In order to understand how this virus causes disease, we’re going to look at how bacteria and viruses work on the cellular level.
A virus is a tiny strand of RNA or DNA with a protective coat around it. It does not need to eat or breathe to say alive. It cannot reproduce except by injecting its DNA or RNA into another cell. When it enters a cell, it takes over that cell’s mechanisms for its own purposes. A virus can live in a human cell or in bacteria because it is a single living cell with a hard cell wall. Bacteria can live in the human body, but don’t need the body’s mechanisms to reproduce. Many simple organisms float around in the air and reproduce when they settle in suitable conditions. Some bacteria are helpful, some are harmful. Harmful ones are called germs. Germs can cause disease when they settle in the human body and reproduce. Disease caused by bacteria can be cured because antibiotics kill bacteria. Disease caused by viruses cannot be cured; there are no medicines which kill viruses. Since they live inside human cells, killing the virus would mean killing the human cell. The way we recover from viral infections is by our body fighting off the virus. Some diseases caused by bacteria include pneumonia, tuberculosis, diphtheria, typhoid, whooping cough, strep throat, infections in cuts, gonorrhea, syphilis, chlamydia. There are antibiotics which can treat all these. Some diseases caused by viruses are Chicken pox, colds, flus, measles, mumps, rubella, small pox and herpes. Once we are sick with these, we have to wait until we get well by ourselves.
The body’s way of fighting off disease is called the immune system. It is how the body defends itself against invading harmful organisms which make someone sick. It is a very complicated system starting with the skin and mucus membranes which keep germs out of the body. Germs which get past these barriers have to deal with the internal immune system. Scientists are working hard to understand the body’s immune system. Some of what is known is that there are certain cells in the blood stream called T-cells whose job it is to recognize foreign invaders (antigens—a word which means generates antibodies). When the T cell bumps into an antigen, the T-cell calls for another kind of cell called a B-cell, to make a marker to identify that specific invader. The marker is called an antibody and it matches up exactly with the antigen. They stick together like pop-beads. A third kind of cell is called a macrophage, which means “big eater”. The macrophages are everywhere in the body, constantly on patrol, able to cross most barriers. When they find an antigen-antibody pair, they swallow and digest it. Sometimes they swallow the invader before it is marked.
IMMUNE SYSTEM FUNCTION
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When AIDS virus enters the body, antibodies are produced to HIV and mark the virus. The macrophages do swallow the pair or the virus alone. But scientists now think that the macrophage do not digest the virus. One theory is that since the virus is able to hide out in the macrophage, it is disguised as a friendly part of the system and escapes the destructive action of the immune system. In fact, it is the macrophages and T cells which are destroyed by the virus. While inside the cell, the virus causes its own RNA to become a part of the cell’s DNA so that every time the cell reproduces, it is making a copy of the virus, not of itself. The result is that the macrophages are not able to recognize other foreign invaders and the immune system stops being able to defend the body.
With AIDS
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When people talk about the AIDS test, what they mean is a blood test for antibodies to the HIV virus—it means the virus was there, the T-cells recognized it and told the B-cells to make antibodies to it. We do know that the body is able to make antibodies to HIV but we don’t yet know why the immune system is not able to kill this identified invader. Scientists are trying to solve this mystery right now.
The other way the body can fight off disease besides taking medicines to kill the invader is by having a vaccine. A vaccination is a shot of a harmless piece of the disease-causing organism into the body to trigger the immune and make antibodies to mark it, those antibodies will always be available to recognize that antigen and mark it if it is ever introduced into the body again. So a vaccine for polio causes the body to be ready to neutralize the polio virus anytime that it enters the body.
Because so little is known about how the immune system works and how the AIDS virus cripples it, scientists have not yet been able to make a vaccine that can protect against HIV.
After this basic groundwork in how the AIDS virus works, students need to have all the following information about AIDS presented to them
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There are a few movies which are appropriate for 5th and 6th grade levels, many for older students. Even younger middle school students need this basic information. The preceding lessons about puberty and human sexuality will prepare students and teachers to talk about the AIDS material with minimal discomfort.
