Differential diagnosis of Dirofilaria immitis nematodes (Nematoda, Onchocercidae)

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Kryvoruchenko, D.
Prykhodko, Y.
Mazannyі, O.
Titarenko, O. V.
Reva, I.
Sherstiuk, L.
Тітаренко, Олена Вікторівна
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Heartworm disease is a widespread anthropozoonotic disease of carnivorous animals, as well as humans. It is caused by nematodes belonging to the suborder Filariata, family Onchocercidae, genus Dirofilaria. There are about 26 species of heartworms in nature, the most common and pathogenic species in dogs and cats in most countries is Dirofilaria immitis Leidy, 1856. Mature helminths parasitize in the right ventricle and pulmonary arteries, large veins of animals and cause heart and vascular disorders, and death. Therefore, the aim of the study was to investigate the features of morphological and metric structure of adult nematodes of D. immitis isolated from the heart of dogs. Morphological studies have shown that in males the most characteristic differential features are the presence of two unequal spi-cules, specifically positioned relative to each other, as well as well-defined preanal and less pronounced adanal and postanal papillae. In female heartworms, the characteristic morphological features are the shape and location of the vulva. There is a difference in the struc-ture of the esophagus in males and females. In females, the anterior and posterior parts of the esophagus are well expressed, with enlarge-ments, in males these divisions are not pronounced. To increase the efficiency of species identification of D. immitis nematodes, it is pro-posed to use metric parameters that characterize the overall body size, body and width of esophagus in different areas, length of esophagus, and the location of the nerve ring. In males, 11 indicators are also suggested that characterize the size of the spicules and the location of the cloaca. In females, seven additional parameters are pointed out that characterize the location of the vulva, anus and body width in these areas. The obtained data expand the already existing data on the peculiarities of the morphological structure of parasitic nematodes of the species D. immitis and their identification.
dirofilariasis; dogs; helminths; morphological characters; species characteristics