Rice agroecosystem and malaria risk in India
Authors: Shweta Pasi, Gaurav Kumar, Syed Shah Areeb Hussain, Jaspreet Kaur
Journal: The Lancet Planetary Health (2022)

Malaria remains a challenging infectious disease with the major global burden shouldered by sub-Saharan Africa and India. Interestingly, both countries have developing economies and the agricultural sector is the major contributor to their gross domestic products. Agricultural practices, particularly rice cultivation, have been traditionally linked to malaria transmission. Kallista Chan and colleagues1Chan K Tusting LS Bottomley C Saito K Djouaka R Lines J Malaria transmission and prevalence in rice-growing versus non-rice-growing villages in Africa: a systematic review and meta-analysis.Lancet Planet Health. 2022; 6: e257-e269Summary Full Text Full Text PDF PubMed Scopus (18) Google Scholar in The Lancet Planetary Health reviewed malaria prevalence between rice-growing and non-rice-growing communities in Africa and concluded that rice cultivation is associated with an increased risk of malaria. India is the second-largest rice producer in the world with about 44 million hectares of area under rice cultivation and is committed towards malaria elimination by the year 2030. Past studies have shown that the rice agroecosystem in India supports profuse breeding of anophelines. Anopheles culicifacies, and An fluviatilis, the major Indian malaria vectors, abundantly breed in rice fields at the time of early plantation and in rice-field channels.2Kant R Pandey SD Breeding preferences of Anopheles culicifacies in the rice agro-ecosystem in Kheda district, Gujarat.Ind J Malariol. 1999; 36: 53-60PubMed Google Scholar, 3Sadanandane C Sahu SS Gunasekaran K Jambulingam P Das PK Pattern of rice cultivation and anopheline breeding in Koraput district of Orissa state.J Comm Dis. 1991; 23: 59-65PubMed Google Scholar Although breeding of An culicifacies correlated inversely with plant height, An fluviatilis bred at all stages of paddy growth. However, the rice–malaria association in the Indian context is poorly understood. A solitary report by Sharma and colleagues4Sharma VP Srivastava A Nagpal BN A study of the relationship of rice cultivation and annual parasite incidence of malaria in India.Soc Sci Med. 1994; 38: 165-178Crossref PubMed Scopus (28) Google Scholar in 1994 found poor or no relation between malaria prevalence and rice production at the macro level in India. In the 1990s, the prevalence of malaria in India was quite high. Chan and colleagues1Chan K Tusting LS Bottomley C Saito K Djouaka R Lines J Malaria transmission and prevalence in rice-growing versus non-rice-growing villages in Africa: a systematic review and meta-analysis.Lancet Planet Health. 2022; 6: e257-e269Summary Full Text Full Text PDF PubMed Scopus (18) Google Scholar highlight that the rice–malaria association in Africa became important only upon reduction in malaria intensity, and this finding might also explain the results of Sharma and colleagues.4Sharma VP Srivastava A Nagpal BN A study of the relationship of rice cultivation and annual parasite incidence of malaria in India.Soc Sci Med. 1994; 38: 165-178Crossref PubMed Scopus (28) Google Scholar Over the past decade, malaria burden in India has reduced substantially. However, some states continue to report a high number of cases. When we mapped the state-wise rice cultivation area and average slide positivity rate (2015–19),5National Vector Borne Disease ControlMalaria situation in India from 2014.https://nvbdcp.gov.in/index4.php?lang=1&level=0&linkid=564&lid=3867Date accessed: March 25, 2022Google Scholar states with high malaria burden strikingly also had a high area under rice cultivation, such as Uttar Pradesh, Bihar, Jharkhand, Chhattisgarh, and Odisha (appendix). Preliminary observations warrant micro-level studies to understand the malaria risk associated with rice cultivation in India. Further, climatic conditions and topography are highly diverse in India, and hence rice-growing seasons vary across the country. Although southern and eastern India raise two to three crops per year, the northern and western parts cultivate a single rice crop per year. Therefore, focussed research is required to determine the areas, months, and rice agroecosystems that support high vector breeding. Vector-control interventions, such as the introduction of larviviorous fishes, silicone-based liquids (that form surface film on standing water) in rice fields could be explored, and most importantly entomologists and agronomists should work together to grow more rice and no mosquitoes. We declare no competing interests. SP and GK contributed equally to this Correspondence. Download .pdf (.23 MB) Help with pdf files Supplementary appendix Malaria transmission and prevalence in rice-growing versus non-rice-growing villages in Africa: a systematic review and meta-analysisIrrigated rice-growing communities in sub-Saharan Africa are exposed to greater malaria risk, as well as more mosquitoes. As increasing rice production and eliminating malaria are two major development goals in Africa, there is an urgent need to improve methods for growing rice without producing mosquitoes. Full-Text PDF Open Access