The recent occurrence of plague has brought the disease to the forefront.

According to Center for disease control and prevention,

The bacteria that cause plague, Yersinia pestis, maintain their existence in a cycle involving rodents and their fleas. Many types of animals, such as rock squirrels, wood rats, ground squirrels, prairie dogs, chipmunks, mice, voles, and rabbits can be affected by plague. Wild carnivores can become infected by eating other infected animals. plague bacteria circulate at low rates within populations of certain rodents without causing excessive rodent die-off. These infected animals and their fleas serve as long-term reservoirs for the bacteria. This is called the enzootic cycle.

Occasionally, other species become infected, causing an outbreak among animals, called an epizootic. Humans are usually more at risk during, or shortly after, a plague epizootic.This makes the disease zoonotic(animals-humans).

Ways of transmission:-

  • Directly by bite of infected vector flea
  • Contact with animal carrying the bacteria
  • Contact with infectious fluids expelled by the animals
  • Human to Human transmission by cough droplets


There are two types of plague infection as defined by WHO(World Health Organisation):

  • bubonic PLAGUE

            The most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself. The lymph node then becomes inflamed, tense and painful, and is called a ‘bubo’. At advanced stages of the infection the inflamed lymph nodes can turn into open sores filled with pus. Human to human transmission of bubonic plague is rare. Bubonic plague can advance and spread to the lungs, which is the more severe type of plague called pneumonic plague.

  • Pneumonic PLAGUE

It is a lung-based plague, is the most virulent form of plague. Incubation can be as short as 24 hours. Any person with pneumonic plague may transmit the disease via droplets to other humans. Untreated pneumonic plague, if not diagnosed and treated early, can be fatal.



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


The Black Death, which hit Europe in 1347 killing more than 200Mn over the time.The concept of quarantine was introduced during this time.

The plague emerged from its wild rodent reservoir in the remote Chinese province of Yunnan in 1855.


  • PUNE PLAGUE 1896
  • 1994 PLAGUE

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


In 1900  Australia the first major outbreak  of plague occurred 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, most cases occurring in Sydney.

Recently there is an outbreak of plague in Australia.Reasons range from bumper harvest due to bountiful rains previous year,favourable weather conditions for the rodent to grow and reproduce etc. Over the past six months, millions and millions of mice have terrorised the people of regional New South Wales.

Australia has ordered a banned poison from India to counter an infestation -Bromadiolone.

Reports of birds dying after ingesting the bait laid down for mouses has been coming up(galahs).Dogs,cats and domestic animals are also under high risks.


As per CDCP,the following instructions are to be followed during such outbreak.

  1. Reduce rodent habitat around your home, work place, and recreational areas. Remove brush, rock  piles, junk, cluttered firewood, and possible rodent food supplies, such as pet and wild animal food. Make your home and outbuildings rodent-proof.
  2. Wear gloves if you are handling or skinning potentially infected animals to prevent contact between your skin and the plague bacteria. Contact your local health department if you have questions about disposal of dead animals.
  3. Use repellent if you think you could be exposed to rodent fleas during activities such as camping, hiking, or working outdoors. Products containing DEET can be applied to the skin as well as clothing and products containing permethrin can be applied to clothing (always follow instructions on the label).
  4. Keep fleas off of your pets by applying flea control products. Animals that roam freely are more likely to come in contact with plague infected animals or fleas and could bring them into homes. If your pet becomes sick, seek care from a veterinarian as soon as possible.
  5. Do not allow dogs or cats that roam free in endemic areas to sleep on your bed.

Treatment :-

WHO has laid down guidelines for treatment which you shall find in the link attached below:


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