Which disease is a zoonosis?

• A. Lyme disease
• B. Measles
• C. Mumps
• D. Tuberculosis

Answer: (A)

Zoonosis means an infectious disease that can be transmitted from animals to humans. Lyme disease fits this because its pathogen, Borrelia burgdorferi, lives in wildlife and is maintained in nature by tick vectors. Ticks become infected when they feed on animal hosts like small mammals or deer, and when an infected tick bites a person, the bacteria can be transmitted, causing illness. This animal-to-human transmission route via a vector is the hallmark of a zoonosis.

Measles and mumps are spread from person to person through respiratory droplets and do not rely on an animal reservoir in their typical transmission cycles. Tuberculosis is mainly transmitted between humans as well, though there are rare animal reservoirs in some contexts; however, in common public health terms it’s considered a human disease rather than a classic zoonosis.