Episootic situation of dirofilariasis in dogs in Kiev
Authors:   State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination, Lozhkina O. V. , Kupnevska M. V. ,   State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination, Pavlunko V. G. ,   State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination, Lytvynenko S. М. ,   State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination, Omelyanenko M. M. ,   State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination, Lytvynenko V. M. ,   National University of Life and Environmental Sciences of Ukraine
Published: July 2021

In most countries, dogs are more likely to have two types of heartworm pathogens: Dirofilaria repens ‒ localized in the subcutaneous tissue and causes skin lesions and Dirofilaria immitis ‒ parasitizes in the right ventricle and pulmonary arteries and is accompanied by cardiovascular disorders in animals. The increase in the number of dogs infected with heartworms occurs with increasing age, depending on the sex and breed of animals. Laboratory tests are important in diagnosing heartworm disease because the clinical signs are nonspecific. Heartworm disease is a global disease, the geographical area of which continues to increase The aim of the study was to clarify the epizootic situation regarding heartworm disease of dogs in Kyiv, to study the dynamics of the disease for the period 2017-2020, depending on the age of dogs, economic use in the city of Kiev, also to analyze the similarity of pathological and anatomical changes of affected animals by parasites Dirofilaria immitis. The material for the epizootic situation were reports on the results of studies of dogs in Kyiv for 2017-2020 and the results of our own research. Pathological and anatomical examinations were performed in the section hall of the Research Pathomorphology Department of the State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Examination. The object of research is 96 dogs of different ages: puppies up to 1 year, dogs from 1 year to 12 years. Autopsies were performed according to generally accepted methods. According to official research results in Kyiv for 2019 - 2020, heartworm disease has decreased significantly (8 - 5.7%). The highest rate of invasion was in 2017 (29.6%) and with each passing year the percentage of the disease decreased, reaching 5.7% in 2020. This situation may be due to changes in weather and climate conditions (reduced rainfall), timely prevention, treatment and treatment of animals from mosquitoes. According to the results of pathological and anatomical studies, it was found that dogs under 1 year of age were not infested, and with increasing age in animals the incidence rate begins to increase and reaches the highest percentage of infestation in adult animals aged 10-12 years to ‒ 60%. Which is due to biological vectors (infested mosquitoes) and reduced resistance of animals. Pathological autopsy was performed on dogs of different breeds. However, 16 dogs were infected, including: German Shepherds ‒ 7, mestizos ‒ 4, outbred ‒ 5. In general, it is not the breed that affects dogs, but the conditions of keeping and economic use. The intensity of the invasion among service dogs ‒ 12,5%, domestic ‒ 18,2%, among homeless dogs were not found, which indicates a higher resistance of the body to this disease. According to the results of pathological and anatomical autopsies in the corpses of 16 affected animals with heartworms, similar postmortem changes were observed: 1. The presence of parasites Dirofilaria immitis approximately 20-30 cm long of light yellow color in the lumen of the right ventricle in aorta and pulmonary artery in 16 corpses ‒ 100% cases; 2. Acute venous hyperemia and pulmonary edema in 12 corpses ‒ 75% of cases; 3. Dilatation of the right ventricle of the heart in 9 corpses ‒ 56.3%; 4. Aneurysm and thrombosis of the pulmonary artery adjacent to the right ventricle of the heart was found in 8 corpses ‒ 50% probability; 5. Myocardial dystrophy among 8 corpses ‒ 50%; 6. Pericarditis was found in 3 carcasses of animals ‒ 18.8%; 7. Endocarditis in one dog, i.e. ‒ 6.3%; 8. With myocarditis one corpse ‒ 6.3%; 9. Gastro-enteritis was observed in 12 corpses in the total number ‒ 75%, but: catarrhal in 8, catarrhal-hemorrhagic in 3, hemorrhagic in 1; 10. Pneumonia in 3 corpses ‒ 18.8%, distinguishing interstitial, serous-catarrhal, catarrhal-purulent in one case. Own research has established the infestation of dogs with parasites, and the similarity of pathological and anatomical changes at the autopsy of animals depending on age, breed and economic use. In the future, it is planned to conduct histological and histochemical studies of organs in which the presence of helminths Dirofilaria immitis was detected in order to study the characteristic morphological changes.