BIOTOPES OF INTERMEDIATE HOSTS
OF FASCIOLA HEPATICA ON TRANSFORMED LANDSCAPES
S. M. Shermatov
Naryn State Univercity, Naryn, Kyrgyz Republic, E-mail: email@example.com
Key words: Fasciola hepatica, Lymnaea truncatula, biotopes, biogeocenos
С. М. Шерматов
Нарынский государственный университет, г. Нарын, Киргизская Республика,
Ключевые слова: Fasciola hepatica, Lymnaea truncatula, биотопы, биогеоценозы
Currently, in connection with the arisen serious economic problems in the field of an agriculture, veterinary science and medicine, the question is especially sharply put before science on the necessity of deeply researching mechanisms of an intensification of individual farms influencing the environment. Agricultural and domestic animals are in close relation with the society and of a very special social importance. These animals, being also the objects of human habitat, are included in its common environment together with it and exposed to pollution. On of the sources of the environmental pollution is receipt in environment of various biological agents – activators contagious and invasive illnesses. Hence, specific groups of helminthes can spread and get new aerials where there are kinds necessary for them – definitive and intermediate owners. The separate ingredients of biogeocenosis, in particular the soil, pastures and reservoirs at specific favorable geo- and hydrobiological conditions can be a source of infection of animals with helminthes.
A nature of the «parasite–host» system is also changed, disturbing the existing, which becomes a reason for the extension of the parasites natural habitat, and as a result, the reason for contamination by parasites. Thus, the irrigation of lands allocated for agricultural crops, located near pastures, resulted in creation of small lakes, bogs, ponds with low running water, mochezhinas, which were the main biotopes of fresh-water mollusks. According to the data of the State Land Cadastre 89,3 th. ha (0,9 %) of agricultural arable lands, including 79,1 th. ha of pastures, is swamped at present in the KyrgyzRepublic, the area of irrigated swamped pastures is 1,4 th. ha.
Under the natural-climatic conditions of the Internal Tien-Shan a distribution of trematodas, in particular, fascioliasis of agricultural cattle, has a zonal nature, i. e. it is connected with a place of habitat of the intermediary host-fresh-water mollusk – Lymnaea truncatula and Lymnaea pervica. In spite of the fact that there is a voluminous literature devoted to ordinary fasciole, the ecological–parasitical investigations of pastures in the aspect of agricultural cattle fascioliasis, as well as the matters connected with a biotopical existence of intermediary hosts of fascioles – fresh-water mollusks in transformed meadow–pasture biogeocenoses – are not sufficiently carried out. The investigations of fresh-water mollusks in transformed meadow–pasture biogeocenoses – are not sufficiently carried out. The investigations of fresh-water mollusks place of habitat were implemented on the inter-farm pastures of At-Bashi depression of the Internal Tien-Shan. According to the climatic conditions the investigated zone is characterized by the average annual temperature +4,2°C, in
June–August up to +20…+25°C and by a large humidity. The average annual precipitation is
294–332 mm. lts maximum is observed during the spring–summer period.
The field investigations revealed that biotopes of fresh-water mollusks were spread basically on the inter-farm pastures, which represented the excessively moistened areas. Under the conditions of the increased sub-soil moistening there are developed mountainous-meadow-chestnut soils with a rich meadow vegetation. Hygrophilous, basically rhizome, more rarely tussock perennial herbs, dominated in the vegetation cover. A level of fresh-water mollusks distribution depended on the nature of ponds. A majority of freshwater mollusk populations inhabited more often the riverside sites, ponds with low running water, and in locations of high occurrence of subsoil water («green lawns»), rich in aquatic vegetation. Such ponds are used usually for cattle watering. The indicator pН of water in such biotopes was within a range of 6,4–7,3, a temperature range was +15,6…+19,8°C, a total hardness was within 0,25–1,34 mg.equiv./l, a content of chlorides was within 1,3–7,5, of calcium – 0,21–0,56 and iron – within 1,67–1,89 mg/1.
It was found out during the investigations, carried out on the flood plains of At-BashiRiver and its tributaries, that biotopes of Lymnaea truncatula were basically small flood plain ponds. And a majority of mollusc populations was available in the well-warmed inshore part of the ponds. A dispersion of molluscs is observed in the bed area of ponds with low running water. A density of mollusc population in such biotopes made up 5–13 specimen/m. Besides, we found out that abundant quantity of precipitation ensured the existence of mollusks in temporary ponds of pastures (low-moistened sites of pastures near forests, microbiotopes– «small pits made by hoofs»). These biotopes were widely spread. More often they were observed in common pastures near populated areas.
The analysis of molluscs invasion testified that on pastures there was observed a certain tendency to the growth of extensive invasion of small mollusc by fascioloses beginning from spring to autumn. In winter molluscs are in hibernation. The decrease of their quantity in early spring is connected with the dying off of old infected specimen. In spring and summer a number of infected molluscs is increased. The first invasion maximum is registered in July. The second peak of a number of infected small mollusc is observed in September and October. This indicator was 3,1 % in the investigated zone.
So, the results of the implemented work justify that all biological and natural preconditions for creation of new hotbeds and increase of extensive fascioliasis invasion are available in the studied zone.
Zoocenosis — 2005
Біорізноманіття та роль зооценозу в природних і антропогенних екосистемах: Матеріали ІІІ Міжнародної наукової конференції. – Д.: Вид-во ДНУ, 2005. – С. 354-356.