DIAGNOSIS OF MICROFILARIASIS IN THE MUNICIPALITY OF FRANCA, SÃO PAULO: A CASE REPORT IN A DOG

Abstract

Infections by filarial nematodes are responsible for producing microfilariae observed in the bloodstream of their domestic hosts. The species responsible for causing filariasis in canines are: Dirofilaria immitis, Dirofilaria rapens, Acanthocheilonema reconditum, and Acanthocheilonema dracuncoloides. Due to the wide geographic distribution of these species, differentiation between them is paramount, since Dirofilaria sp. exhibits high pathogenicity due to its predilection for the cardiovascular system. While infections by Acanthocheilonema sp. are reported as poorly pathogenic and transient, with a predilection for cutaneous, subcutaneous tissue and the peritoneal cavity, the absence of clinical signs makes the infection underdiagnosed. Diagnostic methods are based on the observation of microfilariae present in peripheral blood, morphological differentiation using the Knott test, immunochromatography tests, Polymerase chain reaction (PCR), and cardiological evaluation, such as echocardiography and electrocardiography. This report describes the case of a non-domesticated canine with no clinical history, presenting with extensive skin lesions, apathy, cachexia, and pale mucous membranes. During examinations, microfilariae were noted in the peripheral blood. Due to the worsening of the patient's clinical condition and lack of response to therapy, the dog was euthanized and its carcass submitted to necropsy. The findings suggest the occurrence of microfilariasis as an incidental finding, reinforcing the importance of thorough diagnostic investigation to differentiate between filarial worms of distinct clinical relevance.