Ecological plasticity of Echinococcus granulosus Batsch, 1786; Rud., 1801 eggs in the Mountainous Zone of Kabardino-Balkaria

Abstract

The purpose of the research is to study the ecological plasticity of the eggs of Echinococcus granulosus in the mountainous zone of Kabardino-Balkaria.
Materials and methods. In the conditions of biotopes in the foothill zone, we set up experiments to determine the timing of development of the eggs of E. granulosus Batsch, 1786; Rud., 1801. The experiments were carried out using fresh eggs washed from the uterus of the indicated cestode. Egg samples in the amount of 10–15 thousand put on the experimental site monthly from March to November. For this, the eggs of E. granulosus were placed in glass jars, which were then placed on the biological site. To determine the viability of infective elements, samples of soil, water, faeces, hay, silage, and compound feed with parasite eggs were taken daily. In each case, 100 eggs from these samples were examined under a microscope. The possibility of overwintering E. granulosus eggs was studied in the mountainous zone. At the end of November, eggs of E. granulosus were added to samples of soil, water, faeces, hay, silage, and compound feed and left during the winter until March of the next year in the external environment. At the end of the winter period, these samples were examined by ovoscopy methods. The data were processed statistically.
Results and discussion. It has been established that the timing of reaching the infective stage by E. granulosus eggs in dog feces samples is in direct proportion to the ambient temperature. In March, at an average air temperature of 3.2 ºС, helminth eggs reach the infective stage in 27 days, in June and August – 7–9 days. In autumn, with a decrease in temperature, the maturation of the eggs of the parasite slows down. In September (20.6 ºС), the maturation of eggs to the infective stage was noted in 12 days, in November (8.0 ºС) – in 21 days. 28.0; 22.6; 37.4; 81.6; 74.2 and 92.6% of E. granulosus eggs, respectively in samples of soil, water, faeces, hay, silage and compound feed, retained their viability during the winter. On the distant pastures of Kabardino-Balkaria at an altitude of 1000, 1500, 2000, 2500 m above sea level, 3.2–7.6 times more E. granulosus eggs overwinter in the body of terrestrial mollusks than in the soil, which confirms the fact of their active mechanical participation in the contamination of pastures with infective elements and in the implementation of the epizootic process.