Author : Kumlung Chumponbunchorn

Summary : A serological survey of cattle on two selected farms in Malaysia revealed that 87.7 percent (150/171) of the animals examined had leptospiral antibodies. Sixty percent of the positive sera had titres to two or more serovars. Overall, serovar australis was found to be the most frequent serovar affecting the animals in these two farms. Among three age groups of cattle, the yearling group had the highest prevalence (62/64) of infection. A bacteriological survey of cattle on the two farms revealed 11.5 percent (13/113) of the animals were leptospiruric. Almost all of the isolates (12/13) were isolated from the yearling group. The isolates belonged to either the Sejroe or Pomona serogroup. Representative isolates have been sent to the Leptospirosis Reference Laboratory in Brisbane, Australia for definitive identification. The enzyme-linked immunosorbent (ELISA) using genus-specific (sonicated) antigen was employed for the detection of leptospiral infection. It was found to be more sensitive than the microscopic agglutination test (MAT). However, it is only suitable for screening and epidemiological purposes. The Coomassie blue-stained protein profiles of selected serovars examined by polyacrylamide gel electrophoresis (PAGE) were generally identical except for a few discernible differences but the silver-stained lipopolysaccharide (LPS) profiles were more distinguishable. Almost all of the proteins were blotted during electrophoretic transfer from the polyacrylamide gels to nitrocellulose membranes and a majority of the protein bands that were detected on the membranes were shown to be immunogenic. A few of the proteins were serovar-specific but others appeared to be common among the serovars tested.