Dirofilaria immitis: incidência, fatores associados à infecção e concomitância com leishmaniose e tumor venéreo transmissível em cães no semiárido do Nordeste, Brasil.

Abstract

This dissertation consists of two chapters composed of one scientific article each, produced through research on the nematode Dirofilaria immitis in dogs in the semiarid region of Paraíba. The first article, entitled “Incidence and factors associated with Dirofilaria immitis in dogs in the semiarid region of Northeastern Brazil”, was submitted to the journal Veterinary Parasitology: Regional Studies and Reports. The objective of this study was to determine the incidence, risk factors and efficacy of diagnostic tests for D. immitis in dogs from the Municipal Kennel of Sousa, Paraíba. Immunochromatographic test, modified Knott test, peripheral blood smear and capillary blood smear, and necropsy tests were performed in 100 dogs, in addition to data collection such as age, sex, breed, length and coat color, and whether the animal was reactive for Canine Visceral Leishmaniasis (CVL). Univariate and multivariate analyzes were performed to interpret the data obtained, in addition to the kappa coefficient (p≤0.05), sensitivity, specificity, positive predictive value, and negative predictive value to assess the effectiveness of the tests. Necropsy was considered the gold standard, and an incidence of 27% of dogs with adult D. immitis parasite was obtained. In 13% of the animals antigens of D. immitis were detected through the rapid immunochromatographic test. Kappa coefficient analysis resulted in moderate agreement (k=0.576; p>0.001) between necropsy and rapid immunochromatographic tests. In addition, the sensitivity values (0.4814) and NPV (0.8390) were higher when compared to other tests, confirming that the immunochromatographic test was considered the most effective to be used in the diagnosis in live animals. CVL was considered a statistically significant factor (p=0.03), being a risk factor for parasitosis. The second article, entitled “Dirofilariasis, Leishmaniasis and Transmissible Venereal Tumor: concomitant affections in dogs in the Paraíba backwoods”, to be submitted to the journal Acta Scientiae Veterinariae, aimed to report cases of D. immitis, CVL and TVT under concomitant presentation in dogs necropsied at the Animal Pathology Laboratory (LPA) of the Federal University of Campina Grande (UFCG). For this, we reviewed the necropsy records performed on dogs in the years 2003 to 2019, and selected the cases of D. immitis and associated diseases, for data collection such as sex, breed, age, origin, clinical signs and pathological findings. Of 2465 dogs necropsied during the study period, four had D. immitis and leishmaniasis (4/4) and two also had TVT (2/4). On macroscopic examination, the main findings were reactive lymph nodes, splenomegaly with lymphoid follicle hyperplasia, and the presence of D. immitis in the right ventricle of the heart and pulmonary trunk. Histopathological evaluation showed amastigote figures of Leishmania spp. in bone marrow, lymph nodes, spleen and skin, as well as membranoproliferative glomerulonephritis in the kidneys and densely cellular and expansive round cell neoformation in the penis of two dogs, characteristic of TVT. Through these studies, it is possible to determine the incidence of D. immitis in the semiarid region of Paraíba, in addition to describing the occurrence of important concomitant diseases, as they are transmissible, and of veterinary medical interest and unique health.