Plague: Types, Causes, Occurrence And Everything Else You Should Know

The infamous and dreaded disease

Aishwarya Ukey

8 months ago|4 min read


Causes Of Plague

According to the Center for Disease Control and Prevention, the Public Health Agency of The United States of America-

PLAGUE is caused by a BACTERIA named Yersinia pestis. Their existence is dependent mostly on a cycle involving rodents and fleas. Several creatures like wood rats, rock squirrels, chipmunks, rabbits, moles, etc can be affected by the plague. 

Wild carnivores can get infected by eating other infected creatures. Plague bacteria circulate at minimal rates within populations and amongst rodents without causing extreme rodent die-off. These affected creatures and their infected fleas serve as long-term reservoirs for the bacteria. This is called the enzootic cycle.

Sometimes, other species get infected, causing an outbreak among animals, called an epizootic cycle. Humans are generally more at threat during, or shortly after, a plague epizootic. This makes the disease zoonotic ( Transmission from animals to humans).

Ways of transmission-

  • Due to the bite of infected vector flea
  • Contact with creature carrying the bacteria
  • Contact with contagious fluids expelled by the animals
  • Human-to-Human transmission by cough droplets

The actual number of people who lost their lives to the plague is still unknown.

Types Of Plagues

We can categorize Plague into two types, as outlined by WHO (World Health Organisation)


It is the most common form of plague and is caused by the bite of an infected flea. The bacteria enter with the bite and travels through the lymphatic network to the nearest lymph node where it replicates itself. The lymph node additionally becomes inflamed, tense and painful, and is called a bubo. At advanced stages of the infection, the inflamed lymph nodes can turn into open blisters filled with pus. Human to human transmission of bubonic plague is rare.


It is a lung-based plague, the most malignant form of plague. The incubation time can be as short as Twenty-Four hours. Any person with pneumonic plague or similar symptoms may transmit the disease through nasal, saliva-like droplets to other human beings. Untreated pneumonic plague, if not diagnosed and treated beforehand, can prove lethal.





The Plague of Justinian appeared in Constantinople, the capital of the Byzantine Empire, in 541 CE. It spread across Europe, Asia, Africa killing more than 30 million people.


The Black Death, which impacted Europe in 1347 killed more than 200 million over time. The concept of quarantine was introduced during this time.

The Poem we learned as children- Ring around the Rosie written by James FitzGerald, highlights the grave and disastrous Black Plague.

3. In the remote Chinese province of Yunnan in 1855, several people lost their lives to the plague.



• 1994 PLAGUE

More than 26Lakh people died in the time period between 1896 & 1904.


In 1900 Australia the first major outbreak of plague happened in Sydney, leaving over a hundred dead. There were 12 major outbreaks of plague in Australia from 1900 to 1925 with 1371 cases and 535 deaths, the utmost cases being in Sydney.

An outbreak of plague was recently seen in Australia. Reasons vary from the production of bumper crops due to bountiful precipitation the previous year to favorable weather conditions for the rodents to grow and reproduce, etc. Over the past six months, millions of mice have terrorized the people of New South Wales.

Australia even had ordered a banned poison named Bromadiolone from India to counter infestation. Reports of birds dying after ingesting the bait laid down for mouses caused huge concern to the government.


Below are some advisory preventions to be adopted when an outbreak of Plague occurs:-

1. Reducing the rodent niche around your home and workplace. Removing possible rodent food supplies, such as pet and wild animal food.

2. Wearing gloves while handling potentially infected creatures to prevent contact between your skin and the plague bacteria.

3. Using a repellent if necessary. Products containing DEET can be applied to the skin as well as apparel and products containing permethrin can be applied to apparel.

4. Keeping fleas off of your pets by applying flea control products and not allowing pets of endemic areas to sleep on your bed.

5. Following the Government Guidelines and contact the Local Health Department as and when necessary.

Also, there are medications available in the market now to reduce the casualties. Earlier the lives took a toll due to a lack of understanding of the whereabouts of the disease and insufficient medical knowledge.

Now there are vaccines available ranging from Subunit Vaccine, Live attenuated, and Live Vector Vaccine, along with monoclonal antibody therapies.

Different Antibiotics like Chloramphenicol, Gentamicin, Ciprofloxacin, Doxy, Levofloxacin endorsed by WHO, are prescribed by Doctors to cure Plague.


Aishwarya Ukey

I live life to the fullest of my capability. You can call me an ambivert who loves exploring new stuff and is curious 24*7.



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