Yersinia Pestis Can Be Transmitted in More Than One Way

question 4

Multiple Choice

Yersinia pestis can be transmitted in more than one way. Most commonly, a person is bitten by an infected flea from which he or she may contract bubonic plague, characterized by large and tender lymph nodes (called buboes) . If a person inhales respiratory droplets from an infected patient or animal, he or she may develop pneumonic plague with signs and symptoms of pneumonia (rare) . When the causative organism spreads via the bloodstream, the person may develop septicemic plague in which there is bleeding in the skin and organs (rare) . Which of the following would you tell your friend to put his mind at ease about going to Yosemite?

• A) Most people who get plague actually get the pneumonic form of the disease, transmitted through inhaled droplets. If you wear a face mask while you hike, you will be perfectly safe and will not contract the disease.
• B) The people who contracted plague while in Yosemite were camping and were likely exposed to fleas from ground squirrels in the camp grounds. As you will be staying in a hotel, your risk of getting bitten by squirrel fleas is very low.
• C) Plague is really not a very serious disease. People in the Middle Ages died from it because their immune systems were very weak in those days because of bad air pollution.
• D) Plague is a serious disease but your immune system can easily get rid of it because the causative agent has no way to avoid your immune defenses. As such, it doesn't matter if you contract plague because you will easily recover.
• E) Plague is a seasonal disease because the causative organism only grows at 28ᵒC. It has only been reported to occur during May or October, so if you hike in July, there will be no risk.

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