The terms "HIV" and "AIDS" are sometimes used interchangeably. However, these two acronyms stand for two related, but different, conditions. HIV stands for human immunodeficiency virus. HIV causes AIDS, which stands for acquired immunodeficiency syndrome. A person can have HIV without having AIDS: AIDS is diagnosed when a person with HIV meets a certain set of criteria indicating an extremely weakened immune system. The Centers for Disease Control and Prevention, or CDC, estimates that there are more than a million people in the United States who are infected with HIV, and about 470,000 people living with a diagnosis of AIDS.
History
The AIDS advocacy organization AIDS Health Foundation reports that AIDS first started being recognized in the United States in the early 1980s. According to the National Institutes of Health, by 1982, there was convincing evidence to show that some sort of infectious agent was causing a new disease that resulted in patients having rare forms of pneumonia, a type of cancer called Kaposi's sarcoma, and other infections that are known as "opportunistic" infections--conditions that arise when the immune system is greatly weakened. In July of 1982, the disease was given the name acquired immune deficiency syndrome, or AIDS. It wasn't until 1984 that the cause of AIDS was finally identified as a type of virus called a retrovirus. At the time, the specific virus was given different names depending on whose lab had discovered it. In 1987, the virus was given the name it has today: human immunodeficiency virus, or HIV. This was a great discovery in that it gave researchers a target for potential treatment and cure, and allowed blood banks to screen for the disease-causing organism.
Symptoms of HIV Infection
According to the AIDS Health Foundation, the difficulty in diagnosing HIV is its initial lack of symptoms--a person may be infected for years without showing any sign of infection. This is dangerous for two reasons: The person is not receiving valuable treatment, and, he is at risk of infecting others through unprotected sex. As HIV invades the body's immune system, some symptoms be experienced; the time course of being infected with HIV and starting to feel symptoms may range from months to years. John Bartlett, a physician of the Johns Hopkins University School of Medicine, writes in the medical reference UpToDate that certain conditions appear to be more common with HIV infection. These include fevers, diarrhea lasting over a month, and thrush, which is a painful whitish coating on the tongue and inside of the mouth caused by the accumulation of a fungus in the mouth.
Progression to AIDS
As HIV progresses, patients will meet criteria for AIDS. As in the case with feeling symptoms from HIV infection, the progression from HIV infection to an AIDS diagnosis may take only a few months, or many years. The AIDS Health Foundation reports that three of four patients with HIV progress to AIDS within 15 years of being infected. For an AIDS diagnosis to be made, a patient must meet a certain set of criteria established by the CDC. Key aspects of the diagnosis of AIDS include a very low CD4 T cell count--this is the immune system cell affected by HIV--and the presence of any one of a variety of AIDS-defining illnesses. An example of an AIDS-defining illness is a kind of pneumonia known as PCP, or Pneumocystis carinii pneumonia; another example is a viral infection called CMV, or Cytomegalovirus. A person who has a CD4 count of less than 200 cells per microliter, and one of the AIDS-defining opportunistic infections, is considered to have progressed from HIV infection to a diagnosis of AIDS.
Significance
Despite a lot of progress on a variety of fronts related to HIV and AIDS--greater knowledge about how the virus is transmitted, steps to prevent transmission during blood transfusions, treatment options that have prolonged the lives of patients with HIV--HIV and AIDS continue to be a major public health issue. Of the more than one million people who are infected with HIV, the CDC estimates that about one in five of them--21 percent--do not know they are infected, putting their sexual partners at risk for infection. Furthermore, more than 56,000 people become infected with HIV each year. AIDS also continues to kill about 18,000 people each year in the United States. The CDC points out that while gay or bisexual men continue to represent the majority of cases, women are not exempt from the potential for infection. People who have unprotected heterosexual contact or use intravenous drugs also account for a large number of cases. For instance, in 2006, 27 percent of new cases of HIV infection occurred in women. Intravenous drug users accounted for 12 percent of new cases. These numbers give a glimpse of the impact that HIV and AIDS continue to have.
Misconceptions
Although the terms HIV and AIDS have been around for over two decades, myths and misconceptions continue to spread. An especially common myth is that HIV can only infect gay men or only infect intravenous drug users. Another common set of misconceptions concerns the way HIV is transmitted. It was once thought and feared that HIV could be transmitted by a handshake with an HIV-infected person; a hug with an HIV-infected person; or touching a doorknob used by an HIV-infected person. Even mosquitoes were feared as potential HIV transmitters. In reality, AIDS can only be spread via exposure to blood, vaginal fluid, semen, or mother's milk that is infected with HIV. The saliva of a person infected with HIV does contain a small amount of HIV virus but is not an issue unless either person has open cuts or sores in his mouth. Finally, mosquitoes, while they can carry other viral infections, do not transmit the HIV virus.
