It’s brain swelling that has been killing children who die of malaria infections, a new study has found.

Malaria, which is spread by mosquitoes in the tropic regions, killed 500,000 people in 2013 mostly in Africa, and there have been a reported 198 million cases with no vaccine for the disease, according to a New York Times report.

Although drugs can be used to prevent the infection and treat it if it is found, malaria can be particularly deadly to young children. The finding that it is brain swelling that can be fatal to children suffering from a particularly severe form of the disease known as cerebral malaria may be helpful to improve treatment in the future.

Cerebral malaria is very dangerous and leads to comas and eventually death, with up to 25 percent of African children dying after contracting this particularly deadly type of malaria. Those that survive often have permanent disabilities, such as deafness, blindness, and brain damage.

While brain swelling was long suspected by doctors as a culprit, the new study, which was published in the New England Journal of Medicine, confirms that theory. The results are based on MRI scans of 168 children who had this type of malaria. A full 84 percent of those that died had severe brain swelling, compared to just 27 percent for survivors.

Brain swelling causes the children to stop breathing as the brain stem’s respiratory center becomes compressed, which may lead to doctors using ventilators to keep children alive until the swelling can be brought under control, which can take several days.

Although it won’t be a quick fix, as ventilators are not widely available in Africa, it does provide a route that relief organizations can take to bring malaria deaths under control.

There are also drugs that can help with swelling, but these will need to be investigated further, according to the report.