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Background: Cryptosporidium spp. are globally distributed parasites that infect epithelial cells in the microvillus border of the gastrointestinal tract of all classes of vertebrates. Cryptosporidium chipmunk genotype I is a common parasite in North American tree squirrels. It was introduced into Europe with eastern gray squirrels and poses an infection risk to native European squirrel species, for which infection is fatal. In this study, the biology and genetic variability of different isolates of chipmunk genotype I were investigated. Methods: The genetic diversity of Cryptosporidium chipmunk genotype I was analyzed by PCR/sequencing of the SSU rRNA, actin, HSP70, COWP, TRAP-C1 and gp60 genes. The biology of chipmunk genotype I, including oocyst size, localization of the life cycle stages and pathology, was examined by light and electron microscopy and histology. Infectivity to Eurasian red squirrels and eastern gray squirrels was verified experimentally. Results: Phylogenic analyses at studied genes revealed that chipmunk genotype I is genetically distinct from other Cryptosporidium spp. No detectable infection occurred in chickens and guinea pigs experimentally inoculated with chipmunk genotype I, while in laboratory mice, ferrets, gerbils, Eurasian red squirrels and eastern gray squirrels, oocyst shedding began between 4 and 11 days post infection. While infection in mice, gerbils, ferrets and eastern gray squirrels was asymptomatic or had mild clinical signs, Eurasian red squirrels developed severe cryptosporidiosis that resulted in host death. The rapid onset of clinical signs characterized by severe diarrhea, apathy, loss of appetite and subsequent death of the individual may explain the sporadic occurrence of this Cryptosporidium in field studies and its concurrent spread in the population of native European squirrels. Oocysts obtained from a naturally infected human, the original inoculum, were 5.64 × 5.37 μm and did not differ in size from oocysts obtained from experimentally infected hosts. Cryptosporidium chipmunk genotype I infection was localized exclusively in the cecum and anterior part of the colon. Conclusions: Based on these differences in genetics, host specificity and pathogenicity, we propose the name Cryptosporidium mortiferum n. sp. for this parasite previously known as Cryptosporidium chipmunk genotype I. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]