Two equine parvoviruses discovered in recent years have been detected in horses in South Korea, with researchers finding an apparent association between the viruses and colic.
Since the first isolation of the equine parvovirus in 1985, three equine parvovirus species have been identified. Equine parvovirus-cerebrospinal fluid (EqPV-CSF) was identified in 2015, equine parvovirus-hepatitis (EqPV-H) in 2018, and Eqcopivirus (EqCoPV) in 2019.
Except for EqPV-H, which can cause equine serum hepatitis, the other two species have not been well investigated.
Jungho Yoon and his fellow researchers, reporting in the journal Veterinary Sciences, set out to explore the prevalence of EqPV-CSF and EqCoPV in 133 serum samples and 77 fecal samples taken from horses in Jeju Province, a major horse breeding region in Korea.
Eighty-eight of the horses presented for medical treatment with a range of clinical problems, and 111 were healthy.
For the serum samples, five (3.8%) were positive for EqPV-CSF DNA and 13 (9.8%) were positive for EqCoPV DNA. One horse was co-infected with both viruses.
No parvovirus DNA was detected in any of the fecal samples.
Among the five horses positive for EqPV-CSF, two had been imported from the United States and one from Australia, while the remaining two horses were born in Korea as offspring of imported dams.
The imported horses showed a higher prevalence of EqPV-CSF DNA (3 of the 25 horses, or 12%) than Korean horses (2 of 108 horses, or 1.9%).
Unlike EqPV-CSF, EqCoPV showed a high prevalence rate of viral DNA in both Korean (10 of 108 horses, or 9.3%) and imported horses (3 of 25 horses, or 12%).
The researchers noted that, in previous studies, the correlation of clinical disease with EqPV-CSF or EqCoPV infection was unclear.
In a bid to find any clinical relevance, the study team sorted the clinical diseases of the infected horses and then analyzed the disease association with the virus infection.
Among the 17 positive horses for EqPV-CSF or EqCoPV, seven horses showed colic signs, one horse had laminitis, one horse had a wasting syndrome, and the others were healthy. There was a significant relationship between colic signs and equine parvovirus infection, they said.
“However, it does not mean that EqPV-CSF or EqCoPV causes clinical colic, or vice versa, because we still cannot verify the causal relationship between colic and virus infection.”
There is a need for a wide range of investigations into EqPV-CSF and EqCoPV, given the high number of symptom-free equine parvovirus infections reported, they said.
The study team comprised Yoon, Taemook Park, Ahram Kim, Heeeun Song, Byung-Joo Park, Hee-Seop Ahn, Hyeon-Jeong Go, Dong-Hwi Kim, Joong-Bok Lee, Seung-Yong Park, Chang-Seon Song, Sang-Won Lee and In-Soo Choi, variously affiliated with the Equine Clinic at Jeju Stud Farm, operated by the Korea Racing Authority; and the Department of Infectious Diseases, part of the College of Veterinary Medicine at Konkuk University in Seoul.
Yoon, J.; Park, T.; Kim, A.; Song, H.; Park, B.-J.; Ahn, H.-S.; Go, H.-J.; Kim, D.-H.; Lee, J.-B.; Park, S.-Y.; Song, C.-S.; Lee, S.-W.; Choi, I.-S. First Detection and Genetic Characterization of New Equine Parvovirus Species Circulating among Horses in Korea. Vet. Sci. 2021, 8, 268. https://doi.org/10.3390/vetsci8110268