PROTOZOAN PARASITES AFFECTING FOOD ANIMALS, FOOD SAFETY, AND PUBLIC HEALTH
Title: Cryptosporidium ubiquitum n.sp. in animals and humans
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2010
Publication Date: April 28, 2010
Citation: Fayer, R., Santin, M., Macarisin, D. 2010. Cryptosporidium ubiquitum n.sp. in animals and humans. Veterinary Parasitology. 172(1-2):23-32.
Interpretive Summary: Cryptosporidiosis is a diarrheal disease of humans and animals caused by parasites in the genus Cryptosporidium, a genus with 20 species and 40 genotypes. Molecular characterization of these species and genotypes has revolutionized our understanding of the biological diversity of this genus. Although most human infections are caused by C. hominis and C. parvum, the Cryptosporidium cervine genotype also infects humans and more animals and over a greater geographic range than most other species of Cryptosporidium. It has been found in: (1) humans in Canada, New Zealand, and England, (2) ruminants including white-tailed deer, blesbok, mouflon, nyala, ibex, and sheep at an abattoir in Western Australia and on farms in the USA, Scotland, China, and Spain, and (3) wild rodents including squirrels, chipmunks, and a woodchuck, beaver, deer mouse, and raccoon. It has been identified in storm water and watersheds in New York State. Different names have been used for the cervine genotype in publications and in GenBank leading to confusion of its identity. To improve identification and thereby the detection, reporting, and understanding of the epidemiology of this genotype the present study was undertaken to obtain physical, biological, and molecular data so the cervine genotype could be identified as a distinct and valid species. Data obtained in the present study indicate that this genotype qualifies as a new species based on its biological and molecular uniqueness and as such is named Cryptosporidium ubiquitum because of its great geographic range and numerous host species.
A new species, Cryptosporidium ubiquitum, previously identified as the Cryptosporidium cervine genotype is described. In published studies the cervine genotype was reported in wild and domesticated ruminants, rodents, carnivores, and primates including humans. Molecular data for C. ubiquitum have been recorded in GenBank. In the present study oocysts were found in feces from 9 of 44 farm raised sheep and a captive female prehensile-tailed porcupine and her infant. Oocysts from the porcupine were transmitted to boer goats. Oocysts from the goats were transmitted to a calf (calf 1) and oocysts from calf 1 were transmitted to gerbils and BALB/c mouse pups. Calf 2 housed near calf 1 became contaminated and excreted oocysts. When C. ubiquitum oocyst excretion ended both calves were challenged with oocysts of C. parvum and both excreted oocysts of C. parvum. Oocysts of C. ubiquitum from a calf measured 4.71-5.32 x 4.33-4.98 µm (mean = 5.04 x 4.66 µm) with a length/width shape index of 1.08 (n=50). Purified PCR products of the SSU-rDNA, HSP-70, and actin genes were sequenced and analysis of the 3 unlinked loci demonstrated the new species to be distinct from all other species and also demonstrated a lack of recombination, providing further evidence of species status. Based on morphological, molecular and biological data, this geographically widespread parasite infectious for a wide range of mammalian hosts is recognized as a new species and is named Cryptosporidium ubiquitum.