Infectious diseases also known as Communicable 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, drinking or breathing something that contains a germ. Germs can also spread through animal and insect bites, kissing and sexual contact. Vaccines, proper 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
Germs and Hygiene
When you cough or sneeze, you send tiny germ-filled droplets into the air. Colds and flu usually spread that way. You can help stop the spread of germs by
- Covering your mouth and nose when you sneeze or cough. Sneeze or cough into your elbow, not your hands.
- Cleaning your hands often - always before you eat or prepare food, and after you use the bathroom or change a diaper
- Avoiding touching your eyes, nose or mouth
Hand washing is one of the most effective and most overlooked ways to stop disease. Soap and water work well to kill germs. Wash for at least 20 seconds and rub your hands briskly. Disposable hand wipes or gel sanitizers also work well.
Each year, 48 million people in the U.S. get sick from contaminated food. Common culprits include bacteria, parasites and viruses. Symptoms range from mild to serious. They include
- Upset stomach
- Abdominal cramps
- Nausea and vomiting
Harmful bacteria are the most common cause of foodborne illness. Foods may have some bacteria on them when you buy them. Raw meat may become contaminated during slaughter. Fruits and vegetables may become contaminated when they are growing or when they are processed. But it can also happen in your kitchen if you leave food out for more than 2 hours at room temperature. Handling food safely can help prevent foodborne illnesses.
The treatment in most cases is increasing your fluid intake. For more serious illness, you may need treatment at a hospital.
Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods, or spirals. They are so small that a line of 1,000 could fit across a pencil eraser. Most bacteria won't hurt you - less than 1 percent of the different types make people sick. Many are helpful. Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese.
But infectious bacteria can make you ill. They reproduce quickly in your body. Many give off chemicals called toxins, which can damage tissue and make you sick. Examples of bacteria that cause infections include Streptococcus, Staphylococcus, and E. coli.
Antibiotics are the usual treatment. When you take antibiotics, follow the directions carefully. Each time you take antibiotics, you increase the chances that bacteria in your body will learn to resist them. Later, you could get or spread an infection that those antibiotics cannot cure.
Viruses are capsules with genetic material inside. They are very tiny, much smaller than bacteria. Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox and hemorrhagic fevers.
Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This eventually kills the cells, which can make you sick.
Viral infections are hard to treat because viruses live inside your body's cells. They are "protected" from medicines, which usually move through your bloodstream. Antibiotics do not work for viral infections. There are a few antiviral medicines available. Vaccines can help prevent you from getting many viral diseases.
If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is a primitive organism. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.
Some fungi reproduce through tiny spores in the air. You can inhale the spores or they can land on you. As a result, fungal infections often start in the lungs or on the skin. You are more likely to get a fungal infection if you have a weakened immune system or take antibiotics.
Fungi can be difficult to kill. For skin and nail infections, you can apply medicine directly to the infected area. Oral antifungal medicines are also available for serious infections.
Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.
Parasites range in size from tiny, one-celled organisms called protozoa to worms that can be seen with the naked eye. Some parasitic diseases occur in the United States. Contaminated water supplies can lead to Giardia infections. Cats can transmit toxoplasmosis, which is dangerous for pregnant women. Others, like malaria, are common in other parts of the world.
If you are traveling, it's important to drink only water you know is safe. Prevention is especially important. There are no vaccines for parasitic diseases. Some medicines are available to treat parasitic infections.