Evaluationof Molluscicidal And Antischistosomal Activities Of Selected Medicinal Plants Traditionally Used In Makueni County-Kenya

ABSTRACT

Schistosomiasis (also known as Bilharzia) is a disease caused by species of parasitic worms or helminths of the genus Schistosoma. It continues to be a serious world wide public health problem. The pathological changes in schistosome infestations are caused mainly by the deposition of the eggs into various tissues and organs where granulomas or pseudo tubercles are formed around them. Schistosomes and their intermediate snail hosts are integral parts of the freshwater aquatic environments in which they are found. Biomphalaria and Bulinus are the two primary genera of snails capable of harbouring infections with Schistosoma mansoni and Schistosoma. haematobium. Some of the methods of controlling of schistosomiasis include: control of snails, public health education, sanitation, and community-based chemotherapy employing praziquantel. No single method, regardless of location, has been shown to work because of the large number of environmental variables involved in the parasitic transmission. Some of the control programmes include curbing transmission. The objective of this study was to bioscreen aqueous extracts of five medicinal plants identified using ethnobotanical and pharmacological information gathered from traditional healers for molluscicidal and antischistosomal activity. Molluscicidal activity was assessed by determining the ability of various concentrations of the aqueous plant extracts to kill adult Biomphalaria pfeifferi, the intermediate host ofS. mansoni. The antischistosomal effect was determined by oral administration of various concentrations of the aqueous plant extracts to S.mansoni infected BALB/c mice, and observing the effects of these extracts on the worm burden, histological sections of the liver and serum IgG levels of the infected mice.Amaranthus hybriduscaused the greatestmortality to Biomphalaria pfeifferi of 44.0±2.3. This value was considered statistically significant compared to the reference molluscide Niclosamide which caused mortality of 48.67±0.7. Azadirachta indica exhibitedthe most encouraging antischistosomal effects. This was determined using the following parameters: least worm recovery of 6.8±3.1 compared to praziquantel which exhibited 4.8±3.1; least mean granuloma diameter of 7.6±3.4 μM compared to praziquantel which showed 5.6±1.1 μM, and greater ability to boost immunological response.Based on these findings it was concluded in this study that Azadirachta indicaand Amaranthus hybridus have antischistosomal and molluscicidal activity respectively, and recommends that toxicity studies be conducted to establish their safety in bilharzia control.