[Epidemiological characteristics and control of filariasis in Hunan Province]

Of 98 counties or cities in Hunan Province, 55 were endemic areas of filariasis. The average microfilaria rate was 5.64% (180,046/3,194,102), and the incidence of advanced filariasis, including elephantiasis and hydrocele was 3.29%. The number of filariasis patients in the whole province was estimated to be 1.63 million, comprising 1.25 million of microfilaremia cases, Culex fatigans and Anopheles hyrcanus sinensis were the major vectors of bancroftian and malayan filariasis respectively in the province. Control strategies concentrated on the elimination of infection source were implemented on the basis of extensive investigations, and the ensuing examination and treatment of filariasis cases in pilot areas prior to the implementation of province-wide filariasis control. Repeated blood examinations and medications for 3-4 times were carried out in hypo-endemic areas of malayan filariasis, whereas mass treatment with hetrazan-medicated salt containing 0.2% to 0.5% DEC was carried out in meso- and hyper-endemic areas of bancroftian filariasis as well as those situated in remote mountainous regions for six months. Subsequent evaluation and clearance checking showed that microfilaria rate of the whole province has already dropped to less than 1%. That filariasis was basically eliminated in Hunan was recognized by the Evaluation Mission Group sent by the Ministry of Public Health in 1986.