Anopheles mosquitoes spread the malaria parasite to humans.Credit: NHPA/Photoshot

The World Health Organization (WHO) declared Argentina and Algeria malaria-free on 22 May, after the two countries reported zero transmission of the disease for more than three years. The success brings the total number of malaria-free countries to 38.

Algeria — where scientists discovered the disease-causing parasite in 1880 — reported its last native malaria case in 2013, and is the third African country to banish the disease; Argentina’s last case was in 2010.

Both nations had maintained low malaria transmission rates for decades, and universal health coverage and rigorous surveillance were crucial in their fight against the disease. Argentina also worked closely with neighbouring countries to spray homes with insecticides and test people for the disease to prevent cross-border transmission.

Source: WHO

The WHO’s Global Malaria Eradication Programme (GMEP) and local efforts relied on the insecticide DDT and medication to help 27 countries become malaria-free from the 1960s to the 1980s (see ‘Malaria-free nations﻿’﻿). But the agency abandoned the GMEP in 1969 after scientists realized that global eradication was not feasible in the short term.

Efforts restarted in the 2000s. In 2016, the WHO targeted 21countries with the goal of eliminating malaria in them by 2020. Two of those are now malaria-free: Paraguay and Algeria.

Around 200 million malaria cases occur each year in more than 80 countries. In 2017, an estimated 435,000 people died from the disease.