SECTION I:

III. MALARIA CONTROL POLICIES AND STRATEGIES

Appropriate malaria control strategies vary with local malaria endemicity. The national control policies of malarious countries (Table A.1) generally conform to the key strategies advocated by RBM for their epidemiological setting (Table 5).

Table 5. Priority malaria control strategies, by epidemiological setting

1. Treatment policies

All 107 malarious countries and territories have a national antimalarial treatment policy, and most continually update the policy based on evidence of drug efficacy, safety, cost and availability.

Artemisinin-based combination therapies

In response to widespread resistance of P. falciparum to monotherapy with conventional antimalarial drugs such as chloroquine and sulfadoxine–pyrimethamine (Map 5), WHO now recommends combination therapies as the treatment policy for falciparum malaria in all countries experiencing such resistance. The preferred combinations contain a derivative of the plant Artemisia annua, which is presently cultivated mainly in China and Viet Nam. Artemisinin-based combination therapies (ACTs) are the most highly efficacious treatment regimens now available.

Since 2001, 42 malaria-endemic countries have adopted ACTs: 38 as first-line treatment and 14 as second-line treatment (Map 6). Of these 42 countries, 23 are in Africa, although only 9 countries were actually implementing ACT treatment policies as of 2004. An additional 14 countries are in the process of changing their malaria treatment policy.

In areas of high malaria transmission and poor access to facility-based health care, particularly in rural Africa, RBM advocates home management of children under 5 years of age with malaria as a strategy to achieve high coverage of prompt and effective antimalarial treatment in this highly vulnerable group (22). This involves educating mothers, training community-level providers—including shopkeepers— and supplying pre-packaged quality-assured medicines. Home management is now included in the national control strategies in 22 African countries and 2 countries in the Eastern Mediterranean.

2. Insecticide-treated nets

In areas of malaria transmission where sustained vector control is required, ITNs are the principal strategy for malaria prevention. All countries in Africa south of the Sahara, the majority of Asian malaria-endemic countries and some American countries have adopted ITNs as a key malaria control strategy (Table A.1). To promote the usage of ITNs, the NMCPs use various implementation methods including: (i) stimulating the growth of commercial markets; (ii) reducing taxes and tariffs; (iii) cost-sharing; (iv) social marketing subsidies; and (v) ITN distribution free of charge among vulnerable groups such as children under 5 years of age, pregnant women and the poorest or most marginalized populations. Services for (re-)treatment of existing untreated nets are another powerful means of increasing ITN coverage.

Recently developed techniques for the long-lasting insecticide treatment of nets provide a possible solution for the need to regularly re-treat nets. Although longlasting insecticidal nets (LLINs) are more expensive than conventional ITNs, the cost of maintaining coverage is lower, since they remain effective for 4 to 5 years. Two brands of LLINs are now recommended by WHO (23), and they are rapidly being adopted in many countries. Whereas previously production of LLINs was centered in Asia, a producer in the United Republic of Tanzania began production of a WHOrecommended LLIN in November 2004. Technology transfer to high-malaria settings is seen as the way to bring prices down.

3. Indoor residual spraying and other methods of vector control

IRS is a highly effective method for malaria vector control that is particularly useful for achieving a rapid reduction in transmission during epidemics and other emergency situations—provided it is well timed and high coverage is achieved. In areas of intense malaria transmission, IRS could have a long-term impact similar to that of ITNs, although ITNs are generally recommended in such areas because of better sustainability.

The dwindling availability of low-risk and cost-effective insecticides is a threat to malaria vector control. This is a result of increasing vector resistance and the lack of development over the past 20 years of new insecticide compounds for public health use. In May 2004, the Stockholm Convention on Persistent Organic Pollutants became operational. While enforcing strict measures to reduce environmental damage from persistent organic pollutants, the Convention stated that DDT is still needed in some countries for disease vector control (24). WHO recommends that countries select the insecticide for IRS based on local situation analysis; DDT is one of the 12 insecticides that can be used for this purpose.

In the Americas and in Asia, vector control—mostly involving IRS—is included in the national control policies of all countries. About half of African countries also include IRS as part of their malaria control efforts.

4. Malaria control during epidemics and complex emergencies

Up to 1 billion people throughout the world live in areas at risk of epidemic or hypoendemic malaria (21). A considerable proportion of global malaria deaths occurs among populations affected by conflicts, currently affecting 18 countries in Africa alone. Population displacement, increased vulnerability as a result of malnutrition and concurrent infections, exposure to malaria vectors from poor or lack of housing, collapse of health services and supply lines, and environmental deterioration resulting in increased vector breeding all contribute to the increased malaria burden in populations affected by complex emergencies.

Timely prevention of malaria epidemics requires robust early warning systems. Effective control requires early detection through weekly disease surveillance, combined with adequately funded preparedness plans of action that ensure the availability of control tools—such as drugs, IRS and ITNs—for rapid deployment. Malaria early warning systems can predict the risk of epidemics from seasonal climate forecasts and from monitoring anomalies in rainfall and temperature based on satellite observations (25). Weekly disease surveillance allows early detection— within 2 weeks (8)—of any unusual increase in malaria cases and immediate action to be taken (26). Most countries in Africa and Asia with areas at risk of highly seasonal or epidemic malaria include epidemic preparedness in their malaria control policies. In Africa, weekly reporting of malaria cases is implemented in at least 15 of the 25 epidemic-prone countries, either under a system of integrated disease surveillance and response or in sentinel sites. At least 8 African countries are developing a malaria early warning system. However, the effective use of these weekly surveillance data for timely, targeted interventions remains an area of ongoing operational research.

For malaria control during complex emergencies, the challenge is to implement priority interventions that are scientifically optimal and operationally feasible, in both the short and the longer term. Case management with ACTs is recommended in complex emergencies, and ACTs must be made widely available in health facilities and through outreach to affected populations. Vector control measures should aim for high coverage to be fully effective; and coordination among implementing agencies is key.

5. Malaria prevention and treatment in pregnant women

To reduce the negative consequences of malaria in pregnancy, WHO recommends the use of intermittent preventive treatment (IPT) for pregnant women in all areas with stable transmission of falciparum malaria. IPT involves provision of at least 2 treatment doses of an effective antimalarial during routine antenatal clinic visits to all pregnant women in these areas (27). As an integral part of the WHO Making Pregnancy Safer strategy, IPT is included in the control policies of 26 African countries with highly endemic malaria. Several other countries in Africa are reviewing their policies in light of the WHO recommendation, or are piloting IPT in selected areas. All malaria-endemic countries in Africa have policies for treatment of malarial illness in pregnancy, and the majority of highly endemic countries recommend that pregnant women have access to ITNs.