Alex Ehsan, MD, PhD · Medical search

Infectious Diseases

Educational information. Individual clinical review of this presentation by Dr. Ehsan is not yet documented. It does not replace personal medical evaluation.

Source: MedlinePlus, National Library of Medicine. Read the original source

MedlinePlus data edition September 26, 2026. Imported September 27, 2026. These dates do not indicate a new clinical review of the article.

What are infectious diseases?

Germs, or microbes, are found everywhere - in the air, soil, and water. There are also germs on your skin and in your body. Many of them are harmless, and some can even be helpful. But some of them can make you sick. Infectious diseases are diseases that are caused by germs.

What are the different types of germs that cause infectious diseases?

There are four main types of germs:

How can you get infectious diseases?

There are many different ways that you can get an infectious disease, depending on the type of germ. They can include:

What are the symptoms of infectious diseases?

Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening.

What are the treatments for infectious diseases?

There are treatments for some infectious diseases, such as antibiotic, antiviral, antifungal and anti-parasitic medicines. But for other infections, such as some caused by viruses, you can only treat your symptoms while you wait for your immune system to fight off the germ.

Can infectious diseases be prevented?

You can take steps to help prevent many infectious diseases:

Questions for your care team

General prompts to help prepare for your appointment.

For a life-threatening emergency, call 911 in the U.S. or your local emergency number.

Browse all patient guides