The Immune System
The immune system is the body’s main defence against pathogens. It recognizes, attacks, destroys and “remembers” each type of invaders in your body.
The immune system fights the infection through the production of cells that inactivate foreign substances or cells. This process is called immunity. Two general categories make up the immune system:
Immunodeficiency Disease In one type of the Immunodeficiency Disease, the immune system fails to develop normally. A second type of Immunodeficiency Disease is AIDS. |
AIDS
Results from a viral infection that destroys helper T cells. As the number of helper T cells declines, the normal immune response breaks down.
During the late 1970s, some patients were dying from infections produced by benign microorganism that did not normally cause disease; such infections are normally prevented by the immune system. Some doctors recognized that the immune system of their patients had been weakened and was symptom of a new disease. AIDS (acquired immune deficiency syndrome) was actually an infectious disease caused by a pathogen that was unknown to the scientific community.
In 1983, researchers found that the cause of AIDS is a virus that they named HIV (human immunodeficiency virus. HIV is a retrovirus, a virus that carries its genetic information in RNA, rather than DNA. HIV evades the defenses of the immune system, attacks key cells in the immune system and it destroying the body’s defenses and leaving the body with no protection against other pathogens. It turned out to be a deadly and efficient virus.
Results from a viral infection that destroys helper T cells. As the number of helper T cells declines, the normal immune response breaks down.
During the late 1970s, some patients were dying from infections produced by benign microorganism that did not normally cause disease; such infections are normally prevented by the immune system. Some doctors recognized that the immune system of their patients had been weakened and was symptom of a new disease. AIDS (acquired immune deficiency syndrome) was actually an infectious disease caused by a pathogen that was unknown to the scientific community.
In 1983, researchers found that the cause of AIDS is a virus that they named HIV (human immunodeficiency virus. HIV is a retrovirus, a virus that carries its genetic information in RNA, rather than DNA. HIV evades the defenses of the immune system, attacks key cells in the immune system and it destroying the body’s defenses and leaving the body with no protection against other pathogens. It turned out to be a deadly and efficient virus.
When the HIV virus attacks a helper T cell, it attaches to receptor molecules on the cell membrane. This allows the virus to enter the cell. Once the viral core is inside the cell, it forces the host cell to make DNA copies of the virus’s RNA. Some of those copies insert themself into host cell DNA and stay there permanently; other copies remain in the cytoplasm. The viral DNA may remain inactive in the host cell for varying periods of time. When activated, it directs the production of viral RNA and proteins that are assembled into new virus particles. The immune system produces antibodies for HIV but they are not effective in stopping the progression of the disease. HIV destroys ever increasing numbers of T cells, crippling the immune system.
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Transmission of HIV
HIV is not easily transmitted. HIV is not transmitted through casual contact.
There are four main ways that HIV can be transmitted:
HIV is not easily transmitted. HIV is not transmitted through casual contact.
There are four main ways that HIV can be transmitted:
- Through any form of sexual intercourse with an infected person;
- through shared needles or syringes that are contaminated with the blood of an infected person;
- through contact with blood or blood products of an infected person; and
- from an infected mother to child, either during pregnancy, during birth, or during breastfeeding.
Preventing HIV Infections
Fortunately you can choose behaviors that will help you reduce your risk of becoming infected with HIV.
Before 1985, HIV was transmitted to some hemophiliacs and surgical patients through transfusions of infected blood or blood products. Such cases have been nearly eliminated by screening the blood supply for HIV antibodies and by discouraging potentially infected individuals from donating blood.
Fortunately you can choose behaviors that will help you reduce your risk of becoming infected with HIV.
Before 1985, HIV was transmitted to some hemophiliacs and surgical patients through transfusions of infected blood or blood products. Such cases have been nearly eliminated by screening the blood supply for HIV antibodies and by discouraging potentially infected individuals from donating blood.
Can AIDS be cured?
There is no cure for AIDS. However progress has been made in developing drugs that make it possible to survive HIV infections for years. Unfortunately, HIV mutates and evolves very rapidly, the virus has been able to evolve into many different strains. For this reason, no one has developed a vaccine that offers protection for any length of time. Thanks to some drugs, more HIV-infected people are now living with HIV rather than dying from it.
Unfortunately, the knowledge that HIV can be treated has given people the idea that HIV infection is not as serious as it was decade ago.
In one year, more than 5 million people around the world became infected with HIV, including roughly 800,000 people under 15 years old. That same year, more than 3 million people around the world died of AIDS.
There is no cure for AIDS. However progress has been made in developing drugs that make it possible to survive HIV infections for years. Unfortunately, HIV mutates and evolves very rapidly, the virus has been able to evolve into many different strains. For this reason, no one has developed a vaccine that offers protection for any length of time. Thanks to some drugs, more HIV-infected people are now living with HIV rather than dying from it.
Unfortunately, the knowledge that HIV can be treated has given people the idea that HIV infection is not as serious as it was decade ago.
In one year, more than 5 million people around the world became infected with HIV, including roughly 800,000 people under 15 years old. That same year, more than 3 million people around the world died of AIDS.
Kanneth R. Miller & Joseph S. Levine. Biology. Pearson Education, 2017.