The physiological state of the larvae and infestation of domestic ungulates by Echinococcus granulosus (Cyclophyllidea, Taeniidae) in North-Eastern Ukraine

Abstract

Echinococcus granulosus (Batsch, 1786) has a worldwide distribution. Different types of carnivores (dogs, jackals, wolves, foxes), domestic and wild ungulates are included in its life cycle. There are significant differences in its pattern of contamination of domestic ungulates in the various regions of Ukraine. Pigs are major intermediate hosts of E. granulosus in the northern and western regions of the country, sheep and cattle in the southern and eastern regions. These differences are associated with strains of Echinococcus. The article presents the results of research conducted on 1,884 pigs, 1,025 sheep and 1,406 cattle in Polesia and the forest-steppe zone of the north-east of Ukraine. We have established the development of Echinococcus larvae in pigs (extent of invasion 10.2 ± 0.6%) and sheep (extent of invasion 0.7 ± 0.2%). The cysts did not develop in cattle. Pigs generally had a low invasion intensity (less than 6 larvae). A high level of invasion intensity (more than 10 larvae) was infrequently recorded in these animals. All sheep had a low level of invasion intensity.The E. granulosus larvae found in sheep were dead. In pigs, most cysts developed to fertile state (139 cases). Young, sterile and dead larvae were less common (39, 10, 4 cases). Pigs older than 10 months had the highest number of fertile cysts. Young larvae dominated in pigs younger than 10 months. In these animals, larvae were localized predominantly in the liver. The kidneys and lungs were infected less frequently. The large number of fertile cysts in pigs older than 10 months made this group of animals the main intermediate hosts of E. granulosus in the north-eastern part of Ukraine. They enable the parasite to function actively here. Analysis of infestation by E. granulosus larvae of domestic ungulates of the Polesia and the forest-steppe zone showed no significant differences. Identified differences were not statistically confirmed.