Multiplication of blood by mosquitoes can increase the spread of malaria

Multiple strokes of blood feeding with mosquitoes shorten the stimulation period for malaria parasites and increase malaria transmission potential, according to a study published on December 31 in the journal Open Access Pathogens PLOS by Lauren Childs of Virginia Tech, Flaminia Catteruccia of the TH Harvard School of Public Health TH Chan, and colleagues. Because mosquitoes eat blood several times in natural conditions, the results suggest that eradicating malaria may be much more challenging than suggested by previous tests, which usually lead to malaria. into one blood food.

Malaria remains a devastating disease for tropical and subtropical regions, accounting for an estimated 405,000 deaths and 228 million cases in 2018. Under natural conditions, the woman Anopheles gambiae mosquitoes – the main vector of malaria – feed on blood many times in their lives. Such complex behavior is routinely monitored when mosquitoes are in experiments with malaria parasites, limiting our ability to accurately account for potential transmitted effects. In the new study, the researchers examine how supplemental blood feeding affects the ability to develop and transmit Plasmodium falciparum malaria parasites in An. gambiae female.

We wanted to capture, in endemic regions, that mosquitoes that spread malaria feed on blood about every 2-3 days. Our study shows that this natural behavior strongly stimulates the spread of malaria parasites, in ways that were not previously appreciated “.

W. Robert Shaw, Lead Author

The results show that extra blood feeds three days after infection P. falciparum accelerates the growth of the malaria parasite, thus shortening the incubation period required before it is transmitted to humans. Incorporating this data into a mathematical model across sub-Saharan Africa reveals that malaria transmission capacity is higher than previously thought, making disease eradication more difficult. .

In addition, parasite growth is accelerated in genetically modified mosquitoes with reduced reproductive capacity, suggesting that control strategies could use this approach, with the aim of inhibit Anopheles populations, favoring the unforeseen spread of malaria. The data also suggest that parasites can be transmitted by younger mosquitoes, which are less likely to kill insects, with a negative impact on the success of insect-based strategies. Taken together, the results indicate that younger mosquitoes and those with less reproductive capacity may make a greater contribution to disease than previously thought.

According to the authors, the findings have important implications for properly understanding malaria transmission potential and estimating the true impact of current and future mosquito control measures.