Aetiology of endomyocardial fibrosis (EMF).

On epidemiological basis EMF behaves like a vector transmitted disease. The cardiac pathologies of EMF and HES are identical. In some cases of HES, hypereosinophilia may return to normal, leaving residual heart disease that is exactly like EMF. Most temporary residents from Europe and North America who developed EMF while resident in the endemic areas of Africa had hypereosinophilia that was induced by helminths. In our case studies from the EMF endemic areas of Nigeria, most children with acute idiopathic myocarditis associated with helminth induced hypereosinophilia, developed clinical EMF on follow up. We showed also that the rate of decline in the incidence of hypereosinophilia in EMF cases was significantly related to the duration of symptoms. Our studies and other observations show that EMF, like HES is a multiple system disease with similar organ damage. The morphologic evolution of cardiac damage in EMF appears similar to that reported for HES; with a stage of myocarditis/pericarditis, followed by a stage of cardiac necrosis, a stage of thrombosis and by the chronic fibrotic stage. Also during larval migration, all the helminths associated with EMF induce the same spectrum of damage in the central and peripheral nervous system, in the lungs, kidneys and skin, as are reported for HES. The cardiovascular damage reported for these worms (which include hypersensitivity vasculitis, acute myocarditis/ pericarditis) are also similar to what is reported for HES. Acute endomyocardial necrosis and thrombosis that are similar to what is found in HES, have been documented in Trichinella Spiralis and in filariasis. Increased cerium concentrations have been documented in the endocardium of EMF cases from South India. It remains to be established whether cerium excess, which is known to stimulate collagen synthesis does accelerate the process of endomyocardial fibrosis, following cardiac necrosis (which may have been triggered by helminths and the associated hypereosinophilia).