Prevalence of Cryptosporidium species in intensively farmed pigs in Ireland.

Natural Cryptosporidium infections in pigs are widespread but generally apathogenic. This study was undertaken to determine the prevalence of zoonotic Cryptosporidium spp. in piggeries in Ireland, where the drinking water supply is particularly vulnerable to contamination with zoonotic species. Overall, infections were detected in 39 out of 342 animals (11.4%), with highest infection rates among weaners (15%) and sows (13.3%). Twenty-nine positive samples were genotyped based on SSU rRNA sequence analysis. Infections with Cryptosporidium parvum, the most important zoonotic species were rare and are likely to be of greater concern to animal handlers than suppliers of drinking water. In addition to C. parvum, Cryptosporidium suis, Cryptosporidium pig genotype II, Cryptosporidium muris and a previously undescribed genotype were identified. ABI-profiles indicated the presence of different alleles in at least 40% of all genotyped isolates. This was confirmed in 3 isolates by cloning of the PCR products. Since chronic mixed infections appear to be quite common in pigs they could be considered as models for mixed infections in immunocompromised humans.