The infection and molecular characterization of Cryptosporidium spp. in diarrheic pigs in southern China.

Cryptosporidium spp. is recognized as an opportunistic zoonotic parasite that infects humans, wild and domestic animals, and is also a major cause of diarrhea-related disease in immunocompromised individuals, considered a global public health concern. Pig is considered as one of the reservoir hosts of Cryptosporidium spp. can transmit cryptosporidiosis to humans and other animals. However, limited studies on the distribution of Cryptosporidium spp. in diarrheic pigs have been published. Objective of the current study was to investigate the infection and species/genotypes of Cryptosporidium spp. from feces of diarrheic pigs in southern China. A total of 1254 fresh fecal samples were collected from 37 intensive pig farms in Jiangxi, Hunan and Fujian provinces, and were screened for Cryptosporidium spp. infection using a nested PCR assay targeted the small subunit rRNA (SSU rRNA) genes. The overall infection rate of Cryptosporidium spp. was 4.5% (57/1254), including 5.5% (17/307) in suckling piglets, 2.7% (8/299) in weaned piglets, 7.4% (7/95) in fattening pigs and 4.5% (25/553) in sows, respectively. In addition, two human-pathogenic species Cryptosporidium scrofarum (80.7%, 46/57) and Cryptosporidium suis (19.3%, 11/57) were identified. C. scrofarum and C. suis were observed in pigs tested in all age groups. Interestingly, a high colonization incidence of C. scrofarum (16/57) was observed in suckling piglets. This study revealed the prevalence and species of Cryptosporidium spp. in diarrheic pigs in three provinces of southern China, which suggested that diarrhea maybe not a direct factor affecting the prevalence of Cryptosporidium spp. in pigs. More prevention and control of this parasite in pigs should receive greater attention from farmers in investigated provinces.