Prevention of reintroduction

Last update: 31 March 2017

After malaria cases have been reduced to zero in a particular area or country, preventing re-establishment of the disease is a key concern. Re-establishment of transmission is defined as the occurrence of 3 or more indigenous cases of malaria of the same parasite species per year in the same foci for 3 consecutive years.

Malaria imported by visitors and migrants carries the risk of resuming local transmission of malaria in areas where Anopheles mosquitoes are still present and conditions for spread are favourable.

Countries that achieve a “malaria-free status” may be reluctant to commit personnel, time and expenditure to a disease that has been eliminated within their borders. It is vital that they retain adequate surveillance systems to detect cases quickly, and skilled personnel to diagnose and treat them.

Countries that have been certified by WHO as malaria-free and countries on the WHO Supplementary list to the official register are also exposed to the threat of re-establishment of malaria and may, from time to time, see local transmission of malaria linked to imported cases of the disease.

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