A 60-year-old man from an area endemic for leishmaniasis presented with 2 months of fever and hepatosplenomegaly. He had normal complete blood counts and negative blood and urine cultures. Chest x-ray revealed miliary shadows in both lung fields. A transbronchial lung biopsy showed granulomata with tubercle bacilli.

A bone marrow biopsy, performed as part of an assessment for fever, was normocellular with normal hematopoietic cell lines. However, while screening the marrow for Leishman-Donovan bodies, a few microfilariae were seen (shown). These were identified as Wuchereria bancrofti by the presence of a hyaline sheath, elongated terminal nuclei, length of cephalic space, and the pointed posterior end without terminal or subterminal swellings. On wet mount preparation, the filamentous translucent organisms exhibited brisk motility. Scanty microfilariae were seen on reviewing the blood film. Treatment for tuberculosis and filariasis was initiated.

Tropical pulmonary eosinophilia is usually characterized by cough, fever, and hepatosplenomegaly with an absence of circulating microfilariae, but marked eosinophilia. In this case, the microfilariae in the blood and an absence of peripheral eosinophilia were consistent with asymptomatic microfilaremia. The patient had no history of lymphangitis, hydrocele, or limb swelling. The hepatosplenomegaly and fever might have been caused by concomitant tuberculosis.

India is one of many countries endemic for filariasis. The World Health Organization has recommended the use of mass drug administration (annual dose of diethylcarbamazine with albendazole) to those living in endemic areas in an effort to eliminate the infection.