Attention, chocolate lovers: You may not be able to help yourselves. Swiss and British scientists have linked the widespread love of chocolate to a chemical "signature" that may be programmed into our metabolic systems.
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AIDS - HIV
- Overview, Causes, & Risk Factors
- Symptoms & Signs
- Diagnosis & Tests
- Prevention & Expectations
- Treatment & Monitoring
- Attribution
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Overview, Causes, & Risk Factors
Human immunodeficiency virus, or HIV, infection damages the body's immune system. Over time, it leads to acquired immune deficiency syndrome, or AIDS.
What is going on in the body?
HIV affects the immune system in broad and devastating ways. Its main target is a special immune system cell called the CD4+ T lymphocyte. These cells help the body fight infections of all kinds. When HIV infects these cells, it decreases their numbers and affects how the cells that are left function.
After an adult is infected with HIV, he or she usually has no obvious symptoms for 5 to 10 years. During this time, however, the virus is slowly attacking the immune system. When the immune system is weakened enough, it becomes susceptible to other organisms that the body can usually fight off or keep under control. These other organisms include bacteria, other viruses, fungi, and parasites.
Many serious health problems occur as a result of the immune system damage caused by HIV. The most serious is AIDS.
What are the causes and risks of the disease?
HIV infection is caused by a type of virus known as a lentivirus. Seventy percent of HIV infections worldwide are sexually transmitted, or spread by sexual contact. The remaining 30% of the infections are spread in one of the following ways:
Following are some of the risk factors for HIV infections: