Seroprevalence, geographic distribution and risk factor analysis of Borrelia burgdorferi sensu lato in naturally exposed dogs of Iran

Abstract

Lyme borreliosis is a worldwide tick-borne zoonotic disease caused by spirochetes of the Borrelia burgdorferi sensu lato group. The aims of the current study were to determine seroprevalence of lyme borreliosis caused by B. burgdorferi sensu lato among dogs and to analyze its environmental risk factors in Iran. Blood samples were collected from 273 asymptomatic dogs in three northern Caspian provinces of Iran, known habitats of Ixodes ricinus ticks. Enzyme-linked immunosorbent assay (ELISA) and Western blot were used as screening and confirmatory tests, respectively. For evaluation of environmental risk factors, a geographic information system (GIS) was utilized. A logistic regression model was developed to analyze multiple risk factors associated with seropositivity. Of 273 serum samples from the studied area, 22 (8.1%) showed antibodies against B. burgdorferi sensu lato. Out of the seven protein bands analyzed by Western blot, OspC, flagellin and OspA were found at highest proportions. Dogs living in forested areas, at altitudes ≤ 200 m, with tick infestation and between 3 and 5 years of age exhibited higher risk of infection than other dogs (P < 0.05). The majority (97.3%) of ticks collected from the sampled dogs were identified as Rhipicephalus spp., while only 2.7% were I. ricinus.