MOSQUITOES have returned to the world headlines amid mounting fears surrounding the Zika virus, with World Health Organisation officials saying it has moved from being a "mild threat to one of alarming proportions."

But valuable light has been shed on the insect by an expert in Glasgow.

Dr Heather Ferguson, a Reader in the Institute of Biodiversity, Animal Health and Comparative Medicine at the University of Glasgow, says there are many thousands of different species of mosquito - including 30 in the UK alone.

And only a "relatively small proportion of them" have any role in transmitting disease, she says.

Dr Ferguson's main focus is on the mosquitoes that transmit malaria in Africa and south-east Asia. She herself lived in Tanzania for three years and contracted malaria on several occasions.

She said: "There are lots of mosquitoes that have positive impacts. Birds, spiders and bats can eat them, and they can have a useful role in ecosystems.

"It's not mosquitoes per se that are the enemy, but there are certain species that have adapted to spread diseases."

It's hard to be precise about the total number of mosquito species that are capable of spreading disease, she added.

"Some of them might be very rare species that might not have been studied very extensively but there are many others that we do know about, because they transmit malaria and diseases like dengue fever and other viruses."

Asked how close we are to eradicating disease-carrying mosquitoes, Dr Ferguson said: "There are a number of ways in which you can try to control or eliminate disease-carrying mosquitoes, with the most effective strategy depending on what mosquito you are dealing with.

"Insecticide-treated nets have been really successful for controlling malaria in Africa, because the mosquitoes that carry it bite inside houses and at night.

"This approach would not work for Zika or Dengue because the Aedes aegypti mosquitoes that transmit the bite during the day, and often outside. So unless you were literally wearing a bed-net while you were out and about, this approach wouldn't work."

She added: "Numerous options are being considered when it comes to controlling Aedes aegypti, and one of the most novel approaches is based on the development of a genetically-modified strain of the Aedes aegypti mosquito carried out by the UK company Oxitec.

"Its approach is based on releasing male Aedes aegypti, which don't bite, and which have been genetically modified to be sterile. On release, they will mate with wild females and also cause them to be sterile.

"The idea is that if you release enough of these GM males through time, the mosquito population will eventually crash because they are producing no offspring."

This project is not in wide use, but promising results have been obtained from a few small pilot studies in south America.

Dr Ferguson said that as an ecologist she was passionate about using her knowledge to improve public health, especially in the poorest parts of the world, such as Africa.

"All of these diseases, whether we're talking about Zika, malaria or dengue, are all diseases of poverty.

"Mosquitoes thrive where poverty thrives, in places where there is poor health infrastructure, inadequate drainage, and low-quality houses. I want to be part of the fight to improve global health, and feel that as an ecologist I can contribute to this by studying mosquitoes.

"The kind of problems we are seeing right now are ultimately to do with poverty combined with environmental change, I believe.

"Many of the solutions for these diseases are already in our hands: good health systems, careful surveillance, and mosquito control combined with effective diagnosis and treatment. Unfortunately treatments are not yet available for diseases like Zika and Dengue, but could be forthcoming with more research.

"But we need political will, commitment and investment to find the kind of solutions that could work here."