What chemical was historically used to treat soldiers with malaria?

The correct answer is DDT, which stands for dichloro-diphenyl-trichloroethane. DDT was widely used during and after World War II for its effectiveness in controlling mosquitoes, which are the primary vectors of malaria. Its ability to kill insects made it a vital tool for military operations in preventing mosquito-borne diseases among soldiers stationed in malaria-endemic regions.

The use of DDT significantly reduced malaria transmission rates in various parts of the world, contributing to its historical significance in public health, particularly when combatting malaria among military personnel. While it has since been banned or restricted in many countries due to environmental and health concerns, its role during that period remains a key point in the history of disease control.

The other chemicals listed are not historically linked to malaria treatment in the same context as DDT. Chlorpyrifos is an insecticide primarily used in agriculture, while malathion is also an insecticide used to control mosquitoes but did not have the same historical impact in military settings. Glyphosate is a herbicide used for weed control and is not related to malaria treatment.