But they are bigger than bacteria and contain a nucleus and other cell structures, making them more similar to plant and animal cells. Protozoa love moisture, so intestinal infections and other diseases they cause, such as amebiasis and giardiasis, often spread through contaminated water.
Some protozoa are parasites, which means that they need to live on or in another organism like an animal or plant to survive.
For example, the protozoa that causes malaria grows inside red blood cells, eventually destroying them. Some protozoa are encapsulated in cysts, which help them live outside the human body and in harsh environments for long periods of time. Did you know that the most important thing you can do to keep from getting sick is to wash your hands? Find out how to protect yourself. The germs that get into food and cause food poisoning are tiny, but can have a powerful effect on the body.
Find out what to do if you get food poisoning — and how to prevent it. The good news is that ringworm is easy to treat. The good news is that STDs can be prevented. Learn why food safety is important and how you can avoid the spread of bacteria when you are buying, preparing, and storing food. Washing hands well and often is the best way to prevent germs from leading to infections and sickness.
Some bacteria are good for our bodies — they help keep the digestive system in working order and keep harmful bacteria from moving in. Some bacteria are used to make medicines and vaccines. But bacteria can cause trouble too, as with cavities, urinary tract infections , ear infections , or strep throat.
Antibiotics are used to treat bacterial infections. Viruses are even smaller than bacteria. They aren't even a full cell. They need to use another cell's structures to reproduce, which 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 countertop or toilet seat can live there for a short time, but quickly die unless a live host comes along. How do they each infect us, and how can we recover from them? As physicians, we evaluate to determine the best tests and treatments for each infection.
Fayyaz Sutterwala , director of Infectious Diseases at Cedars-Sinai , says infections are sometimes difficult to diagnose. Though certain microbes can cause very specific disease, many others can infect any organ and cause similar symptoms and immune response. A virus is the simplest of germs—it is nothing but genetic material encased in protein. Researchers debate whether a virus is even "alive. By itself, a virus can accomplish nothing—it needs to enter a living thing to perform its only function, which is to replicate.
When a virus gets inside a human body, it can hijack a person's cellular machinery to produce clones of itself, overtaking more cells and continuing to reproduce. When the virus reproduces faster than the immune system can control it, it begins to destroy cells and harm the body. Viruses are also the smallest germ, making them generally the easiest to contract—they're so tiny they can spread through the air in a cough or a sneeze.
Some viruses also are spread by mosquitoes or through bodily fluid. Since each virus is very different, no one drug exists to attack whichever virus is in your body. Vaccines give preemptive protection from certain viruses by training the body's immune system to recognize and attack a specific virus. Common forms: Bacteria cause food poisoning, strep throat and urinary tract infections , as well as infections such as tuberculosis.
Bacteria are bigger and more complex than viruses, though they can still spread through the air. A bacterium is a single cell, and it can live and reproduce almost anywhere on its own: in soil, in water and in our bodies.
For the most part, we live peacefully with bacteria—the colonies in our guts are helpful to us and strengthen our immune system. But like viruses, bacteria can also harm us by replicating quickly in our bodies, killing cells.
0コメント