What is the primary disease caused by Yersinia pestis?

• A. Pneumonia
• B. Bubonic plague
• C. Meningitis
• D. Sepsis

Answer: (B)

Yersinia pestis is the bacterium responsible for causing the bubonic plague, which is its primary and most well-known disease manifestation. The bubonic plague typically presents with swollen and painful lymph nodes, known as buboes, fever, chills, and malaise. This disease is historically significant, having caused widespread pandemics throughout history, including the Black Death in the 14th century.

The bacterium can also cause other forms of plague, such as septicemic plague and pneumonic plague, but the classic presentation is specifically associated with bubonic plague. Bubonic plague occurs when the bacterium is transmitted to humans through the bite of an infected flea, and it can spread to the bloodstream, potentially leading to septicemia or pneumonia in more severe cases. However, the defining characteristic of Yersinia pestis infections is the development of bubonic plague.