Asymptomatic/submicroscopic infection: A systematic review and META-analysis on the hidden challenge for preventing -establishment of malaria transmission.

BACKGROUND

is not only the second most prevalent cause of malaria worldwide, but also the second leading cause of imported malaria in China. This poses a significant threat to preventing the re-establishment of malaria transmission, as the competent vector () suitable for malaria transmission is widely distributed in China. Particularly, the asymptomatic infection as another important source of infection deserves further study, but it is rarely reported.

METHODS

PubMed, CNKI and Wanfang databases were systematically searched for asymptomatic infection relevant studies published between February 2014 and February 2024. I-squared statistics ( ) was used to assess heterogeneity among included studies. The pooled prevalence and pooled odds ratio and their corresponding 95 % Confidence Interval were estimated using the random effects model in Review Manager 5.4 software.

RESULTS

Seventy-one eligible studies were included in this analysis. Both study countries ( < 0.001,  = 95 %) and diagnostic methods ( = 0.001,  = 95 %) were the source of heterogeneity. The rates of asymptomatic malaria infection detected by the gold standard method of microscopy in the countries from Africa, Asia, Oceania and Americas were 9.2 %, 4.8 %, 15.6 % and 14.5 %, respectively. And the corresponding rates of asymptomatic infection were 4.0 %, 2.1 %, 10.6 % and 13.0 %. In terms of diagnostic methods, the rate of asymptomatic infection (5.6 %) detected by polymerase chain reaction in the population was the highest ( < 0.001).

CONCLUSION

According to the asymptomatic infection worldwide, the countries with the higher rate of asymptomatic infection are the main source of malaria cases imported into China, which indicates a potentially higher potential risk of importation of asymptomatic infection. Therefore, it is necessary to develop more sensitive, easier to operate, and more cost-effective techniques to detect and screen asymptomatic malaria infections in a timely manner, so as to prevent re-establishment of malaria transmission.