Researchers explore new way of killing malaria in the liver

Malaria infected mosquitoes ready for dissection in the manufacturing facility of Sanaria, Inc, in Rockville, Maryland during va
Malaria infected mosquitoes ready for dissection in the manufacturing facility of Sanaria, Inc, in Rockville, Maryland during vaccine production

In the ongoing hunt for more effective weapons against malaria, international researchers said Thursday they are exploring a pathway that has until now been little studied—killing parasites in the liver, before the illness emerges.

"It's very difficult to work on the liver stage," said Elizabeth Winzeler, professor of pharmacology and at University of California San Diego School of Medicine.

"We have traditionally looked for medicines that will cure malaria," she told AFP.

For the latest research, published in the journal Science, scientists dissected hundreds of thousands of mosquitoes to remove parasites inside them.

Each parasite was then isolated in a tube and treated with a different chemical compound—500,000 experiments in all.

Researchers found that certain molecules were able to kill the parasites.

After around six years of work, 631 candidate molecules for a "chemical vaccine" have been identified—a normal vaccine that would allow the body to make antibodies.

"If you could find a drug that you give on one day at one time that will kill all the malaria parasites in the person, both in the liver and in the bloodstream, and last for three to six months. Yeah, that'd be super but there is no drug like that right now," said Larry Slutsker, the leader of PATH's Malaria and Neglected Tropical Diseases (NTDs) programs.

Reducing the number of doses is crucial.

That's because many medications available today must be taken over three days, said David Reddy, CEO of Medicines for Malaria Ventures.

But often, after the first dose, a child begins to feel better and the fever lessens. Parents then keep the other two doses in case another of their children falls ill.

"That has two impacts. First the child does not get cured properly and secondly it builds ," Reddy said.

Illness develops

Malaria is caused by a miniscule parasite, called Plasmodium.

Female mosquitoes transmit the parasite when they bite people for a meal of blood (males do not bite).

Then, the parasite lodges in the liver and multiplies. After a couple of weeks, the population explodes and run rampant in the blood.

At this stage, fever, headache and muscle pain begins, followed by cold sweats and shivering. Without treatment, anemia, breathing difficulties and even death can follow, in the case of Plasmodium falciparum, which is dominant in Africa.

The research published Thursday offers a "promising path, as long as it last several months," said Jean Gaudart, professor of public health at the University of Aix-Marseille.

Gaudart said new approaches are necessary because resistance is on the rise in Asia against the most using artemisinin, derived from a Chinese plant.

"We really need new compounds," he said.

Now it's up to researchers to confirm which of the 631 molecules identified have a real shot at wiping out this global scourge.

The World Health Organization said last month that global efforts to fight malaria have hit a plateau, with two million more cases of the killer disease in 2017—219 million—than the previous year.

Malaria killed 435,000 people last year, the majority of them children under five in Africa.

The first malaria vaccine for children—called RTS,S—will be distributed in thee African countries in 2019, though it only reduces the risk of malaria by 40 percent after four doses.

Despite billions of dollars spent, the world still has not found a real effective solution to .


Explore further

First drug-resistant malaria parasite detected in Africa

More information: Y. Antonova-Koch el al., "Open-source discovery of chemical leads for next-generation chemoprotective antimalarials," Science (2018). science.sciencemag.org/cgi/doi … 1126/science.aat9446
Journal information: Science

© 2018 AFP

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Dec 08, 2018
Finding more effective treatments is, of course, a good and necessary measure. But eliminating the pest entirely should be the goal. We have gene drive mechanisms which can, at least theoretically, eliminate the mosquito carriers of the disease but we seem hesitant to use these tools.

Dec 08, 2018
Finding more effective treatments is, of course, a good and necessary measure. But eliminating the pest entirely should be the goal. We have gene drive mechanisms which can, at least theoretically, eliminate the mosquito carriers of the disease but we seem hesitant to use these tools.

Hesitant because of our inability to accurately predict any of the myriad unintended consequences...

Dec 08, 2018
Whydening Gyre,
I think the loss of a few species of mosquito would be far preferable to the known illnesses and deaths associated with malaria.

Dec 08, 2018
Whydening Gyre,
I think the loss of a few species of mosquito would be far preferable to the known illnesses and deaths associated with malaria.


That is probably true. But the same analysis led to quite a few ecological disasters caused by screwing around with things without knowledge. It would be far better to have a cure, and leave mother nature alone.

Dec 08, 2018
Whydening Gyre,
I think the loss of a few species of mosquito would be far preferable to the known illnesses and deaths associated with malaria.

Dog,
You have to consider those "pests" in the context of a larger ecosystem, not just human...

Dec 08, 2018
Whydening Gyre,
You have to consider those "pests" in the context of a larger ecosystem, not just human...


They are parasites. They provide food for some other species, but there are plenty of other insects to take their place in the food chain.


Dec 09, 2018
I think a reasonable compromise would be to develop an artificial gene that specifically repels mosquitoes & other disease bearing pests from approaching a protected host.

Dec 09, 2018
use DDT to kill it before it gets to the liver.

Dec 16, 2018
Shootist,
We were well on the way to controlling malaria mosquitos, bed bugs, and a lot of other harmful insects when we decided that DDT was too effective and that malaria was preferable to harming those parasites.

I think the parents of children dying of malaria feel differently.

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