending concentrations of alcohol. The tissues were transferred to phosphate buffer and fixed finally in osmium tetroxide and embedded in epon. Ultrathin sections were cut and stained with uranyl acetate and lead citrate and examined and photographed with an electron microscope. Grossly, the mesenteric portion of the small intestine and cecum were dilated and thickened markedly. Mesenteric lymph nodes were enlarged. The abdominal cavity contained 20 to 30 ml of clear fluid and the liver was yellow and fatty. Histologically, the small intestinal lesions consisted of the fusion of villi, an increased number of goblet cells, and hyperplastic crypt epithelium with a few dilated cystic crypts containing necrotic cell debris (fig. 1). The lamina propria was infiltrated mildly with lymphocytes and neutrophils. Numerous round or ovoid organisms ranging from 1 to 3 pm in diameter were found free in the lumen and attached to the microvillus border of the villous epithelium and luminal epithelium of crypts (fig. 2). These organisms were concentrated more in crypts and the lower half of the villi. They scarcely were seen on the villous tips. The lesions in the cecum were limited to crypts and consisted of several dilated cystic crypts; the lumens of which contained mucus and necrotic cell debris. Few organisms were found attached to crypt epithelium. The hepatic lesions were primarily a mild diffuse fatty metamorphosis and bile stasis.
Cryptosporidium oocysts were found in the feces of a 6-month-old female cat with persistent diarrhea. The oocysts disappeared from the feces immediately after treatment with paromomycin (165 mg/kg of body weight, PO, for 5 days), and the diarrhea eventually resolved.
Sera from 258 healthy and sick domestic and feral cats were screened for specific anti-Cryptosporidium antibodies using an indirect immunofluorescence antibody test (IFA). Sera were positive for IgG, IgM and IgA antibodies in 192 (74%), 84 (32%) and 67 (26%) samples, respectively. Antibody was not detected at dilutions of 1:10 and 1:20 or greater in any of eight specific pathogen-free kittens. IgM and IgA antibody classes were more prevalent in sick than in healthy domestic cats. The presence of IgM and/or IgA antibodies indicated early infection. However, these antibody classes were present in sera from cats either positive or negative for Cryptosporidium infection by faecal examination. Pronounced polar fluorescence was observed in the sporozoites in positive samples under fluorescence microscopy. The higher prevalence of specific anti-Cryptosporidium antibodies and the absence of Cryptosporidium oocysts in faecal samples from some IFA-positive animals suggests that detection of these antibodies in sera from cats could be helpful for the diagnosis of feline cryptosporidiosis.
Two neonatal lambs were inoculated orally with purified Cryptosporidium species oocysts isolated from a farm cat. Oocysts first appeared in the faeces of the two lambs three and 10 days after infection. Two distinct sizes of oocysts were observed in the faeces of both the cat and the lambs, the smaller measuring approximately 5.0 x 4.5 microns and the larger measuring approximately 6.0 x 5.0 microns in diameter. The smaller type predominated. Histological examination of the alimentary tract of the lambs revealed endogenous stages of Cryptosporidium in the epithelial borders of the ileum. In addition, Cryptosporidium oocysts were detected in impression smears from the jejunum, ileum, caecum and colon. Suspensions of 10(3) oocysts from the faeces of the farm cat were inoculated into each of 10 newborn mice and 10(4) oocysts from the two experimentally infected lambs were inoculated into each of 20 newborn mice. Cryptosporidium oocysts were detected in gut homogenates from 19 of the 20 mice inoculated with oocysts from the lambs but in none of the mice inoculated with oocysts from the cat.
