Malaria status & challenges of the epidemic

7. Can malaria be completely eradicated?

The WHO Global Malaria programme aims not only to reduce the burden of malaria in countries where it is present, but also to reduce the geographical extent of malaria in the world and therefore to eliminate it completely at the local level.

The WHO identified four phases on the path to malaria elimination: malaria control, pre-elimination, elimination, and prevention of reintroduction (see chart). The 109 countries in the world that are affected by malaria were classified according to how far they had progressed towards malaria elimination by July 2008:

• Eleven countries are in the pre-elimination phase: Azerbaijan, Georgia, Iran, Kyrgyzstan, Malaysia, Mexico, North Korea, Sri Lanka, Tajikistan, Turkey and Uzbekistan. In those countries, diagnostic tests showed that less than 5% of suspected malaria cases are actually malaria.

• Another ten countries have gone further in the path towards malaria control and are in the elimination phase: Algeria, Argentina, Armenia, Egypt, El Salvador, Iraq, Paraguay, Republic of Korea, Saudi Arabia and Turkmenistan. Those have fewer than one malaria case per 1000 inhabitants per year in areas at risk.

• Six countries are in the phase of preventing malaria reintroduction: Jamaica, Mauritius, Morocco, Oman, Russia and Syria. These countries have no malaria infections carried by mosquitoes. If this is achieved for three or more consecutive years, countries are certified malaria-free. In addition, China, Indonesia, Philippines, Solomon Islands, Sudan, Vanuatu and Yemen are attempting to establish malaria-free zones in parts of their territory.

In January 2007, the United Arab Emirates was the first formerly-endemic country to eliminate malaria since the 1980s, bringing the total number of malaria-free countries or territories in the world to 92.

Despite some successes, there is no evidence yet to show that malaria elimination can be achieved and maintained in areas where malaria transmission is currently high (one or more malaria cases per 1000 inhabitants per year).

It is not easy to say with certainty whether or not a particular control measure has had any specific impact on malaria as the effects of different interventions are not easily separable.

A few countries with relatively small populations and very thorough malaria control programmes seem to have cut malaria burden significantly. There have also been some successes with insecticide indoor spraying campaigns. However, the effects of malaria control measures are less obvious in countries with larger populations. In several African countries, malaria has not declined despite offering prevention and treatment services to a high proportion of their populations.

In many countries outside the WHO African Region, the numbers of reported cases and deaths were falling over the period 1997–2006 but it is not clear that this decline in malaria is caused by improved control measures.

Using records of numbers of cases and deaths to estimate the progress of malaria can be misleading. However, if the data are compiled and analysed carefully they are very useful to estimate trends and to get continuous feedback on the progress of malaria in different countries, regions and health centres. This would not only result in more accurate statistics but would also help make control programmes more effective.

This text is a summary of: WHO, World Malaria Report (2008) ,
5. Impact of malaria control, Malaria Elimination and Comment, p.31-32