Seroprevalence of Leptospira spp. in horses from Rio Grande do Norte, Brazil

This study aimed to determine the prevalence and risk factors associated with the presence of anti-Leptospira spp. antibodies in horses reared in the Eastern and Western Potiguar mesoregion, State of Rio Grande do Norte, northeastern Brazil. Seven hundred and eighty-five animals (785) were used from 90 properties from 2018 to 2019. The serological diagnosis was performed by the microscopic agglutination technique (MAT), using a collection of live antigens composed of twenty serovars belonging to sixteen serogroups. Variable data associated with risk factors were obtained from questionnaires carried out to herd owners and statistically analyzed. The absolute and relative frequencies were determined by descriptive analysis and risk factors by univariate analysis of the variables using the Pearson’s chi-square test and Fisher’s exact test, when necessary, and then assessed by Poison regression. The positivity frequency among animals was 97.2% (763), and from all properties, there was at least one seropositive animal. The main reactive serogroup was Icterohaemorrhagiae (72.88%), followed by reactive animals to Australis (14,94%), Sejroe (4.43%), Shermani (2.77%), Autumnalis and Pomona (1.29%). It was observed occurrences lower than 1% to serogroups Canicola, Ballum, Grippotyphosa and Hebdomadis, with titles ≤400 in 78,97% of cases. The significant occurrence of seropositive horses and the serogroup Icterohaemorrhagiae predominance highlights the importance of vaccination and hygiene in Potiguares herds facilities to prevent leptospirosis cases and the consequent elimination of the agent in the environment. RESUMO: Este estudo objetivou determinar a prevalência e os fatores de risco associados à presença de anticorpos anti-Leptospira spp. em equinos criados na mesorregião Leste e Oeste Potiguar, estado do Rio Grande do Norte, Nordeste do Brasil. Foram utilizados 785 animais oriundos de noventa propriedades durante o período de 2018 e 2019. O diagnóstico sorológico foi realizado pela técnica de soroaglutinação microscópica (MAT) utilizando coleção de antígenos vivos composta por vinte sorovares, pertencentes a dezesseis sorogrupos. Os dados das variáveis associadas aos fatores de risco que podem predispor a presença de equinos soropositivos, foram obtidos a partir de questionários aplicados aos proprietários dos rebanhos e analisados estatisticamente. As frequências absolutas e relativas foram determinadas por análise descritiva e os fatores de risco por análise