Faecal samples from 81 dogs aged between 2 months and 13 years were collected in the small animal clinic (37 domestic dogs) and the animal shelter (44 stray dogs) located in the Faculty of Veterinary Sciences in Zaragoza city (northeast Spain) and screened for the presence of Cryptosporidium oocysts. Faeces were concentrated by the formalin-ethyl acetate method and smears of the sediment were stained by using the modified Ziehl-Neelsen technique. Cryptosporidium parvum oocysts were detected in six dogs (7.4%) aged from 2 months to 6 years. Infection was detected in both domestic (three) and stray (three) dogs and all of them excreted few oocysts (0-1 oocyst per 20 x field). No statistically significant differences in prevalence occurred between dogs younger than 6 months (11.8%) and the older dogs (6.2%). Prevalences were not significantly different between domestic (8.1%) and stray dogs (6.8%). Diarrhoea was recorded in three of the positive dogs (50%), although additional enteric parasites such as oocysts of Isospora spp. were also detected in their faeces. Nevertheless, prevalence was significantly higher in diarrhoeic (30%) versus non-diarrhoeic (4.2%) dogs (P < 0.05). Cryptosporidium was one of the parasites most frequently detected in the dogs surveyed.
Fecal samples were collected from 257 dogs in four areas in Korea during the period of January 1996 to November 1997 and examined by immunofluorescence assay for Cryptosporidium oocysts using a commercial diagnostic kit (Meridian Diagnostics, Cincinnati, Ohio). Of the 257 samples, 25 (9.7%) were positive for Cryptosporidium. Differences were noted in the prevalence of canine cryptosporidiosis in both areas and dog types. The results provide a further evidence of environmental contamination and widespread distribution of the parasite in Korea.
Faecal samples were collected from domestic cats in the metropolitan area of the city of Perth, Western Australia, and screened for the presence of Cryptosporidium by both microscopy and PCR. Of 162 samples screened, two were positive for Cryptosporidium (a prevalence of 1.2%). Sample Ct33 was from an 18-month-old female and sample Ct131 from a 12-month-old female. Morphological studies revealed oocysts with an average size of 4.6 x 4.0 microm, smaller in size than isolates typically seen in humans (5.0 x 4.5 microm). Sequence analysis of PCR products showed sequences from cat isolates to be different to previously sequenced human and calf isolates, with cat isolates exhibiting 8.1% sequence divergence from these isolates. Phylogenetic analysis grouped the cat isolates into a distinct group, separate from other C. parvum isolates and Cryptosporidium species. These results lend support to the existence of a cat-adapted Cryptosporidium strain or species.
Polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis of the Cryptosporidium parvum outer wall protein (COWP) gene was applied to specimens collected from 95 patients with cryptosporidiosis associated with two suspected waterborne outbreaks, 46 sporadic human cases and 62 infected livestock from other areas, and 12 patients infected with other gastrointestinal parasites. Ninety-six per cent of C. parvum isolates from patients linked to the two suspected waterborne outbreaks were of genotype 1; all the isolates from livestock were of genotype 2. Isolates from 59% of the sporadic human infections were of genotype 1 and 35% were of genotype 2. Specimens from two patients yielded both genotypes. Specimens from patients infected with other parasites yielded no amplicons.
The objective of this study was to determine the regional prevalence of Cryptosporidium parvum-specific IgG in the sera of cats in the United States. The continental United States was partitioned into eight regional areas. Serum samples from 75 cats from each region were assayed for C. parvum-specific IgG using an indirect enzyme-linked immunosorbent assay (ELISA). Age, sex, breed, and indoor/outdoor status were examined as possible risk factors for developing a positive C. parvum-specific IgG antibody titer. The presence of gastro-intestinal signs and Toxoplasma gondii-specific IgG in the serum were also evaluated for association with C. parvum seropositivity. Of the 600 samples assayed, 50 (8.3%) were positive for C. parvum-specific IgG. Regional seroprevalence ranged from 1.3% in the mid-Atlantic states to 14.7% in the south-eastern states. The oldest group of cats (>10 years) had the highest seroprevalence (15.3%). The prevalence of C. parvum-specific IgG was higher among male (10.1%) than among female cats (6.9%), although, the difference was not statistically significant (p = 0.17). Seropositivity was not associated with pure-bred status. C. parvum-specific IgG antibodies was detected most frequently in T. gondii-specific IgG seropositive cats, outdoor cats, and cats with gastro-intestinal signs. These results suggest that cats in the United States are commonly exposed to C. parvum.
