[Second sampled survey on the distribution of human parasites in Zhejiang Province]

OBJECTIVE

Twenty-six species of human parasites were recorded in Zhejiang Province in 1987-1989 as a part of the national investigation on the distribution of human parasites, and the total prevalence was 80.2%. In order to find out possible changes on the composition of parasite species and decrease of prevalence after control intervention particularly mass chemotherapy in the past years and provide evidence for an improved control strategy, the second sampled survey was carried out from 1998 to 1999.

METHODS

Ten counties were identified randomly out of 28 counties where the last survey was conducted following the same sampling method. Same technics were used for case detection and data processing.

RESULTS

The total infection rate in a sample of 15,698 was 22.84% was 22.84% in 30 investigation spots in 10 counties, and 17 species of parasites were revealed. The overall prevalence was reduced by 71.51% in comparison to that of 1989, and the number of parasite species was 17, 9 less than that of the last investigation.

CONCLUSIONS

The prevalence of human parasites has greatly declined in this province due to the socioeconomic development and adoption of comprehensive control measures focusing on mass chemotherapy in the past decade.

Study of simplified measures for malaria surveillance in the late consolidation phase in China

This paper presents the results of a study on simplified surveillance methods conducted in 23 pilot counties in 11 provinces and municipalities in China where reside 15 million people and malaria control has been in the late consolidation phase. Two simplified surveillance Schemes (A and B) taking treatment of clinical cases as the main measure were implemented in 1992-1994. The rate of annual blood examination for case detection was 1.0% in pilot Scheme A, while in areas of scheme B it was 0.3%. The implementation of both Scheme A and Scheme B, simplified or without treatment of infection foci and management of mobile populations, acquired satisfactory effects against malaria. Consequently, malaria incidence was declining steadily, only a few indigenous and introduced cases were detected. The parasite rate in residents and the IFA positive rate in children were very low. The results of pilot studies and cost-effectiveness analysis indicated that Scheme B is effective, rational and economic, and can be implemented to replace the routine surveillance measures in areas where malaria has been at the late consolidation phase in China.