A review of the current advances on the role of limnology in the epidemiology of schistosomiasis: The snail vector experience

Abstract

Schistosomiasis infection produces a degenerating effect on victims. The areas most affected are the intestinal blood vessels and organs (for Schistosoma mansoni) and the urinary blood vessels and tissues (for S. haematobium). Schistosomiasis, like other parasitic diseases, has pre-disposing factors which, if not avoided, lead to increase in the spread of the disease. The major point of interest in the case of schistosomiasis is its transmission-link with aquatic environment. The intermediate hosts of schistosomiasis are snails and these snails live in the freshwater habitats. The establishment, survival maturity and reproduction of these snails, and consequently schistosomes, are therefore dependent on the limnological characteristics of the water in which they find themselves. Some of these factors include water temperature, water level, calcium hardness, pH, water velocity and aquatic vegetation among other minor intrinsic and extrinsic factors. These limnological factors affect the snail vectors significantly (P<0.05) either positively, neutrally or negatively and the manipulation of these factors have been successfully applied in the control of the snails and subsequently, control of schistosomiasis.