A study was conducted to determine the prevalence of gastrointestinal parasites in a sample of urban dogs in Perth and the knowledge of their owners about the control and zoonotic transmission of these parasites. Faecal samples (421), collected from dogs originating from five sources, were examined by microscopy and questionnaires administered to dog owners and managers/owners of pet shops. The prevalence of gastrointestinal parasitism was higher in pet shop puppies (51%), than in dogs from refuges (37%), breeding kennels (32.7%), veterinary clinics (15.6%) and exercise areas (5.3%). Protozoa, in particular Giardia, were detected more frequently (22.1%) than helminth parasites. After adjusting for other factors with multiple logistic regression, puppies less than 6 months of age, dogs living in households with more than one dog, and dogs from refuges were significantly more likely to be parasitized. The prevalence of Giardia was found to be directly associated with the number of doses of anthelmintics given in a year, increasing 1.2 times for each dose administered. The majority of owners were aware of the potential risk to human health from canine helminths, however only one third were aware of the means of transmission to humans. It is concluded that veterinarians can play an important role in increasing the level of awareness of canine zoonotic parasites.
An eight-week-old puppy with chronic diarrhea was diagnosed with simultaneous opportunistic pathogens (i.e., cryptosporidiosis, coccidiosis) and total colonic mucosal collapse. Lack of lymphoid follicles in the spleen and lymph nodes suggested a primary underlying immunosuppression that most likely permitted infection with these pathogens. Intensive antibiotic therapy was most likely responsible for the severe colonic lesion, and bismuth subsalicylate administration in this severely dehydrated puppy may have contributed to renal failure as the ultimate cause of death.
Isolates of Cryptosporidium were characterized using nucleotide sequence analysis of the 18S rRNA and dihydrofolate reductase genes and also random-amplified polymorphic DNA analysis. Phylogenetic analysis confirmed the validity of the species of Cryptosporidium examined in this study such as Cryptospordium muris and Cryptosporidium baileyi, and also reinforced evidence from numerous researchers worldwide suggesting that Cryptosporidium parvum is not a single uniform species. The data obtained provided strong support for the validity of Cryptosporidium felis. Evidence suggests that the newly identified marsupial and pig genotypes may also be distinct and valid species, but biological studies are required for confirmation.
To determine prevalence of enteric zoonotic organisms in cats in north-central Colorado.
Prospective study.
Serum and fecal samples from 87 cats with diarrhea, 106 cats without diarrhea, and 12 cats for which fecal consistency was unknown.
Samples were obtained from client-owned cats and cats at a humane society shelter. Serum was assayed for feline leukemia virus antigen and antibodies against feline immunodeficiency virus, IgM antibodies against Toxoplasma gondii, and IgG antibodies against T gondii and Cryptosporidium parvum. Microscopic examination of unstained feces was performed after centrifugation in a zinc sulfate solution, thin fecal smears were stained with acid fast stain and examined for C parvum, and bacteriologic culture of feces was used to detect aerobic and anaerobic bacteria.
Enteric zoonotic organisms were detected in feces from 27 of 206 (13.1%) cats and included C parvum (5.4%), Giardia spp (2.4%). Toxocara cati (3.9%), Salmonella enterica serotype Typhimurium (1.0%), and Campylobacter jejuni (1.0%); each organism was detected in samples from cats with and without diarrhea. Although differences between groups were not significant, a higher proportion of shelter cats (18.2%) had enteric zoonotic organisms than client-owned cats (10.1%).
Enteric zoonotic organisms were detected in feces of 13.1% of cats, suggesting that cats, particularly those in homes of immunocompromised humans, should be evaluated for enteric zoonotic organisms.
