Malaria

Graphic

The National Institutes of Health (NIH), a part of the US Department of Health and Human Services and the country’s medical research agency, is the world’s largest funder for medical research. The NIH website states that more than 80% of the agency’s budget is used to cover research costs at over 2,500 universities and research institutions.

This graphic, from a recent paper reviewing current knowledge of antimalarial drug resistance, illustrates nine stages in the life cycle of the malaria parasite. The paper describes the cycle thus:

The feasibility of eliminating malaria differs among countries because of differences in the technical challenges, measured in terms of malaria endemicity and importation rate, and operational capabilities, measured in terms of government stability and effectiveness, quality and development of health systems, and factors associated with the population at risk. The forty circles graphically represent a relative ranking of operational feasibility for eliminating P. falciparum malaria.

25 Apr 2014
Elyse Franko

In 2012, there were an estimated 207 million cases of malaria and 627,000 deaths caused by malaria worldwide, according to the WHO. While malaria deaths have been greatly reduced in recent years, it is imperative that governments and global health organizations continue investing in malaria research to ensure consistent progress in fighting the disease.

Malaria

Journal of Theoretical Biology (340)
January 2014

Research Area: Malaria
Type: Article
The Question

How does heterogeneous transmission affect the spread of antimalarial drug resistance?

What We Found

In malarious regions, individuals are bitten by infectious mosquitoes regularly. Continuous re-exposure often leads to simultaneous infection with multiple genetically distinct malaria parasites. These parasites compete within the host, which can affect the epidemiological dynamics of the disease, particularly when drug-resistant and drug-sensitive parasites compete. This is exacerbated by heterogeneous transmission, which results in certain members of the community having significantly more within-host competition than others.

By including within-host competition and heterogeneous transmission in our model, we were able to show that heterogeneous transmission slows the rate at which resistance becomes established. This is largely due to drug-susceptible strains out competing resistant strains within the host. However, once resistance in the community is established, heterogeneous transmission speeds the spread of resistance. 

Why It Matters

Our model has shown that understanding how heterogeneous transmission interacts with within-host competition is important for understanding the emergence and spread of drug resistance. Our findings should encourage additional research into within-host competition, while our model could be extended to include other important components of antimalarial drug resistance such as immunity.


21 Feb 2013
Alison Buki

Below is a press release issued by the Johns Hopkins Bloomberg School of Public Health. Among the authors of the article "The Stability of Malaria Elimination," published February 22 in Science, are CDDEP director Ramanan Laxminarayan and senior fellow David Smith.

Malaria

International Journal of Antimicrobial Agents

Research Area: Malaria | Region: Africa; East Asia and Pacific; South Asia
Type: Article | Hot Topic(s): Elimination; ACTs
The Question

This article examines what is known about how resistance to antimalarial drugs emerges and spreads, and reviews various strategies for controlling the spread of resistance.

What We Found

This paper is a literature review, and as such there are no new findings to report. However, the author concludes that "the emergence of an artemisinin-resistant phenotype threatens one of the key components of elimination and eradication plans, and new control strategies are ugently needed." He also notes that devising these strategies will require "a better understanding of how drug resistance emerges and spreads."

Why It Matters

Artemisinin-based therapies are currently the most effective treatment for malaria. If these drugs were to be lost to resistance, which already appears to be emerging in Southeast Asia, the results could be globally catastrophic.



Malaria

Non-resident Fellow

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Carlos Guerra's research interests have focused mainly on global malaria epidemiology. He worked as a full time researcher for the Malaria Atlas Project (MAP) from 2005 to 2011. During this period he assembled medical intelligence and malaria survey data to provide evidence-based maps on the distribution of malaria risk, human population, disease burdens, mosquito vectors, inherited blood disorders and malaria financing and control worldwide. He is still a collaborator of MAP.

The Question

What lessons can be taken away from the Affordable Medicines Facility-malaria pilot?

What We Found

After examining the results of a 2-year pilot in seven African countries (Ghana, Kenya, Madagascar, Niger, Nigeria, and Tanzania, including Zanzibar and Uganda), the authors drew four main conclusions that should be taken into account in subsequent phases of AMFm:

  1. "The more countries involved, the lower the drug prices and risk of leakage to other countries."
    As a result of the AMFm pilot, wholesale drug prices have dropped up to 80% from direct negotiations with manufacturers. Expanding AMFm to more countries would help stabilize ACT prices across borders.

  2. "There should be a transition to reduce subsidies over time."
    While countries with high malaria burden and low purchasing power may need subsidies for ACTs for the next few years, over time this need should decrease due to technological advancements and increased demand for AMFm drugs.

  3. "Rapid diagnostic tests for malaria are needed in the private sector."
    Since many fevers in malaria-endemic countries are not caused by malaria, integrating rapid diagnostic tests (RDTs) into the treatment of febrile illness will be an important way to conserve antimalarials moving forward. This can be done using pricing strategies that encourage providers to sell RDTs and patients to use them.

  4. "A broader febrile illness agenda is crucial."
    The authors state: "We believe it is time to expand our approach to fever case management from disease-focused treatment to patient-centered treatment...Health systems could more effectively manage both malaria and pneumonia by addressing the more general problem of febrile illness, rather than proceeding from a specific etiology or funding source."

 

Why It Matters

In mid-November 2012, the board of directors of Global Fund to Fight AIDS, Tuberculosis, and Malaria will decide whether to continue, modify, or terminate AMFm. This decision has broad implications for the availability and affordability of effective malaria medications going forward. As the piece concludes:

"Termination of AMFm will create instability in artemisinin production, will reduce access to affordable ACTs, and will be seen as abandonment - both by the many people who depend on AMGm and by the ACT producers. It will cause the kind of reaction that will detract from efforts to reduce deaths from malaria, to engage the private sector in providing community-based health care in poor countries, and to build credible health diplomacy."