STUDIES ON BRUCELLOSIS IN CATTLE IN JIGAWA STATE, NIGERIA, A RESEARCH PROJECT TOPIC ON MICROBIOLOGY
ABSTRACT
A serological and bacteriological study of Brucella infection in cattle was carried out in Jigawa State Nigeria in order to determine the seroprevalence, identify isolates and assess factors responsible for the introduction, maintenance and spread of the Brucella infection in cattle herds in selected Local Government Areas of Jigawa State. The study employed Rose Bengal plate test (RBPT) and Serum Agglutination test (SAT) as screening tests and Complement Fixation test (CFT) as a confirmatory test. Brucella organisms were isolated using cultural methods and biochemical tests were used to identify Brucella species. Milk Ring (MRT) and Whey Agglutination tests (WAT) were used to screen milk samples. Questionnaires were used to identify presence of exposure factors to Brucella species. From the results of the study, 93 (4.98%), 83(4.44%) and 68(3.64%) out of the 1867 serum samples were positive with RBPT, SAT and CFT tests respectively. There was a strong degree of agreement between the screening and the confirmatory tests as indicated by Kappa value of 0.926 0.846 and 0.827. Prevalence of Brucellaantibodies in the study herds indicated that 30 out of the 147 herds sampled were positive using RBPT, SAT and CFT tests, with an individual animal prevalence (IAP) ranging from 0 to 18.6% and a within herd prevalence (WHP) from 0 to 57.14% based on the CFT tests. The overall herd prevalence in the study based on the confirmatory test was 20.40 % (30/147). The results of Milk samples screened by MRT and WAT tests showed that 0.5% (5/869) and 0.72% (2/274) tested positive with the two different tests respectively. The results also showed that prevalence of Brucella infection was higher among female cattle 3.4% (70/2053) than males 0.52% (5/957) in all the study herds. The rate of seropositivity was highest among cattle of age group 37-72 months, 4.55% (37/813). Foreign breeds presented higher seropositivity of 3.2% (8/249) than the local breeds 2.4% (67/2746). A total of 900 milk, 460 vaginal swabs, 325 prepucial swabs, 14 placentae, 11 stomach contents, 11 spleen and 11 liver samples were cultured for Brucella isolation. Two isolates were obtained, one each from placenta and vaginal swabs of Friesian and Bunaji cattle in the North Central and North West Senatorial Zones. Biochemical characterization of the isolates indicated that they were both Brucella abortus. From the study all the herd owners interviewed were aware of brucellosis as a disease entity with the local name Bakkale, but they differed in ways of recognizing it.