Cryptosporidium parvum is usually considered to be the pathogen responsible for human cryptosporidiosis. We genotyped Cryptosporidium in 132 stool specimens from 80 Peruvian children, representing 85 infection episodes, using techniques that differentiate
Cryptosporidium species and C. parvum genotypes. Five types of Cryptosporidium were identified: C. parvum human (67), bovine (8), and dog (2) genotypes, C. meleagridis (7), and C. felis (1). Twenty-five (29%) of the 85 infection episodes were associated with diarrhea. There was no significant difference in
age, antecedent stunting, percentage with diarrhea, or duration of diarrhea for episodes with human genotype, compared with
those of zoonotic Cryptosporidium. Duration of oocyst shedding was longer for human genotype than for zoonotic Cryptosporidium (mean, 13.9 days and 6.4 days, respectively; P = .004). Serum samples from 8 children with C. meleagridis, C. felis, or C. parvum dog genotype were tested for anti—human immunodeficiency virus (HIV) type 1 antibodies; all were found to be negative. Contrary
to common belief, novel Cryptosporidium species and C. parvum genotypes can infect HIV-negative children.
Cryptosporidium parvum, an intestinal coccidian parasite, was isolated from faeces and intestinal biopsies of a 9-week-old puppy with acute parvoviral gastroenteritis. Gene sequence analysis identified a Cryptosporidium genotype not previously recorded in Australia. The puppy recovered after treatment with crystalloid fluids, synthetic and natural colloids and jejunostomy tube feeding.
To investigate the incidence and genotype of Cryptosporidium parvum oocysts in drinking water sources in Northern Ireland for the period 1996-1999, and to compare conventional and molecular methods of detection.
Four hundred and seventy-four waters were investigated by conventional methods, namely immuno-fluorescent antibody detection (IFA; 380) and immuno-magnetic separation-IFA (IMS-IFA; 94), of which 14/474 (3%) were positive. Two hundred and fourteen samples (214/474) were also investigated by PCR techniques, targeting both the 18S rRNA and TRAP-C2 genes, of which 11/214 (5.1%) were positive. These 11 samples were classified as genotype II following sequence analysis of the TRAP-C2 amplicon.
This study demonstrated the low incidence of oocysts of C. parvum in water sources in Northern Ireland.
Such molecular-based techniques offer a number of advantages over conventional detection methodologies, namely greater sensitivity and specificity as well as the ability to provide accurate genotyping data rapidly, which may be valuable in directing operational management in potential outbreak situations.
Oocysts of Cryptosporidium, from the feces of a naturally infected dog and from an HIV-infected human, were identified as the previously reported canine genotype of Cryptosporidium parvum, hereafter referred to as Cryptosporidium canis n. sp. Also among the oocysts from the dog, a trace amount of C. parvum bovine genotype was detected. Cryptosporidium canis oocysts from both the dog and human were infectious for calves. Oocysts excreted by calf 1 (dog source) were approximately 90% C. canis and 10% C. parvum, whereas those excreted by calf 3 (human source) were 100% C. canis. Oocysts from calf 1 infected calf 2 resulting in excretion by calf 2 of oocysts approximately 90% C. parvum and 10% C. canis. Oocysts of C. canis were not infectious for BALB/c neonatal mice or immunosuppressed C57 juvenile mice, although all control mice became infected with the C. parvum Beltsville isolate. Oocysts of C. canis from calf 1 and the human were structurally indistinguishable from oocysts of the C. parvum Beltsville isolate (bovine). However, C. canis oocysts differed markedly at the molecular level from all known species of Cryptosporidium based on sequence data for the 18S rDNA and the HSP 70 gene. The differences in genetics and host specificity clearly differentiate C. canis as a new species.
Cryptosporidium parvum is the most common of the protozoal pathogens associated with gastrointestinal disease in Northern Ireland. Genotyping techniques are valuable in helping to elucidate sources and modes of transmission of this parasite. There have been no reports on the prevalence of genotypes in Northern Ireland, mainly due to a lack of discriminatory genotyping techniques, which recently have become available.
To investigate the genotype of C. parvum oocysts isolated from human faeces in sporadic cases of cryptosporidiosis in Northern Ireland.
Thirty-nine isolates of C. parvum, representing 79.6% of the total 1998 laboratory reports for the Eastern Health and Social Services Board, were investigated. Following DNA extraction from oocysts the thrombospondin-related adhesive protein 2 (TRAP-C2) locus was amplified by polymerase chain reaction (PCR) and subsequently sequenced.
The majority of isolates (87.2%) were classified as bovine genotype II with the remainder (12.8%) being the human genotype I.
