Publications (186)

  • Source
    Full-text available · Article · Oct 2016 · Folia parasitologica
  • Radka Pecková · Peter D. Stuart · Bohumil Sak · [...] · Ivona Foitová
    [Show abstract] [Hide abstract] ABSTRACT: Excystation of sporozoites of Cryptosporidium parvum from oocysts is essential for successful in vitro assays. It has also been traditionally used as a measure for oocyst viability and infectivity. Laboratories use various excystation protocols so there is a need to clarify which method is the best. In this study, six different protocols for in vitro excystation of C. parvum oocysts were compared to find the most efficient excystation method (expressed as percentage excystation). Tested protocols differed in chemical pre-incubation steps, excystation media or time of incubation.
    Article · Oct 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Cryptosporidium is an opportunistic protozoan parasite that can cause severe diarrhoea in immunocompromised patients. The transmission of this pathogen in humans and animals is not fully understood. C. meleagridis, originally described in birds, is the only Cryptosporidium species known to naturally infect mammalian and avian species. This study documents the first detection of C. meleagridis in an HIV-infected woman in Poland.
    Article · Oct 2016
  • [Show abstract] [Hide abstract] ABSTRACT: This study describes cryptosporidiosis in an overwintering group of 15 European hedgehogs (Erinaceus europaeus), comprising 3 adults and 12 juveniles. Four juvenile hedgehogs were hospitalised with anorexia, malodorous diarrhoea and dehydration. Immediate parasitological examinations revealed the presence of Cryptosporidium sp. in these animals and also in 5 other juveniles. All hedgehogs were coproscopically monitored for 4 months over the winter season. Shedding of Cryptosporidium oocysts persisted from 6 to 70 days. Repeated shedding of Cryptosporidium oocysts occurred in 3 animals after 4 months subsequent to the first outbreak. Clinical signs were observed only at the beginning of the outbreak (apathy, anorexia, general weakness, mild dehydration, and malodorous faeces with changed consistence - soft/diarrhoea) in the 4 hospitalised juveniles. Overall 11 hedgehogs were Cryptosporidium-positive, both microscopically and by PCR methods. Sequence analyses of SSU rRNA and gp60 genes revealed the presence of C. parvum IIdA18G1 subtype in all positive hedgehogs. Moreover, 3 hedgehogs had a mixed infection of the zoonotic C. parvum and C. erinacei XIIaA19R13 subtype. Cryptosporidium infections can be rapidly spread among debilitated animals and the positive hedgehogs released back into the wild can be a source of the infection for individuals weakened after hibernation.
    Article · Jun 2016 · European Journal of Protistology
  • Anna Mynářová · Ivona Foitová · Martin Kváč · [...] · Bohumil Sak
    [Show abstract] [Hide abstract] ABSTRACT: The list of screened samples from positive animals. (DOC)
    File available · Data · Mar 2016
  • Source
    Anna Mynářová · Ivona Foitová · Martin Kváč · [...] · Bohumil Sak
    [Show abstract] [Hide abstract] ABSTRACT: Background: Orangutans are critically endangered primarily due to loss and fragmentation of their natural habitat. This could bring them into closer contact with humans and increase the risk of zoonotic pathogen transmission. Aims: To describe the prevalence and diversity of Cryptosporidium spp., microsporidia and Giardia intestinalis in orangutans at seven sites on Sumatra and Kalimantan, and to evaluate the impact of orangutans' habituation and location on the occurrence of these zoonotic protists. Result: The overall prevalence of parasites in 298 examined animals was 11.1%. The most prevalent microsporidia was Encephalitozoon cuniculi genotype II, found in 21 animals (7.0%). Enterocytozoon bieneusi genotype D (n = 5) and novel genotype Pongo 2 were detected only in six individuals (2.0%). To the best of our knowledge, this is the first report of these parasites in orangutans. Eight animals were positive for Cryptosporidium spp. (2.7%), including C. parvum (n = 2) and C. muris (n = 6). Giardia intestinalis assemblage B, subtype MB6, was identified in a single individual. While no significant differences between the different human contact level groups (p = 0.479-0.670) or between the different islands (p = 0.992) were reported in case of E. bieneusi or E. cuniculi, Cryptosporidium spp. was significantly less frequently detected in wild individuals (p < 2×10-16) and was significantly more prevalent in orangutans on Kalimantan than on Sumatra (p < 2×10-16). Conclusion: Our results revealed that wild orangutans are significantly less frequently infected by Cryptosporidium spp. than captive and semi-wild animals. In addition, this parasite was more frequently detected at localities on Kalimantan. In contrast, we did not detect any significant difference in the prevalence of microsporidia between the studied groups of animals. The sources and transmission modes of infections were not determined, as this would require repeated sampling of individuals, examination of water sources, and sampling of humans and animals sharing the habitat with orangutans.
