Estudo epidemiológico para leucose enzoótica bovina no Estado da Paraíba.

Abstract

This dissertation consists of two chapters. In Chapter 1, the objectives were to estimate the prevalence at the herd and animal level, to identify spatial clusters of positive properties and factors associated with the prevalence of positive herds for enzootic leukosis in cattle in the State of Paraíba, Northeast Brazil. The state was divided into three sample groups: stratum 1 (mesoregion of Sertão), stratum 2 (mesoregion of Borborema) and stratum 3 (mesoregions of Zona da Mata and Agreste). For each sampling stratum, the prevalence of positive herds and seropositive animals was estimated by two-stage sampling. In the first stage, a pre-established number of herds (primary sampling units) was selected at random; in the second stage, a preestablished number of cows aged ≥ 24 months (secondary sampling units) was randomly selected. In total, 2067 animals were tested in 400 herds. Enzyme-linked immunosorbent assay (ELISA) test kits were used: IDEXX Leukosis Serum X2 Ab Test. One herd was considered positive for the presence of EBL 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 prevalence at the herd level was 23.4% (95% CI = 19.2-28.1), and the prevalence per animal was 10.8% (95% CI = 7.5-15.3). For the sample groups, the prevalence at herd level and per animal were, respectively, 24.2% (95% CI = 17.5 - 32.4) and 7% (95% CI = 88.7 - 95.7) in the Sertão, 17.5% (95% CI = 12.0 -24.9) and 5.9% (95% CI = 89.1 -96.9) in Borborema and 25.9% (95% CI = 19.2-34.0) and 18.6% (95% CI = 70.0 - 89.2) in the Zona da Mata / Agreste. ), the associated factors were: milking (PR = 1.7), herd size> 23 animals (PR = 2.1), artificial insemination (PR = 1.6), purchase of animals (PR = 1.7) and urban periphery farm (PR = 1.9). No spatial clusters were identified, showing that the infection is evenly distributed throughout the state of Paraíba. In Chapter II, there was a systematic review with metaanalysis about the disease situation worldwide. The results found suggest the free circulation of the virus in the bovine population with the presence of significant associated factors that need to be further investigated for effective infection control.