LITERATURE REVIEW
2.1 Brief History of Schistosomiasis
Schistosomiasis is a debilitating parasitic disease caused by several species of fluke of the genus Schistosoma, affecting both animals and human. The disease is found in tropical countries in Africa, Eastern-South America, Caribbean, Middle East, and Southern-East Asia. The disease is found as endemic in more than 70 countries, affecting about 200 million people all over the world. Most of the affected people live in the African countries. 80-85% distribution of Schistosomiasis in Sub Saharan Africa has been reported. Schistosomiasis has been spreading in the tropics due to changes in landscape for the establishment of irrigation schemes. Like Malaria, it is characterised by increase in morbidity and mortality and decline in productivity of infected persons. In Nigeria, like many other African countries, schistosomiasis caused to reduce income generation, productivity of workers, farm size, and rate of land clearing. It could therefore be said that the direct impacts caused by schistosomiasis lead to enormous annual economic losses and inhibition of socio-economic development due to low production and income of those people infected. In addition it prevents children from attending school and adults from being productive members of their communities. Of significance is the threat to public health due to natural interactions and hybridization between Schistosoma species. The isolation of a hybrid worm from patients in Senegal which was as a result of hybridization between Schistosoma bovis and Schistosoma haematobium. Schistosomiasis is one of the major veterinary problems in many Africa countries. Cattle infected with Schistosoma bovis develop a syndrome characterized by liver damage, roughness of hair coat, pale mucous membrane, serious emaciation and a very poor reproductive performance that results in a significant economic down turn and a threat to public health (Hambali et al., 2016; Usman et al., 2016).