    Full-text available · Article · Mar 2016 · PLoS ONE
  • Source
    A Pelin · H Moteshareie · B Sak · [...] · N Corradi
    [Show abstract] [Hide abstract] ABSTRACT: Encephalitozoon cuniculi is a model microsporidian species with a mononucleate nucleus and a genome that has been extensively studied. To date, analyses of genome diversity have revealed the existence of four genotypes in E. cuniculi (EcI, II, III and IV). Genome sequences are available for EcI, II and III, and are all very divergent, possibly diploid and genetically homogeneous. The mechanisms that cause low genetic diversity in E. cuniculi (for example, selfing, inbreeding or a combination of both), as well as the degree of genetic variation in their natural populations, have been hard to assess because genome data have been so far gathered from laboratory-propagated strains. In this study, we aim to tackle this issue by analyzing the complete genome sequence of a natural strain of E. cuniculi isolated in 2013 from a steppe lemming. The strain belongs to the EcIII genotype and has been designated EcIII-L. The EcIII-L genome sequence harbors genomic features intermediate to known genomes of II and III lab strains, and we provide primers that differentiate the three E. cuniculi genotypes using a single PCR. Surprisingly, the EcIII-L genome is also highly homogeneous, harbors signatures of heterozygosity and also one strain-specific single-nucleotide polymorphism (SNP) that introduces a stop codon in a key meiosis gene, Spo11. Functional analyses using a heterologous system demonstrate that this SNP leads to a deficient meiosis in a model fungus. This indicates that EcIII-L meiotic machinery may be presently broken. Overall, our findings reveal previously unsuspected genome diversity in E. cuniculi, some of which appears to affect genes of primary importance for the biology of this pathogen.Heredity advance online publication, 3 February 2016; doi:10.1038/hdy.2016.4.
    Full-text available · Article · Mar 2016 · Heredity
  • Source
    Nikola Holubová · Bohumil Sak · Michaela Horčičková · [...] · Martin Kváč
    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text available · Article · Feb 2016 · Parasitology Research
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Transplant recipients have been identified as a new risk group for microsporidia infection. We characterize for the first time the prevalence of microsporidia in intestinal and urinary tracts of renal transplant recipients. Molecular examination of eighty-six patients showed 25.5 % of them were infected, 86 % were confirmed to have pathogens in their urine and 45.5 % in stool. Among positive patients 32 % had microsporidia confirmed in both urine and stool. Genotyping revealed Encephalitozoon cuniculi (59 %) and Enterocytozoon bieneusi (23 %) monoinfections as well as co-infections with both species (18 %). Moreover, we found diarrhea and fever as symptoms significantly associated with microsporidia presence. Our results indicate that microsporidial infection should be considered in diagnostics of renal transplant patients, especially in the urinary tract, even if asymptomatic. Molecular identification of microsporidia species is relevant due to their different susceptibility for treatment.
    Full-text available · Article · Jan 2016 · Clinical Microbiology and Infection
  • Source
    Michaela Kotkova · Karel Nemejc · Bohumil Sak · [...] · Martin Kvac
    [Show abstract] [Hide abstract] ABSTRACT: A total of 269 faecal samples of various game animals, including 136 red deer (Cervus elaphus Linnaeus), 64 European fallow deer (Dama dama [Linnaeus]), 26 white-tailed deer (Odocoileus virginianus [Zimmermann]), and 43 mouflon sheep (Ovis orientalis musimon Pallas) were collected at 15 game preserves across the Czech Republic and examined for infection with species of Cryptosporidium Tyzzer, 1910 using microscopy (following aniline-carbol-methyl violet staining) and molecular tools. Oocysts of Cryptosporidium spp. were detected in one faecal sample originating from red deer. Ten positive cases of infection with cryptosporidia, including the case that was positive by microscopy, were detected using nested PCR. No associations between infection with cryptosporidia and diarrhoea were detected. Phylogenetic analyses based on the small subunit of the rRNA gene revealed the presence of three Cryptosporidium species/genotypes in ten positive samples: Cryptosporidium ubiquitum Fayer, Santín et Macarisin, 2010 was identified in five red deer, C. muris Tyzzer, 1907 in three samples (from a red deer, white-tailed deer and mouflon sheep), and Cryptosporidium deer genotype in two white-tailed deer. Subtyping of isolates of C. ubiquitum based on sequence analysis of the 60-kDa glycoprotein gene revealed that they belong to the XIId family. Finding C. muris and C. ubiquitum XIId for the first time in various wild cervids and caprines broadens their host range.
