[Epidemiological surveillance of filariasis after its being basically eradicated in Shandong Province].

This paper reports the results of epidemiological surveillance in areas where filariasis has been basically eradicated and control measures no longer adopted in Shandong Province. A 3-year longitudinal surveillance in 18 villages in 5 counties and a cross-sectional survey in 13 villages of 4 counties were carried out. The results showed that the average microfilaria rate was further reduced from 0.28% and 0.15% in 1980 to 0.19% and 0.05% in 1986, decreased by 32.1% and 66.7% respectively. 34.2% of the microfilaremic cases were found to be negative during the two-year follow-up. The positive rate of IFA and skin test was 34.2% and 38.6% respectively. In longitudinal surveillance. of the 240,992 Culex pipiens pallens dissected, 152(0.06%) were found to harbour different stages of larvae, among them, 5 were infective larvae from 4 vector mosquitoes. In cross-sectional survey, of the 3,875 Culex pipiens pallens dissected only 1 which had bitten immigrant from Zhejiang was found to contain one larvae at stage 1. No positive mosquito was found in the household of native villagers. No new infection was discovered at longitudinal and cross-sectional survey. The transmission of filariasis in these areas was interrupted. The results showed that in areas where filariasis has been basically eradicated, further control measures may not be instituted, but the management population movement and surveillance should be strengthened.