Epidemiology Of Swine Cryptosporidiosis In Shandong Province And The Effect Of Sodium Selenite And Vitamin On The Infection

Cryptosporidiosis is caused by the obligate intracellar protozoan parasites, Cryptosporidium, which infects animals and humans. Nowadays, cryptosporidiosis was considered as one of the six diseases leading to diarrhea worldly. However, up to the present, there is no effective treatment available for cryptosporidiosis in human and animals. Furthermore, the epidemiology and genotypes of Cryptosporidium parasites were not investigated systematically in pigs in Shandong province. Consequently, the present study was undertaken to investigate the molecular epidemiology in pigs, and screening of sodium selenite and vitamin E against cryptosporidiosis in mice.1. Epidemiology of Cryptosporidium parasites in pigs in Shandong province.The present study was designed to investigate the epidemiology of cryptosporidiosis by the MAFS technique in pigs in Shandong province. The results showed that, a total of 78 (12.04%) positive pigs were detected, in which, 84.85% was the intensity of infection as"+"and"++". The prevalence of the diarrhea was significantly higher than that of the undiarrhea (P<0.01), and the infection rate in summer was significantly higher than those of others. The prevalence of 2-6-month pigs was significantly higher than those of 13-24-old and 24-48-old pigs (P<0.05). It is concluded that the prevalence of pigs in Shandong province was high, and lower intensity was found in most of pigs. Cryptosporidiosis might be one of the pathogens causing aniaml diarrhea.2. Isolation and molecular identification of Cryptosporidium in pigsThe present study was designed to analyze the morphology and infection of Cryptosporidium oocysts, and identify the genotypes of Cryptosporidium in pigs by RT-PCR technique and analysis of the 18s rRNA homologous rate and phylogenetic tree after the total RNA was isolated from 6 strains. The results showed that there were two kinds of oocysts with different morphology, which infect mice. These sequences showed that the two isolates belonged to the species C. parvum and C. muris, the homology were 100% and 99.8%, and located in the same branch, respectively. It is concluded that there are two species of Cryptosporidium in pigs, the isolates of C. parvum is C. parvum"mouse"genotype. There might be a cross-transmission between pigs and mice.3. The suppressive effect of sodium selenite and vitamin E on the infection of Cryptosporidium in miceThe present study was designed to investigate the suppressive effect of sodium selenite and vitamin E on C. parvum infection and the antioxidant abilities in mice. The results showed that the quantity of C. parvum oocysts discarded from the infected mice orally taked sodium selenite and vitamin E were significantly suppressed as compared with that of the infected groups (P<0.05 or P<0.01). The activity of serum GSH-Px and SOD was significantly higher than that of the infected groups (P<0.01 or P<0.05). And the contents of serum MDA in the infected groups were significantly higher than those of others(P<0.05 or P<0.01). In conclusion, sodium selenite and vitamin E suppress the infection activity of oocysts after the antioxidant abilities of mice were enhanced.