A new study shows that malaria could be killing many more people than some experts previously thought.

The study, published in the British medical journal The Lancet Friday, says more than 1.2 million people died of the mosquito-borne disease in 2010. The disease inflicted a high toll on adults as well as children, most of them in Africa.

Previous estimates said that between 70,000 and 80,000 people died of malaria annually.

The new study also defies the belief that children under five are more likely to die of malaria than adults.

It was conducted by the Institute of Health Metrics and Evaluation at the University of Washington in Seattle. On the positive side, it shows that deaths linked to malaria have been declining because of access to better drugs and insecticide-treated nets.

The research was funded by the Bill and Melinda Gates Foundation. It used new data and new computer modeling to build a historical database for malaria between 1980 and 2010.