Herd-level seroprevalence and associated risk factors for bovine cysticercosis in the State of Paraíba, Northeastern Brazil.

This study focused on estimating the herd-level and animal-level prevalences, and identifying risk factors associated with bovine cysticercosis in the State of Paraíba, Northeastern Brazil. The state was divided into three sampling strata: Sertao, Borborema and Zona da Mata/Agreste. For each sampling stratum, herd-level and animal-level prevalences were estimated by a two-stage sampling survey. First, a pre-established number of herds (primary sampling units) were randomly selected; second, within each herd a pre-established number of cows aged ≥24months were systematically selected (secondary sampling units). Ten animals were sampled in herds with up to 99 cows aged over 24 months; 15 animals were sampled in herds with 100 or more cows aged over 24 months; and all animals were sampled in those with up to 10 cows aged over 24 months. In total, 2382 animals were sampled from 474 herds. Serological diagnosis was initially performed by the indirect ELISA, and positive sera were confirmed by immunoblot. A herd was deemed positive if it included at least one positive animal in herds of up to 29 females, and two positive animals in herds with more than 29 females. The herd-level prevalence in the State of Paraíba was 10.8% (95% CI=8.1%-14.1%), 10.3% (95% CI=6.4%-16.1%) in the region of Sertão, 6.9% (95% CI=3.9%-12.1%) in Borborema, and 13.8% (95% CI=9.3%-20.2%) in Agreste/Zona da Mata. The animal-level prevalence was 2.3% (95% CI=1.6%-3.3%) in the State of Paraíba, 1.4% (95% CI=0.8%-2.5%) in Sertão, 3.6% (95% CI=1.7%-7.4%) in Borborema, and 3.2% (95% CI=1.9%-5.4%) in Agreste/Zona da Mata. The risk factors identified were as follows: animal purchasing (OR=2.19) and presence of flooded pastures (OR=1.99). Our findings suggest that bovine cysticercosis herd-level seroprevalence in the State of Paraíba, Northeastern Brazil, is high, and support the idea that prevention measures should be applied at herd level and farmers should restrict the access of their cattle to flooded pastures.