My clinical work includes gastroenterology, general internal medicine, intestinal infectious diseases, HIV infection and AIDS, travel medicine and medical effects of military occupational environmental exposures, especially in Persian Gulf, Afghanistan, Vietnam (Agent Orange) and Ionizing Radiation exposed veterans. As an Epidemic Intelligence Officer at CDC in Atlanta, Worked in Nigeria in small pox eradication campaign. Worked in Kenya on HIV.

Currently focused on research in intestinal protozoal infections and mucosal immunology. My work has involved delineation of the structure and function of Peyer's patches and other mucosal lymphoid organs, using ultrastructure, immunohistology, morphometric analysis, and FACS analysis in immunocompetent and immunodeficient animal models. Clinical research interests include diarrhea and intestinal infections, identifying the role of opportunistic pathogens including Giardia, Cryptosporidia, Microsporidia and Mycobacterium avium.