There are different pneumonia causes; and they include viruses, bacteria, fungi and aspiration.
- Bacteria: Bacteria are the commonest cause of pneumonia in adults. And they usually affect an area of the lung – causing what is called lobar pneumonia. Many of these bacteria cause increased production of mucous.
Some of the bacteria that can cause pneumonia include:
a. Streptococcus pneumonia – commonest cause of bacterial pneumonia in children.
b. Haemophilus influenza type B – second most common cause of pneumonia caused by bacteria.
c. Mycoplasma pneumonia
d. Legionnaire’s disease
e. Chlamydophila pneumonia (also called Chlamydia pneumonia)
- Pneumonia that is caused by bacteria (bacterial pneumonia) is usually more serious and has more pronounced symptoms than pneumonia that is caused by other micro-organisms.
- Though bacteria is the commonest cause of pneumonia in adults, it does not mean that they do not also cause pneumonia in children because they do.
- Bacterial pneumonia is common among teenagers and children of school age. And as earlier mentioned, the symptoms are more pronounced.
- Pneumonia caused by Mycoplasma pneumonia and Chlamydophila pneumonia usually affect children of school age and cause mild symptoms. This is usually called walking pneumonia or atypical pneumonia.
- Chlamydia is an infection that is transmitted sexually (STI). It can be passed from the mother to the baby, and cause pneumonia that is life-threatening in the newborn.
- Viruses: Another cause of pneumonia are viruses. They are the commonest cause of pneumonia in children – especially in children younger than 5 years of age.
- Viral pneumonia usually clears up after about one to three weeks. Pneumonia caused by viruses tends not to be as serious as bacterial pneumonia. Viral pneumonia increases the chances of an individual coming down with bacterial pneumonia.
Some of the viruses that cause pneumonia are:
a. Respiratory syncytial virus (RSV) – commonest cause of viral pneumonia.
b. Influenza virus
c. Parainfluenza virus
- Fungi: Some fungi also cause pneumonia.
d. Pneumocystis jirovecii – causes about 25% of all deaths from pneumonia in children with HIV.
- Pneumonia caused by these fungi usually affects people who have a weak immune system (for instance, individuals who have HIV/AIDS). And so, if a person with a healthy and strong immune system inhales these fungi, the person will not develop fungal pneumonia. The symptoms of fungal pneumonia develop faster than pneumonia caused by other micro-organisms.
The most commonly known pneumonia causes are the infectious causes.
- Aspiration: Pneumonia can also be caused by aspiration; this is called aspiration pneumonia. It is caused by inhaling or breathing in a foreign object, a chemical, any liquid, food or vomit into the lungs.