The end of the “Paddies Paradox”

Last July 31, 2025, IRRI joined partner CGIAR Centers at a media visit hosted by the Global Development and Health Communication Center (GDHCC) with the Gates Foundation to explore the innovations and impact of CGIAR work in Africa. Read how IRRI Researcher Everlyne Nganga explains the changing dynamics of rice farming and malaria-causing mosquitoes in Africa.

Rice fields in Africa are breeding grounds for several malaria-causing mosquitoes, the most important of which is Anopheles gambiae complex. This complex carries the most dangerous malaria parasite called Plasmodium falciparum, which accounts for 90% of the world’s malaria mortality. Despite this, in the early 1990s, research showed that malaria cases were not higher in rice-farming villages than those without rice fields. This is the “Paddies Paradox”. Rice fields are breeding grounds for malaria vectors, yet farming communities recorded fewer malaria cases. The malaria mystery was attributed to two main reasons: first, some of the mosquito species that grew in the rice field were less harmful, and second, the increased income from rice farming helped farmers access better healthcare, antimalarials, and mosquito nets.

However, there have been recent developments in the relationship between rice production and malaria in Africa. Initial research results have shown that communities living near rice irrigation schemes are now more exposed to malaria. A study by the London School of Hygiene and Tropical Medicine showed that for every one hectare of irrigated rice, about 700,000 malaria vectors develop during a single cropping season.

Since interventions to combat malaria were significantly and equitably scaled across Africa, we can no longer assume that non-rice growing communities are less protected against the disease. Furthermore, as governments position rice as a strategic crop for national food security, more land is needed to increase rice production. This means more rice will be produced to meet these growing demands. Still, irrigation is required, so there are now greater areas of opportunity for malaria-causing mosquitoes to develop. The end of the Paddies Paradox spells a significant threat to rice production in Africa.