What disease has the insecticide DDT been primarily used to control?

DDT, or dichloro-diphenyl-trichloroethane, has been primarily used to control malaria. This insecticide became widely recognized for its effectiveness in reducing mosquito populations that transmit the malaria parasite, particularly in the mid-20th century. The application of DDT played a significant role in large-scale malaria eradication efforts across various countries, contributing to a substantial decrease in malaria cases and mortality rates.

The use of DDT is particularly notable in this context because it targets the insect vectors of malaria, especially Anopheles mosquitoes, which are responsible for transmitting the Plasmodium parasites that cause the disease in humans. DDT disrupts the nervous system of the mosquitoes, resulting in their inability to survive and reproduce, thereby controlling their population and reducing the incidence of the disease.

Other diseases mentioned in the options, such as dengue, Zika, and West Nile Virus, are also transmitted by mosquitoes but DDT has not been a primary control measure for these diseases. Instead, different strategies and insecticides have been developed and recommended to combat these specific infections.