Caracterização epidemiológica da linfadenite caseosa em pequenos ruminantes no Nordeste do Brasil.

Abstract

This thesis consists of three articles. In Chapter I, seroprevalence of C. pseudotuberculosis infection in sheep in Northeastern Brazil was determined by indirect enzyme linked immunosorbent assay (i-ELISA). Samples were collected from 2,638 sheep from 223 farms of five states (Ceara, Paraiba, Piaui, Rio Grande do Norte, and Sergipe). From 2,638 sheep tested, 996 (37.76%; 95% CI = 35.93 - 39.62%) were seroreactives and from 223 properties evaluated, 210 (94.17%; 95% CI = 90.28 - 96, 56%) were positive. The i-ELISA test showed sensitivity and specificity of 91.84% e 97.01%, repectively, proving to be useful in diagnosis of caseous lymphadenitis (CLA) in sheep. In Chapter II, factors associated with seroreactivity for C. pseudotuberculosis in the Northeast region were evaluated. Samples were collected from 2,312 sheep from 196 farms studied in Chapter I. It was identified 93.88% (184/196) of the properties and 37.46% (866/2312) animals with positive serological result for C. pseudotuberculosis. Purebred animals (PR = 1.189; p = 0.017), source of exposure breeder (PR = 1.192; p = 0.020), separate lambs from ewes (PR = 1.132; p = 0.048), lakes water source ( PR = 1.65; p = 0.002) and eliminating infected animals as a control measure (PR = 1.263; p = 0.027) were identified with factors associated with seropositivity. Measures to increase disease control are recommended in purebred animals that participate in agglomerations of animals, to reduce environmental contamination by the agent, stress in handling weaning, proper disposal of the infected and isolation with inspection on recently acquired animals before introducing them to herds, as well as to encourage the use of early diagnosis and vaccination to reduce the occurrence of the disease. In Chapter III a seroprevalence study of caseous lymphadenitis was conducted in goats sold in animals fair on northeastern semiarid. Samples were collected from 233 goats and the diagnostic was performed by the i-ELISA. Eighty-seven (37.34%; 95% CI = 31.38 - 43.71%) seroreacitive goats were identified. C. pseudotuberculosis infection is present in marketed goat herds. Policies to encourage early access to disease diagnosis by producers and the implementation of a CLA control program are recommended to reduce the high prevalence observed in farms and animals.