HUMAN CERCARIASIS IN AQUATIC ECOSYSTEMS OF UZBEKISTAN

The geography of human cercariasis is extensive. It covers urbanized areas of many modern metropolitan cities. Cercariasis is also known in the inland waters of the Amu Darya and Zarafshan River basins (within Uzbekistan). The causative agents of cercariasis consist of two clearly differentiated cercariae groups: Schistosoma and Bilharziella. The article presents the results of field and experimental studies on nonspecific human cercariasis caused by cercariae Schistosoma turkestanicum and Trichobilharzia ocellata in various reservoirs of Uzbekistan. In this paper, the studies were conducted in Uzbekistan in 2020–2022. The material was collected in the delta and floodplain reservoirs of the Amu Darya and Zarafshan rivers. The material was collected in the deltaic and bottomland water bodies of the Amu Darya and Zarafshan Rivers which were intensively visited by water birds and mammals. In different seasons of the year, spring, summer, and autumn, more than 25 thousand specimens of freshwater mollusks belonging to the families Lymnaeidae, Planorbidae, Physidae and Thiaridae were collected and studied. Morphological study of cercariae was conducted. In different types of reservoirs, the population of mollusks, intermediate hosts, of discussed trematodes, turned out to be quite high. Their total infection with parthenita and the cercariae bilharzia ranged from 0.3 to 6.2% in Lymnaeidae, and 4.0% in Melanoididae. Schistosome larvae (Sch. turkestanicum) infection was only recorded in Lymnaea auricularia (Lymnaeidae), which was 12.6 to 22.6%.