Common Diseases in Human Beings - Bacterial Diseases



  • Bacterial diseases in human beings
  • Typhoid ( Enteric fever)
  • Pneumonia
  • Shigellosis (Bacillary dysentery)
  • Bubonic plague (Black death)
  • Diphtheria
  • Cholera
  • Tetanus (Lock jaw)
  • Tuberculosis
  • Syphilis
  • Whooping cough (Pertussis)
  • Dysentery
  • Plague


Bacterial diseases:

  • Though the number of bacterial species is very high, only a few bacteria are associated with human diseases and are called pathogenic bacteria.
  • Such pathogens may emit toxins and affect the body.
  • Bacteria spread through the air, water, or by inhaling the droplets/aerosols or even by sharing utensils, and dresses with an infected person.


1) Typhoid fever:

  • Typhoid fever is a bacterial infection that can be life-threatening.
  • Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings.
  • These pathogens usually enter the small intestine by contaminated food and water and then travel to other organs via the bloodstream. 
  • The symptoms of this condition include a persistent high fever (39° to 40°C), weakness, stomach pain, constipation, headache, and loss of appetite. In severe cases, intestinal perforation and death may result. 
  • Typhoid fever could be confirmed by the Widal test.
  • Mary Mallon, often known as Typhoid Mary, is a well-known medical case worth highlighting. She worked as a cook and was a typhoid carrier who disseminated the disease for numerous years through the food she cooked.

2) Pneumonia: 

  • Human pneumonia is caused by bacteria such as Streptococcus pneumoniae and Haemophilus influenzae, which infect the alveoli (air-filled sacs) of the lungs. 
  • As a result of the infection, the alveoli fill up with fluid, causing serious breathing problems. Fever, chills, cough, and headache are all signs of pneumonia.  
  • Lips and fingernails may turn grey to bluish in colour in extreme cases. 
  • A healthy individual contracts the infection by inhaling the infected person's droplets/aerosols or by sharing glasses and utensils with an infected person.

Other Bacterial Diseases:  

  • Dysentery, plague, diphtheria, etc., are some of the other bacterial diseases in man. 

3) Dysentery:  

  • It is caused by Shigella dysenteriae. 
  • It is characterized by abdominal pain and blood and mucus in the stool. It is transmitted through the faeco-oral route. 

4) Plague: 

  • It is caused by Yersinia pestis which is spread by Xenopsylla cheopis (rat flea).  
  • Symptoms include high fever, headache, and enlargement of axillary lymph nodes. 
  • Also called bubonic plague.  

5) Diphtheria: 

  • Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae.  
  • Symptoms often come on gradually, beginning with a sore throat and fever. In severe cases, a gray or white patch develops in the throat. This can block the airway and create a barking cough. 
  • Diphtheria is usually spread between people by direct contact or through the air. It may also be spread by contaminated objects. 
  • A vaccine, known as diphtheria toxoid, is effective for prevention. 
  • It can be diagnosed by schick test. 


Some of the diseases caused by bacteria in humans are as follows:


Bacterial resistance:

If an antibiotic is used too often to fight a specific bacterial infection, the bacteria may become resistant to the specific antibiotic. Hence the specific antibiotic can no longer be used to treat bacterial infection. Some bacteria have developed resistance to many antibiotics. Therefore, infections caused by these bacteria are difficult to be cured.

Risk of bacterial resistance can be reduced by observing the following steps:

  • Avoid using antibiotics to treat minor infections that can be taken care by our immune system.
  • Do not use an antibiotic to treat viral infections such as the common cold or flu.
  • Always follow the prescription. Skipping doses or failing to complete the prescription may allow antibiotic resistance to develop.
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