Heartworm disease in a dog in the region of Maringá, PR, Brasil – case report

Abstract

Heartworm disease (Dirofilaria spp) is zoonosis transmitted by hematophagous mosquitoes. It has a larval phase, microfilaremia, and an adult phase. The infestation with the adult form is typically manifested by the presence of worms in the cardiac chambers, which can cause right congestive heart failure and caudal vena cava syndrome. We describe a case in which microfilaremia was confirmed by rapid ELISA and direct parazitologic examination in an asymptomatic dog in Maringá, PR, region with no previous reports of canine dirofilariasis. Echo Doppler Cardiography showed no evidence of adult form in cardiac chambers of the dog. The patient was treated with subcutaneous administration of ivermectin (50 µg/kg) three times with an interval of 60 days between doses, and doxycycline (10 mg/kg day) for 30 days, along with the third dose of ivermectin. A repellent collar based on imidacloprid was prescribed for continuous use. Sixty day after beginning the treatment, the patient was reevaluated, and blood samples were negative for the presence of microfilariae. Heartworm disease can remain silent in dogs, and it may be emerging in the region. The ubiquitous presence of vectors is a cause for concern and could contribute to disease spreading in the region of North Paraná, Brazil.