As part of the ongoing drive for more effective anti-malaria weapons, international researchers said on Thursday that they are studying a pathway that has not yet been studied too much – the killing of parasites in the liver before the disease occurs.
"It's very difficult to work on the liver stage," says Elizabeth Winzeler, professor of pharmacology and drug discovery at the San Diego School of Medicine.
"Traditionally, we've been looking for drugs that cure malaria," AFP said.
For the latest research, published in the journal Science, scientists scattered hundreds of thousands of mosquitoes to remove the parasites inside them.
Each parasite was then isolated in a tube and treated with another chemical compound – a total of 500,000 experiments.
Scientists have found that some molecules could kill parasites.
After six years of work, 631 candidate molecules were identified for a "chemical vaccine" – a normal vaccine that would allow the body to produce antibodies.
"If you find the drug you give one day at a time that kills all malaria parasites in a person, both in the liver and in the bloodstream, and lasts for three to six months, super, but that's not the kind of drug," said Larry Slutsker, leader of the PATH Malaria and Neglected Tropical Diseases (NTD) programs.
Reducing the number of doses is essential.
This is because many drugs available today have to be taken over within three days, said David Reddy, Director General of Medicines for Malaria Ventures.
Often, however, after the first dose, the baby begins to feel better and the fever decreases. Parents then maintain two more doses if another of their children becomes ill.
"This has two consequences: first, the child is not experiencing the disease properly, and secondly, he puts resistance to drugs," Reddy said.
Diseases are evolving
Malaria is caused by a minor parasite called Plasmodium.
Female mosquitoes carry parasites when they bite people to eat blood (men do not cough).
Then the parasite is given in the liver and multiplied. After a few weeks the population explodes and the parasites melt in the blood.
At this stage, fever, headaches and muscle pains begin, followed by cold sweat and trembling. Without treatment, anemia, breathing difficulties and even death may occur in the case of Plasmodium falciparum, which is dominant in Africa.
Research published on Thursday offers "a promising journey if it lasts for several months," said Jean Gaudart, professor of public health at the University of Aix-Marseille.
Gaudart said new approaches are necessary because resistance in Asia is against the most effective treatment using artemisinin, which comes from a Chinese plant.
"We really need new blends," he said.
It is now up to scientists to confirm which of the 631 identified molecules has a real shot at eradicating this global disaster.
The World Health Organization last month said that global efforts to combat malaria hit the platform with two million more cases of killer disease in the years 2017-219 million – than in the previous year.
Malaria killed 435,000 people last year, most of them in Africa under five years.
The first vaccine against childhood malaria – called RTS, S – will be distributed in African countries in 2019, although it will reduce the risk of malaria by 40% after four doses.
Despite the billions of dollars spent in the world, the world has not yet found real effective malaria solutions.