Detection of living adult Wuchereria bancrofti in a patient with tropical pulmonary eosinophilia

Tropical pulmonary eosinophilia (TPE) is a relatively unusual and diagnostically challenging manifestation of infection with Wuchereria bancrofti. The pathogenesis of TPE remains unclear, although immune hyperresponsiveness to the microfilarial stage of the parasite is thought to play an essencial role. Microfilariae are almost never detected in the peripheral blood of persons with TPE and living adult worms have not been reported. Thus, no parasitologic marker has existed with which to assess the effectiveness of antifilarial treatment. In 1986, a 74-year old man from Olinda, Pernambuco, Brazil, developed classic signs and symptoms of filarial TPE. Within 48 h after beginning treatment with diethylcarbamazine (DEC), the drug of choice for TPE, his symptoms dramatically improved. He remained symptom-free until June 1994, when he again developed signs and symptoms of TPE. To visualize the adult worm and monitor the macrofilaricidal effectiveness of DEC treatment, ultrasound examinations of the scrotal area were performed before, during, and for 6 months after treatment. These examinations revealed diffuse dilatation of the lymphatic vessels of the spermatic cord and movements characteristic of living adult W. bancrofti known as the "filaria dance sign". Although the patient responded clinically to treatment, no change was noted in the filaria dance sign throughout the observation period. Visualization of adult W. bancrofti by ultrasound can be used to monitor the parasitologic effectiveness of treatment for TPE and to explore the relationship between death of the adult worm and recurrence of symptoms.