Common Bacterial Diseases in Humans: Typhoid, Pneumonia, Tuberculosis, Diphtheria, Plague, Practice Problems and FAQs

You all heard about bacteria. They help human beings in many ways. For example, they help in making curd and softening the dosa dough. We all know that bacteria causes infections also. However, not all bacteria are infectious or pathogenic. So can you name a disease caused by bacteria?

Ofcourse, you are correct. There are many examples of bacterial diseases like typhoid, tuberculosis, plague, pneumonia, dysentery, cholera, diphtheria, tetanus etc.

Do you think all these bacterial diseases are caused by the same bacteria? Well, the answer is No. It is necessary to know that these diseases are caused by different bacteria and each bacterium has a different mode of causing and transmission of infection. Depending upon the type of bacteria, it will target a specific organ in the host body where it will find the hostile conditions for its survival and cause infection majorly in that organ. Let us take a deep dive into the details of these bacterial diseases.

Table of contents

Typhoid
Pneumonia
Tuberculosis
Diphtheria
Plague
Practice Problems
FAQs

Typhoid

It is caused by a bacterium Salmonella typhi. These bacteria can be identified by the presence of numerous flagella around the cell. This disease is also called enteric fever. This disease is common in children of the age group of 1-15 years.

Mode of Transmission

Salmonella can be spread by consuming contaminated food or drinking contaminated water or by insects such as flies. These bacteria can be picked up by flies that land on human faeces. When the same fly sits on our food, it might spread bacteria to it, functioning as a carrier.

Mechanism

Salmonella enters the alimentary canal when a person drinks water contaminated with the bacteria. Ingested bacteria travel through the intestine with the food. Salmonella invades the epithelial cells of the intestinal wall once it reaches the small intestine eventually causing damage to the epithelial cells. After that it passes the cell lining and enters the circulation after destroying epithelial cells. The germs can then enter the bloodstream and affect different organs.

As a result, inflammation develops in that area. Inflammation can induce severe diarrhea and stomach pain.

Symptoms

The following are the common symptoms of typhoid:

Sustained fever (39℃ to 40℃)
Loss of appetite
Constipation
Stomach pain
Headache
Weakness
In severe cases, the intestinal perforation are observed which leads to death of the patient

Diagnostic test - Widal test

The Widal test can be used to confirm typhoid. It is detected using a Widal card as a testing tool.

Salmonella antigens are spread on the card. The patient's serum is administered and dispersed on the widal card. Antibodies to Salmonella would be present in the serum of people who had typhoid. Antibodies bind to antigens on the card when serum from a typhoid patient is distributed. Binding of antibodies results in formation of clumps, indicating that the test is positive.

Treatment

The common treatment methods include antibiotics and oral dehydrations.

Antibiotics

Antibiotics can aid in the death of bacteria, preventing the spread of disease.

Oral rehydration

To replace lost bodily fluids caused by typhoid, oral rehydration solution or salts (ORS) can be utilised.

Prevention

Milk that has not been pasteurised should not be consumed.
Avoid eating unwashed fruits and vegetables.
Raw eggs and raw meat should not be consumed.

Typhoid Mary

Typhoid Mary is a classical example of typhoid carriers. For numerous years, Mary Mallon, a cook, disseminated typhoid fever through the meals she prepared. Later on, she was known as Typhoid Mary. She was the main source of multiple outbreaks of typhoid fever in New York City and Long Island between 1900 and 1907.

Pneumonia

Pneumonia is derived from the word ‘pneumon’ which means related to lungs. It is caused by two bacterium Haemophilus influenzae or Streptococcus pneumoniae.