Efficacy of diethylcarbamazine in eradicating infection with lymphatic-dwelling filariae in humans.

Diethylcarbamazine (DEC) is an effective microfilaricidal drug against Wuchereria bancrofti, Brugia malayi, and Brugia timori--the three lymphatic-dwelling filariae infecting humans. However, effectiveness in killing the adult stage of these parasites has been more difficult to establish. The present review of available evidence from the literature suggests that: (1) in addition to being a microfilaricidal agent, DEC in conventional dosages effectively kills adult worms of these three parasites in many patients; (2) relatively high total dosages of DEC (including dosages considerably in excess of those currently recommended) generally give better long-term therapeutic results than lower dosages; (3) spaced doses of DEC (weekly or monthly) are more effective than the same total dosage given in consecutive daily doses; (4) chronic administration of low-dose DEC, as in medicated salt, can effectively control filariasis caused by W. bancrofti or B. malayi; and (5) rational determination of the DEC regimen ideal for the killing of adult filarial parasites awaits the development of assays capable of sensitively detecting the presence of living adult parasites.