| Cryptosporidium spp. are important zoonotic protozoa, it can cause Cryptosporidiosis with the characteristic of enterogastrtis and diarrhea. At present, it happened everywhere in the world. Cryptosporidium cuniculus is Novel and Zoonotic parasite, it has become recognized worldwide. In July 2008, an outbreak caused by C.cuniculus was linked to consumption of tap water in Northamptonshire, England; there is also a report about child Cryptosporidiosis caused by C. cuniculus.In light of C.cuniculus is a newly identified Zoonotic Pathogen, and it happened widespread in our country, it request us understand its host range, biology characteristics and its potential threat. The present study was conducted to determine the prevalence of Cryptosporidium in rabbits in Henan Province, and researched the biology characteristics of C. cuniculus, consist of morphology, zoogenetic infection experiment, host range, pathogenicity and inherited characteristic.Henan is a province with large amount of rabbit, to obtain the data of the prevalence of Cryptosporidium in rabbits in Henan Province, meanwhile to separate C.cuniculus isolate, the prevalence of Cryptosporidium in rabbits in Henan Province were stydyed in this paper. 1144 rabbit faecal samples from 11 farms were detected with by microscope of smears stained with a Modified acid-fast stain and saturation sugar floatation method. The mean prevalence rate of Cryptosporidium was 3.85%(44/1144),1~6 months old rabbits has a higher prevalence rate, the rabbits older than 7 months has a lower prevalence rate, the prevalence rate in 1~3 months old rabbits is 7.62%, 4~6 months old rabbits is 4.43%, 7~12 months old rabbits is 0.56%, older than one year rabbits is 1.43%.The morphology and diagnostic characteristics are 4.9～5.4×4.5～5.1μm; mean 5.14×4.8μm; length:width = 1.07; n = 50.To study the host range and pathogenicity of C.cuniculus, experimental infections have been established in weanling rabbits (O. cuniculus), adult rabbits (O.cuniculus) and immunosuppressed Mongolian gerbils (Meriones unguiculatus), but not in BABL/c mice and chicken. Different dose has different infectivity, also cause different tissue damage and Clinical symptoms. Experimental infections have been established in weanling rabbits with 10 oocysts.According to Clinical symptoms, polypide parasitic rate, parasitic position and pathological change, simultaneous determination ovulate oocyst regular and body weight changes,we found different animal or different dose have distinct results. The rabbits culled during shedding of C. cuniculus was found to have occasional structures consistent with cryptosporidial infection in the apical brush borders of the small intestinal villi, and infiltrations of eosinophils in the base of the lamina propria and occasionally in the tips of the villi. Both C.cuniculus-infected immunosuppressed Mongolian gerbils that were examined showed multiple protozoan parasites on the brush border of the epithelium of the small intestinal villi, with some disruption of the villous structure.This consequence settled rationale for C. cuniculus mechanism of transmission and prevention and cure.Fragments of the SSUrRNA gene were amplified for all 44 isolates, generating sequences identical to each other. Specimens were subtyped by amplifying and sequencing the gp60 gene. Nucleotide sequences obtained from the study were aligned with each other and with reference sequences downloaded from GenBank by use of ClustalX 1.83. Result display all oocysts we got are C. cuniculus, and belong to Vb family, cladogram analysis shows they at the same clade with GU971648.1, which from a human Cryptosporidiosis Sporadic cases in England.And the isolate we used to infect animal is VbA36, has 100% homology with GU971648.1. |
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