What Causes Pneumonia?

Pneumonia is a viral, bacterial, or fungal infection that causes inflammation of the air sacs in one or the two lungs. The sacs become filled with pus or mucus, which causes hot temperature, shakes, and shortness of breath. It is a serious condition that must be well-managed to prevent mortality.

It is important to know the different causes of chronic illnesses like pneumonia to avoid putting yourself at risk of getting infected. Here are six known causes of pneumonia.


Community-acquired pneumonia is an infection caused by bacteria, viruses, or fungi which occurs outside hospitals.


People with weak immune systems are most prone to get pneumonia caused by fungi after large amounts of dangerous organisms have entered the body. These organisms are mostly found in soil or animal droppings and may differ based on different geographical locations. This infection targets at the lungs and is known as coccidioidomycosis. It has a high mortality rate but patient with strong immune systems have a higher chance of recovery.[1]


Streptococcus pneumonia is the most common of this condition and usually accompanies a cold or the flu. [2] In persons with strong immune systems, the streptococcus bacteria may live in the throat over a significant period without causing any health problems. It is contagious and spreads through droplets from an infected person (saliva, sweat). The bacteria enter the body through the eyes, nose, or mouth.


This infection is caused by viruses and usually follows after the flu or cold. [3] The germs stay in the upper part of the respiratory tract then go down into the lungs, causing inflammation of the air sacs.

Other Organisms

Mycoplasma is a genus of bacteria that causes other types of pneumonia also known as walking pneumonia because the symptoms are usually mild and do not require bed rest. Symptoms include sore throat, tiredness, mild chills, and persistent coughing or sneezing. It is otherwise called atypical pneumonia and affects the upper and lower respiratory tract.