Mosquitoes can be genetically modified to prevent them from spreading dengue fever to humans, a study has revealed.
Working in a laboratory, scientists created mosquitoes that were immune to the tropical disease and were therefore unable to pass it on through bites.
They injected the insects with human immune system proteins that were able to fight all four dengue strains.
These proteins prevented the virus from multiplying in the mosquito, meaning that it never became strong enough to be transmitted.
Dengue fever threatens the health and life of millions of people who live in warm countries every year and can cause fever, vomiting and fatal bleeding.
The scientists’ process worked by injecting immune system proteins called antibodies into the mosquitoes. These would then spread throughout the body and, in theory, to the offspring of the mosquitoes to make them all resistant to dengue viruses and unable to spread them
Aedes aegypti mosquitoes are the most important transmitter of dengue fever, which infects millions of people every year and leaves around 500,000 hospital treatments. Researchers have found a way to make the insects immune to the virus and therefore prevent it from passing on (stock image)
Scientists from the University of California, San Diego, implanted the dengue immune proteins, called antibodies, into female mosquitoes.
Antibodies are naturally produced by the body and ensure that the immune system destroys bacteria and viruses without medical assistance.
But someone must be infected with or exposed to a disease before the body can develop it, which is risky with such a deadly disease.
The researchers discovered that putting human dengue antibodies in mosquitoes stopped the spread of the disease among insects.
And by manipulating the insect’s genes to ensure that those with the antibodies in them were successful breeders, researchers said it would be possible to spread this immunity through the wild insect population.
Professor Omar Akbari, who led the study, said: “As soon as the female mosquito takes blood, the antibody is activated and expressed – that is the trigger.
“The antibody can interfere with the replication of the virus and prevent its spread in the mosquito, thereby preventing its transmission to humans. It is a powerful approach.
“It is fascinating that we can now transfer genes from the human immune system to confer immunity on mosquitoes.”
Dr. Prasad Paradkar, co-author of the study, told it ABC: ‘Because she [the mosquitoes] don’t get infected, they can’t pass that on to someone else. “
WHAT IS DENGUE FEVER?
Dengue fever is a viral infection that is spread by mosquitoes.
It is caught by people who visit or live in Asia, the Caribbean and North, South or Central America.
Mosquitoes in the UK do not spread the virus.
In most cases, the infection is mild and occurs for about a week.
Symptoms are usually:
- Severe headache
- Pain behind the eyes
- Muscle and joint pain
- Nausea and vomiting
- Broad result
- Stomach ache
- Loss of appetite
There is no cure or specific treatment.
Patients can relieve their symptoms through pain killers, stay hydrated and rest.
In rare cases, dengue symptoms can develop into severe dengue.
Older patients or patients with other medical conditions are most at risk.
Severe symptoms of dengue fever can be:
- Severe skin bleeding with blood stains on and under the skin
- Blood in the urine and stool
- Respiratory problems – when the lungs cannot provide the vital organs with sufficient oxygen
- Organ failure
- Changes in mental state and unconsciousness
- Dangerously low blood pressure
Severe dengue fever is usually treated through a blood and platelet transfusion, IV fluids for rehydration and oxygen therapy when the levels are low.
The breakthrough marks the first time that all four species of the dengue virus have been targeted by technical mosquitoes.
Previous attempts had only succeeded in tackling some tribes.
Professor Luke Alphey, head of arthropod genetics at the Pirbright Institute, which investigates the spread of infectious diseases, was not involved in the investigation, but told MailOnline that it was a big deal.
“This type of work has worked on one virus at a time,” he said.
‘The principle that this approach can offer you broad-spectrum resistance to these viruses [all four types of dengue] is really exciting. ”
The dengue fever virus, for which no cure is known, is generally mild and passes within about a week.
Normal symptoms are fever, severe headache and nausea and vomiting.
In rare cases, however, the virus can become life-threatening, with symptoms such as severe skin bleeding, organ failure and dangerously low blood pressure.
About 390 million people catch dengue every year, with cases that are common in Asia, the Caribbean and North, South or Central America.
There are also an estimated 12,500 deaths a year from the virus.
The Aedes aegypti is the most important mosquito that spreads dengue fever. It also spreads yellow fever and Zika.
A disadvantage of the approach, Professor Alphey said, was that it focused on the use of only one antibody.
Antibodies are highly specific and do not work against viruses to which they are not linked.
Professor Alphey warned that a small mutation in the dengue virus would make it resistant to the antibody that the scientists used, allowing it to spread again.
“It’s just one antibody, so you expect the resistance to evolve fairly quickly,” Professor Alphey added.
“In this example there is only one antibody. So a small change in the virus would lead to resistance to that one antibody.
“If you could pair a few antibodies that attack other parts of the virus, that would be more effective.”
The research is published in the journal PLOS Pathogens.