Top Menu


Infectious Diseases


Infectious diseases kill more people worldwide than any other single cause. Infectious
diseases are caused by germs. Germs are tiny living things that are found everywhere – in
air, soil and water. You can get infected by touching, eating, drinking or breathing something that contains a germ. Germs can also spread through animal and insect bites, kissing and sexual contact.
Vaccines, proper hand washing and medicines can help prevent infections.

There are four main kinds of germs:

  • Bacteria – one-celled germs that multiply quickly and
    may release chemicals which can make you sick
  • Viruses – capsules that contain genetic material, and
    use your own cells to multiply
  • Fungi – primitive plants, like mushrooms or mildew
  • Protozoa – one-celled animals that use other living things for
    food and a place to live

NIH: National Institute of Allergy and Infectious Diseases

National Institute of Allergy and Infectious Diseases

Related Issues

Find an Expert


Clinical Trials

Living With


Statistics and Research


Start Here

Prevention and Risk Factors

Journal Articles

Print Friendly, PDF & Email
Community Health

Your Health Our Mission