Plague is caused by Yersinia pestis bacteria, which commonly circulates among small animal populations like rats and fleas. In humans, plague presents in three main forms: bubonic, septicemic, and pneumonic. According to specialist doctor level one Nguyen Hoang Anh from the Infectious Diseases Unit, General Internal Medicine Department at Tam Anh General Hospital, TP HCM, each form has distinct manifestations and transmission routes.

Bubonic plague is the most common form. The bacteria typically enter the body through the bite of an infected flea, then travel via the lymphatic system to lymph nodes near the entry site, where they multiply. Patients often experience sudden fever, chills, headache, and fatigue, accompanied by one or more swollen, tense, and painful lymph nodes, known as buboes.

If left untreated, the bacteria can spread from the bubonic form to the bloodstream or lungs, leading to more severe forms of the disease. Bubonic plague rarely transmits directly from person to person.

Doctor Hoang Anh explains health issues to a patient. Illustration: Tam Anh General Hospital

Septicemic plague occurs when Yersinia pestis bacteria enter and multiply in the bloodstream. This form can develop initially or progress from untreated bubonic plague. Patients typically experience high fever, chills, abdominal pain, nausea, vomiting, diarrhea, and extreme weakness. Severe cases involve subcutaneous bleeding, tissue damage, organ failure, shock, and necrosis of the extremities.

Unlike bubonic plague, individuals with septicemic plague may not develop obvious swollen lymph nodes, making diagnosis difficult if relying solely on characteristic signs. This is also a severe form that requires early treatment.

Pneumonic plague is a rare but serious form that occurs when the bacteria invade and infect the lungs, according to Doctor Hoang Anh. This form can develop from bubonic or septicemic plague, or it can be contracted directly by inhaling bacteria-laden respiratory droplets from an infected person or animal with pneumonic plague.

Patients typically experience acute onset with fever, headache, and weakness, followed quickly by respiratory symptoms such as cough, shortness of breath, chest pain, and potentially coughing up blood-tinged sputum.

Doctor Hoang Anh notes that unlike the other two forms, pneumonic plague can transmit from person to person, primarily through respiratory droplets during close contact. The disease can progress rapidly, with a risk of death within 18-24 hours if not detected and treated promptly.

Plague is a severe bacterial infection, but it is treatable with antibiotics if detected early. Doctor Hoang Anh states that it is not a common infectious disease in Vietnam. However, because Yersinia pestis bacteria still exist in nature in some parts of the world, ongoing surveillance and proactive prevention remain essential.

Currently, Vietnam's Ministry of Health classifies plague as a Group A infectious disease, meaning it is a particularly dangerous infectious disease requiring close monitoring.

The doctor advises everyone to maintain hygiene in living areas, control rats and fleas, and avoid direct contact with dead animals or those showing unusual signs of illness. If symptoms such as sudden high fever, chills, swollen and painful lymph nodes, or respiratory symptoms like cough and shortness of breath appear, especially after exposure to a risk source, individuals should seek medical attention for early diagnosis and timely treatment.

Nhat Thanh