Plague: Infectious Disease (Download PDF)

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  • A class of dangerous, life-threatening and infectious disease. Prevailed from medieval times in the 13th century.
  • Mainly caused by:
    • The gram-negative
    • Rod-shaped coccobacillus called Yersinia pestis
  • In the middle ages ( 5th -15th century) it was also known as the ‘Black Death’ as it caused the death of millions of people in Europe.
    • Black rats are the carrier of this dangerous disease.
  • This disease still exists in countries like:
    • South America
    • Africa
    • Many other countries
Article Bubonic Plague

Causes of Plague

  • Sneezing
  • On consumption of contaminated food and water.
  • Touching a contaminated soil or any surface.
  • Direct physical contact with the infected person.
  • Bite from the insects:
    • Previously fed on infected animals.
    • Like a rat, squirrel, rodents, etc.
Causes of Plague

Yersinia Pestis

  • Mainly found in animals like rodents or rats.
  • Rod-shaped, coccobacillus bacterium.
  • No spores are present.
  • Belongs to the class of Gammaproteobacteria.
  • The family name is Yersiniaceae.
  • A facultative anaerobic organism.
  • Transmitted through the insects that feed on the blood of these animals.
Yersinia Pestis

Symptoms of Plague

  • Fever
  • Nausea
  • Seizures
  • Diarrhoea
  • Vomiting sensation
  • General weakness
  • Frequent headaches
  • Breathing problems
  • Swelling in the joints
  • Muscle and joint pains
  • Pain in the abdomen region
  • Cough with pain in the chest region

Diagnosis of Plague

Diagnosis of Plague


  • A small clinical procedure.
  • Used to detect the presence of bacteria and other pathogens inside of the lungs airways including the bronchi.
  • A thin tube containing a light and camera is inserted either through the nose or mouth.
Types of Bronchoscopy

Treatment & Prevention

  • Effective use of antibiotics regularly.
    • Aminoglycosides, streptomycin, gentamicin, tetracyclines, doxycycline, fluoroquinolone and ciprofloxacin are some of the antibiotics.
  • Those in close contact are also given a dose of antibiotics.
  • Those infected are kept in isolation since it is highly contagious.
  • Good precautionary measures.
  • Apart from antibiotics:
    • Intravenous fluids and extra oxygen are required to treat a person.
  • Without prompt treatment:
    • Disease can result in serious illnesses.
    • Death
  • Keeping the rodent population in control.
  • Pest control measures.
    • Rodents feed on stacks of wood such surrounding areas should be cleared.
  • New born babies should be vaccinated with the plague vaccine.
  • Keep the surroundings clean to reduce the rodent around.
  • Avoiding contact with the pathogens by regular use of gloves and face mask.
  • The holes or gaps near our homes should be blocked to avoid the entry of mice and rats
  • Other preventive measures:
    • Regular use of insect repellents.
    • Wearing full clothes covering the skin to prevent flea bites.

History of Plagues

The Plague of Justinian

  • Justinian I is believed to be the most influential Byzantine emperor.
  • This plague originated in Africa and then spread to Europe through the infected rats (on merchant ships) .
  • Continued to reappear in Europe, Asia and Africa for several years.
  • Started claiming up to 10,000 lives on reaching the Byzantine capital of Constantinople in 541 A. D.
  • Symptoms:
    • Sudden fever
    • Swollen lymph nodes
  • This pandemic is believed to have killed at least 25 million people.

The Black Death

  • Took place during the early 19th century in Europe from the East.
  • Believed to have killed 75 to 200 millions of people.
  • Almost one-third of the continent՚s population was destroyed.
  • Many historians believe:
    • Labour shortages caused became a boon to lower class workers.
    • Increased economic and social mobility.

The Italian Plague of 1629 - 31

  • The Republic of Venice lost nearly a third of its population of 1,40, 000.
  • Striked the major cities of Verona, Milan, Venice and Florence.
  • Preventing the spread of infection:
    • Clothes were burned.
    • Those infected were quarantined in pesthouses.
  • This disease is believed to have killed some 2,80, 000 people.

The Great Plague of London

  • London was affected several times during the 16th and 17th centuries.
  • Mostly between 1665 and 1666.
  • At its peak some 8,000 people started dying every week.
  • Red Cross marking was used over those infected and quarantined.
  • By the time this outbreak vanished it took lives of 75,000 to 1,00, 000 people.

The Great Plague of Marseille

  • Western Europe՚s last major outbreak.
  • Medieval plague began in 1720.
  • The disease arrived in merchant ship (Grand Saint Antoine) .
  • Picked up infected passengers during a journey to the Middle East.
  • Plan carrying rat fleas spread across the city.
  • Plague walls were built to contain the infection.
  • Spilled over Southern France before it disappeared in 1722.
  • This disease is believed to have killed 10,000 people.

The Third Plague Pandemic

  • Erupted in 1855 in the Chinese Province of Yunnan.
  • Spreaded to the entire globe over the next several decades.
  • The bites from rat fleas where the main way the infection spread to humans.
  • Worldwide outbreak took some 15 million lives before it stopped in 1950s.
  • Devastation mostly took place in India and China.
  • Bacillus Yersinia pestis was identified by a Hong Kong based doctor as a major breakthrough during this disease spread.
  • According to WHO, the pandemic was considered active until 1981, when worldwide casualties dropped to 200 per year.

Bubonic Plague

  • A serious bacterial infection transmitted by fleas from rodents.
  • A zoonotic disease that can be transmitted to other animals or humans.
  • Spread by Yersinia pestis bacteria.
  • No reports of human to human transmission.
  • Results from:
    • The bite of an infected flea.
    • Exposure to the body fluids from a dead plague-infected animal.
  • Infects a person՚s lymphatic system.
    • Causes inflammation in the lymph nodes.
    • Lymph nodes swell and cause serious pain.
  • If not treated in time an adult is likely to die in less than 24 hours.
  • May also convert into either pneumonic of septicemic plague (other two types of plague) if left untreated.
  • Bubonic plague has been recently reported in Bayannur, a city in northern China.


  • Fever
  • Chills
  • Weakness and headaches
  • Swollen lymph nodes (in the groin, armpit or neck)
  • Headaches
  • Fatigue and muscle aches


  • People are generally advised to not touch dead animals.
  • Wear insect or fleas repellent in case of an outbreak.
  • According to WHO:
    • A vaccine is available.
    • For individuals with high exposure to the plague.

Pneumonic Plague

  • The ‘most virulent form of plague’ according to WHO.
  • Highly contagious.
  • Can be fatal within 24 to 72 hours.
  • The bacteria infects the lungs.
  • Can be transmitted from human to human.


  • Chest pain
  • Fever and Cough

Septic Emic Plague Disease

  • Infection of the blood.
  • The bacteria kills the cells of the blood in the human body resulting in death.
  • Skin turns black.


  • Fever
  • Chills
  • Extreme weakness
  • Abdominal pain
  • Skin and other tissues may turn black (fingers, toes, and the nose) .

Other Major Epidemics

  • Modern Plague (1894 - 1903) took away 10 million lives.
  • The Russian Flu in 1889 - 1890 killed 1 million people.
  • 6th Cholera Pandemic (1899 - 1923) resulted in the deaths of 1.5 million people.
  • Spanish Flu in 1918 took away 20 million lives.
  • Asian flu (1957 - 1958) took 2 million people.
  • The Hong Kong Flu of 1968 - 1969 killed 1 million people.

- Published/Last Modified on: October 31, 2020

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