Tropical filarial pulmonary eosinophilia (TFPE) is a clinical manifestation of lymphatic filariasis, a parasitic infection caused by filarial nematodes (roundworms) that inhabit the lymphatics and bloodstream. Three species cause human lymphatic filariasis: Wuchereria bancrofti, Brugia malayi, and Brugia timori. Infection is transmitted by mosquito vectors; humans are definitive hosts.
TFPE is caused by an immune hyperresponsiveness to microfilariae trapped in the lungs [1-4]. The syndrome has been termed tropical eosinophilia, tropical pulmonary eosinophilia (TPE), or tropical filarial pulmonary eosinophilia (TFPE).
Issues related to TFPE will be reviewed here. Issues related to lymphatic filariasis are discussed separately. (See "Epidemiology, pathogenesis, and clinical manifestations of lymphatic filariasis" and "Diagnosis, treatment and prevention of lymphatic filariasis".)
TFPE can occur in any tropical area where filariasis occurs and is most common among young adults. It is more common in individuals from the Indian subcontinent, and occurs four to seven times more frequently in males than in females [5,6].
The majority of cases of TFPE occur in endemic areas; cases in nonendemic settings have also been described. In a review of 17 cases observed in Toronto, all received an incorrect diagnosis at presentation (most often asthma), and a median of two consultations was required before the diagnosis was established .