PILLING DIET mosquitoes could fight the spread of malaria, dengue fever and Zika while scientists discover that reducing appetite prevents them from sucking blood
- Female mosquitoes suck blood to feed their developing eggs
- As it digests, the insect releases proteins that suppress appetite
- Giving the mosquitoes drugs with these proteins has stopped them looking for blood
Although mosquitoes do not need to look at their weight, giving the diet pills against parasites could fight the spread of malaria, Zika and dengue fever.
The researchers found that insects given drugs containing NPY-like receptors were less likely to suck the blood when they were presented with a human arm.
These receptors regulate appetite in everything from nematodes to humans, and are even used in experimental drugs against obesity to curb our desire for food.
Scientists believe that if female mosquitoes could be convinced to receive these drugs, it could help control deadly diseases with limited treatment options.
Although mosquitoes do not need to watch their weight, giving the diet pills for pests could fight the spread of malaria, Zika and dengue fever, research suggests (warehouse)
The research was conducted by Rockefeller University in New York and led by Professor Leslie Vosshall, from the laboratory of neurogenetics and behavior.
Female mosquitoes suck human blood to help their eggs mature, with each insect having several cycles of blood-sucking and spawning in its life.
This means that when a female bites a human with a disease like Zika, she has several opportunities to pass on that infection.
WHAT IS ZIKA VIRUS AND HOW DOES IT?
The Zika virus is widespread from mosquito bites, between people during unprotected sex, and from pregnant mothers to their children.
It can not be cured or prevented with drugs. Although most adults do not become seriously ill from the infection, they can cause severe birth defects if pregnant women take it.
The brain of fetuses can be influenced by the virus when it is transmitted by the mother and can cause microcephaly.
Microcephaly is a condition in which children's heads are unusually small, which can lead to convulsions, delayed development and other disabilities.
The virus can also increase the risk of unborn children developing Guillain-Barre syndrome – a rare disease in which the immune system attacks the nerves and can cause muscle weakness and paralysis.
Zika is a tropical disease and is more common in Central and South America, in Africa and in Southeast Asia.
There was a virus outbreak in the Brazilian capital, Rio de Janeiro, in 2016 and there were fears that the Olympic Games that year were to be canceled after more than 200 academics have written to the World Health Organization on the matter.
The virus is not commonly found in developed countries such as the United Kingdom, the United States and Australia. But it is present in the Pacific islands such as Fiji and Tonga, where the pregnant Duchess of Sussex will visit her royal tour this month.
Source: Centers for disease control and prevention
Almost half of the world's population is at risk of malaria, with around 212 million cases and 429,000 dead only in 2015, according to the World Health Organization.
And Zika – which is most commonly found in South America but has spread to the United States – causes birth defects in about one in ten pregnant women who are infected with the mosquito-spread virus.
"Preventing mosquitoes from biting humans is an important point of intervention in the global public health strategy," wrote the authors in Cell magazine.
After a female feed, she stops looking for blood for several days while letting her eggs ripen.
Some peptides – which make up proteins – have been shown to activate NPY type receptors.
These suppress the appetite of a mosquito after it is nourished.
It has also been shown that NPY receptors influence food intake, fullness and obesity in humans.
To test whether drugs containing these receptors could control mosquitoes, the researchers fed NPY receptors to females of the Aedes aegypti mosquito species.
This has made the insects less likely to look for food, in addition to biting or sucking blood, if exposed to a human arm.
"When they're hungry, these mosquitoes are super-motivated," Professor Vosshall said.
"They fly to the scent of a human in the same way we could approach a chocolate cake.
"After receiving the drugs, they lost interest".
NPY-receptors can be administered by dragging mosquitoes into "baited traps" that mimic signs of a host to which insects are attracted, such as body odor and carbon dioxide.
This may be preferable to other techniques that aim to eradicate mosquitoes – even the male ones – despite being important pollinators and food for many fish.
Existing control methods, such as insecticides, have limited success due to insects that often develop resistance.