The AIDS virus is very fragile. It cannot live outside the body. That is why you cannot contract AIDS from drinking fountains and door knobs. In the body, the virus lives in macrophages. The greatest concentration of macrophages are found in blood, semen, and cervical mucus.
In order for someone to catch AIDS, these infected cells must enter his/her own blood stream. There are three ways that this virus is transmitted. The first is blood to blood contact. There are many ways that other people’s blood can enter the bloodstream. People who use illegal IV drugs often share their needles. The blood of the first person is still in the needle when the second person shoots up. This is a major way that the AIDS virus has been spread. Other ways the virus has been spread by blood to blood contact include blood transfusions and accidents when AIDS infected blood gets into open cuts. Transfusions are now quite safe because donated blood is screened for the presence of antibodies to the AIDS virus. This is a direct blood to blood contact and a very good way to spread it if the first person has the virus.
AIDS can be caught by sexual contact with someone who has the virus. People can pass it to each other by having any type of sexual interaction in which semen or cervical secretions or blood are exchanged.
The third way the virus can be spread is from a pregnant woman to her baby in utero or at birth or possibly through breast milk.
You cannot catch AIDS from Kleenex, toilet seats, chewing on a pencil, a drinking fountain, spitting, eating utensils, insects, shots at the doctors, giving blood, or from urine, tears, seat, saliva or any kind of casual contact. There is no need to be afraid of people with AIDS because you cannot catch AIDS From them unless you have sex with them or share a needle with them.
A most important piece of information about AIDS is that it takes so many years for someone to know they have it. There are no symptoms of sickness for eight years on the average. A person can have the virus, not know it, not be sick, and still pass it on to someone she/he has sex with or shares a needle with. You can only catch AIDS from someone who has it. The problem is that it is difficult to know when someone has AIDS.
We all need to develop a new respect for other people’s blood. Learn not to touch other people’s blood. Kids should not be blood brothers/sisters, share needles for ear-piercing or tattooing or share razors. If somebody has a cut or bloody nose, get an adult or use a cloth, glove, or wad of Kleenex before helping out.
The only certain way to avoid catching the virus is to not do the things that spread it: intimate sexual contact and sharing needles (works) for illegal IV drug use. If people are going to engage in these behaviors, they can reduce the risk of catching the virus by taking certain precautions. Limit the number of sex partners; always use condoms. Use a spermicide which kills the virus too for even more protection. Do not have sex with people who have AIDS.
Remember that no one can tell who has AIDS by looking at them.
Don’t use intravenous drugs. If you do, don’t share needles.
If you do, clean the needles every time before using them with a solution of bleach and water.
For older middle school students and high school students, there are many good curricula and materials available. See bibliography. It may be appropriate to go into more detail about sexual transmission and means of preventing transmission.
There is a difference in approach with younger middle school kids. We want to emphasize that human sexuality is normal and healthy and the naturalness of puberty. We want to decrease their fears and give them a sense of control over whether they will catch AIDS or not. We must connect all information to the personal and concrete level because they don’t have the faculties to grasp abstract ideas otherwise. Young adolescents don’t need details about adult sexual practices that spread the virus but rather the concept that the virus can be caught by sexual interaction.
Whey they decide to have sex they need to know what precautions to take.
However, any subject that comes up can be answered simply and truthfully. If a question is asked about sexual practices, it must be addressed. According to group theory, if someone in a group asks a question, it’s not an individual question but something that everyone in the group potentially has.
One problem of teaching about AIDS with young adolescents is our confusion about values we hold which are in conflict. We believe in the importance of education. We also may attach negative value to sexual interaction in adolescents, to homosexuality, or to specific sexual behaviors. Unfortunately kids need the facts in order to protect themselves from AIDS. Sometimes we are unaware that we withhold information because of values. We don’t tell our students the clear truth.