A study released Friday has shaken up much of what we thought we knew about malaria.

Patients wait to hear the results of their tests for Malaria at a hospital in Guayaquil, Ecuador. (Dolores Ochoa/AP)

The number of people who die annually of the tropical disease is roughly double the current estimate, according to the report, published in the science journal Lancet. Additionally, many of malaria’s victims are now believed to be adults, overturning the previous belief that adults almost never die of the disease.

After organizations such as the United Nations, the Global Fund and the British aid group DFid have spent millions of dollars fighting malaria, many public health experts are now trying to explain why the reporting was so wrong.

Dr. David Brandling-Bennett, deputy director of malaria and infectious diseases for the Bill and Melinda Gates Foundation, said data-gathering and taxes are two places to lay blame.

“Data-gathering is really difficult in resource-poor settings. There are different estimation efforts involved [in reporting malaria] and the methods are very complex,” Brandling-Bennett said in a phone interview. “Most people you will talk to will agree that what we want to do is keep improving the collecting and shareability of better data.”

As new modeling tools are made and more data become available, information we long held true — like numbers of malaria victims — are often proved wrong.

Another major, less-talked about impediment to the malaria fight is the prevalence of taxes and tariffs.

Countries with malaria problems sometimes heavily tax much-needed anti-malarial commodities such as medicines, bed nets or insecticides.

“It’s really counterproductive for countries to be charging for measures that benefit their populations,” Brandling-Bennett said. “It’s an impediment because it becomes that much more expensive.”

While some countries have lowered taxes and tariffs on these goods, or taken them away altogether, many remain in place.

A map from the Malaria Taxes and Tariffs Advocacy Project, which is funded by the Bill and Melinda Gates Foundation, shows just how many taxes and tariffs are left. (Note: The numbers have not been updated since August 2010.)

Despite the new malaria numbers, the Gates Foundation says it isn’t changing its overall approach to fighting the tropical disease.

“I think malaria is either a big problem or a bigger problem,” Brandling-Bennett said. “If there are more deaths, then there’s more work to do to get those deaths down.”

More reading:

Health: New study doubles estimate of global malaria deaths

Graphics: Malaria deaths around the world