Section 21.3 Common Infectious Diseases Objectives Identify some diseases caused by bacteria and by viruses. Describe behaviors that can help you get healthy and stay healthy.

Health Stats Note the difference between the leading causes of death in the United States in 1900 and in 2000. Were any of the leading causes of death in 2000 infectious diseases? Explain why you think this is the case.

Bacterial Diseases There are thousands of infectious diseases, and over 40 kinds commonly occur in the United States. Four infectious diseases caused by bacteria are strep throat Lyme disease meningitis tuberculosis

Strep Throat “Strep” is short for Streptococcus, the bacterium that causes the disease. Strep bacteria, which are usually found in the nose and throat, can be spread by contact with mucus from an infected person. Symptoms include sore throat swollen lymph nodes on the sides of the neck headache fever

Lyme Disease Humans can become infected with the bacteria that cause Lyme disease when they are bitten by an infected tick. Symptoms of Lyme disease include a red rash at the site of the tick bite fever chills body aches The best way to protect yourself from Lyme disease is by avoiding tick bites.

Bacterial Meningitis An infection of the fluid in the spinal cord and the fluid that surrounds the brain is called meningitis. Symptoms of meningitis include high fever, headache, vomiting, and a stiff neck. There are two types of meningitis—one is caused by bacteria, the other by a virus.

Tuberculosis A highly contagious bacterial infection of the lungs is tuberculosis (too bur kyuh LOH sis), or TB. It is transmitted when droplets from an infected person’s cough or sneeze are inhaled. Symptoms, which include fatigue, weight loss, a mild fever, and a constant cough, may not show up for many years after the initial infection.

Treating Bacterial Diseases An antibiotic (an tih by AHT ik) is a drug that inhibits or kills bacteria. Using antibiotics exactly as they are prescribed is very important to prevent bacteria from developing resistance to the medicine. Antibiotic resistance can result if you don’t finish your prescription and some of the bacterial pathogens in your body survive.

Viral Diseases Viral diseases include the common cold influenza pneumonia hepatitis

The Common Cold The common cold is really a group of symptoms that is caused by a number of different viruses. One or two days after exposure to a cold virus, people develop sneezing sore throats runny noses coughing chest congestion fever headaches muscle aches Colds spread when a person touches a contaminated object or inhales droplets from a sneeze or a cough.

Influenza The flu, or influenza, is a common viral infection of the upper respiratory system. Influenza is spread by airborne droplets and contact with contaminated objects. High fever, sore throat, headache, and a cough are typical symptoms of the flu.

The Stages of the Flu

Pneumonia In people who are elderly, or who have heart disease or breathing problems, flu may develop into pneumonia (noo MOHN yuh), a serious infection of the lungs. Many people die each year from pneumonia, which can be caused by viruses, bacteria, or even fungi.

Hepatitis A group of viruses that infect the liver can cause hepatitis (hep uh TY tis), or inflammation of the liver. Symptoms of hepatitis include fever nausea pain in the abdomen jaundice (JAWN dis), or yellowing of the skin. Hepatitis A is transmitted in human wastes and in contaminated water and food. Hepatitis B can be transmitted in blood, during sexual contact, or during tattooing or body piercing. Hepatitis C can be transmitted in blood, during sexual contact, or during tattooing or body piercing.

Treating Viral Diseases In most cases, there is no particular medicine that can cure a viral infection. The best treatments for viral infections are rest, a well-balanced diet, and plenty of fluids. Many over-the-counter medicines can treat the symptoms of viral infections.

For: Updates on infectious diseases Click above to go online.

Evaluating Antibacterial Products Products claiming to rid your home of pathogens seem to be everywhere. Do you think these products stand up to their claims? Evaluate products claiming to have antibacterial action using this questionnaire.

Does the product claim to inhibit or destroy all pathogens? Does the product seem to be using scare tactics to get you to buy it? Does the product use nonscientific words, such as “germs” or “bugs”? Do the benefits sound too good to be true? Are the ingredients identical to those in non-antibacterial products? A “Yes” answer to one or more questions indicates that the product may not live up to its claims.

Evaluating Antibacterial Products Choose a product from a local store that claims to be antibacterial. Devise an experiment to test the effectiveness of the product.

Getting Healthy, Staying Healthy When you do get sick, you can help your body recover by going to bed and resting. This treatment and well-balanced meals are all that you need to recover from most mild infections.

When to Seek Medical Care If you are worried about your health for any reason, see a doctor and discuss your concerns with him or her. Seek professional medical care if you have an extremely sore throat, earache, vomiting, diarrhea, or a temperature of 101°F that lasts more than two days mucus from your nose or throat that is thick and yellowish green difficulty breathing, or severe pain anywhere a cut, scrape, or sore that does not seem to be healing as it should an illness that lasts longer than usual

Preventing Infectious Diseases You can protect yourself from infectious diseases in three ways avoiding contact with pathogens making sure that your immunizations are current choosing healthful behaviors

Preventing Infectious Diseases Here are some healthful behaviors you should practice to help you avoid disease. Wash your hands several times a day, especially before eating and after using the bathroom. Do not share items that can transfer pathogens, such as towels, eating utensils, cups, or hairbrushes. Cook and store foods properly. Meats should be cooked thoroughly. Hot foods should be kept hot, and cold foods should be kept cold. Avoid close contact with people who are ill.

Preventing Infectious Diseases Here are some healthful behaviors you should practice to help you avoid disease. Stay home when you are not feeling well. Learn to manage stress in healthful ways, and get at least eight hours of sleep each night. Eat well-balanced meals, and do not skip meals. Exercise regularly, at least three or more times a week. Avoid unhealthful substances, such as tobacco, alcohol, and illegal drugs.

Vocabulary antibiotic A drug that inhibits or kills bacteria.

QuickTake Quiz Click to start quiz.

End of Section 21.3 Click on this slide to end this presentation.