SEASONAL DYNAMICS OF CANINE EHRLICHIOSIS: EPIDEMIOLOGICAL PROFILE IN A VETERINARY TEACHING HOSPITAL IN NORTHWESTERN PARANÁ

Abstract

Canine monocytic ehrlichiosis (CME) is an infectious disease caused by the bacterium Ehrlichia canis, transmitted mainly by the tick Rhipicephalus linnaei. The disease affects blood cells, with varied clinical symptoms and difficult diagnosis due to its heterogeneous presentation. The prevalence of CME is high in several regions of Brazil, being a challenge for veterinarians, especially due to the relationship with environmental and biological factors, such as tick infestation. Considering the epidemiological relevance of the disease, the objective of this study was to analyze its prevalence associated with the diagnosis of E. canis in dogs treated at the University Veterinary Hospital of the State University of Maringá,  Umuarama campus, from November 2022 to October 2024. A data survey was carried out in 2,503 clinical records of dogs, diagnosed by immunochromatographic tests or by visualization of intracytoplasmic morulae. The variables analyzed were prevalence, time of year, sex, age group, and history of tick infestation. The results showed a predominance of 7.83%, with a higher incidence in winter (33.7%), in disagreement with previous studies that point to summer as the period of highest prevalence. The research also showed that adult and elderly dogs were the most affected, while puppies had a low prevalence, which corroborates previous findings about the greater susceptibility of adults to the disease. In addition, the presence of ticks was observed in 63.8% of the cases, highlighting the strong correlation between ectoparasite infestation and the development of infection. CME has a high prevalence in dogs treated in the Umuarama region, with factors such as age group and tick infestation influencing the prevalence. The data suggest that tick control, more than seasonality, significantly impacts the primacy of the disease, highlighting the importance of parasite control throughout the year, especially before periods of higher incidence, such as winter and summer.