Natural Products from Plant Diversity and their Potential in Management of Neglected Diseases

Abstract

Conventionally, neglected diseases are considered as a group of 13 infectious diseases that are . endemic in the low income populations in the tropical developing world. They can be classified as those caused by trypanosomal parasites, helminthes, bacteria and viruses. They cause death to an estimated 0.5- 1m people annually. Trypanosomal diseases are represented by Kala-azar or visceral leshmaniasis, African sleeping sickness (African trypanosomiasis) and Chaga's disease (American trypanosomiasis); the current drugs for these diseases are relatively toxic even though the disease is not that lethal. Helminth infections include schistosomiasis treated with the inexpensive praziquantel but which cannot stop re-infection; onchocerciasis (river blindness), on which anthelmintic treatment is being tried; dracunculiasis (guinea worm), which should have been eradicated in 2009; lymphatic filiriasis (elephantiasis), managed by anthelmintic treatments. The others are soil transmitted worms such as ascariasis (round worms), trichuriasis (whipworms) and hookworms which are really best controlled by good hygienic practices. Leprosy, trachoma, Buruli ulcer and cholera represent the prevalent bacterial problems. Viral infections are yellow and dengue fevers caused by flavivirus transmitted by Aedes aegyptii and Japanese encephilitis caused by a flavivirus transmitted by Culex tritaeniorhynchus; the viral infections can be controlled through vaccination (WHO, 2008).