Malaria Deaths Grossly Underestimated

When George Clooney was recovering from his second bout of malaria after vising Sudan last year he demonstrated that the tropical infectious disease can create a very unpleasant ten days but they don’t have to be life-threatening.

But in many parts of Africa, South America and Asia, it is a killer. The presumption is that malaria kills mostly children under 5. And that’s in part why the World Health Organization which tracks the disease placed its annual death toll at about 655,000. But new research just doubled the annual malaria kill to 1.2 million people per year.

The news comes as a punch to the gut of large malaria eradication programs around the world. A study in the British journal The Lancet found that 42 percent of cases in 2010 appeared in people older than five who were previously uncounted by other tracking methods.

Dr. Christopher Murray, the Director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington and the study’s lead author says, “You learn in medical school that people exposed to malaria as children develop immunity and rarely die from malaria as adults.”

But that’s not what the new numbers are saying. This information is sure to be controversial but could shift the malaria prevention efforts to include adults instead of just children.

Immediately following the announcement last week, the WHO disputed the new numbers, saying IHME used unreliable verbal testimony, rather than clinical autopsies, to arrive at its figure. But this is not the first time IHME and the WHO have butted heads. Last year, the WHO quietly adjusted down their maternal mortality numbers by a whopping 34 percent (from over 500,000 to about 350,000) after the IHME released the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study in the spring of 2010.

Tom Paulson from Seattle-based blog Humanosphere says numbers in global health flow like the tide. He says, “When an organization wants to ask for help and more money to its cause, the numbers showing the need tend to rise. When you want to show that your project to reduce death or disease is working, the numbers tend to ebb.”

The IHME is an independent global health research center that began in 2007 with a $105 million grant from the Bill & Melinda Gates Foundation, which also funded this malaria study.

While the study found the overall number of malaria deaths is higher than in earlier reports, the trend in malaria deaths is following a consistent downward pattern. Starting in 1985, malaria deaths grew every year before peaking in 2004 at 1.8 million deaths worldwide. Then the death rate began to fall. Between 2007 and 2010, the decline in deaths was more than seven percent each year.

Insecticide on Bed Nets Kills Malaria Carrying Mosquitoes

Insecticide-coated bed nets and anti-malarial drugs get the credit for reducing the malaria mortality since 2004. And the global health community has spent billions of dollars trying to reduce those numbers to zero.

Dr. Alan Lopez, Head of the School of Population Health at the University of Queensland and one of the study’s co-authors says, “We have seen a huge increase both in funding and in policy attention given to malaria over the past decade, and it’s having a real impact.”

He credits programs like Nothing But Nets, Malaria No More, World Health Organization’s Roll Back Malaria, and the Global Fund to Fight AIDS, Tuberculosis and Malaria with keeping the malaria mortality rate on a downward trajectory.

According to current IHME estimates, when the Global Fund to Fight AIDS, Tuberculosis and Malaria began in 2001 the world spent about $250 million a year fighting the disease. In 2009 that number rose to more than $2 billion a year.

India is in the process of revising its malaria mortality numbers, possibly up to 40 times what it was reporting. The Times of India says that health officials will revise the number of Indians who die from the mosquito-borne disease every year to 40,297. Overall, the number of malaria infections hovers around 9.75 million per year.

The IHME study found that malaria killed 46,800 Indians in 2010. But the official numbers from India show those numbers at 1,023.

India’s National Vector Borne Disease Control Programme agrees with Dr. Murray’s study figures. It says only 11 percent of malaria deaths in India were in children. An official tells the Times of India, “As against Africa where most malaria deaths occur among the pediatric age group, in India it is mostly adults who succumb to malaria infection.”

Even the WHO says India has been under-reporting its malaria deaths. The WHO places malaria deaths somewhere in the 15,000 range still far fewer than the IHME study. India only counts a malaria death if the case goes to the hospital and the malaria parasite is found in the blood of the victim at the time of death.

The IMHE study uses a new method called a verbal autopsy. This includes asking the friends or relatives of the deceased if the patient had died of malaria. IHME and collaborators around the world published a series of articles in a special edition of Population Health Metrics in August 2011 focused on advancing the science of verbal autopsy. In poor countries, the cause of death is often misidentified due to broken or incomplete medical infrastructure.

The WHO refutes the new malaria numbers largely because of the verbal autopsy, which it considers an unreliable verbal diagnosis not particularly effective when it comes to identifying adults with malaria.

WHO spokesman Gregory Hartl says, “Basically, there is no diagnosis done in laboratory or after death of how a person actually died. He says, “You rely on the verbal record of a friend or relative saying that X person died of fever, for example. However, we know that there are many different diseases which cause fever.”

And when learning about infectious diseases in medical schools doctors-in-training are taught that most people who survive malaria in the first five years of life have a much higher immunity to the mosquito-borne disease later in life.

Hartl says it is important to look more carefully at the sources and the quality of data before arriving at any conclusions that will require a policy revision.

In Africa, malaria is blamed in 25 percent of all deaths in children under 5. There a child dies from the disease every 30 seconds, according to accepted WHO figures. But that’s also where the progress of malaria drugs and mosquito nets can bee seen. According to the IHME study Tanzania and and Zambia saw malaria deaths fall by more than 30 percent between 2004 and 2010.

But Dr. Stephen Lim, University of Washington Professor of Global Health and IHME study co-author is worried that economic troubles in Africa could destabilize the progress being made against malaria. Between 2009 and 2011 IHME found that development aid for global health slowed. And in November the Global Fund to Fight AIDS, Tuberculosis and Malaria announced it would cancel its next round of funding, casting doubt over the future of malaria control.

Dr. Lim says, “If the Global Fund is weakened, the world could lose 40 percent of all the funding dedicated to fighting malaria.” He adds, “We need to think of ways to fill funding deficits in order to ensure continued progress on malaria mortality.”

Perhaps that’s why in the conclusion of the 30-year analysis of malaria mortality the researchers find, “Donor support, however, needs to be increased if malaria elimination and eradication and broader health and development goals are to be met.”

Alex Perry at Time magazine’s blog, Global Spin explains that this isn’t the first time the people running developing world health campaigns have been shown to have only the loosest understanding of the problems they are tackling.

In 2005 India briefly held the top spot for number of AIDS patients at 5 million. By 2007 that number was revised to 2.5 million. Similarly Perry saw a statistic in 2009 that said there would be 5 million AIDS orphans in South Africa by 2015. He says this year that figure was quietly cut by three quarters.

He says, “Some people look at these statistical about-turns and smell a rat.” They blame global health campaigners for manipulating numbers to fulfill their own agenda — thereby creating the perception of a crisis to drive fund-raising.

He says, “But the disputed malaria figures would seem to reveal a different truth. In a world that sometimes seems wondrously connected, and where people worry about information overload, it’s a sobering thought that, more often than we’d like, we really don’t know what’s going on out there.”

Malaria Plasmodium Falciparum Parasite in Blood under a Microscope

Dr. Bernhards Ogutu at Kenya’s Medical Research Institute (KEMRI) says malaria figures are just as elusive there as the plasmodium parasite itself. He says he hears people say they have malaria when they may have another fever-causing disease. He believes that may lead to overestimating the malaria problem in some places.

IHME is advocating for more resources to fight what it believes is a bigger problem. But Perry says, “That seems premature before the WHO and the IHME have even figured out who is right.”