RAMALHO, G. C.; http://lattes.cnpq.br/8424598609544091; RAMALHO, Gisele Cândida.
Resumo:
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.