Using insecticide-treated bed nets and indoor sprays has been a successful strategy in preventing malaria by protecting against mosquito bites. However, a new article reveals a concerning unintended consequence: these measures have inadvertently led to a resurgence of household pests due to pesticide resistance.
A recent study conducted at North Carolina State University analyzed existing research on indoor pest control. It discovered that as household pests developed resistance to the insecticides used to target mosquitoes, pests such as bed bugs, cockroaches, and flies returned to homes. This resurgence not only eroded trust in the pest control methods but also contributed to an increase in malaria cases.
The effectiveness of insecticide-treated bed nets in preventing mosquito bites and malaria transmission inadvertently led to the unintended consequence of causing household pest resurgence as the insecticides became less effective against pests like bed bugs.
Chris Hayes, a Ph.D. student at NC State and co-corresponding author, highlighted that while the bed nets were not designed to eliminate household pests, they were remarkably efficient in doing so. This unexpected benefit, known as non-target effects, is now posing challenges as the effectiveness of these insecticides diminishes against household pests.
Researcher Coby Schal noted that the key benefit of these interventions was not solely in malaria reduction but in controlling other household pests. This unintended consequence of targeting malaria-carrying mosquitoes potentially contributed to the development of insecticide resistance in household pests, particularly in regions like Africa.
The study also pointed out other factors such as famine, conflict, urbanization, and population movements that could be influencing the increase in malaria cases.
To conduct the review, Hayes analyzed over 1,200 academic papers on indoor pests, malaria, bed nets, pesticides, and pest control. After a thorough assessment, 28 peer-reviewed papers meeting the criteria were included in the final analysis.
One study conducted in Botswana revealed that while mosquitoes were a concern for 58% of households, over 40% were more troubled by cockroaches and flies.
Hayes mentioned a recent survey indicating that people tend to associate the presence of bed bugs with the use of bed nets, leading to a decline in bed net usage when pests are not controlled effectively.
Despite the challenges posed by this unintended consequence, the researchers suggest potential solutions. One approach involves a dual strategy targeting both mosquitoes and separate urban pest management to control household pests effectively. Another approach entails developing new tools for malaria control that also address household pests simultaneously, like incorporating different chemicals in bed nets to target pests such as cockroaches and bed bugs.
By offering solutions that combat household pests alongside malaria prevention, there is the likelihood of improving the acceptance and effectiveness of bed nets.
This study was published in Proceedings of the Royal Society B and received support from various funding sources including the Blanton J. Whitmire Endowment at NC State and grants from the U.S. Department of Housing and Urban Development, the Department of the Army, and the Triangle Center for Evolutionary Medicine.
