Isolation and immunohistochemical diagnosis of Haemophilus parasuis from naturally occurring polyserositis in pigs

자연발생한 돼지 다발성 장막염 예로부터 Haemophilus parasuis의 분리와 면역조직화학적 진단

From Jan. 1996 to Oct. 1997, 29 pigs with 40-70 days old showing dyspnea inappetite and polyserositis were collected and carried out necropsy, bacterial culture, histopathology, avidin biotin complex(ABC) stain, fluorescent antibody(FA) test, and electron microscopy. In the study, 4 strains from 3 pigs were isolated from meninges, pleura and synovial fluid and also were identified as Haemophilus parasuis serovar 5. Main histopathological lesions of 29 pigs with polyserositis were frequently composed of fibrinous peritonitis(27), pleurisy(22), interstitial pneumonia(21), fibrinous epicarditis(20), fibrinopurulent meningitis(8) and synovitis(4). By ABC stain, 11/29(37.9%) pigs with polyserositis were confirmed to have H parasuis serovar 5 in the cytoplasm of macrophages and neutrophils in cerebral meninges, epicardium, pleura surface of lung or serosa of spleen. ABC stain(20.8~40.0%) to detect H parasuis serovar 5 in tissues was more sensitive than bacterial culture(10.3%), but less sensitive than FA test(62.5%) using frozen tissues even though the result of 8 cases. By electron microscopy, a bacterium was also detected in the cytoplasm of macrophages in purulent exudate of cerebral meninges. Consequently, we confirmed that H parasuis serovar 5 has been involving to cause pigs with polyserositis and can be detected by FA and ABC stain as reliable diagnostic tools.