Filariasis eradication on Kinmen Proper, Kinmen (Quemoy) Islands, Republic of China.

A control program for bancroftian filariasis was conducted on Kinmen Proper from 1970 to 1982. The combined method of mass chemotherapy with diethylcarbamazine (DEC) for microfilarial carriers and larvicide with sumithion for mosquitoes was used on the island for 3 years (1974-76). The microfilarial rate and microfilarial density decreased from 8.4% and 14.6/20 microns in 1970-73 to 0.7% and 5.3/20 microns in 1976. The infection rate, infective rate, and larval density of Culex quinquefasciatus, the only mosquito vector of the parasite, decreased from 10.3%, 6.4%, and 6.4 in 1970-73 to 0.3%, 0.2%, and 1.3, in 1976, respectively. For final elimination of the infection, DEC medicated salt (0.33%, w/w) was then administered to the whole population for 6 months (March-September 1977). All accepted the program and no adverse side-effects were noted. Six annual follow-up surveys (1977-82) revealed only 3 out of 3853 previous carriers to be positive. These carriers were cured with a course of 5 g DEC. All family members of the 3 carriers and of the 12 neighbouring families were also given DEC medicated salt for 4 months in order to clear the only remaining source of filarial transmission. In conclusion, administration of DEC medicated salt is simple, rapid, safe, inexpensive, efficient, and practical for filariasis control or eradication.