The First Identification of Cryptosporidium parvum Virus-1 (CSpV1) in Hanwoo (Bos taurus coreanae) Calves in Korea

SIMPLE SUMMARY: Cryptosporidium is a parasite that causes digestive diseases in cows, and a virus called Cryptosporidium parvum virus-1 (CSpV1) is associated with it. We investigated the presence and features of CSpV1 in diarrhea samples of Hanwoo calves (Korean indigenous cattle). Out of 140 samples, 70 were positive for Cryptosporidium and 70 were negative. CSpV1 was found in 20% of the samples, more commonly in those already positive for the parasite. This is the first study on CSpV1 in Korea, offering insights into the relationship between the parasite and virus in cows. ABSTRACT: Cryptosporidium is an obligate coccidian parasite that causes enteric diseases in bovine species. A double-stranded RNA virus associated with C. parvum oocysts, Cryptosporidium parvum virus-1 (CSpV1), has been characterized. However, the relationship between the abovementioned coccidian parasite and the virus has not been studied in the context of the known clinical outcomes. This study aimed to characterize the prevalence and molecular traits of CSpV1 in diarrheal feces of Hanwoo (Korean indigenous cattle) calves. Of the 140 fecal samples previously tested for C. parvum, which were obtained from Hanwoo calves aged 60 days, 70 tested positive and 70 tested negative. These samples were included in this study. By using the polymerase chain reaction (PCR) analysis targeting the RdRp gene of CSpV1, we detected CSpV1 in 28 samples (20.0%), with infection rates of 31.4% (22/70) in C. parvum-positive and 8.6% (6/70) in C. parvum-negative samples. CSpV1 samples detected in the same farm were clustered together. To the best of our knowledge, this is the first study to report the prevalence and molecular characteristics of CSpV1 in Hanwoo calves in the Republic of Korea, providing important insights into the relationship between C. parvum and CSpV1 in bovine hosts.