| Cryptosporidium is an important foodborm and waterborn zoonotic protozoan in the world, and it is an important factor for acute diarrhea or chronic lethal diarrhea. There are various species among the genus Cryptosporidium, in addition to 26 recognized species of Cryptosporidium, more than 70 genotypes have been described. Cryptosporidiosis caused by Cryptosporidium spp. is important zoonotic disease, which can infect more than 280 animals,and was transmitted by the fecal-oral route, via either direct contact or ingestion of contaminated food or water. Currently, the mechanism of pathogenicity is not clear, and no effective drug or vaccine is available for cryptosporidiosis. Thus, this disease cause serious threat to livestock husbandry, as well as produce large affect to human health.To estimate the prevalence and public health significance of cryptosporidiosis in goats,1265 fecal samples from seven farms in Henan province and Chongqing city were examined for Cryptosporidium oocysts. The overall infection rate of Cryptosporidium was 3.48%(44/1256). Significant difference was observed among age groups, with the postweaned kids having the highest infection rate (4.58%). Cryptosporidium spp. were characterized by PCR-RFLP analysis and DNA sequence analysis of the small subunit (SSU) rRNA gene. The SSU rRNA-based PCR identified three Cryptosporidium species, including C.ubiquitum (24/44) in Henan and Chongqing, and C.andersoni (16/44) and C.xiaoi (4/44) in Henan. Among which, the C.ubiquitum and C.andersoni were first identified in goats thus far and were found in all age groups except no C.andersoni being found in the postparturition nannies, whereas the C.xiaoi was detected in pre-weaned kids and pregnant nannies. Subtyping of C.ubiquitum by DNA sequence analysis of gp60 gene suggested that the 15 isolates all belonged to zoonotic Ⅻa subtype 2. Thus, the dominant zoonotic C.ubiquitum found in this study indicated goats are a potential source for zoonotic infections with the C.ubiquitum.To understand the prevalence of Cryptosporidium spp. in Ningxia,1615 fecal samples from 21 dairy farms were obtained. Microscopy showed that the overall prevalence was 4.39%(71/1615) from 10 Cryptosporidium-positive farms, with farm 21 having the highest prevalence of 19.68%(49/249). The infection rate of Cryptosporidium spp. was 19.09%,0.87%,0.00%and 0.65% in pre-weaned, 3-11-month-old,12-24-month-old, and more than 24-month-old dairy cattle, respectively. PCR-RFLP analysis and DNA sequence analysis of the small subunit (SSU) rRNA gene showed 62 C.parvum (in 6 farms),5 C.bovis (in 4 farms), and 4 C.andersoni (in one farm). As to the species distribution associated with age group, the pre-weaned calves had C.parvum (n=58) and C.bovis (n=5) infections, 3-11-month calves had 4 C.parvum, more than 2-year-old cattle had C.andersoni (n=4) infection, whereas no Cryptosporidium-positive was found in 1-2-year cattle. Gp60 gene subtyping analysis suggested 14 C.parvum isolates were IIdA19Gl subtype in farm 1-20, whereas the 48 isolates in farm 21 all belonged to subtype IIdA15G1. Thus, the distribution of Cryptosporidium species and subtype characterization were different from that in Henan and Heilongjiang provinces and Sweden.To understand the population genetic characterization and the origin of C.parvum, 111 C.parvum Ⅱd isolates from several species of animals in China, Sweden, and Egypt were subtyped by multilocus sequence typing (MLST). One to eleven subtypes were detected at each of the 12 microsatellite, minisatellite, and SNP loci, forming 25 MLST subtypes. Host-adaptation and significant geographical segregation were both observed in the MLST subtypes. A clonal population structure was seen in C.parvum Ⅱd isolates from China and Sweden. Three ancestral lineages and the same RPGR sequence were shared by these isolates examined. Therefore, the present genetic observations including the higher nucleotide diversity of C.parvum ⅡGP60 sequences in Western Asia, as well as the unique distribution of Ⅱd subtypes (almost exclusively found in Asia, Europe, and Egypt) and in combination with the domestication history of cattle, sheep, and goats, indicated that C.parvum Ⅱd subtypes were probably dispersed from Western Asia to other geographical regions.In summary, the present study analysed the distribution of Cryptosporidium in goats and the first identification of C.ubiquitum and C.andersoni; we found that Cryptosporidium species distribution and subtype in dairy cattle in Ningxia differed from those detected in Henan and Heilongjiang; the population genetics of C.parvum Ⅱd isolates was conducted and our obserbations indicated C.parvum Ⅱd had a clonal population structure and which was dispersed from Western Asia to other geographical regions. Thus, these results will provide an important reference for deep elucidating the prevalence and transmission of Cryptosporidium in China. |
PDF Full Text Request