Pneumonia is when one or both of the lungs become infected, causing inflammation in the air sacs of the lungs, known as the alveoli. When these alveoli are infected, they can fill with pus or fluid, which makes it difficult to breathe.
Pneumonia isn’t one single condition, however; there are a variety of different types that are classified based on what caused the infection, where it was contracted, or how it was acquired. In this article, we’ll be looking at the five major types of pneumonia by the type of germ.
1. Bacterial Pneumonia
This type of pneumonia is caused by—you guessed it—bacteria. The most common strain is Streptococcus pneumonia; however, it can also be caused by Chlamydophila pneumonia and Legionella pneumophila. Symptoms of bacterial pneumonia can include fever, chest pain, and an increased heart rate.
According to The Johns Hopkins University, this type of pneumonia generally occurs “when the body is weakened in some way, such as by illness, poor nutrition, old age, or impaired immunity, and the bacteria are able to work their way into the lungs.” It can affect people of any age, but the source says those who smoke, abuse alcohol, or have respiratory illness or infection are at greater risk.
2. Viral Pneumonia
Viral pneumonia is among the most common types of pneumonia, as Dr. Joseph Mercola says it accounts for approximately one-third of all cases. As its name implies, respiratory viruses—such as influenza, chickenpox, adenoviruses or respiratory syncytial—are what cause the condition.
Viral pneumonia is contagious, which the source says can be caught “via coughing, sneezing or touching an object that was contaminated by an infected person,” and it is characterized by swollen lungs and blocked oxygen flow.
3. Mycoplasma Pneumonia
This condition is caused by Mycoplasma pneumoniae, which Healthline.com says is not a virus or a bacteria, but “has traits common to both.” Mycoplasma pneumonia, which is also referred to as atypical or walking pneumonia, can affect people of all ages but is particularly common in those less than 40 years old.
It is often quite mild, but can be passed from person to person through respiratory fluids. And while symptoms of this condition can differ greatly among each individual who is infected, a dry cough is common.
4. Aspiration Pneumonia
Aspiration pneumonia results from the inhalation of food, fluids, gases or dust lead into the lungs, resulting in inflammation and infection. It may also be referred to as necrotizing pneumonia, anaerobic pneumonia, aspiration pneumonitis, or aspiration of vomitus.
According to the U.S. National Library of Medicine, this type of pneumonia is characterized by symptoms such as difficulty swallowing, shortness of breath, chest pain, and fever. Aspiration pneumonia is more likely to affect people who are older, as well as those who abuse alcohol, or individuals who have been sedated or received general anesthesia.
5. Fungal Pneumonia
Fungal pneumonia occurs due to exposure to certain fungi, such as those from soil or bird excrement, says Healthline.com. It is a fairly rare condition in the United States, most often affecting those with an impaired immune system, such as those with HIV or AIDS. According to Dr. Joseph Mercola, however, it is far more common in Mexico, as well as South American and African countries.
Livestrong.com indicates the symptoms associated with fungal pneumonia are similar to those of other types, including a cough, troubles breathing, fever, fatigue, and weight loss.