What is bubonic plague⁠— its symptoms, fatality rate and history

• China has reported a bubonic plague infection — a bacterial infection that is transmitted by fleas.
  
• The authorities have issued a warning for plague prevention and control — and directed its residents to report any sick or dead rodents and refrain from eating animals that may be carrying the plague.
  
• According to the World Health Organisation (WHO), plague can be transmitted between animals and also spread from animals to humans. However, human to human infection is rare, in this case.
  
• The infection causes a sudden fever, bodyache, vomiting and a feeling of nausea.
  
• As many as 3,248 cases of plague have been reported globally — including 584 deaths — between 2010 to 2015.

While the world is battling coronavirus pandemic, showing no signs of dying down, China has reported a bubonic plague infection — a bacterial infection that is transmitted by fleas. The authorities in China issued a warning for plague prevention and control after Bayannur in Northern China confirmed two such cases.

“At present, there is a risk of a human plague epidemic spreading in this city. The public should improve its self-protection awareness and ability, and report abnormal health conditions promptly,” PTI reported citing the local health authority in Bayannur.

The officials have directed its residents to report any sick or dead rodents and refrain from eating animals that may be carrying the plague.

1. What is a bubonic plague?
   
   Plague is an infectious disease caused by a bacteria Yersinia pestis, present in mammals and fleas. According to the World Health Organisation (WHO), plague can be transmitted between animals and also spread from animals to humans.However, human to human infection is rare, in this case.The human transmission of plague happens with the bite of infected fleas, either via direct contact or by inhalation.
2. How many people can die of the infection?
   
   This is one of the rare but serious diseases that can be transmitted. WHO says that the fatality rate in plague — especially septicaemic form caused by the flow of bacteria in the bloodstream — is 30% to 100%, if untreated.
3. What are the symptoms of a bubonic plague infection?
   
   There are two kinds of plague infections — bubonic and pneumonic. Usually, the incubation period for people infected with plague is upto seven days and the infection causes a sudden fever, bodyache, vomiting and a feeling of nausea.Bubonic plague is caused when the bacteria enters the lymphatic system (part of the immune system) in the body and there it replicates itself. As a result, the infected node gets swollen and painful — called a ‘bubo.’ The infection can further spread to the lungs, which is called the pneumonic plague.
4. What is the past history of such a plague?
   
   As per the data by WHO, as many as 3,248 cases of plague have been reported globally — including 584 deaths — between 2010 to 2015. Plague epidemics have occurred in Africa, Asia, and South America earlier. In fact in Madagascar, bubonic plague cases are reported every year during September to April — which is usually known to be the epidemic season. Plague, which was also known as ‘black death’ in the 14th century, caused over 50 million deaths in Europe.