Medical microbiology – reservoirs of sylvatic (wild-rodent) plague In zoonotic epidemiology, “sylvatic plague” refers to Yersinia pestis maintained in wild rodent reservoirs. In which of the following animals is sylvatic plague characteristically observed?

Introduction / Context:
Sylvatic plague is the wildlife (non-urban) cycle of Yersinia pestis, distinct from the urban cycle involving commensal rats. Understanding natural reservoirs is crucial for public health surveillance, outbreak prediction, and zoonosis control strategies.

Given Data / Assumptions:

• Sylvatic plague involves Y. pestis maintained among wild rodents and their fleas.
• Typical hosts include small mammals such as ground squirrels, mice, and chipmunks; prairie dogs and voles are also notable in some regions.
• Transmission to humans is usually via flea bites or contact with infected animals.

Concept / Approach:
Wild rodent populations serve as enzootic reservoirs where Y. pestis persists with periodic epizootics. The diversity of susceptible species increases ecological stability. Public health guidance emphasizes that multiple small-rodent taxa can harbor the pathogen, so any single list of “only one” host is incomplete.

Step-by-Step Solution:
Identify the animals listed: mice, squirrels, and chipmunks are all wild rodents.Recall that all three have documented roles in sylvatic plague cycles in various geographies.Because each listed animal can participate, the inclusive option is correct.

Verification / Alternative check:
Ecological and epidemiological reports from North America and Asia consistently implicate multiple rodent genera and their fleas (e.g., Oropsylla, Xenopsylla) as vectors and reservoirs in the sylvatic cycle.

Why Other Options Are Wrong:

• Mice only or squirrels only: too narrow; many rodents are involved.
• Chipmunks only: again, incomplete.
• Only prairie dogs: prairie dogs are important sentinels but not the sole hosts.

Common Pitfalls:
Confusing urban plague reservoirs (Rattus spp.) with sylvatic reservoirs; assuming a single “primary” host worldwide despite regional variation.

Final Answer:
All of these.