Bovine and human brucellosis in the Trans-Amazonian agricultural frontier, Uruará, Pará, Brazil

Abstract

We evaluated the prevalence of brucellosis in cattle and humans on properties characterized as family farms in the municipality of Uruará, state of Pará, located on the border of the Trans-Amazon Highway, in a serological study. We randomly sampled cattle and humans from 67 family farms. Cattle sera were tested with buffered acidified antigen and human samples were tested using the slow tube agglutination test (titration of 80 as a cutoff point). The prevalence of bovine brucellosis was 52% [90% CI: 42; 63]. The prevalence of households with at least one brucellosis positive individual was 21% [13; 31]. In households with at least one positive test, 23% of subjects were positive (range 8% and 50%). Five percent (21/422) of all human samples tested were positive. This high exposure rate in humans is a result of high cattle infection rates. We expect that in regions of Brazilian with a high prevalence of bovine brucellosis, there is also a high rate human exposure; however, few human cases have been reported. This is likely because of the largely non-specific symptoms of human Brucella abortus infections. Hopefully this study will bring about new information to public and animal health authorities involved in formulating policies aimed at decreasing disease prevalence.