Ectopic Heartworm in an Asymptomatic Canine Patient: Case Report

Abstract

Heartworm disease is a parasitic disease resulting from the infection caused by the nematode Dirofilaria immitis, transmitted through the inoculation of third stage larval forms, after stinging culicidae vectors. It is common in dogs and less frequent in cats, but it also affects other hosts, such as wild carnivores and humans. Its distribution is important worldwide. In Brazil, canine heartworm disease is endemic and it is estimated that the national prevalence is around 23.1%, with its transmission occurring mainly in coastal cities and in hot climates, where there is a greater probability of the development of the vectors. The severity of the disease may be due to the chronicity of this infection and the number of parasites in the vascular lumen, resulting in lesions at the endothelial level and thrombus formations. When the animal is already in a more advanced stage of the disease, it can present vena cava syndrome, which is commonly fatal due to the accumulation of adult parasites that move from the pulmonary arteries and invade the right ventricle and atrium, which can reach the mouth of the vena cava, evolving in this way, to a process of congestion of the venous system. In cases of major infestations and in cases where the animal has intolerance to physical exercise, activity should not be forced, as this can stimulate the translocation of the parasites, leading to an embolic obstructive process. Cases of erratic cycles are rarely reported, and when they occur, they affect animals with a high rate of infestation. The present study aims to report a clinical case of an asymptomatic patient, with an erratic manifestation of the disease, perceived in the abdominal cavity after undergoing an ovariohysterectomy surgical procedure. Some tests were carried out, after detecting the adult worm in the surgical procedure, to assess the stage of the disease. However, they did not show significant changes. A treatment protocol was started, using doxycycline as a basis for the control of the symbiotic bacteria for the nematode, Wolbachia spp. associated with macrocyclic lactone (moxidectin), as a way of controlling microfilaremia. The patient remains under observation, with no clinical signs.