The discipline of medical entomology, or public health entomology, and also veterinary entomology is focused upon insects and arthropods that impact human health. Veterinary entomology is included in this category, because many animal diseases can "jump species" and become a human health threat, for example, bovine encephalitis (known as "mad cow disease"). Medical entomology also includes scientific research on the behavior, ecology, and epidemiology of arthropod disease vectors, and involves a tremendous outreach to the public, including local and state officials and other stake holders in the interest of public safety.

Medical Entomologists are employed by private and public universities, private industries, and federal, state, and local government agencies, including all three branches of the military - who hire medical entomologists to protect the troops from infectious diseases that can be transmitted by arthropods. Historically, during wars, more people have died due to insect-transmitted diseases, than to all the battle injuries combined.