The study found that unborn babies whose mothers were infected with malaria had lower levels of the substances needed for normal brain development and function. It was published in the journal PLOS Pathogens last week (24 September).
“We need to confirm the findings in humans.”
Kevin Kain, University of Toronto, Canada
The reduction was thought to be caused by excess activation of an immune response in the mother that is used to tackle malaria, but that also appears to interfere with the production of these substances, the researchers say.
As a result of their mothers’ malaria infection, the mice developed symptoms of depression and cognitive impairment after birth, such as memory problems and reduced social interaction, the study says.
“We need to confirm the findings in humans,” says Kevin Kain, co-author of the study from the University of Toronto in Canada.
The research was carried out to investigate how malaria might affect unborn children. This is particularly important as pregnant women have a higher risk than other women of being infected with the malaria parasite Plasmodium falciparum and of developing a severe form of the infection. This is because pregnancy reduces their immunity to malaria.
Malaria is estimated to affect around 200 million people a year. The disease is most dangerous for children living in poor areas, with most of the 90 per cent of malaria deaths in Africa occurring among the under-fives, according to the World Health Organization.
Harry Tagbor, a public health researcher at Kwame Nkrumah University of Science and Technology in Ghana, says previous research on malaria and unborn babies focused on maternal anaemia and resulting low birth weight, rather than on brain development. He tells SciDev.Net that the findings in mice should motivate researchers to investigate how malaria in pregnancy affects mental health development in humans. The research team also tried to stop malaria from harming unborn baby mice by blocking the immune response that had become excessively activated. This restored the key brain substances to their normal levels, so the baby mice no longer developed symptoms of depression and mental impairments after birth.
This treatment would be too expensive to roll out on a large scale in humans, admits Kain. Nonetheless, the team’s “vital goal” is to find a safe and inexpensive human treatment, he says.