Department of Parasitology, Faculty of Medicine, Universitas Airlangga, Campus A, Jalan Prof. Moestopo No. 47, Surabaya, 60131, Indonesia.
Entomology Study Group, Institute of Tropical Diseases, Universitas Airlangga, Campus C, Jalan Ir. Soekarno, Surabaya, 60115, Indonesia.
Malar J. 2018 Jan 5;17(1):2. doi: 10.1186/s12936-017-2147-7.
Trenggalek district is a hypoendemic malaria area with mainly imported cases brought by migrant workers from islands outside Java. During malaria surveillance in 2015, no malaria cases were found microscopically, but some cases were positive by PCR. Therefore, a study was conducted to prove that local malaria transmission still occur.
The adult villagers were invited to the house of the head of this village to be screened for malaria using aseptic venipuncture of 1 mL blood upon informed consent. Thin and thick blood films as well as blood spots on filter paper were made for each subject. The blood films were stained with Giemsa and the blood spots were used to extract DNA for polymerase chain reaction (PCR) amplification to determine the malaria infection. In addition, the history of malaria infection and travel to malaria endemic areas were recorded. Entomologic survey to detect the existence of anopheline vector was also conducted.
Of the total 64 subjects that participated in the survey, no malaria parasites were found through microscopic examination of the blood films. The PCR analysis found six positive cases (two Plasmodium falciparum, one Plasmodium vivax and two mixed infection of both species), and two of them had no history of malaria and have never travelled to malaria endemic area. Entomologic survey using human bait trap detected the existence of Anopheles indefinitus that was found to be positive for P. vivax by PCR.
The results indicated that although we did not find any microscopically slide positive cases, six PCR positive subjects were found. The fact that 2 of the 6 malaria positive subjects have never travelled to malaria endemic area together with the existence of the vector confirm the occurence of local transmission of malaria in the area.
特伦加莱克区是一个低疟区，主要由来自爪哇岛以外岛屿的外来务工人员输入疟疾病例。在 2015 年的疟疾监测中，显微镜检查未发现疟疾病例，但 PCR 检查呈阳性。因此，进行了一项研究以证实当地仍存在疟疾传播。
征得知情同意后，邀请成年村民到村长家无菌静脉采血 1ml 进行疟疾筛查。为每位受试者制作薄血膜和厚血膜以及滤纸上的血斑。血片用吉姆萨染色，血斑用于提取 DNA 进行聚合酶链反应（PCR）扩增，以确定疟疾感染情况。此外，还记录了疟疾感染史和前往疟疾流行地区的旅行史。还进行了蚊媒调查以检测按蚊媒介的存在。
在参与调查的 64 名受试者中，通过显微镜检查血片未发现疟原虫。PCR 分析发现 6 例阳性病例（2 例恶性疟原虫、1 例间日疟原虫和 2 例混合感染），其中 2 例无疟疾史且从未前往疟疾流行地区。使用人饵诱捕的蚊媒调查发现存在按蚊未定种，PCR 检测为阳性。
结果表明，虽然我们没有发现任何显微镜下阳性病例，但发现了 6 例 PCR 阳性病例。6 例疟原虫阳性病例中有 2 例从未前往疟疾流行地区，且存在媒介，证实该地区存在疟疾的本地传播。