    Full-text available · Article · Jan 2016 · Folia parasitologica
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The morphological, biological, and molecular characteristics of Cryptosporidium muris strain TS03 are described, and the species name Cryptosporidium proliferans n. sp. is proposed. Cryptosporidium proliferans obtained from a naturally infected East African mole rat (Tachyoryctes splendens) in Kenya was propagated under laboratory conditions in rodents (SCID mice and southern multimammate mice, Mastomys coucha) and used in experiments to examine oocyst morphology and transmission. DNA from the propagated C. proliferans isolate, and C. proliferans DNA isolated from the feces of an African buffalo (Syncerus caffer) in Central African Republic, a donkey (Equus africanus) in Algeria, and a domestic horse (Equus caballus) in the Czech Republic were used for phylogenetic analyses. Oocysts of C. proliferans are morphologically distinguishable from C. parvum and C. muris HZ206, measuring 6.8-8.8 (mean = 7.7 μm) × 4.8-6.2 μm (mean = 5.3) with a length to width ratio of 1.48 (n = 100). Experimental studies using an isolate originated from T. splendens have shown that the course of C. proliferans infection in rodent hosts differs from that of C. muris and C. andersoni. The prepatent period of 18-21 days post infection (DPI) for C. proliferans in southern multimammate mice (Mastomys coucha) was similar to that of C. andersoni and longer than the 6-8 DPI prepatent period for C. muris RN66 and HZ206 in the same host. Histopatologicaly, stomach glands of southern multimammate mice infected with C. proliferans were markedly dilated and filled with necrotic material, mucus, and numerous Cryptosporidium developmental stages. Epithelial cells of infected glands were atrophic, exhibited cuboidal or squamous metaplasia, and significantly proliferated into the lumen of the stomach, forming papillary structures. The epithelial height and stomach weight were six-fold greater than in non-infected controls. Phylogenetic analyses based on small subunit rRNA, Cryptosporidium oocyst wall protein, thrombospondin-related adhesive protein of Cryptosporidium-1, heat shock protein 70, actin, heat shock protein 90 (MS2), MS1, MS3, and M16 gene sequences revealed that C. proliferans is genetically distinct from C. muris and other previously described Cryptosporidium species.
    Full-text available · Article · Jan 2016 · PLoS ONE
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Within the microsporidian genus Encephalitozoon, three species, Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis have been described. Several orders of the Class Aves (Passeriformes, Psittaciformes, Apodiformes, Ciconiiformis, Gruiformes, Columbiformes, Suliformes, Podicipediformes, Anseriformes, Struthioniformes, Falconiformes) and of the Class Mammalia (Rodentia, Lagomorpha, Primates, Artyodactyla, Soricomorpha, Chiroptera, Carnivora) can become infected. Especially E. cuniculi has a very broad host range while E. hellem is mainly distributed amongst birds. E. intestinalis has so far been detected only sporadically in wild animals. Although genotyping allows the identification of strains with a certain host preference, recent studies have demonstrated that they have no strict host specificity. Accordingly, humans can become infected with any of the four strains of E. cuniculi as well as with E. hellem or E. intestinalis, the latter being the most common. Especially, but not exclusively, immunocompromised people are at risk. Environmental contamination with as well as direct transmission of Encephalitozoon is therefore highly relevant for public health. Moreover, endangered species might be threatened by the spread of pathogens into their habitats. In captivity, clinically overt and often fatal disease seems to occur frequently. In conclusion, Encephalitozoon appears to be common in wild warm-blooded animals and these hosts may present important reservoirs for environmental contamination and maintenance of the pathogens. Similar to domestic animals, asymptomatic infections seem to occur frequently but in captive wild animals severe disease has also been reported. Detailed investigations into the epidemiology and clinical relevance of these microsporidia will permit a full appraisal of their role as pathogens.
    Full-text available · Article · Jan 2016 · International Journal for Parasitology: Parasites and Wildlife
  • Source
    Martin Kváč · Vendula Tomanová · Eva Samková · [...] · Bohumil Sak
    [Show abstract] [Hide abstract] ABSTRACT: This study describes the prevalence of Encephalitozoon cuniculi in raw cow's milk and evaluates the effect of different milk pasteurization treatments on E. cuniculi infectivity for severe combined immunodeficient (SCID) mice. Using a nested polymerase chain reaction approach, 1 of 50 milking cows was found to repeatedly shed E. cuniculi in its feces and milk. Under experimental conditions, E. cuniculi spores in milk remained infective for SCID mice following pasteurization treatments at 72°C for 15 s or 85°C for 5 s. Based on these findings, pasteurized cow's milk should be considered a potential source of E. cuniculi infection in humans.
