Pathologic characteristics for the Rhodococcus equi infection in foals in Jeju |
Kyung-Ok Song1, Hyoung-Seok Yang2, Won-Geun Son3, Jae-Hoon Kim3 |
1Animal Health Division, Jeju Special Self-Governing Province 2Jeju Special Self-Governing Provincial Veterinary Research Institute 3College of Veterinary Medicine and Veterinary Medical Research Institute, Jeju National University |
제주지역 망아지에서 Rhodococcus equi 감염증의 병리학적 특징 |
송경옥1, 양형석2, 손원근3, 김재훈3 |
1제주특별자치도 동물방역과 2제주특별자치도 동물위생시험소 3제주대학교 수의과대학 및 수의과학연구소 |
Correspondence:
Jae-Hoon Kim, Tel: 82-64-754-3387, Fax: 82-64-702-9920, Email: kimjhoon@jejunu.ac.kr |
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Abstract |
From 1996 to 2014, 14 foals from nine farms in Jeju were diagnosed with a Rhodococcus equi infection. Clinically, most foals showed characteristic respiratory signs, including hyperthermia and dyspnea. The seasonal occurrence of R. equi infection in foals was higher in summer, such as June (eight foals; 57.1%) and July (four foals; 28.6%), than in the other seasons. The major cases of R. equi infections were observed among two-month-old (eight foals; 57.1%) and three-month-old (three foals; 21.4%) foals. Histopathologically, bronchopneumonia, abscess, and granulomatous pneumonia were the most prevalent lesions in the lungs of foals. Colonic ulcers and submucosal abscesses were found in a foal. Some foals showed granulomatous lymphadenitis and abscesses in the mesenteric and other lymph nodes. According to the polymerase chain reaction using 10 tissue samples of foals and nine R. equi isolates, the vapA gene was detected in 11/11 (100%) foals. Immunohistochemical staining using the anti-VapA monoclonal antibody was applied to detect the R. equi VapA antigen in the organs of foals. R. equi VapA antigens were demonstrated in most lungs and some mesenteric and hilar lymph nodes of 13 foals. Isolated virulent R. equi VapA bacteria showed high sensitivity to gentamicin, quinolones, rifampin, and vancomycin. |
Key Words:
foal, immunohistochemistry, polymerase chain reaction, Rhodococcus equi, VapA |
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