Comparison of methods for detecting asymptomatic malaria infections in the China–Myanmar border area

• Published in: Malaria Journal
• Main Authors: Yonghong Zhao, Yan Zhao, Yanmin Lv, Fei Liu, Qinghui Wang, Peipei Li, Zhenjun Zhao, Yingjie Liu, Liwang Cui, Qi Fan, Yaming Cao
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2017
• Subjects: Malaria; Light microscopy; Nested PCR with DNA; Nested RT-PCR; Capture and ligation probe-PCR; Asymptomatic; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-017-1813-0; https://doaj.org/article/6ff3d81b99654d47aabc945781168f79

Abstract Background Sensitive methods for detecting asymptomatic malaria infections are essential for identifying potential transmission reservoirs and obtaining an accurate assessment of malaria epidemiology in low-endemicity areas aiming to eliminate malaria. PCR techniques to detect parasite nucleic acids (DNA or RNA) are among the most commonly used molecular methods. However, most of these methods are of low throughput and cannot be used for large-scale molecular epidemiological studies. A recently developed capture and ligation probe-PCR (CLIP-PCR) is claimed to have the sensitivity of molecular techniques and the high throughput capacity needed for screening purposes. This study aimed to compare several molecular methods for detecting asymptomatic and submicroscopic Plasmodium infections in healthy residents of a malaria-hypoendemic region in Southeast Asia, where malaria elimination is in sight. Method This study compared three molecular detection methods side-by-side, namely nested PCR targeting the rRNA genes, nested RT-PCR to detect parasite rRNA, and CLIP-PCR to detect parasite rRNA in 1005 healthy individuals in northeastern Myanmar. For nested PCR and RT-PCR, parasite DNA and total RNA were extracted from ~100 µL of blood, whereas RNA used for CLIP-PCR was from a 3 mm disk of dried blood filter paper. The sensitivity and specificity of these methods were compared with those of conventional light microscopy. In addition, RT-PCR and quantitative RT-PCR (qRT-PCR) targeting the Pvs25 gene in Plasmodium vivax were used to assess gametocyte prevalence in the samples. Results Light microscopy detected Plasmodium infections in only 1.19% of the residents harbouring the parasites. CLIP-PCR had slightly better performance and detected Plasmodium infections in 1.89% of the population. Further improvement was achieved by nested PCR to detect parasite DNA, which detected P. vivax and Plasmodium falciparum infections in 2.39% of the residents. The nested RT-PCR targeting rRNA, however, detected as many as 187 ...