To understand better the pathogenesis of filarial infections (onchocerciasis, loiaisis, lymphatic filarasis) clinical assessments of patients with these and other related non-filarial (strongyloides, malaria) infections have been studied in detail. The influence that filarial infections have on the clinical expression of non-filarial infectious diseases have also been studied by performing clinical trials in filarial-endemic regions of the world that are co-endemic for malaria (Mali), tuberculosis (India) and HIV (India). Understanding of the pathogenesis of eosinophil-related disorders has been a major focus of our clinically related studies. Multiple groups of hypereosinophilic patients (parasite-infected, familial hypereosinophilia, idiopathic hypereosinophilic syndrome, benign hypereosinophilia, episodic angioedema with eosinophilia) have been assessed clinically;moreover, lymphocytes (and their subsets) and eosinophils have been examined functionally and at the molecular level (human microarrays and RT-PCR) to identify the molecules and pathways involved in conditions associated with increased blood and tissue eosinophilia as well the fibrosis that the tissue eosinophilia induces. New diagnostic approaches have been developed and utilized for the rapid and specific diagnosis of Strongyloidiasis, loiasis, and onchocerciasis.