Prevalence of influenza A, C and D viruses in Korean swine farms

초록

Influenza viruses are enveloped, segmented, single-stranded, negative-sense RNA viruses that belong to the Orthomyxoviridae family. There are four types of influenza viruses, influenza A, B, C, and D viruses (IAV, IBV, ICV, and IDV), and only three types of influenza viruses, IAV, ICV, and IDV, can infect swine with zoonotic potential. However, in Korea, the prevalence of ICV and IDV as compared with IAV has not been much studied yet. To determine the prevalence of IAV, ICV, and IDV among swine farms in Korea, 1,602 nasal swabs and 200 oral fluid samples were collected from 40 pig farms between October 31 and December 14, 2023. The samples were subsequently screened for IAV, ICV, and IDV by polymerase chain reaction (PCR) using gene-specific primers. The study reveals that 23 (57.5%) out of 40 farms were positive for IAV, among which IAV was detected in 72 (4.0%) of the total 1,802 tested samples. The rate of positive samples was 2.7% from the nasal swabs and 14.5% from the oral fluids, much higher than the previous studies. The weaning pig shows the highest positive rate (8.9%) among all ages. However, none of the tested samples was positive for ICV or IDV. Consistent with previous studies, only IAV has been confirmed to be prevalent in Korean swine herd, but not ICV and IDV. However, continuous surveillance of various influenza types in swine population is needed as they pose a potential zoonotic threat.

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