There is a high prevalence of the bovine genotype II parasite in sporadic cases around the greater Belfast area. Epidemiologically, this suggests that the most frequent mode of transmission may be from animals to humans, but does not suggest a high proportion of human to human spread.
Cryptosporidiosis is a coccidian parasitism which has been implicated as a cause of diarrhea in man and a variety of animals. Cryptosporidiosis was diagnosed in a one-week-old pup which had a history of acute diarrhea. Organisms, 2 to 3 mm in diameter, covered the microvillous border of intestinal epithelium. Ultrastructurally, the cryptosporidia had one or more nuclei with prominent nucleoli and abundant cytoplasmic endoplasmic reticulum. Cryptosporidia may have played a role in the enteritis seen in this pup but further studies are needed to establish its pathogenicity.
Ninety-five years after discovery and after more than two decades of intense investigations, cryptosporidiosis, in many ways, remains enigmatic. Cryptosporidium infects all four classes of vertebrates and most likely all mammalian species. The speciation of the genus continues to be a challenge to taxonomists, compounded by many factors, including current technical difficulties and the apparent lack of host specificity by most, but not all, isolates and species. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.
Cryptosporidium parvum is a zoonotic pathogen composed of genetically distinct but morphologically identical genotypes. Recent molecular study indicates that dogs may transmit the cattle genotype, which is known to be pathogenic to humans. Although large-scale studies of Cryptosporidium infection in dogs have been performed in several countries, the isolates were not accurately identified because of the lack of a method for molecular analysis. It is important to identify the isolates harbored in dogs, which come in close contact with humans, in order to control human cryptosporidiosis. The aim of the present study was to calculate the prevalence of Cryptosporidium infection in dogs in Osaka city, Japan, and to characterize the isolates molecularly. The prevalence was determined to be 9.3% (13/140) by PCR. All isolates were found to be Cryptosporidium canis (previously known as the dog genotype), which is thought to be non-pathogenic in humans, based on the sequencing of diagnostic fragments. These results indicate that PCR-based diagnostic methods are a useful tool for the diagnosis and molecular epidemiology of Cryptosporidium infection in dogs, and that dogs living in Osaka are not a significant reservoir for human cryptosporidiosis. It is unclear why C. canis is dominant in dogs. Further study is required to understand this partial parasitism.
The structure and infectivity of the oocysts of a new species of Cryptosporidium from the feces of humans are described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum. Oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). Oocysts were not infectious for ARC Swiss mice, nude mice. Wistar rat pups, puppies, kittens or calves, but were infectious to neonatal gnotobiotic pigs. Pathogenicity studies in the gnotobiotic pig model revealed significant differences in parasite-associated lesion distribution (P = 0.005 to P = 0.02) and intensity of infection (P = 0.04) between C. parvum and this newly described species from humans. In vitro cultivation studies have also revealed growth differences between the two species. Multi-locus analysis of numerous unlinked loci, including a preliminary sequence scan of the entire genome demonstrated this species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further support for its species status. Based on biological and molecular data, this Cryptosporidium infecting the intestine of humans is proposed to be a new species Cryptosporidium hominis n. sp.
The epidemiology of chronic diarrhoea in adults with late-stage HIV infection was investigated in a prospective study in Bangkok, Thailand. During this investigation, 34 Cryptosporidium isolates were obtained from the faeces of 36 patients, with mean CD4(+) counts of only 14 x 10(6) CD4(+) cells/litre (range = 2 x 10(6) - 53 x 10(6)/litre), who had symptomatic cryptosporidiosis. Genotyping of these isolates, by RFLP analysis and DNA sequencing of the hypervariable region of the 18S rRNA gene, indicated that only 17 (50%) were of the C. parvum human genotype. The rest were of C. meleagridis (seven), the C. parvum 'bovine' genotype (five), C. felis (three) and C. canis (two). Extensive genotypic heterogeneity was observed among the C. parvum isolates, and two other isolates, one of C. meleagridis and the other of C. felis, produced atypical restriction patterns and were only identified by sequencing. This appears to represent the first report of C. canis and the 'bovine' genotype of C. parvum in HIV-infected Thai patients.