Black Plague (Bubonic Plague): Causes, Types, Symptoms, and Modern Treatment

The Black Plague is caused by Yersinia pestis, a bacterium transmitted primarily by fleas from infected rodents. It caused the 14th-century pandemic that killed 30–60% of Europe's population.

Three Clinical Forms

Type	Transmission	Key Features	Mortality (untreated)
Bubonic	Flea bite	Swollen, painful lymph nodes (buboes), fever, chills, weakness	30–60%
Septicemic	Flea bite or direct contact	Bacteremia, sepsis, DIC, skin necrosis (blackening), no buboes	Near 100%
Pneumonic	Respiratory droplets	Severe pneumonia, cough, hemoptysis, rapid progression, person-to-person spread	Near 100%

Diagnosis & Treatment

• Diagnosis: culture, PCR, serology from blood, sputum, or bubo aspirate.
• Treatment: Aminoglycosides (streptomycin, gentamicin) or fluoroquinolones (ciprofloxacin, levofloxacin) + doxycycline. Early treatment reduces mortality to <15%.
• Post-exposure prophylaxis: Doxycycline or ciprofloxacin for 7 days.

Current Status

Plague still exists in rodent reservoirs (western US, Africa, Asia). A few thousand cases occur globally each year. No widely available vaccine; prevention focuses on rodent/flea control and prompt antibiotic treatment.