Case report of a triple vector-borne infection in a dog: co-infection with Anaplasma phagocytophilum, Babesia spp., and Dirofilaria repens in North-Eastern Poland.

Background: This is the first case of triple co-infection with vector-borne diseases confirmed by blood smear results and molecular confirmation of the anaplasmosis and dirofilariosis in a dog from North-Eastern Poland.

Case presentation: A 4-year-old, uncastrated male Central Asian Shepherd Dog with symptoms of apathy and lack of appetite was diagnosed with triple vector disease infection. Microscopic examination of a blood smear revealed the presence of Babesia spp., Anaplasma phagocytophilum and microfilariae. PCR confirmed the presence of A. phagocytophilum and Dirofilaria repens. Clinical examination revealed elevated core body temperature and thrombocytopenia. Treatment for the identified pathogens was initiated. Complete improvement of clinical condition was observed on the second day of treatment.

Conclusion: The detection of three different pathogens in a blood smear is not often reported, but it can significantly speed up the diagnosis and initiation of targeted treatment. It should be confirmed using molecular methods, which are commonly used in companion animals, especially for diagnosing co-infections.