Which of the following is NOT a pest carried by deer mice?

Deer mice are known carriers of certain diseases, particularly those that can be transmitted to humans through contact with their droppings, urine, or saliva. Hantavirus is one of the most notable diseases associated with deer mice, as these rodents can shed the virus in their excretions, leading to potential infections in humans.

West Nile virus is primarily spread by mosquitoes and is not associated with deer mice as a carrier. However, it does not directly relate to the main focus of deer mice and the diseases they carry.

Smallpox is a viral disease that has been eradicated and is not carried by deer mice or any other wild animals. It is exclusively a human disease, which distinguishes it from the other options that involve animal vectors.

Yellow fever is a disease transmitted by mosquitoes and is not associated with deer mice. It is commonly linked to tropical and subtropical regions where the mosquitoes that carry the virus thrive.

Therefore, smallpox is the correct answer to the question, as it is not a pest associated with deer mice, highlighting the unique nature of certain diseases and their specific hosts or vectors.