Which of the following diseases can be contracted from a rat?

The plague is a disease that can indeed be contracted from rats, specifically through fleas that infest the rodents, as well as through direct contact with an infected animal. The bacterium Yersinia pestis is responsible for the plague, which has historically been associated with rat populations.

Rats may act as hosts for the fleas that carry this bacterium, and when humans are bitten by these fleas, they can become infected. Additionally, handling or coming into contact with a dead or sick rat that has been infected can also lead to the transmission of the plague.

In contrast, West Nile virus is primarily transmitted through mosquito bites, Lyme disease is caused by tick bites, and while influenza can affect many animals, its primary transmission in humans is person-to-person, with some zoonotic strains originating from birds or pigs, rather than from rats specifically. Thus, the only direct association among these diseases and rats is the plague, affirming it as the correct answer to the question.