Which animal is noted for being a carrier of lymphocytic choriomeningitis without showing signs of illness?

The animal known for being a carrier of lymphocytic choriomeningitis (LCMV) without showing signs of illness is indeed mice. Mice can carry the virus and can shed it in their urine, saliva, and feces while remaining asymptomatic. This poses a risk in laboratory settings as they can transmit the virus to other animals and humans inadvertently.

In contrast, while rats, hamsters, and guinea pigs can be exposed to various pathogens, they do not serve as notable carriers for LCMV in the same manner. For example, although rats can host several diseases, they are not specifically recognized for asymptomatically carrying LCMV. Understanding the carriers of such infectious agents is crucial for laboratory animal management and health monitoring, particularly to ensure the safety of research environments and personnel.