About the Disease

Types of Plague

• Bubonic plague
• Pneumonic plague
• Septicaemic plague

Bubonic Plague

Bubonic plague is caused by bacteria called Yersinia pestis. The bacteria are carried by black rats and transferred to rat fleas through blood. Although rats can live with a certain amount of Y. pestis in their blood, they die when the bacteria level gets too high. Then the fleas are forced to look for other hosts, and human beings are good candidates. When fleas bite people, they transfer bubonic plague.

Symptoms:

• Chills, fever, headache, and body pains
• The lymph nodes swell near the groin, armpits, and neck; the swellings are called buboes.
• Internal bleeding causes the skin to turn black.

Death rate: 50% to 60% (without treatment)

Transmission: rodent to flea to human

Pneumonic Plague

Symptoms
This type of plague infects the victim’s lungs. Two to three days after infection, the victim develops a cough and skin discoloration, and begins coughing up bloody sputum. The sputum contains Y. pestis, which is transferred to other people when it becomes airborne. Pneumonic plague can also cause coma.

Death rate: 95%

Transmission: human to human

Septicaemic plague

This type of plague causes high amounts of Y. pestis in the blood of the victim.

Symptoms:

• Rash develops within hours of exposure
• Victim dies in less than a day

Death rate: 100%

Transmission: human to flea to human