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IMAGE: Plasmodium falciparum parasites that develop in the mosquito’s midgut. see plus
Credit: W. Robert Shaw, 2020 (CCBY 2.0)
Multiple episodes of blood feeding by mosquitoes shorten the incubation period of malaria parasites and increase the potential for malaria transmission, according to a study published Dec. 31 in the open access journal. PLOS Pathogens by Lauren Childs of Virginia Tech, Flaminia Catteruccia of the Harvard TH Chan School of Public Health, and colleagues. Since mosquitoes feed on blood multiple times in natural settings, the results suggest that eliminating malaria can be much more challenging than suggested by previous experiments, which typically involve a single blood meal.
Malaria continues to be a devastating disease for tropical and subtropical regions, accounting for an estimated 405,000 deaths and 228 million cases in 2018. In natural settings, women Anopheles gambiae The mosquito, the main vector of malaria, feeds on blood several times throughout its life. This complex behavior is often overlooked when mosquitoes are experimentally infected with malaria parasites, limiting our ability to accurately describe possible effects on transmission. In the new study, researchers examine how feeding extra blood affects the development and transmission potential of Plasmodium falciparum malaria parasites in A. Gambiae females.
“We wanted to capture the fact that, in endemic regions, malaria-transmitting mosquitoes feed on blood about every 2-3 days,” says W. Robert Shaw, lead author of this study. “Our study shows that this natural behavior strongly promotes the transmission potential of malaria parasites in ways that were previously not appreciated.”
The results show that an additional blood feed three days after infection with P. falciparum accelerates the growth of the malaria parasite, thus shortening the incubation period required before transmission to humans occurs. Incorporating these data into a mathematical model in sub-Saharan Africa reveals that the potential for malaria transmission is probably higher than previously thought, making elimination of the disease more difficult. Furthermore, parasite growth is accelerated in genetically modified mosquitoes with reduced reproductive capacity, suggesting that control strategies using this approach, with the aim of suppressing Anopheles populations, may inadvertently favor malaria transmission. The data also suggest that the parasites may be transmitted by younger mosquitoes, which are less susceptible to insecticide death, with negative implications for the success of insecticide-based strategies. Taken together, the results suggest that younger mosquitoes and those with reduced reproductive capacity may contribute more to infection than previously thought.
According to the authors, the findings have important implications for accurately understanding the potential for malaria transmission and estimating the true impact of current and future mosquito control measures.
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Peer reviewed; Experimental study; Animals; Cells
In your coverage, use this URL to provide access to the article freely available at PLOS Pathogens: http: // magazines.
Citation: Shaw WR, Holmdahl IE, Itoe MA, Werling K, Marquette M, Paton DG, et al. (2020) Multiple blood feeding in mosquitoes shortens the Plasmodium falciparum incubation period and increases the potential for malaria transmission. PLoS Pathog 16 (12): e1009131. https: /
Funding: FC is funded by a Faculty Research Academic Award from the Howard Hughes Medical Institute (HHMI) and the Bill & Melinda Gates Foundation (BMGF) (Grant ID: OPP1158190, http: // www.
Conflicts of interest: the authors have declared that there are no conflicts of interest.
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