Occurrence of microfilaremia in dogs (Canis familiaris) from municipalities in Rio de Janeiro

Abstract

This work aimed to carry out the epidemiological survey of dogs with microfilaremia in a Veterinary Diagnostic Center located in the city of Niterói, state of Rio de Janeiro. Microfilaremia can be caused by several species of filarids, such as Dirofilaria immitis, Dirofilaria repens and Acanthocheilonema reconditum. These species release microfilariae into the bloodstream of their infected host, being the species that most affects dogs, Dirofilaria immitis, which causes the parasitosis called canine dirofilariasis. In order to carry out this study, 10,996 hematological exams were analyzed, from January to September 2020, of which 292 were positive (2.66%) for microfilaremia, 284 (97.26%) using the blood smear technique, two (0.70%) using the thick drop technique and six (2.05%) using both methods. Data were collected from the municipalities of Niterói (36%), São Gonçalo (30.5%), Maricá (29.5%) and Itaboraí (4.1%). The month of January had 42 positive cases (3.77%), February 34 (3.48%), March 9 (0.86%), April 41 (4.15%), May 42 (3.54%), June 40 (2.45%), July 48 (3.45%), August 17 (1.12%) and September 19 (1.37%). Among the animals positive for microfilaremia 147 were males (50.3%), 144 females (49.3%) and 1 was not informed (0.3%), with an average age of 6 years, with no statistical differences found between the genera and breeds of animals. In view of the above, the average number of positive cases for canine microfilaremia was 2.65% in the total number of tests analyzed, emphasizing the importance of hematological findings and the requesting more sensitive methods in the clinical routine.