Answer :
The subject of the question relates to how the bacterium Yersinia pestis, which causes plague, affects humans and why the route of infection, known as the 'portal of entry,' is significant.
1. Importance of Portal of Entry:
The portal of entry is crucial because it determines the progression and severity of the infection. For Yersinia pestis:
- Bubonic plague: If the bacteria enter through the skin, usually via a flea bite, it travels to the lymphatic system, causing swollen lymph nodes or 'buboes'. This form is less deadly if treated promptly.
- Pneumonic plague: If the bacteria are inhaled, they go directly to the lungs, resulting in severe pneumonia. This form spreads easily between people.
2. Pulmonary Plague and Prognosis:
Pulmonary, or pneumonic, plague is the most severe form. Here’s why a patient with pulmonary plague has a lower chance of survival:
- Rapid Progression: Pneumonic plague progresses rapidly. Symptoms can occur as quickly as 24 hours after exposure, including fever, weakness, and rapidly developing pneumonia.
- High Mortality Rate: Without immediate treatment, this form has a much higher mortality rate compared to bubonic plague.
- Transmission: It can be transmitted from person to person through respiratory droplets, making it dangerous for outbreaks.
Early diagnosis and treatment with antibiotics can improve the chances of survival, but any delay can significantly decrease them. This is why public health measures and early treatment are critical in managing outbreaks of plague.
