Analysis of free-living seabirds from Brazil as potential hosts of Toxoplasma gondii and Leptospira spp

Dispersal patterns of zoonotic pathogens can be strongly influenced by mobility and contact among hosts. Toxoplasmosis has been documented in many avian species, however, there is few information regarding free-living seabird populations. Leptospira can infect domestic and wild animals, with birds being potential carriers of the bacteria. The continental shelf of the southwestern Atlantic Ocean is a foraging area for seabirds breed locally, as well as migratory seabirds wintering in the area, which may come into contact with each other in prey aggregation areas and contribute to Leptospira spread. Therefore, this study aimed to investigate the prevalence of important zoonotic pathogens in free-living seabirds, encompassing species that nest on islands as well as migratory visitors sampled at sea. Blood samples were collected from 322 birds of three local breeders ( Phaethon aethereus , Sula leucogaster and S. dactylatra ) in the eastern coast of Brazil (Abrolhos archipelago), and two migratory species using the area during the pre-laying ( Pterodroma arminjoniana ) and the non-breeding periods ( Thalassarche chlororhynchos ). Serological agglutination tests for detection of anti- Toxoplasma gondii and anti- Leptospira spp. antibodies were performed. None of the seabirds in this study was reagent to anti- Leptospira spp., whereas 34.5% ( n = 111) of the animals presented antibodies against T. gondii . Antibody titers in seropositive birds ranged from 10 to 640. There were seropositive birds in all sampled localities. This study provides the first records for P. arminjoniana and T. chlororhynchos as seropositive to T. gondii , suggesting their potential role as sentinels for the disease. These findings indicate the circulation of the parasite in the Brazilian coastal and oceanic regions, suggesting the influence of anthropogenic activities over the studied regions that could lead to the ingestion of T. gondii oocysts by the birds. The epidemiological involvement of migratory birds as hosts of pathogens, as well as the role of the historical introduction of invasive vertebrates on Brazilian islands. Therefore, seabird colonies need to be better understood to be included in the risk analysis of the wildlife cycle of toxoplasmosis.