Canglin Zhang1, Somphad Sorchampa2, Hongning Zhou1, Jinyong Jiang1, Rui Yang3, Yilong Zhang4. 1. Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Academician Workstation of Professor Jin Ningyi, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention (Developing), Pu'er 665099, China. 2. Sing District Hospital of Luang Namtha Province, Luang Namtha 010000, Lao Democratic People's Republic. 3. Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Academician Workstation of Professor Jin Ningyi, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention (Developing), Pu'er 665099, China. Electronic address: jody877@163.com. 4. Department of Tropical Diseases, Faculty of Naval Medicine, Second Military Medical University, Shanghai 200433, China. Electronic address: Jamesyilong1010@aliyun.com.
Abstract
OBJECTIVES: The China-Laos border has been identified as an important origin of imported malaria outside China. The aim of this study was to describe the asymptomatic malaria infections and epidemic trend of malaria in the China-Laos border region. METHODS: A prevalence survey and surveillance of mosquito vectors was conducted in Muang Khua District of Phongsaly Province, China-Laos border, to determine the parasite carriage rate using nested PCR and microscopy. The species composition of malaria vectors was determined by overnight trapping. Blood samples were collected from 354 local residents aged 1-72 years in Sankang village in 2016. A total of 2430 adult mosquitoes were collected from four other villages in Muang Khua District from June to August 2016. RESULTS: The parasite carriage rate was 7.63% (27/354) by microscopy or 7.91% (28/354) by nested PCR. The results of surveillance of the mosquito vectors revealed that the predominant genera of adult mosquitoes were Culex (69.92%, 1699/2430) and Anopheles (21.48%, 522/2430). Anopheles sinensis (82.95%, 433/522) was identified as the predominant species among the seven members of Anopheles found in this border region. CONCLUSIONS: A high prevalence of asymptomatic malaria was present and the most important malaria vector was Anopheles sinensis, suggesting that the malaria epidemic situation on the China-Laos border is serious.
OBJECTIVES: The China-Laos border has been identified as an important origin of imported malaria outside China. The aim of this study was to describe the asymptomatic malaria infections and epidemic trend of malaria in the China-Laos border region. METHODS: A prevalence survey and surveillance of mosquito vectors was conducted in Muang Khua District of Phongsaly Province, China-Laos border, to determine the parasite carriage rate using nested PCR and microscopy. The species composition of malaria vectors was determined by overnight trapping. Blood samples were collected from 354 local residents aged 1-72 years in Sankang village in 2016. A total of 2430 adult mosquitoes were collected from four other villages in Muang Khua District from June to August 2016. RESULTS: The parasite carriage rate was 7.63% (27/354) by microscopy or 7.91% (28/354) by nested PCR. The results of surveillance of the mosquito vectors revealed that the predominant genera of adult mosquitoes were Culex (69.92%, 1699/2430) and Anopheles (21.48%, 522/2430). Anopheles sinensis (82.95%, 433/522) was identified as the predominant species among the seven members of Anopheles found in this border region. CONCLUSIONS: A high prevalence of asymptomatic malaria was present and the most important malaria vector was Anopheles sinensis, suggesting that the malaria epidemic situation on the China-Laos border is serious.