Seroprevalence of Paratuberculosis in Pure-bred Breeding Cattle in Korea

Paratuberculosis (Johne's disease), a chronic wasting disease caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a major cause of economic loss in the cattle industry. In Korea, national monitoring of breeding stock for MAP has been implemented. In this study, we report the results of serological testing to determine the prevalence of MAP in breeding stock of Korean native and dairy cattle during 2008 and 2009. A total of 3,927 serum samples were submitted (3,692 Korean native cattle and 235 dairy cattle) to Animal Disease Diagnostic Division, Animal, Plant and Fisheries Quarantine and Inspection Agency. The samples were classified into four different age groups for MAP; group 1 (${\leq}2$ year, n = 1,509), group 2 (>2 years to ${\leq}3$ years, n = 486), group 3 (>3 years to ${\leq}4$ years, n = 441), and group 4 (>4 years, n = 1,491). Overall seroprevalence of MAP in this study was 0.5% (21/3,927), which was much lower than that of conventional cattle (1.2-16.4%) in Korea. Also, the seroprevalence was determined by age groups: three of group 1 (0.2%), two of group 2 (0.4%), three of group 3 (0.7%), and 13 of group 4 (0.9%) were seropositive for MAP, respectively. Although seropositive samples were found in all age groups, the seroprevalence tended to increase with age. Our study showed that the seroprevalence of MAP in pure-bred breeding dairy cattle (0%) was lower than that in pure-bred breeding Korean native cattle (0.6%).

국가 종축우에 대한 요네병 항체 양성률 조사

요네병은 Mycobacterium avium subspecies paratuberculosis에 의해 발생하며 반추동물에서 만성 쇠약을 일으켜 전세계적으로 양축산업에 커다란 경제적 손실을 일으키는 질병이다. 본 연구에서는 2008년부터 2009년까지 2년동안 의뢰된 총 3,927건의 국가 종축우의 혈청에 대한 요네병의 항체 양성률에 대해 조사한 결과 21두(0.5%)에서 항체 양성을 나타내었으며 이는 국내 일반 농가의 양성률(1.2-16.4%) 보다 현저히 낮은 수준이었다. 또한 연령별 양성률은 2세 미만에서 0.2% (3두), 2-3세에서 0.4% (2두), 3-4세에서 0.7% (3두), 4세 초과에서 0.9% (13두)로 전 연령에서 양성이 나타났으나 연령이 높아짐에 따라 양성률이 증가하는 경향을 보였다. 품종 별로는 젖소는 모두 음성이었으며 한우에서만 양성률 0.6%를 나타내었다.