在中国云南消除疟疾后期使用多表位嵌合抗原估算恶性疟原虫传播。

Estimation of Plasmodium falciparum transmission using multiepitope chimeric antigen in the postelimination phase in Yunnan, China.

机构信息

Key Lab of Environment and Health, School of Public Health, Xuzhou Medical University, No.209, Tongshan Road, Xuzhou 221004, Jiangsu, China.

Yunnan Institute of Parasitic Diseases, No.6 Xiyuan Road, Simao City, Puer 665000, Yunnan, China.

出版信息

Parasitol Int. 2022 Aug;89:102597. doi: 10.1016/j.parint.2022.102597. Epub 2022 May 6.

DOI:10.1016/j.parint.2022.102597

PMID:35533962

Abstract

BACKGROUND

The continuous monitoring of malaria transmission intensity is still required to maintain elimination status after reaching the malaria elimination stage. In this study, serological surveillance with multiepitope artificial antigen was used to assess the transmission of Plasmodium falciparum in Yunnan, China, where malaria elimination has just been achieved, to provide data to support malaria control in the postelimination period.

METHODS

Samples were collected in three border counties and one inland county in Yunnan Province in 2016 using a stratified whole-group sampling method. Fingerstick blood was collected from all participants, and antibodies to Malaria Random Constructed Antigen-1 (M. RCAg-1) were detected by indirect ELISA. The transmission intensity of P. falciparum malaria was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR).

RESULTS

A total of 5566 samples were collected. There was no statistically significant difference in antibody level between the inland county and the nonendemic area, but the antibody level in border counties was significantly higher than those in the inland county and the nonendemic control area. No seropositive cases were found in Yanjin County, and the seropositivity rate increased with age in the three border counties. The highest intensity of P. falciparum malaria transmission was in Zhenkang County (SCR = 0.0030, CI: 0.0029, 0.0031), followed by Gengma County (SCR = 0.0013, CI: 0.0012, 0.0015) and Yingjiang County (SCR = 0.00088, CI: 0.00083, 0.00090).

CONCLUSION

The transmission intensity of P. falciparum malaria in Yunnan Province has obviously decreased in recent years, but for the border areas where malaria has just been eliminated, the transmission intensity will not immediately drop to zero, and it still needs to be monitored for a period of time to maintain malaria elimination status.

摘要

背景

在达到消除疟疾阶段后，仍需要持续监测疟疾传播强度，以维持消除状态。本研究采用多表位人工抗原血清学监测，评估中国云南消除疟疾后疟疾的传播情况，为消除后疟疾控制提供数据支持。

方法

2016 年，采用分层整群抽样方法，在云南省 3 个边境县和 1 个内陆县采集样本。采集所有参与者的指血，采用间接酶联免疫吸附试验检测抗疟随机构建抗原-1（M.RCAg-1）抗体。采用基于最大似然生成社区血清转化率（SCR）的催化转换模型估计恶性疟原虫疟疾的传播强度。

结果

共采集 5566 份样本。内陆县与非流行区抗体水平无统计学差异，但边境县抗体水平显著高于内陆县和非流行对照区。在盐津县未发现血清阳性病例，3 个边境县的血清阳性率随年龄增长而增加。恶性疟原虫疟疾传播强度最高的是镇康县（SCR=0.0030，CI：0.0029，0.0031），其次是耿马县（SCR=0.0013，CI：0.0012，0.0015）和盈江县（SCR=0.00088，CI：0.00083，0.00090）。