How can we fight against communicable diseases?
How can we fight against communicable diseases? Pathogens are in the air you breathe and the food you eat. They are on almost everything you touch and everyone you get close to. So why aren’t you sick all the time?
Your body has a natural ability to fight pathogens. This ability is called resistance (rih-zis-tuhnts). Think of resistance as a series of defenses meant to keep pathogens out. Some defenses keep pathogens from entering your body. When those defenses fail, other defenses find and kill pathogens that do get in. However, when your own resistance is not enough and you become sick, medical science works to cure you.
Your body’s first line of defense is the skin and the mucous membranes lining your mouth, throat, and other surfaces inside your body. Your skin and your mucous membranes form a barrier that helps keep pathogens out. Some of the substances produced by the skin and mucous membranes, including sweat, tears, and saliva, contain chemicals that kill pathogens.
If pathogens push past the barrier formed by the skin and mucous membranes, a second line of defense goes into action. This is the immune system (ih.MYOON), the body system that recognizes and destroys invading pathogens. White blood cells are a key part of your immune system. One kind of white blood cell makes antibodies (AN-tih-band-eez) that help fight disease by attaching to specific pathogens.
Your immune system “learns” how to fight specific pathogens each time you become ill. The next time the pathogen enters your body, your immune system rapidly produces antibodies to fight it. This ability of the body to “remember” how to make antibodies to a specific pathogen is called immunity (ih-MYOON-uh-tee). Often when you have an infection, you may run a fever-a body temperature higher than 100°F (37.8°C). The fever helps fight the infection by speeding your body’s defensive response.
What are the body’s defenses?
- Mucous membranes produce mucus, a sticky substance that traps pathogens as they enter your body. Some mucous membranes are lined with tiny hairlike structures that move with a wavelike motion. These sweep pathogens toward the outside of the body.
- The thymus and spleen produce white blood cells called lymphocytes. One type of lymphocyte produces antibodies Antibodies attach themselves to pathogens.
- If you feel particularly sick, your doctor might test your blood to find out how many white cells it contains and the percentage of each kind of white blood cell. This test can help your doctor understand how sick you are and may help identify the specific pathogen causing the problem.
- Fever helps your body produce the kinds of cells that fight invading pathogens. Fever also slows the growth of some bacteria and speeds cell repair. Look at the temperature shown by the thermometer. What does it mean?
- Blood platelets are fragments of cells that live in your bone marrow. When you get cut and puncture a blood vessel, platelets rush to the wound. The platelets release chemicals that start a clotting process. Your blood forms a ciot-called a scab on the surface of your skin. Your punctured blood vessel is repaired.
- Skin blocks many pathogens from entering the body.
- The cells inside long bones produce phagocytes. Phagocytes surround and destroy pathogens.
How can we improve our body defense?
Some communicable diseases can cause death if they are left untreated. Others can be dangerous for people whose immune systems are weak, including the very old, the very young, and people with AIDS. You can boost your body’s defenses with vaccines and antibiotics.
A vaccine (vak SEEN) is a medicine that contains dead or weakened pathogens. These dead or weakened pathogens cause the immune stem to form antibodies. In turn, the antibodies produce immunity to the disease without having the pathogens cause the disease. Vaccines are given either by mouth or by injection that is, in a shot.
You can be vaccinated against many viral diseases, including measles, rubella (German measles), mumps, and chickenpox. A few vaccines for diseases caused by bacteria, including tetanus and whooping cough, are also available. An immunization (ih-myuh nuh.ZAY-shuhn) is a dose of vaccine that makes you immune to a disease. To remain immune, you sometimes must be vaccinated more than once. For some diseases, including tetanus, you need boosters, or later doses of vaccine, to stay immune.
Vaccines have saved millions of lives, but the real miracle medicines are antibiotics. An antibiotic (an-ty-by.AHT•ik) is a medicine that kills pathogens such as bacteria. Antibiotics can quickly and completely cure many communicable diseases that once were deadly. For example, today an antibiotic called streptomycin helps control bubonic plague. In the 1300s this plague killed about one-third of Europe’s population.
Antibiotics can also kill pathogens that cause less serious diseases, including ear infections and acne. Most antibiotics cure infections caused by bacteria. Others fight harmful fungi and protozoa. Antibiotics do not kill viruses, so they cannot be used to cure colds, the flu, AIDS, or other viral diseases. However, some antiviral medicines do help control viral infections.
One of the first antibiotics was discovered by accident. In 1928 English scientist Sir Alexander Fleming was growing Staphylococcus bacteria in a lab dish. The dish was contaminated by a mold called Penicillium. The mold oozed a fluid that killed Staphylococcus. Fleming called the fluid penicillin. Today many types of penicillin are used to treat many kinds of bacterial infections.
When a large number of people have been using an antibiotic for a long time and for many minor infections, pathogens can develop resistance to the drugs. If this happens, the antibiotic can no longer kill the pathogen. Almost all the important human pathogens that can be treated with antibiotics have developed some resistance to them
You can avoid making a bad problem worse. Take only antibiotics that your doctor has prescribed. Finish your whole prescription, even if you feel better before MAIN IDEA AND DETAILS Explain the importance of antibiotics. Include one supporting detail.