The three types of plague, a zoonotic disease (a disease transmitted to humans from animals), are:

**Bubonic Plague**
The most common form of the disease is called bubonic plague. Symptoms usually appear within 2-6 days after exposure to the plague bacteria. Bubonic plague infects the lymphatic system, causing inflammation of the lymph nodes. If left untreated, it can spread to the bloodstream, causing septicemic plague, or to the lungs, causing pneumonic plague. The most important symptoms of bubonic plague are:

* Sudden onset of fever
* Chills
* Weakness
* Headache
* Muscle aches

**Pneumonic Plague**
Pneumonic plague is a form of plague that can spread from person to person through respiratory droplets. It occurs when the *Yersinia pestis* bacteria spreads to the lungs, resulting in the most deadly form of the disease. Untreated pneumonic plague can lead to multiple organ failure and death due to respiratory distress. The most prominent symptoms of pneumonic plague are:

* Fever
* Chills
* Rapid heart rate
* Difficulty breathing
* Cough
* Chest pain
* Severe headache
* Bloody sputum

**Septicemic Plague**
Septicemic plague occurs when *Yersinia pestis* bacteria spread to the bloodstream. Septicemic plague progresses rapidly and requires prompt diagnosis and treatment to prevent death. Symptoms of septicemic plague include:

* Diarrhea
* Nausea
* Vomiting
* Abdominal pain
* High fever
* Chills
* Weakness
* Headache
* Muscle aches