STUDIES ON THE TRYPANOCIDAL ACTIVITIES OF SOME ANGIOSPERMS AND FUNGI AGAINST TRYPANOSOMA BRUCEI BRUCEI AND TRYPANOSOMA CONGOLENSE

STUDIES ON THE TRYPANOCIDAL ACTIVITIES OF SOME ANGIOSPERMS AND FUNGI AGAINST TRYPANOSOMA BRUCEI BRUCEI AND TRYPANOSOMA CONGOLENSE

CHAPTER ONE

1.0         INTRODUCTION

1.1         Introduction

African trypanosomiasis is an important unicellular blood protozoan parasitic disease of both humans and animals. The disease in animal is commonly called Nagana in Zululand which means powerless, useless, or depressed spirits. It is mainly transmitted cyclically by tsetse fly of Glossina species and mechanically by other biting flies(WHO, 2014). Different species of trypanosomes infects cattle and other ruminants. These include Trypanosoma brucei brucei, Trypanosoma congolense and Trypanosoma vivax. The two species infective to humans are Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense in humans (Nok and Nock, 2002; WHO, 2014). Nagana has become a major hindrance to livestock production where it thrives in different parts of Sub Saharan Africa restricted to latitude of about 15⁰N and 29⁰S of the equator which covers over 10 million km²(Delespaux,2010).

Reports of drug resistance or treatment failure, to limited classes of available trypanocideshas been on the increase (Shaba et al., 2012). There is a resurgence of the disease in the endemic regions of Africa, where millions of human population and cattle are affected with considerable morbidity and mortality (WHO, 2006; Merck, 2010). Estimated losses in agricultural production as a result of the disease are approximately 3 billion pounds annually (Shimelis et al., 2011; Tesfaheywet and Abraham, 2012).

After continued effort especially in the control of the fly vector, there has been decline in number of new cases. The number of Human African Trypanosomiasis (HAT) casereported in 2012 is about 6, 314 new cases(WHO, 2012).

However, the estimated numberof actual human cases is about 20,000 while the estimated population at risk is 65 million people (WHO, 2014). African Trypanosomiasis remains a disease with unsatisfactory medical control to date. The control of Human African Trypanosomiasis (HAT) continues to rely principally on old expensive medicines such as pentamidine, nitrofurans and arsenicals (Delespaux et al., 2010; Vitouley et al., 2011). In recent times, drug development has led to the production of eflornithine (DMFO) as the only new trypanocide in the last fifteen years and it is only effective in the last stage of Gambian sleeping sickness and its regimen is complex and difficult toapply (Priotto, 2009).

STUDIES ON THE TRYPANOCIDAL ACTIVITIES OF SOME ANGIOSPERMS AND FUNGI AGAINST TRYPANOSOMA BRUCEI BRUCEI AND TRYPANOSOMA CONGOLENSE