Caracterização epidemiológica da leptospirose em ovinos no Nordeste do Brasil.

Abstract

This thesis consists of three articles. In Chapter I, seroprevalence, most frequent serogroups and factors associated with infection by Leptospira sp. in sheep flocks belonging to two biomes in northeastern Brazil. The frequency of seroreactive sheep (titer ≥ 50) for Leptospira sp. was e 23.3%. The state of Alagoas presented the highest frequency 31.7%, Maranhão 13.3%. The most frequent serogroups for the state of Alagoas were Autumnalis (54.2%) and Icterohaemorrhagiae (18.3%), while for Maranhão they were Pomona (37.2%) and Icterohaemorrhagiae (23.3%). It is concluded that leptospirosis is present in sheep in the Caatinga and Cerrado biomes, with several circulating serogroups, which represents a risk to public health and a problem in animal production. In Chapter II, the factors associated with the seroprevalence of leptospirosis in sheep in Northeast Brazil were determined. In 76.3% of the herds there was at least one animal seropositive for one of the serogroups of Leptospira sp. used, and 14.94% of the animals were seropositive (95% CI = 0.138 0.1618). The state of Paraíba had the highest prevalence at the 95.7% flock level and 26.6% at the animal level, followed by Ceará. The factors associated with seroprevalence obtained were adult age (prevalence ratio PR = 2.03; P < 0.001), absence of dung (PR = 2.14; P = 0.026), not collecting the sheep herd for shelter (PR = 1.54; P = 0.021), high mortality at weaning (RP = 1.39; P = 0.013), provide well water for animals (RP = 1.25; P = 0.034) and do not supply cistern water to animals animals (PR = 2.15; P = 0.002). Factors associated with seropositivity demonstrate the need for the implementation of control and prevention measures, aiming to reduce leptospira infection in sheep, such as the installation of dung warehouses, aiming to reduce environmental contamination; the herd for shelter properly sanitized, provide better quality water for the animals, such as cistern water and the installation of an area to accompany the animals in the puerperium, in order to reduce mortality at weaning. In Chapter III, seroprevalence and spatial distribution were determined of the most frequent serogroups hot for infection by Leptospira sp. in sheep flocks from Northeastern Brazil. Of the 4,197 sheep blood serum samples analyzed, 590 were seropositive (titer ≥ 100) for Leptospira spp., Resulting in a frequency of 14.06% (95% CI = 0.1304 0.1514). The states of Alagoas, Ceará, Paraíba, Piauí, Rio Grande do Norte and Sergipe belonging to the Caatinga biome, presented higher frequencies of seroreagent sheep, Maranhão presented a lower frequency. The highest frequencies of seropositive animals were obtained in the municipalities of União (50%), Passagem (49.06%), Canindé (48.89%), Igaci (28.95%), Gararu (31.2%), Pirapemas (17.5%) and Angicos (16%) located in the states of Piauí, Paraíba, Ceará, Alagoas, Sergipe and Rio Grande do Norte, respectively. The results of this study demonstrate the extent and distribution of Leptospira spp. in sheep in the Northeast of Brazil. Intraspecies transmission seems to be the main route of spread of the disease in sheep, although other species of domestic and wild animals are important sources of infection.