Allison A Phillips

The changing epidemiology of malaria elimination: new strategies for new challenges

Malaria-eliminating countries achieved remarkable success in reducing their malaria burdens between 2000 and 2010. As a result, the epidemiology of malaria in these settings has become more complex. Malaria is increasingly imported, caused by Plasmodium vivax in settings outside sub-Saharan Africa, and clustered in small geographical areas or clustered demographically into subpopulations, which are often predominantly adult men, with shared social, behavioural, and geographical risk characteristics. The shift in the populations most at risk of malaria raises important questions for malaria-eliminating countries, since traditional control interventions are likely to be less effective. Approaches to elimination need to be aligned with these changes through the development and adoption of novel strategies and methods. Knowledge of the changing epidemiological trends of malaria in the eliminating countries will ensure improved targeting of interventions to continue to shrink the malaria map.

Shrinking the malaria map: progress and prospects

Summary In the past 150 years, roughly half of the countries in the world eliminated malaria. Nowadays, there are 99 endemic countries—67 are controlling malaria and 32 are pursuing an elimination strategy. This four-part Series presents evidence about the technical, operational, and financial dimensions of malaria elimination. The first paper in this Series reviews definitions of elimination and the state that precedes it: controlled low-endemic malaria. Feasibility assessments are described as a crucial step for a country transitioning from controlled low-endemic malaria to elimination. Characteristics of the 32 malaria-eliminating countries are presented, and contrasted with countries that pursued elimination in the past. Challenges and risks of elimination are presented, including Plasmodium vivax, resistance in the parasite and mosquito populations, and potential resurgence if investment and vigilance decrease. The benefits of elimination are outlined, specifically elimination as a regional and global public good. Priorities for the next decade are described.

Call to action: priorities for malaria elimination

The Lancet’s four-part Series on malaria elimination summarises the remarkable progress achieved over the past 100 years and discusses the substantial technical, operational, and financial challenges that confront malaria-eliminating countries.1–4 The Series comes at a time when there are increased resources to combat malaria worldwide. A three-part strategy to achieve malaria eradication has been developed and is widely endorsed: aggressive control in high-burden regions; progressive elimination from endemic margins to shrink the malaria map; and research and development, to develop new tools and techniques.5 All three components are important and must proceed simultaneously. This Comment focuses on the priorities, requirements, and responsibilities that are associated with the second part of this strategy: shrinking the malaria map.

The path to eradication: a progress report on the malaria-eliminating countries

In the past several years, as worldwide morbidity and mortality due to malaria have continued to decrease, the global malaria community has grown increasingly supportive of the idea of malaria eradication. In 2015, three noteworthy global documents were released-the WHOs Global Technical Strategy for Malaria 2016-2030, the Roll Back Malaria Partnerships Action and Investment to defeat Malaria 2016-2030, and From Aspiration to Action: What Will It Take to End Malaria?-that collectively advocate for malaria elimination and eradication and outline key operational, technical, and financial strategies to achieve progress toward malaria eradication. In light of this remarkable change in global attitudes toward malaria elimination and eradication, and as the malaria community debates how and when to embark on this ambitious goal, it is important to assess current progress along the path to eradication. Although low-income, high-burden countries are often the focus when discussing the substantial challenges of eradication, the progress toward elimination in middle-income, low-burden countries is a major driver of global progress and deserves better recognition. Additionally, although global support and guidance is essential for success, malaria elimination and eradication efforts will ultimately be driven at the country level and achieved in a collaborative manner, region by region. In this Review, we examine the present status of the 35 malaria-eliminating countries, summarise existing national and regional elimination goals and the regional frameworks that support them, and identify the most crucial enabling factors and potential barriers to achieving eradication by a theoretical end date of 2040.

Preventing the Reintroduction of Malaria in Mauritius: A Programmatic and Financial Assessment

Sustaining elimination of malaria in areas with high receptivity and vulnerability will require effective strategies to prevent reestablishment of local transmission, yet there is a dearth of evidence about this phase. Mauritius offers a uniquely informative history, with elimination of local transmission in 1969, re-emergence in 1975, and second elimination in 1998. Towards this end, Mauritiuss elimination and prevention of reintroduction (POR) programs were analyzed via a comprehensive review of literature and government documents, supplemented by program observation and interviews with policy makers and program personnel. The impact of the countrys most costly intervention, a passenger screening program, was assessed quantitatively using simulation modeling. On average, Mauritius spent

A national policy for malaria elimination in Swaziland: a first for sub-Saharan Africa.

4.43 per capita per year (pcpy) during its second elimination campaign from 1982 to 1988. The country currently spends

The challenge of artemisinin resistance can only be met by eliminating Plasmodium falciparum malaria across the Greater Mekong subregion

2.06 pcpy on its POR program that includes robust surveillance, routine vector control, and prompt and effective treatment and response. Thirty-five percent of POR costs are for a passenger screening program. Modeling suggests that the estimated 14% of imported malaria infections identified by this program reduces the annual risk of indigenous transmission by approximately 2%. Of cases missed by the initial passenger screening program, 49% were estimated to be identified by passive or reactive case detection, leaving an estimated 3.1 unidentified imported infections per 100,000 inhabitants per year. The Mauritius experience indicates that ongoing intervention, strong leadership, and substantial predictable funding are critical to consistently prevent the reestablishment of malaria. Sustained vigilance is critical considering Mauritiuss enabling conditions. Although the cost of POR is below that of elimination, annual per capita spending remains at levels that are likely infeasible for countries with lower overall health spending. Countries currently embarking on elimination should quantify and plan for potentially similar POR operations and costs.

Eliminating malaria and preventing its reintroduction: the Mauritius case study

Swaziland is working to be the first country in mainland sub-Saharan Africa to eliminate malaria. The highest level of Swazilands government recently approved a national elimination policy, which endorses Swazilands robust national elimination strategic plan. This commentary outlines Swazilands progress towards elimination as well as the challenges that remain, primarily around securing long-term financial resources and managing imported cases from neighbouring countries.

Chinese action towards global malaria eradication – Authors' reply

Artemisinin-based combinations are currently the most effective anti-malarials and, in addition to vector control, have led to significant declines in malaria morbidity and mortality. However, foci of artemisinin drug resistance have been identified in the Greater Mekong subregion (GMS) of the Asia Pacific, threatening the major gains made in malaria control and potentially creating a parasite pool that is more difficult to treat and eliminate. Efforts are underway to halt the spread of artemisinin resistance, including coordination of activities and funding, and identification of areas of suspected artemisinin resistance, now using a newly identified molecular marker. However, targeting resources to the containment of resistant parasites is likely inefficient and monitoring impact is challenging. A more sustainable solution is the rapid elimination of all Plasmodium falciparum parasites from the GMS. This strategy is more efficient for several reasons. First, a subregional strategy is in line with current commitment to elimination and will build upon the existing national political support for elimination as well as enhancing collaboration among countries. Second, the challenge of human mobility in the GMS is subregional in scope and requires a harmonized elimination strategy. Third, countries will need to improve and intensify malaria operations to reach elimination, and this will be a singular goal across the subregion. Rallying around the goal of P. falciparum elimination will not only utilize existing regional bodies to catalyze political and funding support, but will also leverage the funding already in place to achieve this subregional goal.

Shrinking the Malaria Map: A Prospectus on Malaria Elimination

This abstract is submitted as part of the panel session on case studies for elimination by the WHO Global Malaria Programme and the UCSF Global Health Group.