Overview

Plague is a serious infectious disease caused by the bacterium Yersinia pestis. Historically known as the “Black Death,” plague has caused some of the most devastating pandemics in human history. Today, plague is rare but still occurs in some parts of the world. It can be life-threatening if not diagnosed and treated promptly but is curable with modern antibiotics. Plague is transmitted primarily through the bites of infected fleas, direct contact with contaminated animals, or inhalation of infectious droplets.

What is Plague?

Plague is a zoonotic disease (transmitted from animals to humans) caused by Yersinia pestis, a gram-negative bacterium found in rodents and their fleas. There are three main clinical forms of plague:

1. Bubonic plague – most common; causes swollen lymph nodes (buboes)
2. Septicemic plague – bacteria enter the bloodstream, leading to systemic infection
3. Pneumonic plague – most severe; affects the lungs and is highly contagious via respiratory droplets

While plague was historically widespread, modern outbreaks are mostly confined to remote rural areas, and global cases number in the hundreds annually.

Symptoms

Symptoms depend on the type of plague but usually develop 2–6 days after exposure.

Bubonic Plague:

• Sudden onset of fever and chills
• Painful, swollen lymph nodes (buboes) near the groin, armpits, or neck
• Headache and fatigue
• Muscle aches
• Sometimes skin necrosis or blackening in advanced stages

Septicemic Plague:

• Fever and chills
• Abdominal pain, nausea, vomiting
• Bleeding under the skin or from orifices
• Shock
• Skin turning black (gangrene), especially fingers, toes, and nose

Pneumonic Plague:

• Rapid onset of fever, cough, and chest pain
• Difficulty breathing or bloody sputum
• High risk of transmission to others through airborne droplets
• Can be fatal within 24–72 hours without treatment

Causes

Plague is caused by Yersinia pestis, which spreads in several ways:

• Flea bites: Infected fleas from rodents (especially rats) bite humans
• Direct contact: Handling infected animals (dead or alive), especially in hunting or agricultural settings
• Inhalation: Breathing in respiratory droplets from an infected person or animal (pneumonic plague)
• Ingestion: Rarely, through consumption of infected meat

Natural reservoirs include wild rodents such as prairie dogs, rats, mice, and squirrels.

Risk Factors

Though plague is rare in most modern countries, risk factors include:

• Living or traveling in plague-endemic areas (e.g., parts of Africa, Asia, and the southwestern United States)
• Handling wild animals or working in veterinary or wildlife settings
• Exposure to fleas or rodents in rural or unsanitary environments
• Close contact with someone with pneumonic plague
• Poor sanitation and overcrowded living conditions
• Immunocompromised individuals are more vulnerable to severe disease

Complications

If not promptly treated, plague can lead to life-threatening complications:

• Septic shock
• Respiratory failure (especially in pneumonic plague)
• Tissue necrosis and gangrene
• Organ failure
• Meningitis
• Death – untreated cases can have a mortality rate of 60–100% depending on the form

Prevention

While no vaccine is widely available for public use, preventive strategies are effective:

• Control rodent populations in living areas
• Use insect repellent and flea control methods when in endemic areas
• Wear gloves when handling wild animals or carcasses
• Avoid contact with sick or dead animals
• Practice good hygiene and sanitation
• Isolate infected individuals with pneumonic plague to prevent spread
• Prompt antibiotic treatment if exposed or symptomatic

In high-risk regions, people may be placed on prophylactic antibiotics after confirmed exposure.

Treatment Options in Korea

Though plague is extremely rare in South Korea, the country has robust infectious disease infrastructure, and any suspected or confirmed case would be managed swiftly and effectively. Treatment includes:

1. Antibiotic Therapy

• Early administration of antibiotics is crucial
• Effective antibiotics include:
  • Streptomycin (first-line in many countries)
  • Gentamicin
  • Doxycycline
  • Ciprofloxacin
• Duration of therapy is typically 7–10 days or until 3 days after fever resolves

2. Supportive Care

• Intravenous fluids
• Oxygen support for pneumonic cases
• Blood pressure monitoring and stabilization
• Intensive care for severe cases

3. Infection Control and Isolation

• Pneumonic plague patients are isolated in negative-pressure rooms
• Personal protective equipment (PPE) is mandatory for healthcare workers
• Contact tracing and prophylactic antibiotics for exposed individuals

4. Laboratory Diagnosis

• Blood cultures, lymph node aspirates, or sputum testing
• PCR testing and bacterial staining available in advanced labs
• Notification to public health authorities for containment measures

5. National Disease Control Infrastructure
South Korea’s Korea Disease Control and Prevention Agency (KDCA) works in close coordination with hospitals for any outbreak. Major hospitals like Samsung Medical Center, Seoul National University Hospital, and Asan Medical Center are fully equipped with infectious disease units capable of managing high-risk diseases like plague.