New York Times examines new surveillance measures in WHO's world malaria report 2008

Sep 24 2008

The New York Times on Tuesday examined the data collection methods used in the World Malaria Report 2008, which was released last week by the World Health Organization (McNeil, New York Times, 9/23).

The report found that there were about 247 million malaria cases in 2006, lower than the estimated 350 million to 500 million annual malaria cases reported in WHO's World Malaria Report 2005. The new report found there were 881,000 malaria deaths in 2006, down from the previous estimate of one million deaths annually (GlobalHealthReporting.org, 9/18).

According to the Times, the new surveillance methods and updated data in Asian countries such as India, Indonesia and Pakistan accounted for the majority of the reduced figures. The number of malaria cases in Africa -- where 91% of malaria deaths occur -- remained steady, according to the report. Other data collection methods used in the report include case reports from clinics; studies of select rural villages; and satellite imagery of vegetation, temperature and humidity. Mac Otten, a WHO epidemiologist, said, "Almost all the drop is in methodology."

According to the Times, it is difficult to estimate malaria prevalence because cases frequently are unreported. Many low-income people buy malaria drugs from local stores instead of visiting a doctor, and some Asian studies have found that as few as 10% of those seeking malaria drugs actually have the disease. In addition, tests of over-the-counter malaria drugs in Southeast Asia found that more than half were counterfeit, the Times reports. Christopher Murray, director of the University of Washington's Institute for Health Metrics and Evaluation, said that given the challenges of data collection, the WHO report is "a pretty impressive improvement in the rigor and quality of the surveillance work."

Bob Snow, an epidemiologist at the University of Oxford and a consultant for the report, said, "Improving on what the WHO did for their 2005 report does not equate to getting it right." Snow said that WHO's practice of calculating cases based on clinic reports and statistical adjustments for those who do not seek treatment is "ludicrous," adding that "even a back-of-the-envelope calculation" would find a higher caseload in Africa and Indonesia. Amir Attaran, a health policy expert at the University of Ottawa, said that the 2008 report used "better fudging, not better reporting," adding that the new surveillance measures were "still assumption built on assumption built on assumption." Eline Korenromp, an epidemiologist at the Global Fund To Fight AIDS, Tuberculosis and Malaria, agreed that the estimates in the 2008 report were "quite uncertain" especially because so few cases were recorded by physicians. Korenromp added that she believed 75% of cases in Myanmar were unreported.

According to Otten, the latest estimates do not account for the recent increase in the availability of artemisinin-based combination therapies, donations of insecticide-treated nets and the use of indoor insecticide spraying. Otten added that the use of rapid diagnostic tests -- instead of microscopes -- will greatly improve malaria diagnosis and data collection (New York Times, 9/23).

U.N. Special Envoy for Malaria Chambers To Release Global Malaria Action Plan

In related news, United Nations special envoy for malaria Ray Chambers on Thursday during the United Nations Millennium Development Goals summit in New York is expected to release and discuss the Global Malaria Action Plan, which was created by the Roll Back Malaria Partnership and aims to control and eradicate malaria worldwide, the Vanguard reports. Chambers on Monday held a global teleconference to discuss the plan -- which is the first comprehensive outline aimed at eradicating malaria worldwide -- with stakeholders, according to the Vanguard (Vanguard, 9/22).