AgroEcoHealth focus: Agriculture’s role in the development of mosquitoes
IITA Molecular Entomologist and Head of the AgroEcoHealth Platform in Cotonou, Rousseau Djouaka, has revealed the role of agriculture in the proliferation of mosquitoes concerning the spread of Buruli ulcer (BU). Djouaka highlighted this in his presentation, “The IITA AgroEcoHealth Platform, Starting from Ground Zero towards New Challenges,” which he gave at the IITA HQ in Ibadan, Nigeria.
Buruli ulcer, caused by Mycobacterium ulcerans, is a chronic and devastating disease that mainly affects the skin and sometimes bone. The organism belongs to the family of bacteria that causes tuberculosis and leprosy, and provides an opportunity for collaboration with these two disease programs. However, Mycobacterium ulcerans is an environmental bacterium and the mode of transmission to humans remains unknown. Currently, early diagnosis and treatment are crucial to minimizing morbidity and costs and preventing long-term disability (WHO 2019).
Thirty-three countries in Africa, the Americas, Asia, and the Western Pacific have reported cases of Buruli ulcer. Most cases occur in tropical and subtropical regions except in Australia, China, and Japan. Out of the 33 countries, 14 regularly report data to WHO. In Africa, the majority of cases are reported from West and Central Africa, including Benin, Cameroon, Côte d’Ivoire, the Democratic Republic of the Congo, Ghana, and Nigeria.
To understand and combat the mode of transmission of the BU disease in the wet agroecosystems, Djouaka said, “A system thinking initiative is the required approach for fighting BU because this neglected, yet emerging disease, occurs in the humid agroecosystems of West Africa. Also, it seems to be exacerbated by water types, soil types, human practices, and environment, which hurt communities’ livelihoods and increases the level of poverty in households.”
The mosquito, a major carrier of malaria, was considered vital while evaluating the mode of transmission of BU for better prevention of the disease. Research on insecticide resistance analyzed the molecular basis of resistance in malaria vectors (the Anopheles mosquito). Insecticide resistance, which refers to changes in an insect that increase its ability to withstand or overcome the effects of one or more insecticides, has been discovered to be caused by agriculture (agricultural insecticides), vector control (insecticides), urbanization and industry (pollutants), natural xenobiotics (allelochemicals), and microbiome (host interactions). Moreover, insecticide resistance management includes biological control, physical control, chemical control, and integrated vector management.
Agriculture favors the development and resistance selection in Anopheles by providing water for breeding, flower (nectar) for feeding, and leaves for resting.
“We are working with extension workers to relay information derived from research to farmers at the grassroots on how to grow rice with fewer mosquitoes and how to avoid stagnant water for vegetable farmers,” Djouaka said.