Epidemiological characteristics and strategies for prevention and elimination of malaria in Qingdao, Shandong Province, China from 1949 to 2021.

Malaria is an insect-borne disease transmitted by Anopheles mosquitoes or the importation of Plasmodium-infected blood, posing a serious threat to human health and life safety. This study aims to analyze the incidence of malaria in Qingdao at various stages from 1949 to 2021, to collate the control measures taken at different epidemic stages to assess the effectiveness of malaria control, and to identify a set of malaria control strategies suitable for Qingdao, while providing Chinese experience for other countries or cities in their malaria elimination efforts. A retrospective survey was used to collect information on malaria cases, control measures and prevention and control effects in Qingdao from 1949 to 2021, and to evaluate malaria control strategies and measures in Qingdao. 704 155 cases have been reported from 1949 to 2021, with three epidemic peaks: the incidence rate was 1715.9/100 000 in 1961, 1409.7/100 000 in 1965, and the most severe case occurred in 1972, with an incidence rate of 1635.6/100 000 and a case count exceeding 90 000. Throughout the various stages of malaria epidemics, Qingdao has effectively eliminated indigenous malaria by implementing diverse preventive and control measures. Since the last indigenous case of Plasmodium vivax was reported in 2002, all locally reported cases have been imported, mainly by returning migrant workers from Africa. This study examines a range of malaria prevention and control strategies and interventions that are appropriate for Qingdao. These measures have enabled Qingdao to successfully eliminate malaria and maintain malaria-free status for more than 20 years. These measures can also serve as a reference for similarly situated cities in Africa and Southeast Asia.