How do infectious diseases spread?

Infectious diseases are illnesses caused by harmful agents (pathogens) that get into your body. The most common causes are viruses, bacteria, fungi and parasites. Infectious diseases usually spread from person to person, through contaminated food or water and through bug bites. Some infectious diseases are minor and some are very serious.

How are infectious diseases diagnosed?

Your healthcare provider usually diagnoses infectious diseases using one or more lab tests. Your provider can look for signs of disease by:

Some test results, like from a nose swab, come back quickly, but other results might take longer. For instance, sometimes bacteria has to be grown in a lab (cultured) from a sample before you can get your test result.

What is antibiotic resistance?

Antibiotic resistance is when bacteria develop mutations that make it harder for our medicines to destroy them. This happens when antibiotics are overused, such as for minor infections that your body could fight off on its own.

Antibiotic resistance makes some bacterial infections very difficult to treat and more likely to be life-threatening. Methicillin-resistant Staphylococcus aureus (MRSA) is an example of a bacterial infection that has become antibiotic-resistant.

Healthcare providers are working to reduce antibiotic resistance. You can help — and protect yourself — by finishing all of your antibiotic medication as prescribed. This helps to make sure all of the bacteria are destroyed and can’t mutate.