Prevalence and Molecular Characterization of spp., , and in Diarrheic and Non-Diarrheic Calves from Ningxia, Northwestern China.

spp., , and are significant parasitic gastrointestinal pathogens with global distribution in humans and domestic animals, including calves. The main symptoms of calf infection are severe diarrhea, dehydration, growth retardation, and sometimes even death. To date, there has been limited information on the prevalence of spp., , and infections in calves in Ningxia, China, especially between diarrheic and non-diarrheic calves. A total of 438 fecal samples were collected from diarrheic (201) and non-diarrheic (237) calves in Ningxia. PCR and DNA sequencing were used to find the prevalence of spp. at 46.8% (205/438), at 16.9% (74/438), and at 10.0% (44/438). The prevalence of spp. infection in diarrheic and non-diarrheic calves was 54.0% (128/237) and 38.3% (77/201), respectively, and statistical analysis showed a positive correlation between the prevalence of spp. infection and calf diarrhea ( < 0.01). However, in this study, there was no statistical correlation between the prevalence of infection as well as infection and calf diarrhea ( 0.05). Furthermore, four known species were successfully identified by comparing them with SSU rRNA gene sequences, including , , and . In addition, all 74 -positive samples were identified as assemblage E by comparative analysis of gene sequences. Among the 44 -positive samples sequenced in the present study, 4 distinct genotypes were successfully identified by comparative analysis of ITS sequences, including 3 known genotypes (J, BEB4, and N) and 1 novel genotype, the latter of which was identified and designated as NX1. These findings indicated that the high genetic diversity and complex population structures of spp., , and in Ningxia diarrhea calves and non-diarrhea calves, which provide new data for understanding the epidemiological status of spp., , and in Ningxia calves.