New research could lead to the development of new mosquito-bite prevention measures. Photo / 123RF
New research could lead to the development of new mosquito-bite prevention measures. Photo / 123RF
Exposing mosquitoes to just ten minutes of light each night suppresses their biting, researchers have found.
They tested the method with the Anopheles gambiae mosquito - which transmits malaria.
The research could lead to the development of new mosquito-bite prevention measures, reports Daily Mail.
The study, conducted by researchers at the University of Notre Dame, also found that the light exposure treatment manipulated flight behavior in the Anopheles gambiae mosquito.
Usually, malaria is transmitted when an infective female Anopheles bites someone.
According to the CDC, only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken from an infected person.
When a mosquito bites an infected person, a tiny amount of blood is taken, containing microscopic malaria parasites.
About one week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito's saliva and are injected into the next person who is bitten - thus transimitting the disease.
The mosquito species is crepuscular - meaning it's primarily active during dawn and dusk.
As such, behaviors such as feeding, egg laying and flying are specific to the time of day, including a greater likelihood of nighttime biting.
A recent report by the World Health Organization said that an estimated 212 million people worldwide are infected with the disease, leading to 429,000 deaths annually - most of which are children.
While insecticide-treated bed nets and walls have helped prevent bites and reduce malaria, researchers say that mosquitoes are adapting to them - leaving adults and children vulnerable.
"Anopheline mosquitoes are adapting to these current methods by developing resistance to insecticides and by shifting feeding to earlier in the evening or later into the early morning, times of the day when people are not in bed and therefore not protected by a net," said Dr Giles Duffield, associate professor of biology in the at the University of Notre Dame and and the corresponding author of the study.
"So what used to be an efficient method is becoming less effective.
"We need to discover new methods to address mosquito control and prevention.
"The systems and tools we currently have including global distribution and usage of insecticide-treated bed nets and spraying are not enough."
So to conduct the study into light as a potential source of behavior modification, Dr Duffield and his team tested mosquitoes' preference to bite during their active host-seeking period by separating them into different control and test batches.
Control mosquitoes were kept in the dark, while test batches were exposed to a pulse of light for ten minutes.
The researchers then tested their propensity to bite directly after the light exposure and every two hours throughout the night by holding their arms up to a mesh lining that allowed uninfected mosquitoes to bite them and feed on their blood while still remaining contained by the net.
The results showed that after ten minutes of light exposure, the mosquitoes' biting propensity was significantly suppressed.
The researchers also conducted another experiment where they exposed the mosquitoes to pulses of light every two hours, which resulted in biting being suppressed during a large portion of the 12-hour long night period.
"Most remarkable is the prolonged effect a short light treatment has on their preference to bite, with suppression lasting as long as four hours after the pulse," Dr Duffield said.
"This may prove to be an effective tool that complements established control methods used to reduce disease transmission."
Pulses of light would probably be more effective than constant exposure, Dr Duffield said, as the mosquitoes would be less likely to adapt to light presented in periodic doses.
The researchers are also testing the effectiveness of different wavelengths of light, such as red light, that would be less disturbing to adults and children while they sleep.
They also aim to develop solutions that can be applied in the field.
HOW THEY DID IT
"We need to discover new methods to address mosquito control and prevention." Photo / 123RF
To conduct the study into light as a potential source of behavior modification, Dr Duffield and his team tested mosquitoes' preference to bite during their active host-seeking period by separating them into different control and test batches.
Control mosquitoes were kept in the dark, while test batches were exposed to a pulse of light for ten minutes.
Approximately 25 mosquitoes were placed into each of 10 small white translucent plastic housing containers.
Five containers received a 10-minute light pulse, and the other five containers received no light exposure and remained in the dark.
The researchers then tested the mosquitoes' propensity to bite directly after the light exposure and every two hours throughout the night.
They did this by holding their arms up to a mesh lining that allowed uninfected mosquitoes to bite them and feed on their blood while still remaining contained by the net.
