Detection and Prevention

It’s just a fact of life: Germs are all around us. Some germs can be helpful to us, but many are harmful. Infectious diseases are sicknesses that are caused by harmful germs.

We can come into contact with harmful germs and contract an illness in many different ways, including:

• By direct contact with a sick person — through actions such as kissing, coughing, sneezing, or sexual contact.
• Indirectly, as when you touch something that has germs on it. If a sick person touches a doorknob, and you then touch the doorknob, you could pick up their germs.
• By coming into contact with food, water, soil, or other substance that has been contaminated with germs.
• Through the bite of an insect or animal.

The four main kinds of germs are:

• Bacteria. These are one-celled germs that multiply quickly and can give off harmful chemicals that can make you sick. Two common bacterial infections are strep throat and urinary tract infections.
• Viruses. These are tiny germs that can invade your cells, where they multiply and make you sick. Two examples of viral infections are HIV/AIDS and the common cold.
• Fungi. These are simple plant-like organisms such as mushrooms, mold, mildew, and yeasts. A common fungal infection is athlete's foot.
• Parasites. These are small animals or plants that survive by living on or in other living things. Malaria is an example of an infection caused by a parasite.

The symptoms caused by infectious diseases vary widely. Some can be so mild that you may not notice symptoms, and others can be severe and life-threatening. You can take steps to help prevent many infectious diseases:

• Get vaccinated
• Wash your hands regularly
• Be aware of food safety concerns
• Don’t approach or contact wild animals
• Practice safe sex
• Don't share items such as toothbrushes, combs, and straws