Kinds of viruses and bacteria

They aren't even a full cell. They need to use another cell's structures to reproduce. This means they can't survive unless they're living inside something else such as a person, animal, or plant. Viruses can only live for a very short time outside other living cells. For example, viruses in infected body fluids left on surfaces like a doorknob or toilet seat can live there for a short time.

They'll die quickly unless a live host comes along. When they've moved into someone's body, though, viruses spread easily and can make a person sick.

Antibiotics are not effective against viruses. Antiviral medicines have been developed against a small, select group of viruses. The microorganisms, or microbes, that can cause disease come in different forms. Viruses and bacteria are probably the most familiar because we hear so much about them. But fungi, protozoa, and helminths are also big players in the story of infectious disease. Learn more about each of these five main categories, as well as a recently discovered one: prions. More about viruses.

More about bacteria. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. Show references Antimicrobial drug resistance. National Institute of Allergy and Infectious Diseases. Accessed Sept.

Questions about bacteria, viruses, and antibiotics. Centers for Disease Control and Prevention. Accessed July 11, Antimicrobial resistance. World Health Organization. See also Antibiotic use in agriculture Antibiotics: Are you misusing them? CRE bacteria: What you should know E. Vaccines for adults Childhood vaccines What are superbugs?

What are superbugs and how can I protect myself from infection? What is chikungunya fever, and should I be worried? Viruses gain their infamy through a combination of large infection rates and death, even when their power has been relatively subdued.

Rabies, measles and chickenpox are still notorious, even though vaccines and medications have drastically reduced their deadliness. There are three different virus types that are made distinct by their shape. The cylindrical helical virus type is associated with the tobacco mosaic virus. Envelope viruses, such as influenza and HIV come covered in a protective lipid envelope.

Most animal viruses are classified as icosahedral and are nearly spherical in shape. The viruses within these categories share similar characteristics.

Viruses are also the most abundant biological form of life on the planet. The first thing a virion does is enter a cell and becomes a virus. Next, it reproduces, creating viral protein and genetic material instead of the usual cellular products.

A virus can then spread through a wide variety of means, such as touching, coughing and sneezing. The body fights viruses by breaking down the viral genetic material via RNA interference.

The immune system then produces antibodies that bind to viruses to make them noninfectious. Lastly, T cells are sent to destroy the virus.