求三人英语对话,主题为艾滋病.

Why is HIV dangerous?
The immune system is a group of cells and organs that protect your body by fighting disease.The human immune system usually finds and kills viruses fairly quickly.
So if the body's immune system attacks and kills viruses,what's the problem?
Different viruses attack different parts of the body - some may attack the skin,others the lungs,and so on.The common cold is caused by a virus.What makes HIV so dangerous is that it attacks the immune system itself - the very thing that would normally get rid of a virus.It particularly attacks a special type of immune system cell known as a CD4 lymphocyte.
HIV has a number of tricks that help it to evade the body's defences,including very rapid mutation.This means that once HIV has taken hold,the immune system can never fully get rid of it.
There isn't any way to tell just by looking if someone's been infected by HIV.In fact a person infected with HIV may look and feel perfectly well for many years and may not know that they are infected.But as the person's immune system weakens they become increasingly vulnerable to illnesses,many of which they would previously have fought off easily.
The only reliable way to tell whether someone has HIV is for them to take a blood test,which can detect infection from a few weeks after the virus first entered the body.
What Happens if I'm HIV Positive?
You might not know if you get infected by HIV.Some people get fever,headache,sore muscles and joints,stomach ache,swollen lymph glands,or a skin rash for one or two weeks.Most people think it's the flu.Some people have no symptoms.
The virus will multiply in your body for a few weeks or even months before your immune system responds.During this time,you won't test positive for HIV,but you can infect other people.
When your immune system responds,it starts to make antibodies.When this happens,you will test positive for HIV.After the first flu-like symptoms,some people with HIV stay healthy for ten years or longer.But during this time,HIV is damaging your immune system.
One way to measure the damage to your immune system is to count your CD4+ cells.These cells,also called "T-helper" cells,are an important part of the immune system.Healthy people have between 500 and 1,500 CD4 cells in a milliliter of blood.
Without treatment,your CD4 cell count will most likely go down.You might start having signs of HIV disease like fevers,night sweats,diarrhea,or swollen lymph nodes.If you have HIV disease,these problems will last more than a few days,and probably continue for several weeks.
There is no cure for AIDS.There are drugs that can slow down the HIV virus,and slow down the damage to your immune system.There is no way to "clear" HIV from the body.
Other drugs can prevent or treat opportunistic infections (OIs).In most cases,these drugs work very well.The newer,stronger ARVs have also helped reduce the rates of most OIs.A few OIs,however,are still very difficult to treat.