Cross-sectional survey for canine leptospirosis in an Atlantic Rainforest area of the semiarid of Paraíba state, Northeastern Brazil

Abstract

Leptospirosis is a worldwide zoonosis caused by the bacteria Leptospira spp. that affects humans, domestic and wild animals. The present work aimed to conduct a cross-sectional survey for leptospirosis in the canine population of the Brejo Paraibano microregion, semiarid of Northeastern Brazil. From May to October 2017, blood samples from 414 dogs were collected in the counties of Alagoa Grande (n=100), Areia (n=79), Bananeiras (n=72), Alagoa Nova (n=73), Serrraria (n=25), Pilões (n=25), Borborema (n=20) and Matinhas (n=20). The tutors of the sampled dogs answered an epidemiological questionnaire, obtaining information about the animals, owner, residence and breeding of the dogs. Subsequently, the serum samples were subjected to the microscopic agglutination test (MAT), using a collection of 23 serovar pathogenic antigens and using the 1:50 dilution as the cutoff point. Of the 414 dogs analyzed 52 were seroreactive, resulting in an apparent prevalence of 12.6% and a real prevalence of 12.2%. Seroreactive dogs were found in the eight counties. Dogs were reactive for the serogroups Icterohaemorrhagiae (76.9%), Autumnalis (13.55%), Pomona (3.8%), Grippotyphosa (3.8%) and Serjoe (1.9%) Antibody titers ranged from 50 to 800. The statistical analysis (robust Poisson regression) detected six factors associated with seropositivity, including the rainy season (prevalence ratio; PR=1.94, P=0.013), male dogs (PR=2.10, P=0.005), animals with age greater than five years (PR=4.21, P=0.012), consumption of untreated water (PR=1.87, P=0.043), free access of dogs to street (PR=2.15, P=0.011) and contact with wildlife (PR=3.54, P=0.050). The serogroup Icterohaemorrhagiae has a high zoonotic potential and was the most frequent in seropositive animals. The high real prevalence of Leptospira spp. in a transmission region of the semiarid region of Paraíba and the occurrence of seroreactive animals in all the counties suggest wide distribution of the infection and reinforce the need for preventive measures to avoid infection in pets and, consequently, to humans. The analysis of factors associated with the prevalence suggest greater manegment cares with the dogs.