Research Of Biology Characteristic For Cryptosporidium Hominis And C. Parvum Different Subtypes

By now, some research indicated that Cryptosporidium hominis is the mainly Cryptosporidium spp. for human cryptosporidiosis in China, but the community heredity structure of C. hominis was not clear, thus cannot infer the infection mechanism. The study were confirmed the oocysts by using a small subunit rRNA-based PCR-restriction fragment length polymorphism genotyping tool and the 60-kDa glycoprotein (GP60) gene sequence analysis to Kaifeng, to analyze C. hominis community heredity structure, summarizes the regularity of epidemic and the dissemination mechanism. And use different C. hominis subtype to infect Mongolian gerbil, newborn piglets and lambs, observes clinical symptoms and pathological changes, studies the pathogenic difference.Kaifeng is the National Excellent Tourist City , Its unique tourism resources and deep tourism culture, hundreds of millions of domestic and overseas tourists come here every year, so it is conducive to spread opportunistic parasites. In order to understand the prevalence of Cryptosporidium spp. in patients in Kaifeng, A total of 6093 stool specimens from two representative hospital were examined between July 2007 and October 2008 to assess the prevalence of human cryptosporidiosis in Kaifeng in Henan Province. Specimens were concentrated by formalin-ethyl acetate sedimentation method and examined for Cryptosporidium oocysts by microscope of smears stained with a modified acid-fast stain. The mean prevalence of Cryptosporidium was 0.10% (6/6093). All Cryptosporidium-positive specimens were further chararacterized by sequence analyses of the small-subunit rRNA and 60 kDa glycoprotein genes. Among those genotyped, five of which had C. hominis Ib subtype and one had Ia. The infection rate of Cryptosporidium spp. in patients in Kaifeng city was lower, however, evolving further health education is needed to pervase health information and to elevate self health protection idea and capability, so to prevent the development and prevalence of parasitic disease.Some research shown that Cryptosporidium hominis was the mainly Cryptosporidium spp. for human cryptosporidiosis in China. However, there were few isolates were passaged in laboratory upto date, so biological characteristics of C. hominis wasn't reported in the our country. In present work, Mongolian gerbils were orally inoculated with 0.75mg of dexamethasone /animal using gastric tube every two days intervals from 10th days before oocyst ingestion. The results showed that gerbils shedded oocysts in the third day after inoculation (DAI), and the number of oocysts increased obviously, the peak of occysts shedding appeared in the DAI 6, and then dropped gradually until DAI 10 or 11. Before and after the passage, the oocysts were confirmed based on small subunit rRNA and gp60 gene sequences analysis as repord technique. We developed the rodent model for C. hominis Ib subtype successfuly,it is of an important value for the further biological characteristics study of C. hominis.In order to seek a more economical effective method to preserve C. parvum generation, 19 days old Mongolian gerbils were divided into 5 groups randomly, Immunosuppressive control and infection groups were given 0.80 mg of dexamethasone (DXE) per animal every other day. 10 days latter the infection group gerbils were orally inoculated C. parvum. The gerbils shedded oocysts in the second day after inoculated, during the patent periods OPG approximated calfs, and the duration compares the calf infection was longer, the study provide a more economical effective method to preserve C. parvum generation.To determine whether different C. hominis subtype do have biology phenotype difference. novo- ablactated Mongolian gerbils, neonatal lambs and pigs were given 1×106 ZZH-1 or WJH-35 oocysts. The prepatent period for ZZH-1was longer than WJH-35 C. hominis ( In Mongolian gerbils, piglets and lambs, the prepatent periods for ZZH-1 and WJH-35 were 4,3,7 and 2,2,4 days respectively ). The patent periods for ZZH-1 was 2 or 3 day shorter than WJH-35 C. hominis. ( In Mongolian gerbils, piglets and lambs, ZZH-1 and WJH-35 sheded oocysts for 7,11,13 and 9,13,15 days respectively ). The OPG of ZZH-1infected animals were smaller than WJH-35 infected ones during the patent period.WJH-35 infected animals developed significantly more severe disease than did ZZH-1 infected . Microscopic examination of HE-stained tissue slice of the intestinal tract of all infected animals revealed numerous Cryptosporidium oocysts in ileum and colon, and both isolates caused intestinal villus shorten, shedding, intestines epithelial cell swelling and other digestive tract changes. WJH-35 infected animals had significantly more parasites in the ileum than did the ZZH-1 infected ones, yet WJH-35 associated intestinal lesions were severely compared with ZZH-1 associated lesions. These findings suggest that the virulence of ZZH-1(IbA20G2)and WJH-35(IbA19G2)was difference.To compare the pathogenesis of Cryptosporidium hominis IbA19G2and Cryptosporidium parvum IId A19G1, neonatal piglets were given 1×106 IbA19G2or IId A19G1 oocysts. IId A19G1-infected piglets developed significantly more severe disease than did IbA19G2-infected piglets by the end of the first 2 weeks after inoculation. IId A19G1 parasites were seen microscopically 2ed day after inoculation and colonized in significantly larger numbers than did IbA19G2 in the 1st week after onset . IbA19G2parasites were only detected during the patent period in the ileum and colon but the patent period was longer than IId A19G1 did. The weight gain of IbA19G2 was significantly slower than IId A19G1 infected piglets and the lymphoid hyperplasia in ileum for the IbA19G2was statistically significant severity than IId A19G1 30 days after inoculation. These findings suggest IId A19G1 appeared more serious clinical manifestations at the early stage of infection, and IbA19G2 showed more serious chronic effects.