    Full-text available · Article · Dec 2015 · Foodborne Pathogens and Disease
  • Source
    Pavla Wagnerová · Bohumil Sak · John McEvoy · [...] · Martin Kváč
    [Show abstract] [Hide abstract] ABSTRACT: The prevalence of Cryptosporidium and microsporidia in feral horses, which have minimal contact with livestock and humans, is not currently known. We report the findings of a study on Cryptosporidium and microsporidia in 34 Mustangs and 50 Chincoteague ponies in the USA. Fecal samples were screened for presence of Cryptosporidium spp. by analysis of the small-subunit rRNA (SSU) and 60-kDa glycoprotein (gp60) genes, and Enterocytozoon bieneusi and Encephalitozoon spp. by analysis of the ribosomal internal transcribed spacer region (ITS). Cryptosporidium spp. and E. bieneusi were detected in in 28/84 (33.3%) and 7/84 (8.3%) samples, respectively. Sequence analysis of SSU and ITS revealed the presence of C. parvum (n=20) and E. bieneusi genotype horse 1 (n=7), respectively. Subtyping of C. parvum isolates at the gp60 locus showed the presence of subtype IIaA17G2R1 in Mustangs and subtypes IIaA13G2R1 and IIaA15G2R1 in Chincoteague ponies. Enterocytozoon bieneusi genotype horse 1 was detected in Mustangs (n=2) and Chincoteague ponies (n=5). No Cryptosporidium or E. bieneusi positive animals had diarrhea. The finding that Mustangs and Chincoteague ponies are host to the zoonotic pathogen C. parvum suggests that their infrequent contact with humans and livestock is sufficient to maintain transmission; however, we should also consider the possibility that C. parvum is an established parasite of Mustangs and Chincoteague ponies that persists in these animals independently of contact with humans or livestock.
    Full-text available · Article · Dec 2015 · Experimental Parasitology
  • [Show abstract] [Hide abstract] ABSTRACT: Diversity of Enterocytozoon bieneusi genotypes in wild small rodent populations still remains incomplete and only few molecular studies have been conducted among these hosts. Therefore, the aim of this study was to determine whether small rodents, i.e., Apodemus agrarius, Apodemus flavicollis, Mus musculus and Myodes glareolus act as hosts of E. bieneusi and can play an important role in spore spreading in the environment of south-western Poland. Molecular analyses were conducted to determine pathogen genotypes. A total of 191 fecal and 251 spleen samples collected from 311 rodent individuals were examined for the occurrence of E. bieneusi by PCR amplifying ITS gene. The overall prevalence of E. bieneusi in rodent samples was 38.9%. The nucleotide sequences of ITS region of E. bieneusi revealed the presence a total of 12 genotypes with two being already known, i.e., D and gorilla 1 genotypes. The remaining ten are novel genotypes (WR1-WR10) which segregated into three groups in a neighbor joining phylogeny. This study reports for the first time E. bieneusi occurrence in wild living rodents in Poland and shows extensive genetic diversity within E. bieneusi isolates of rodent origin.
    Article · Nov 2015 · Veterinary Parasitology
  • Source
    Martin Kváč · Anna Hořická · Bohumil Sak · [...] · John McEvoy
    [Show abstract] [Hide abstract] ABSTRACT: Bats from the families Rhinolophidae (n = 90) and Vespertilionidae (n = 191) in the USA and Czech Republic were screened for the presence of Cryptosporidium by microscopic and molecular analysis of faecal samples collected from rectum of dissected animals and from the ground beneath roosting sites. Cryptosporidium oocysts were not detected in any of the 281 faecal specimens examined using the aniline-carbol-methyl violet staining method. Nested PCR amplification, sequencing and phylogenetic analysis of the small ribosomal subunit rRNA and actin genes were used to identify isolates and infer evolutionary relationships. Cryptosporidium parvum was identified in a western small-footed bat (Myotis ciliolabrum) from the USA and a common pipistrelle bats (Pipistrellus pipistrellus) from the Czech Republic. Two novel genotypes were identified and named Cryptosporidium bat genotype III and IV. Bat genotype III was found in two big brown bats (Eptesicus fuscus) from the USA. Bat genotype IV was detected in two common pipistrelle bats from the Czech Republic.
    Full-text available · Article · Aug 2015 · Parasitology Research
  • M. Kvac · A. Horicka · B. Sak · [...] · J. McEvoy
    File available · Data · May 2015
  • M. Kvac · A. Horicka · B. Sak · [...] · J. McEvoy
    File available · Data · May 2015
  • M. Kvac · A. Horicka · B. Sak · [...] · J. McEvoy
    File available · Data · May 2015
  • M. Kvac · A. Horicka · B. Sak · [...] · J. McEvoy
    File available · Data · May 2015