Researchers explore new way of killing malaria in the liver

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WASHINGTON, Dec 8, 2018 (BSS/AFP) – 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 drug discovery 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 drug resistance,” 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 parasites 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 effective treatment 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 malaria.