Filariasis Control with Diethylcarbamazine in Three Major Endemic Areas in Japan

Hewitt et al. (1947) [1] reported that DEC acted as effective filaricide to Litomosoides carinii in rats. Later, Santiago-Stevenson et al. (1947) [2] showed that this compound was effective in the treatment of Wuchereria bancrofti infection in humans. Hawking et al. (1950) [3] proposed the action mechanism of DEC. Since the extensive studies by Kessel (1957) [4] and his colleagues, the drug’s strong filaricidal activity with few side reactions has been widely recognized and accepted. Studies were thus started by various parasitologists on different dosage regimens for DEC administration. In Japan, immediately after the appearance of DEC, chemotherapeutic studies of filariasis using DEC were performed in the early 1950s in various endemic areas (Katamine, 1952; Kitamura 1951;Nogi et al., 1951; Hayashi et al. 1951; Sasa et al. 1951; Sato et al. 1952) [5-10]. The followings summarize the data reported by those workers and the characteristics of DEC. A more detailed contents of these findings will be seen in the review of Sato (1962) [11]. DEC was able to remarkably clear the microfilaremia of W.bancrofti and Brugia malayi. In the cases of nocturnally periodic filariasis, DEC administration rapidly caused microfilaremia and microfilaruria. Then the rapid reduction of microfilariae was seen in the peripheral blood. DEC caused side reactions, particularly in the first 1-2 days of administration. The reactions included: i) specific allergic reactions such as high fever, swelling of lymph nodes, fatigue, etc.,and ii) toxic reactions such as headache, lumbago, loss of appetite, nausea etc. The intensity of side reactions was dose-dependent, and it was found later that the microfilarial density in the blood was closely related to the degree of fever. The rise of fever was usually accompanied by leukocytosis. A total dose of approximately 70 mg/kg of body weight, to be given in the certain period of days with divided doses, was necessary to obtain long-term clearance of microfilariae in the blood. Eventually a total DEC dose of 72 mg/kg divided in 12-14 days was administered to microfilaria carriers in Japan. Within 24 hours, 60% of DEC was excreted in the urine.