In this latter country, a single amino acid change (L119F) in an up-regulated glutathione S-transferase gene, GSTe2, in Anopheles funestus showed to confer high levels of metabolic resistance to DDT hence representing a promising marker to track the evolution of DDT and pyrethroid resistance in malaria vectors in West Africa [39, 40]. The gene discussed is HPGDS; the disease is malaria.