Question

A patient comes into the clinic with plague. You are curious which type of plague this individual is experiencing, so you take tissue samples from what looks like a swollen lymph node, as well as sputum samples and blood samples. You plate these samples on differential and selective media. Importantly, these tests demonstrate that you have indeed isolated Yersinia pestis. However, colonies are only growing on plates cultured from the tissue samples. Which type of plague does this individual have?

• Hemorrhagic
• Bubonic
• Pneumonic
• Commensalistic
• Pneumonic
• Xenobiotic

Answer 1

Ans. The patient is suffering from Bubonic Plague.

Explanation:

Plague is a bacterial infection caused by the bacteria yersinia pestis and transmitted by fleas.The symptomps of plague disease usually depends on the way the patient got exposed to the bacteria.There are three most common forms of plague, bubonic,septicemic and penumonic.Bubonic and Septicemic plague are the first form of this diesease,which when left untreated turns into a pneumonic plague.Different forms have different symptoms that helps a clinical investigation to differentiate between each other.

Following are the symptoms of Bubonic Plague:

1. Sudde Fever ,Chills and headache
2. Weakness
3. Swollen and painful lymph nodes of the groin,armpit or neck.

When an infected flea bites the individual, the bacteria enters the body and starts to multiply in the lymph node which is closest to the area of bite, hence the main symptomp of a swollen and painful lymph nodes.  

Explanation for why it is not Pneumonic plague:

Pneumonic plague is the most dangerous form of plague as at this stage, the plague can transmit from one person to another through the infectious droplets from coughing and sneezing of an infected individual.At this stage, the bacteria spreads to lungs and cause lung infection The major symptom of pneumonic plague is shortness of breath along with chest pain.Sometimes bloody or watery mucous discharge along with coughing also occurs,indicating pneumonic plague.

Since,In the situation given above, the colonies are only growing on plates cultured from the tissue samples taken from the lymph nodes, it clearly indicates the presence of bacteria in lymph node region. Whereas the samples taken from mucous or blood samples showed no bacterial colony.Hence, it is clear that the individual is having bubonic plague and not pneumonic plague.