What are the other Names for this Condition? (Also known as/Synonyms)

• Black Death
• Black Fever
• Pestilential Fever

What is Plague? (Definition/Background Information)

• Plague is a very dangerous and infectious disease caused by a bacterium called Yersinia pestis. Individuals of any age and gender are susceptible to it
• There are 3 main types of Plague, namely:
  • Bubonic Plague - the bacteria infect the lymph nodes
  • Septicemic Plague - the bacteria infect and multiply in blood
  • Pneumonic Plague - the bacteria infect the lungs and cause pneumonia
• The bacteria get introduced to the humans through infected rodent or flea bites, and rarely, can also enter the body through a skin wound (while handling infected material). Inhaling droplets containing the bacteria (such as when an infected individual coughs or sneezes) when in close contact with an infected animal or human being can cause Pneumonic Plague
• There is a higher risk in tropical and sub-tropical regions for Plague. The risks also include having occupations (such as farming), being a veterinarian, coming in close contact with infected animals, and having hobbies such as hunting and outdoor camping
• Depending on the type of Plague, the symptoms could develop between 3-7 days of infection. Fever, chills, swollen lymph nodes (with Bubonic Plague), bleeding under the skin (in Septicemic Plague), and bloody sputum (observed in Pneumonic Plague) are some symptoms of Plague
• A physician arrives at a diagnosis of Plague from assessing the symptoms, studying the affected individual’s work and travel history, and through blood or sputum tests to check for the causative organism
• If diagnosed and treated in a timely manner, Plague is a curable condition. The treatment usually involves the administration of antibiotics. Individuals with Pneumonic Plague should be isolated in a hospital setting and in some cases, respiratory support may be needed
• If left untreated, Plague is a serious condition. It can lead to gangrene and meningitis; untreated Plague can be fatal in about 50% of the infected individuals. With prompt diagnosis and treatment a full recovery can be ensured
• Maintaining personal hygiene, keeping the immediate home and work environment free of rodents (such as by getting rid of potential or existing rodent nesting places) and taking precautions while handling animals can help prevent Plague. Travelers should heed travel advisories and be aware of plague-infested regions, to avoid contracting the disease

Who gets Plague? (Age and Sex Distribution)

• Plague is a bacterial infection that can affect individuals of all age groups
• There is no gender preference and both males and females are affected
• Plague is observed worldwide and all racial and ethnic groups are at risk. However, the disease spreads rapidly in tropical and sub-tropical places, wherever the rodent population is high

What are the Risk Factors for Plague? (Predisposing Factors)

The risk factors for Plague are generally low. However, the risk increases, depending on the following factors:

• Location: Individuals who live in areas where rat population is more and overcrowding is common have a high risk of contracting Plague
• Occupation: Plague frequently affects individuals whose occupation necessitates close contact with animals such as veterinarians, farmers, and hunters
• Hobbies: Individuals with hobbies, such as camping, hunting, or hiking, are vulnerable to the disease, when such activities are conducted in Plague-affected areas

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Plague? (Etiology)

Plague is caused by a rod-shaped bacterium Yersinia pestis. The bacterium infects rodents and fleas, which in turn, infects humans.

• Infected flea-bite is the most common cause for the spread of Plague
• Bites of infected rodents, such as rats, squirrels, and rabbits, can also spread the disease
• Bubonic and Septicemic types of Plague occur through flea and rodent bites
• While Bubonic Plague and Septicemic Plague rarely spread from one individuals to another, Pneumonic Plague can spread through inhalation of infected respiratory droplets
• An individual can also contract Pneumonic Plague through untreated Bubonic or Septicemic Plague
• Pneumonic Plague:
  • Primary: Infection from being in close contact with an individual infected with Pneumonic Plague through inhalation of infected droplets (that is produced while coughing or sneezing)
  • Secondary: Infection that develops as a result of untreated Bubonic or Septicemic Plague spreading to the lungs

What are the Signs and Symptoms of Plague?

The signs and symptoms of the 3 types of Plague are similar in some aspects and different in other aspects.

• Bubonic Plague: The symptoms usually appear within 3 days of infection, which generally includes:
  • Swollen lymph nodes (called bubos; hence the name Bubonic Plague) on the body
  • Fever and chills
  • Weakness
• Septicemic Plague: The symptoms could take up to 7 days to appear, which might include:
  • Fever and chills
  • Weakness
  • Bleeding under the skin
  • Low blood pressure
• Pneumonic Plague: The symptoms appear usually within 3 days of infection and may include the following:
  • Shortness of breadth
  • Cough with bloody sputum
  • Chest pain
  • Weakness
  • Fever and chills

How is Plague Diagnosed?

The diagnosis of Plague may involve the following tests and exams. A physician may take into account one or more of the following to arrive at an accurate diagnosis:

• The signs and symptoms of the affected individual
• Medical history evaluation, including recent travel history
• Rodent bites (such as from rats or rabbits)
• Blood and/or sputum tests (mucus from saliva and respiratory tract) to check for the presence of the causative bacterium

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Plague?

Plague, if left untreated, can lead to certain serious complications such as:

• Gangrene: Blood clots appear in the blood vessels affecting the free flow of blood to the fingers and toes. This may necessitate amputation of the fingers and toes
• Meningitis: An inflammation of the membranes surrounding the brain and spinal cord

How is Plague Treated?

Any individual who tests positive for Plague should be given immediate medical attention.

• A dose of powerful antibiotics, such as streptomycin, gentamicin, doxycycline, ciprofloxacin, or chloramphenicol, either individually or in combination, is normally administered
• Those with signs of pneumonia should be kept isolated from others
• In some cases, intravenous fluids, oxygen and respiratory support may also be required

How can Plague be Prevented?

Cleanliness, personal hygiene, and proper precautionary measures are important in preventing Plague outbreaks. These include:

• All necessary steps must be taken to ensure that one’s surroundings are free of rodents
• Keeping the residential environment clean is an important preventive method
• Places that can potentially harbor and colonize rodents (especially rats) should be eliminated or sanitized to prevent infestation
• Follow government advisories on disease outbreaks and schedule travel plans accordingly
• Individuals, such as veterinary doctors, who come in contact with animals daily, have to take suitable safety measures before treating the infected animals       

What is the Prognosis of Plague? (Outcomes/Resolutions)

• With early diagnosis and proper treatment, it is possible to treat Plague effectively
• Without treatment Plague can cause death in about 50% of the infected individuals. It can also cause severe and life-threatening complications such as gangrene and meningitis

Additional and Relevant Useful Information for Plague:

In medieval Europe, during the 14th century, Plague was responsible for the death of over 100-200 million people. Historians and researchers use the term ‘Black Death’, citing reference to this Plague pandemic.