Ocorrência de hemoparasitas em cães: diagnóstico molecular e avaliação de coinfecções

Abstract

Tick-borne diseases in dogs represent a significant challenge for veterinary practice in urban areas of tropical regions. In São Luís, Maranhão, Brazil, the circulation of pathogens from the genera Ehrlichia, Anaplasma, Babesia, and Hepatozoon has been presumed based on previous serological studies, but remains poorly documented using molecular methods that allow sensitive detection, species-level identification, and assessment of coinfections. This study aimed to estimate the frequency of these agents and describe coinfection patterns in dogs treated at the Veterinary Hospital “Francisco Edilberto Uchoa Lopes” of the State University of Maranhão. A molecular survey was conducted using 200 whole blood samples collected between November 2024 and September 2025. DNA was extracted using a commercial kit, followed by screening with multiplex qPCR for Ehrlichia canis, Anaplasma platys, and Babesia spp., and nested PCR for Hepatozoon spp. Positive samples were confirmed by Sanger sequencing and BLASTn analysis. Overall, 39% (78/200) of samples were positive for at least one agent: 23% (46/200) for E. canis, 16.5% (33/200) for A. platys, 13% (26/200) for Babesia spp., and 3% (6/200) for Hepatozoon spp. Among positive samples, 32 presented coinfections. The most frequent association was A. platys + E. canis (10%; 20/200), followed by E. canis + Babesia spp. (4.5%; 9/200). Other combinations occurred at a frequency of 0.5% each (1/200): A. platys + Babesia spp., E. canis + Hepatozoon spp., and triple coinfection. Sequencing confirmed Babesia vogeli, A. platys, E. canis, and Hepatozoon canis (98.53–100% identity with national and international isolates). No significant differences were observed regarding sex or age group (p > 0.05), although a higher frequency trend was noted in dogs older than 5 years. These findings demonstrate the circulation of hemoparasites in dogs from São Luís, with predominance of E. canis and a notable occurrence of coinfections, contributing to the epidemiological understanding of these infections.