In vivo characterization and transmission of Korean foot-and-mouth disease virus(FMDV)

국내 발생 구제역 바이러스(foot-and-mouth disease virus)의 특성과 전파력에 관한 연구

A study was conducted to determine the susceptibility of swine to Korean foot-and-mouth disease virus (FMDV; subtype O, isolated from Chungju province) in April, 2ooo. One holstein cow was inoculated intradermolingually with suspension of homogenized tissue from a Korean native cow naturally infected with Korean FMDY. Infected cow was housed with one susceptible cow and one susceptible pig (contact sentinels). Four additional susceptible pigs were housed in the same room but caged separately (non-contacted sentinels). The contacted pig and cow as well as non-contact pigs developed typical clinical signs after 2, 3, and 7 days post exposure, respectively. We compared neutralizing antibody from the animals to FMDV $O_1$ Lombardy, O Taiwan, $O_1$ Campos, and $O_1$ Manisa after 0, 4, 7, 10, 14, 21, 28 days post challenge and post-exposure. The highest viral neutralization titer could be interpreted that serotype O Korea (Chungju isolate) is antigenically more related to $O_1$ Manisa. In addition, immunohistochemistry was used to further characterize Korean FMDV from tissues of infected pigs. Korean FMDV antigen was observed in the tongue, hoof, esophagus, and tonsil tissues of sentinel pigs. These findings suggest that Korean FMD virus isolated from cattle can be rapidly transmitted to pigs both directly and indirectly contrast field observation in which only cattle were clinically ill.