Mosquito bite patterns influence spread of malaria
The spread of malaria and any efforts to control it may be influenced by a small number of people who are bitten and infected frequently, according to new research.
The variation of mosquito bite victims and the frequency with which they are bitten could prove crucial to interventions that reduce the transmission of malaria, the report in eLife says.
By collecting mosquitoes from a village in Burkina Faso, researchers calculated how many people were bitten during a malaria season, allowing them to establish patterns.
The team discovered that the distribution of mosquito bites was much more variable than is usually assumed. Between 76% and 95.5% of the blood meals consumed from the captured mosquitoes came from just 20% of the people tested.
Tellingly, mosquitoes seem to demonstrate a preference of who they bite during a single season. Some people living in households that were particularly susceptible to bites suffered relatively few or no bites at all during the season.
However, some of the most frequently bitten people during this study had received few or no bites in previous surveys, which suggests that mosquito preferences can also change from season to season.
A separate study in Current Biology suggests that mosquitoes can remember the smell of hosts and identify repeat targets. Equally, they can learn to avoid targets who swat at them or perform other defensive behaviours.
With additional challenges to predicting malaria risks and establishing controls, the eLife authors recommend monitoring biting frequency over a sustained period of time.
Beyond the insects
Senior author Chris Drakeley, Professor of Infection & Immunity from the London School of Hygiene & Tropical Medicine, believes research objectives must extend beyond just the insects to learn more about the disease.
"Studying the insects alone will not accurately capture the variation in actual exposure among individuals", he said.
"We have previously shown that mosquitoes feed more often on adults. In this new study we’ve extended this analysis to look at variation in the distribution of mosquito bites among individuals in the same houses at different times during the malaria season", he added.