Epidemiological characterization of bovine paratuberculosis in the State of Paraíba.

Abstract

This study focused on estimating the herd-level and animal-level prevalences, and identifying herdlevel spatial clustering and risk factors associated with herd-level prevalence for bovine paratuberculosis 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, 2504 animals were sampled from 480 herds. Serological diagnosis of Mycobacterium avium subsp. paratuberculosis (MAP) infection was performed by the indirect ELISA kits. A herd was deemed positive if it included at least one positive animal in herds of up to 24 females, and two positive animals in herds with more than 24 females. The herd-level prevalence in the State of Paraíba was 34.5% (95% CI = 30.2–39.1%), 41.4% (95% CI = 34.0–49.1%) in Sertão, 26.6% (95% CI = 20.2–34.2%) in the region of Borborema, and 30.5% (95% CI = 23.9–38.0%) in Agreste/Mata. The animal-level prevalence was 10.7% (95% CI = 7.3–15.4%) in the State of Paraíba, 9.4% (95% CI = 7.3–12.1%) in Sertão, 7.9% (95% CI = 5.2–11.7%) in the region of Borborema and 13.9% (95% CI = 6.2––28.3%) in Agreste/Mata. The frequency of seropositive animals per herd ranged from 6.7% to 100% (median of 20%).The risk factors identified were as follows: Sertão region (OR = 1.9), more than 12 adult animals in the herd (OR = 1.9), and not using maternity pens (OR = 1.7). Two significant clustering of positive herds were detected in Northern part of Borborema mesoregion. Our findings suggest that MAP herd-level seroprevalence in the State of Paraíba, Northeastern Brazil, is high, and support the idea that the use of maternity pens will be important for preventing transmission of MAP in the herds. As serological tests for MAP diagnosis are not widely available and are very expensive, as well as replacement or maintenance of livestock by animal purchasing is common in the region, it is concluded that prevention measures should be applied at herd level.