Toxoplasma gondii in owned and stray dogs from a Northwestern region of São Paulo State, Brazil: Seroprevalence and geospatial distribution from a One Health perspective.

BACKGROUND

Toxoplasma gondii is a coccidian parasite capable of infecting all warm-blooded animals, including humans. While most infections are asymptomatic, severe manifestations can occur in immunocompromised individuals and during pregnancy. In dogs, T. gondii infection is not only of clinical significance but also of considerable epidemiological importance, given their close contact with humans and their potential role as sentinels for environmental contamination.

METHODS

Peripheral blood samples were collected from owned and stray dogs at the Zoonosis Control Center in São José do Rio Preto, northwestern São Paulo, Brazil. The presence of anti-T. gondii antibodies was assessed using the modified agglutination test (MAT). Risk factors were analyzed based on individual animal data and the geospatial distribution of positive cases.

RESULTS

Anti-T. gondii antibodies were detected in 132 out of 662 (19.9 %) owned dogs and 52 out of 211 (24.6 %) stray dogs, with an overall seroprevalence of 21.1 %. Among the risk factors analyzed, age and area were significantly associated with seroprevalence in stray dogs. Geospatial analysis identified 34 hotspots and 144 coldspots throughout the city.

DISCUSSION: This is the first study to assess the prevalence and spatial distribution of T. gondii in dogs in this region, confirming broad environmental dissemination of the parasite. The findings highlight the importance of dogs as indicators of environmental contamination and reinforce the need for integrated control strategies under a One Health approach, particularly in high-risk areas for humans and animals.