1.Screening for malaria infection in residents on the China-Myanmar border: RDT, microscopy and PCR
ZHOU Yaowu ; SUN Weijiang ; TIAN Guangqiang ; XU Jianwei ; YANG Shiman ; DING Chunli ; DUAN Kaixia ; TAIN Peng ; SUN Xiaodong ; LIN Zurui
China Tropical Medicine 2023;23(9):897-
Abstract: Objective To compare the screening effects of RDT, microscopy and PCR for malaria among residents in low
malaria areas and elimination areas, and to investigate the presence of malaria in residents of border Villages in Cangyuan Va
County and asymptomatic infections in surrounding areas, providing a basis for preventing re-introduction of malaria after
elimination. Methods From August 2020 to March 2021, the fingertip blood of the investigated subjects was collected from
three survey sites in the border area between China and Myanmar, namely Banlao Township in Cangyuan Va Autonomous
County of Lincang City, Banwai District, Mengmao County, the Second Special Zone of Shan State, Myanmar, Yongmo and
Dayan Township, Nandeng Special Zone, the Second Special Zone of Shan State, Myanmar. The malaria parasite antigen
detection test kit, malaria parasite microscopic examination, fluorescent quantitative PCR and nested PCR were used to detect
the asymptomatic infection of malaria parasites. Results A total of 1 040 blood samples were collected, including 606 from
China and 434 from Myanmar, with 506 males and 534 females. Among them, , there were 51 individuals aged 0 to <5 years,
283 aged 5 to < years, 187 aged 15 to < years, 232 aged 30 to <45 years, 205 aged 45 to < years, and 82 aged ≥60 years. All
1 040 people tested negative for plasmodium antigen detection kit. One case of Plasmodium vivax detected by plasmodium microscopic etiology, with a detection rate of 0.10%. One case of P. vivax was also detected by fluorescent quantitative PCR and
nested PCR, with a detection rate of 0.10%. Among them, one case of P. vivax was detected in Banwai District, Mengmao
County, the Second Special Zone of Shan State, Myanmar, with a detection rate of 0.35%. The detection rates of malaria
parasites in Banlao Township in Cangyuan Va Autonomous County of Lincang City, Yunnan Province and Yongmo Township
and Dayan Township, Nandeng Special District, the Second Special Zone of Shan State, Myanmar were both 0. The difference in
the detection rate of malaria parasites among the three survey sites was not statistically significant (χ2
=2.682, P>0.05). The
asymptomatic P. vivax infection was detected in a 6-year-old girl from Banwai District, Mengmao County, the Second Special
Zone of Shan State, Myanmar. Conclusions RDT is not suitable for malaria screening in low malaria area and elimination
area. Microscopic examination and PCR can be used for malaria screening, but PCR operation is complex and costly. In
surrounding areas outside of China, malaria is still prevalent, while there is no source of malaria infection in border villages of
Cangyuan Va County. However, there is a risk of importation, and timely and effective measures should be taken to prevent reintroduction and transmission.