Which animal is NOT known to contract Yersinia pestis infection?

The correct answer indicates that all the animals listed are capable of contracting Yersinia pestis, the bacterium responsible for the infectious disease known as plague. Understanding the host range of this pathogen is important for recognizing transmission dynamics and potential public health threats.

Rats are historically well-known hosts for Yersinia pestis, particularly being responsible for transmitting the bacteria to fleas, which then can infect humans. Chipmunks, as small rodents, are also considered susceptible to the infection and can act as reservoirs for the disease, thereby posing a risk for transmission.

Camels, while not the typical host like rodents, have been noted to have some interaction with the pathogen, although they are less commonly associated with plague transmission compared to the other animals listed.

The inclusion of "None of the above" as the answer suggests that all listed animals can, under certain circumstances, become infected with Yersinia pestis, reinforcing the significance of monitoring and controlling these potential reservoirs to prevent outbreaks in both animal and human populations.