Molecular epidemiological surveillance of Africa and Asia imported malaria in Wuhan, Central China: comparison of diagnostic tools during 2011–2018

Background: Malaria remains a serious public health problem globally. Along with indigenous malaria elimination in China, imported malaria gradually became a major hazard. Well-timed and accurate diagnosis could support immediate therapeutic schedule, reveal the prevalence of imported malaria and avoid the disease transmission. Method Blood samples were collected in Wuhan, China from August 2011 to December 2018. All patients first accepted microscopy and RDT examination. Subsequently, each of the positive or suspected positive cases was engaged in total four human Plasmodium species amplication by using 18S rRNA based nested PCR and Taqman probe based real-time PCR. Then performance of microscopy and two molecular diagnosis methods were analyzed. Importation origin was traced by country and prevalence of Plasmodium species was revealed by year. Results Total 296 blood samples containing 288 microscopy and RDT positive, 7 RDT P. falciparum positive and 1 suspected cases were collected and reanalyzed. After two molecular methods and sequencing detection, 291 cases including 245 P. falciparum , 15 P. vivax , 20 P. ovale , 6 P. malariae and 5 mixed infection (3 P. falciparum + P. ovale , 2 P. vivax + P. ovale ) were confirmed. These patients returned from Africa (95.53%) and Asia (4.47%). Although the prevalence displayed a small-scale fluctuation, the overall trend of the imported cases increased yearly. Conclusions Results emphasized the necessity of combined utilization of the four tools for malaria diagnosis in clinic and field survey around potential risk regions worldwide including Wuhan.