Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.
University of Basel, Basel, Switzerland.
Malar J. 2020 Nov 23;19(1):427. doi: 10.1186/s12936-020-03501-4.
Malaria was once a serious public health problem in China, with Plasmodium vivax the major species responsible for more than 90% of local transmission. Following significant integrated malaria control and elimination programmes, malaria burden declined, and since 2017 China has not recorded any indigenous case. To understand the historical malaria transmission patterns and epidemic characteristics in China and insights useful to guide P. vivax malaria control and elimination elsewhere, a retrospective study was carried out.
Historical data from a pilot study conducted in Guantang, Luyi in central China from 1971-1995, were digitized. The data included monthly numbers of reported cases, febrile cases, parasite carriage rates, the neonatal infection rate, and entomological data regarding Anopheles sinensis.
Following 25 years of continuous integrated malaria control activities, malaria incidence in Guantang decreased from 4,333 cases per 10,000 in 1970 before integrated implementation to 0.23 cases per 10,000 in 1991, and no cases in 1992-1995. Some fluctuations in incidence were observed between 1977 and 1981. During the period parasite rates, antibody levels and the neonatal infection rate also decreased. The pattern of seasonality confirmed that P. vivax in Henan Province was primarily of the long incubation type (temperate) during non-transmission period. The findings retrospectively provide a scientific basis for the implementation of mass campaigns of liver stage hypnozoite clearance. Entomological studies indicated that An. sinensis was the only vector, and it preferred bovine to human hosts, predominantly biting and resting outdoors. Mosquito densities declined between 1971 and 1984.
The integrated malaria control approach in Guantang effectively controlled malaria and achieved elimination. Analysis of the effectiveness of the programme can provide guidance to other regions or countries with similar ecological settings aiming to move from malaria control to elimination. There is a potential challenge in the maintenance of non-transmission status owing to imported cases and the long dormancy of liver stage hypnozoites.
疟疾曾是中国严重的公共卫生问题，间日疟原虫是导致 90%以上本地传播的主要物种。经过大规模综合疟疾防控和消除规划，疟疾负担下降，自 2017 年以来，中国未报告任何本土病例。为了解中国历史疟疾传播模式和流行特征，并为指导其他地区间日疟防控和消除提供参考，本研究开展了一项回顾性研究。
对中国中部鹿邑县观堂镇 1971 年至 1995 年开展的一项试点研究的历史数据进行数字化。数据包括报告病例数、发热病例数、寄生虫携带率、新生儿感染率以及按蚊种群数据。
经过 25 年持续的综合疟疾防控活动，观堂疟疾发病率从综合防治前 1970 年的 4333 例/10000 人下降到 1991 年的 0.23 例/10000 人，1992 年至 1995 年无病例。1977 年至 1981 年期间发病率出现波动。在此期间，寄生虫率、抗体水平和新生儿感染率也下降。季节性模式证实，河南省间日疟原虫主要为非传播期的长潜伏期（温带）类型。这些发现为实施大规模休眠子清除肝期疟疾的全民运动提供了科学依据。蚊媒研究表明，中华按蚊是唯一的传播媒介，它更喜欢牛作为宿主，主要在户外叮咬和休息。1971 年至 1984 年，蚊虫密度下降。
观堂综合疟疾防控措施有效控制了疟疾并实现了消除。分析该方案的效果可以为其他具有类似生态环境并希望从疟疾控制转向消除的地区或国家提供指导。由于输入性病例和休眠子的长期休眠，维持非传播状态存在潜在挑战。
