Which of the following diseases is not typically transmitted by an insect?

Tetanus is caused by the bacterium Clostridium tetani, which is typically found in soil, dust, and animal feces, rather than being transmitted by insects. The disease results from infection through wounds or breaks in the skin where the bacteria can enter the body, particularly in deep puncture wounds.

In contrast, malaria, typhus fever, and yellow fever are all diseases transmitted by insect vectors. Malaria is primarily spread by Anopheles mosquitoes, typhus fever often involves lice or fleas, and yellow fever is transmitted by Aedes mosquitoes. Understanding the modes of transmission for different diseases helps public health officials implement appropriate prevention strategies, particularly in regard to vector control for insect-borne diseases.