fbpx

Multiple blood feeding in mosquitoes increases malaria transmission potential

Multiple bouts of blood feeding by mosquitoes shorten the incubation period for malaria parasites and increase malaria transmission potential, according to a study published December 31 in the open-access journal PLOS Pathogens by Lauren Childs of Virginia Tech, Flaminia Catteruccia of the Harvard T.H. Chan School of Public Health, and colleagues.

Given that mosquitoes feed on blood multiple times in natural settings, the results suggest that malaria elimination may be substantially more challenging than suggested by previous experiments, which typically involve a single blood meal.

Malaria remains a devastating disease for tropical and subtropical regions, accounting for an estimated 405,000 deaths and 228 million cases in 2018. In natural settings, the female Anopheles gambiae mosquito — the major malaria vector — feeds on blood multiple times in her lifespan.


Subscribe now to remove this ad, read unlimited articles, bookmark your favorite post and soo much more

Such complex behavior is regularly overlooked when mosquitoes are experimentally infected with malaria parasites, limiting our ability to accurately describe potential effects on transmission. In the new study, the researchers examine how additional blood feeding affects the development and transmission potential of Plasmodium falciparum malaria parasites in An. gambiae females.

“We wanted to capture the fact that, in endemic regions, malaria-transmitting mosquitoes are feeding on blood roughly every 2-3 days,” says W. Robert Shaw, a lead author of this study. “Our study shows that this natural behavior strongly promotes the transmission potential of malaria parasites, in previously unappreciated ways.”

The results show that an additional blood feed three days after infection with P. falciparum accelerates the growth of the malaria parasite, thereby shortening the incubation period required before transmission to humans can occur.

READ MORE  The ambitious effort to piece together America’s fragmented health data

Incorporating these data into a mathematical model across sub-Saharan Africa reveals that malaria transmission potential is likely higher than previously thought, making disease elimination more difficult. In addition, 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.


Subscribe now to remove this ad, read unlimited articles, bookmark your favorite post and soo much more

The data also suggest that parasites can be transmitted by younger mosquitoes, which are less susceptible to insecticide killing, with negative implications for the success of insecticide-based strategies. Taken together, the results suggest that younger mosquitoes and those with reduced reproductive ability may provide a larger contribution to infection than previously thought.

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


Make more money selling and advertising your products and services for free on Ominy market. Click here to start selling now


Source

PLOS

Journal Reference

Multiple blood feeding in mosquitoes shortens the Plasmodium falciparum incubation period and increases malaria transmission potential

Abstract
Many mosquito species, including the major malaria vector Anopheles gambiae, naturally undergo multiple reproductive cycles of blood feeding, egg development and egg laying in their lifespan. Such complex mosquito behavior is regularly overlooked when mosquitoes are experimentally infected with malaria parasites, limiting our ability to accurately describe potential effects on transmission.

Here, we examine how Plasmodium falciparum development and transmission potential is impacted when infected mosquitoes feed an additional time. We measured P. falciparum oocyst size and performed sporozoite time course analyses to determine the parasite’s extrinsic incubation period (EIP), i.e. the time required by parasites to reach infectious sporozoite stages, in An. gambiae females blood fed either once or twice.


Subscribe now to remove this ad, read unlimited articles, bookmark your favorite post and soo much more

An additional blood feed at 3 days post infection drastically accelerates oocyst growth rates, causing earlier sporozoite accumulation in the salivary glands, thereby shortening the EIP (reduction of 2.3 ± 0.4 days). Moreover, parasite growth is further accelerated in transgenic mosquitoes with reduced reproductive capacity, which mimic genetic modifications currently proposed in population suppression gene drives.

We incorporate our shortened EIP values into a measure of transmission potential, the basic reproduction number R0, and find the average R0 is higher (range: 10.1%–12.1% increase) across sub-Saharan Africa than when using traditional EIP measurements.

These data suggest that malaria elimination may be substantially more challenging and that younger mosquitoes or those with reduced reproductive ability may provide a larger contribution to infection than currently believed. Our findings have profound implications for current and future mosquito control interventions.

Author summary
In natural settings the female Anopheles gambiae mosquito, the major malaria vector, blood feeds multiple times in her lifespan. Here we demonstrate that an additional blood feed accelerates the growth of Plasmodium falciparum malaria parasites in this mosquito.


Subscribe now to remove this ad, read unlimited articles, bookmark your favorite post and soo much more

Incorporating these data into a mathematical model across sub-Saharan Africa reveals that malaria transmission potential is likely to be higher than previously thought, making disease elimination more difficult. Additionally, we show that control strategies that manipulate mosquito reproduction with the aim of suppressing Anopheles populations may inadvertently favor malaria transmission.

Our data also suggest that parasites can be transmitted by younger mosquitoes, which are less susceptible to insecticide killing, with negative implications for the success of insecticide-based strategies.

 

READ MORE  4 reasons you shouldn’t trash your neck gaiter based on the new mask study

Ominy science editory team

A team of dedicated users that search, fetch and publish research stories for Ominy science.

What do you think??

Enable notifications of new posts    OK No thanks