Nav: Home

Drugs that stop mosquitoes catching malaria could help eradicate the disease

September 18, 2018

Researchers have identified compounds that could prevent malaria parasites from being able to infect mosquitoes, halting the spread of disease.

Preventing transmission of malaria is a key part of efforts to eliminate the disease. A person can be cured of the disease using drugs that wipe out the replicating form of the parasite, but still carry dormant, sexual forms. These are responsible for transferring the parasite to the mosquito when it bites them.

Inside the mosquito, the dormant parasites rapidly mature and then multiply, leaving them ready to infect a new person when the insect feeds again.

Now, a team led by researchers from Imperial College London have identified a number of compounds that prevent the parasite maturing inside the mosquito. The team screened more than 70,000 compounds and identified six compounds that have the potential to be turned into drugs that block disease transmission. Their results are published today in Nature Communications.

Lead researcher Professor Jake Baum, from the Department of Life Sciences at Imperial, said: "Current antimalarial drugs can cure a person of the disease, but that person is still infectious to mosquitoes, and can therefore still cause someone else to become infected.

"What we propose is antimalarial drugs that protect mosquitoes, blocking the parasites from continuing their infectious journey. By combining such a drug with a conventional antimalarial, we not only cure the individual person, but protect the community as well.

"At the level of the individual person, fighting malaria is a constant battle as parasites become resistant to antimalarial drugs. Since transmission occurs in the mosquito, drugs targeting this process have the added benefit of being naturally much more resistance-proof, which could be essential for eliminating malaria."

One compound has already been shown to block parasite transmission from mice, but the team are researching all the compounds further to determine exactly how each works, and how they could be adapted as future drugs.

For example, these drugs could not be given directly to mosquitoes, so they would need to be stable enough to be given to a human and survive being transferred into the mosquito. Determining exactly what each compound is doing could also reveal more about the biology of the transmission process and identify new targets for future drugs.

The parasite that causes malaria has a complex life cycle. When a person is infected, they will have asexual forms of the parasite in the bloodstream, which cause the symptoms of the disease. However, there will also be male and female sexual forms, which once mature lie dormant in the body.

Because they are dormant and not very reactive, these parasites are very difficult to attack with conventional drugs. However, it is these male and female forms that, after sex in the mosquito, create more newly infectious asexual parasites. These gather in the mosquito's salivary glands, ready to pass on malaria to the next unfortunate human.

While inside the mosquito, the sexual parasites are very active - they are one of the fastest replicating cell types known - making them surprisingly good drug targets. In order to find compounds that could disrupt the sexual parasites, the team mimicked the conditions inside mosquitoes, fooling parasites into starting sexual development.

Once they found the right conditions, they miniaturised the process so that it could be examined with a microscope. This allowed them to screen thousands of compounds and see if they had any effect on active sexual parasites.

Dr Baum added: "It took several years to find the right conditions that would stimulate the sexual parasites and to miniaturise the environment, but it was worth it - at our best we were screening 14,000 compounds a week!"

"Overall we screened around 70,000 molecules and found only a handful of potent compounds that are both active and safe to use with human cells. It was like finding needles in a haystack."
-end-


Imperial College London

Related Malaria Articles:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.
Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the Umeå University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.
Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.
New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.
Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.
Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.
Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.
Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.
Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.
The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.
More Malaria News and Malaria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Sound And Silence
Sound surrounds us, from cacophony even to silence. But depending on how we hear, the world can be a different auditory experience for each of us. This hour, TED speakers explore the science of sound. Guests on the show include NPR All Things Considered host Mary Louise Kelly, neuroscientist Jim Hudspeth, writer Rebecca Knill, and sound designer Dallas Taylor.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

Kittens Kick The Giggly Blue Robot All Summer
With the recent passing of Ruth Bader Ginsburg, there's been a lot of debate about how much power the Supreme Court should really have. We think of the Supreme Court justices as all-powerful beings, issuing momentous rulings from on high. But they haven't always been so, you know, supreme. On this episode, we go all the way back to the case that, in a lot of ways, started it all.  Support Radiolab by becoming a member today at Radiolab.org/donate.