By Richard Feachem, KBE, FREng, DSc(Med), PhD
In 1897, Ronald Ross and his team in India discovered that malaria was transmitted by anopheles mosquitoes. At this time, every country in the world had endemic malaria somewhere within its borders. The only exceptions were the Pacific Island countries of Micronesia and Polynesia, where there are no anopheles mosquitoes and therefore no malaria.
Malaria even occurred in the summer in the Russian port of Murmansk, north of the Arctic Circle. Since that time, we have been progressively shrinking the malaria map.
Achieving total elimination
Country after country has achieved elimination, which means no transmission within the borders of that country. Of the roughly 200 countries in the world, half have eliminated; 19 since the year 2000.
Shrinking the malaria map has generally proceeded from north to south in the northern hemisphere and from south to north in the southern hemisphere. Thus, Canada eliminated before the USA, and Mexico is now completing the task of elimination. Scandinavia eliminated before the United Kingdom, and the last countries in western Europe to eliminate were Spain, Italy and Greece. Similarly, in the southern hemisphere, Chile and Uruguay were the first to eliminate in South America, and Australia eliminated in the early 1960s.
While it is true that temperate countries, in general, have eliminated before tropical countries, there are notable exceptions.
Most of the Caribbean islands eliminated in the 1960s. Brunei, Singapore, and Taiwan eliminated malaria between 1965 and 1987. These are all tropical countries with previously high rates of malaria transmission. In addition, while these Asian countries are wealthy today, when they eliminated, they were not. When Singapore eliminated malaria in 1970, it had GDP per capita lower than Senegal today.
Which countries will be next?
Coming to the present day, the process of shrinking the malaria map is accelerating. Five years ago, Sri Lanka eliminated malaria. China, for the first time in 5,000 years, ended 2017 with zero local malaria transmission across its vast territory and its huge population.
Other countries are close to elimination. In southern Africa, Botswana, Namibia, South Africa and Swaziland have committed to eliminate by 2020. While this may not be achieved in all cases, these countries will be close and will certainly eliminate soon after that date.
Meanwhile, in Asia, Bhutan, Malaysia and Timor Leste are very close to elimination and intend to finish the job by 2020. Ambitiously, the entire Asia Pacific region, from the northwest to Vanuatu in the southeast, has committed to eliminate malaria by 2030.
Eliminating malaria province by province
In large countries, shrinking the malaria map is a process that goes on within the country. For example, Indonesia and the Philippines are eliminating province by province and progressively ending malaria transmission within their large and diverse territories. India is embarking on a similar process. The heartland of malaria in India is in states such as Madhya Pradesh and Odisha.
Some people ask why we should focus on elimination when most malaria deaths are in the high-burden countries in the endemic heartland. Certainly, bearing down on malaria in the endemic heartland is a very high priority. However, at the same time, we must continue to eliminate progressively from the endemic margins inwards. This process of shrinking the malaria map will allow us to increasingly concentrate our efforts in the few remaining endemic countries where elimination will prove extremely difficult.
Accelerating the longstanding process of shrinking the malaria map is an essential element of our global malaria strategy. When the malaria map has been shrunk to nothing, the whole world will be free from this ancient and deadly disease.
Richard Feachem is director of the Global Health Group at the UCSF Institute for Global Health Sciences. This blog post appeared originally at www.fightagainstmalaria.com.