Preliminary studies on pathogenic Leptospira spp. In slaughtered pigs in Abeokuta, Ogun State, Nigeria
This study was undertaken to investigate the occurrence of pathogenic Leptospira spp. and the associated renal morphological changes in pigs slaughtered in slaughter slabs within Abeokuta metropolis, Nigeria. A total of 42 pigs’ kidney samples were randomly collected for the study. The samples were examined using Ellinghausen McCullough Johnson Harris (EMJH) medium, microscopic agglutination test (MAT), Warthin Starry silver stain (WSss) and immunohistochemistry (IH). Thirty (71.43%) of the 42 kidneys showed visible macroscopic lesions. Interstitial nephritis and tubular nephrosis were the most prominent histopathological changes. Leptospira organisms were isolated from 35 (83.3%) of 42 kidneys. The occurrence of Leptospira species from 23 uncontaminated isolates using MAT was 95.7% (22/23). The reactant serovars and respective detection rate were Icterohaemorrhagiae (8/23, 34.8%), Pomona (4/23, 17.4%), Gripptotyphosa (3/23, 13%) Hardjo (3/23, 13%), Bratislava (2/23, 8.7%), Canicola (2/23, 8.7%), and 1 undetermined isolate (4.4%). Leptospira organisms were detected in 20 (87%) and 8 (34.8%) of the 23 renal tissues examined using WSss and IH respectively. Comparison of level of agreement among diagnostic methods [using kappa statistics (ki)] showed very low level of agreement between MAT and IH, and between WSss and IH. However, there was significant P<0.005) measure of agreement between MAT and WSss. The significance of these Leptospira serovars in pig industry and their public health implications were discussed. This is the first investigative study on swine leptospirosis in Nigeria.
Keywords: immunohistochemistry, Leptospirosis, microscopic agglutination test, Pigs, renal pathology, Serovars.