| As economic animal and pet, rabbits are closely related with human. It had been reported that rabbits were easily infected by zoonotic Cryptosporidium rabbit genotype, which is a potential threat to human health. At present, the data about molecular characterization of Cryptosporidium from domestic rabbits is not reported in China. Moreover, so far no information about the epidemiology of Cryptosporidium from domestic rabbits in Henan Province was seen. So in order to understand the epidemiology and the species or genotype of Cryptosporidium from domestic rabbits in Henan Province, In the present study, the epidemiology investigation of Cryptosporidium in domestic rabbits were conducted in Henan province, then the Cryptosporidium isolates obtained were identified according to the morphology of oocysts, transmission study, genotypic analysis of 18S rRNA, GP60, actin, COWP and 70kDa heat shock protein (HSP70) genes.1081 rabbit faecal samples from 8 farms were detected with the convention methods. The results showed that 5 species of intestinal parasites were detected in stool specimens,3 species were protozoon (Coccidian, Cryptosporidium and Giardia),2 belong to nematode (Passalurus ambiguus, Strongyloides stercoralis). The average infection rate of these parasites was 67.72%(732/1081), and the infection rate of Cryptosporidium sp. was 3.42%, Eimeria sp. was 64.11%, Giardia sp. was 5.27%, Passalurus ambiguus sp. was 1.39%, Strongyloides sp. was 8.97%. The results showed that parasites mixed infections are much common in rabbit herds, and especially two kinds of parasites were more commonly co-infected in rabbits.An epidemiologic survey was carried out to determine the prevalence of cryptosporidiosis in demotic rabbits and to identify factors associated with the risk of Cryptosporidium infection in rabbit in Henan province.1081 rabbit faecal samples from 8 farms in 5 regions were detected by the Sheather's sugar flotation and modified acid-fast staining methods. The results showed that oocysts of cryptosporidium were found in 37 samples, the total infection rate was 3.42%(37/1081), and the percentages of animals shedding oocysts was 10.93% and 4.11% in 1-3-month-old rabbits and unweaned rabbits, respectively. The mean size of oocysts was 4.91μm (4.426-5.163μm)×4.28μm (3.934-4.672μm), and the ratio of length to width was 1.15. According to the morphometric values, the Cryptosporidium oocysts were identified as Cryptosporidium parvum or Cryptosporidium rabbit genotype. The results of cross-transmission tests showed that the Cryptosporidium from rabbit not only can infect immunosuppressed rabbits but also can infect immunocompetent rabbits, but the latent period of Cryptosporidium infection in immunosuppressed rabbits was different from that of immunocompetent rabbits, and was 2 days in immunosuppressed rabbits and 8 days in immunocompetent rabbits. Two peak periods were found, and the duration period of oocyst excretion was 8 days and 5 days, respectively.The partial sequence of 18SrRNA, actin and COWP genes were amplified and sequenced. Sequence data were analyzed with BLAST online. Then, sequences alignment, phylogenetic relationships and homological analysis were performed using ClustalX 1.81, Phylip3.65 and DNAstar 4.0, respectively. Based on the phylogenetic analyses of the 18S rRNA, actin and COWP genes, the Cryptosporidium isolates from Henan were identified clearly as Cryptosporidium rabbit genotype.There is seldom report on molecular Characteristics of Cryptosporidium from rabbits in domestic and overseas. Cryptosporidium rabbit genotype at GP60 gene locus was first identified. Sequence analysis showed there was only one subtype family Cryptospordium from rabbits in Henan, which can be divided into two different subtypes according to the the number of trinucleotide repeats.
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