Which of the following microorganisms causes plague?

The correct answer is Bacteria.

Key Points

• Plague is caused by the bacterium Yersinia pestis, a gram-negative coccobacillus.
• Yersinia pestis is primarily transmitted to humans through the bites of infected fleas that are hosted by rodents.
• Plague can present in three main clinical forms: bubonic plague, septicemic plague, and pneumonic plague.
• The bubonic form, characterized by swollen lymph nodes (buboes), is the most common manifestation of the disease.
• Plague outbreaks have historically caused widespread devastation, including the Black Death in the 14th century, which killed millions in Europe.

Additional Information

• Yersinia pestis:
  • A facultative anaerobic bacterium that belongs to the Enterobacteriaceae family.
  • It is highly virulent and can evade immune responses through specialized mechanisms.
• Transmission:
  • Direct contact with infected animals or tissues can also spread the disease.
  • Inhalation of respiratory droplets from a person with pneumonic plague can lead to human-to-human transmission.
• Symptoms:
  • Fever, chills, headache, and painful swollen lymph nodes (buboes) in bubonic plague.
  • Septicemic plague causes tissue necrosis and organ failure, while pneumonic plague leads to severe respiratory distress.
• Treatment:
  • Plague is treatable with antibiotics such as streptomycin, gentamicin, doxycycline, and ciprofloxacin.
  • Early diagnosis and treatment are crucial to prevent severe complications and fatalities.