SNAILS AS RISK FACTOR CONTRIBUTING TO FASCIOLIASIS ENDEMICITY IN TWO FOCI IN DAKAHLIA GOVERNORATE
Saedia A. Sayed El-Ahl1, Atef M. A. El Shazly2, Mai A. Hegazi3and Marwa A. El-Dardiry4
Departments of Parasitology, Faculties of Medicine, Al-Azhar University for Girls1, 3 Cairo, Mansoura University2, Mansoura, and Al-Fayoum University4, Al-Fayoum, Egypt.
The snail intermediate host is generally considered as the weak link in the life cycle of Fasciola spp. For continuous progress in controlling fascioliasis in man and animal, destruction of the snail is a must. Consequently, this work surveyed snails’ abundance over one year and clarified some ecological factors affecting them in two main water drainages in Kafr El-Hessa and Aweesh El-Hager villages (Dakahlia governorate). The total recorded species of Lymnaea were: Lymnaea natalensis (4.62%), Lymnaea truncatula (1.68%), Lymnaea stagnalis (1.40%) and Lymnaea columella (0.27%) in both localities. The studied ecological parameters with reflections on the snail’s population, infectivity with immature stages of Fasciola were seasonal variation, water pH, ammonia concentration and salinity. In Kafr El-Hessa and Aweesh El-Hager winter was the season with maximum snail's population (101 & 38 snail/season) followed by spring (69 & 25 snail/season) then autumn (55 & 24 snail/season) while summer was the season with least abundance of snail population (25 & 10 snail/season) respectively. The pH of different studied water bodies ranged from 7.7- 8. Ammonia concentration in the same water bodies was 0.26 & 0.37 ppm, while water salinity was 220&350 ppm with snail infectivity rate of 2.8%&1.03 respectively. These parameters could explain the higher percentage endemicity of fascioliasis in Kafr El-Hessa than Aweesh El Hager village.