Malaria 2007—Progressing Research, Persisting Challenges

Abstract

MALARIA REMAINS A LEADING CAUSE OF MORBIDity and mortality globally. An estimated 3 billion individuals live in areas of risk and the disease causes more than 1 million deaths annually. Even in the United States, where endemic malaria has been eradicated for decades, an average of 1200 cases are reported annually. The articles in this issue of JAMA on malaria address a number of important issues, including the financial and logistic challenges of implementing new technologies for disease prevention and diagnosis; improvement in understanding risk factors and disease severity, particularly in children; and treatment and surveillance approaches in the face of evolving drug resistance. The diagnosis and management of malaria in endemic areas have tremendous financial impact. As Feachem and Sabot outline in their Commentary in this issue of JAMA, there is currently a resurgence of interest in the burden of malaria and possibilities for its control. The ambitious target set by the Roll Back Malaria Partnership of 50% mortality reduction by 2010 will be challenging to accomplish and will require leadership, management, and funding. Miller and colleagues also address the challenges of achieving the targets set by the Roll Back Malaria Partnership. The authors used data available from national surveys to estimate the number of insecticide-treated bed nets needed to achieve 80% coverage of pregnant women and children. They found that although more than 53% of households had nets available, between 130 million and 264 million nets are required to achieve target coverage. In addition, once the target is achieved, maintaining this target (assuming the life span of an insecticide-treated net is 4 years) would require an additional 37 million nets annually. These findings highlight the fiscal and logistic challenges of care delivery models in the developing countries where malaria is most common. Improving access to accurate diagnosis is no less challenging, as highlighted by Hamer and colleagues. Rapid antigen-detection diagnostic tests (RDTs) are frequently championed as a potential mechanism to improve reliable diagnosis of malaria and decrease inappropriate antimalarial use. However, relatively little is known about how these tests function in real-life circumstances. In this cross-sectional study from Zambia, the use of microscopy and RDTs was considered at a time when a national campaign to increase their use was ongoing. The authors found that despite the national initiative, microscopy and RDT were underused and, when used, still resulted in a high proportion of patients receiving antimalarial therapy despite a negative test result. The authors call for a shift away from empirical treatment that ignores test results and for an increase in education of clinicians on the rational use of artemisinin-based combination therapies. Globally, children account for a substantial proportion of the annual deaths from malaria. Several articles in this issue of JAMA highlight the burden of malaria in the world’s children. Idro and colleagues studied children with falciparum malaria admitted to a Kenyan hospital over a 12year period, with a focus on improving the understanding of neurological manifestations. Almost half the children had neurological involvement, most commonly seizures. In addition, children with neurological involvement had greater mortality compared with those without, and just over 2% had lasting impairment. May and colleagues also considered severe falciparum malaria in children in their examination of the association of disease manifestations with the hemoglobin variants C, S, and -thalassemia. These investigators found that among children in Ghana with severe falciparum malaria, the hemoglobin S carrier state was negatively associated with all forms of severe malaria, consistent with older literature; the hemoglobin C carrier state was negatively associated with cerebral malaria; and -thalassemia trait was negatively associated with severe anemia due to falciparum malaria. The findings of these 2 studies add to current understanding of the pathophysiology of severe malaria in children. Given the increase in resistance to antimalarial agents, combination therapy is generally advocated as first-line treatment of malaria in Africa for both adults and children. Dorsey and colleagues compared 3 treatment regimens among children in Uganda who had uncomplicated falciparum malaria: amodiaquine sulfadoxine-pyrimethamine, amodiaquine artesunate, and artemether-lumefantrine. While the artemether-lumefantrine combination was the most efficacious, prompt delivery of treatment provided