Tropical pulmonary eosinophilia and filariasis in Pakistan

Filariasis is a major health problem in South Asia, particularly India, Sri Lanka and Bangladesh. Pakistan was presumed to be not affected. We report for the first time confirmed cases of tropical pulmonary eosinophilia (TPE) in indigenous patients as a result of infection with Wuchereria bancrofti. Following clinical examination, total leukocyte and eosinophil counts were recorded. Parasitological examinations included blood for microfilariae and stool and urine for eggs of intestinal parasites. Total immunoglobulin (Ig) E and specific antifilarial IgG were measured. Suspected cases of TPE were treated with diethylcarbamazine, 6 mg/kg for four weeks and were followed up to 2 and 4 weeks after treatment. Four persons fulfilled the criteria for TPE. Their response to treatment was marked with clinical improvement, reduction in eosinophil count and reduced titers of specific antifilarial antibodies. Two persons had W. bancrofti antigen in their sera confirmed by filariasis antigen detection test. Tropical pulmonary eosinophilia due to Wuchereria. bancrofti, although rare, is present in Pakistan.