Epidemiological and spatial characterization of bovine cysticercosis in Paraíba State, Northeastern Brazil.

Abstract

This study focused on estimating the herd-level and animal-level prevalences, and identifying herd-level spatial clustering and risk factors associated with herd-level prevalence for bovine cysticercosis in the State of Paraíba, Northeastern Brazil. The state was divided into three sampling groups: sampling stratum 1 (mesoregion of Sertão), sampling stratum 2 (mesoregion of Borborema), and sampling stratum 3 (mesoregions of Zona da Mata and Agreste). For each sampling stratum, herd-level and animal-level prevalences were estimated by a two-stage sampling survey. In the first stage, a pre-established number of herds (primary sampling units) were randomly selected; in the second stage, a pre-established number of cows aged ≥ 24 months were randomly selected (secondary sampling units). 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 the region of Borborema, and 3.2% (95% CI = 1.9%–5.4%) in Agreste/Zona da Mata. The frequency of seropositive animals per herd ranged from 7.1% to 100% (median of 16.7%). The risk factors identified were as follows: animal purchasing (OR = 2.19) and presence of flooded pastures (OR = 1.99). A significant clustering of positive herds was detected in Southern part of Borborema mesoregion. 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 could restrict the access of their cattle to flooded pastures.