The history of the human immunodeficiency virus (HIV) andacquired immunodeficiency syndrome (AIDS) dates back to 1981, when homosexual men with symptoms of a disease that now are considered typical of AIDS were first described in Los Angeles and New York.
The men had an unusual type of lung infection (pneumonia) called Pneumocystis carinii (now known as Pneumocystis jiroveci) pneumonia (PCP) and rare skin tumors called Kaposi's sarcomas.
The patients were noted to have a severe reduction in a type of cell in the blood (CD4 cells) that is an important part of theimmune system. These cells, often referred to as T cells, help the body fight infections. Shortly thereafter, this disease was recognized throughout the United States, Western Europe, and Africa. In 1983, researchers in the United States and France described the virus that causes AIDS, now known as HIV, belonging to the group of viruses called retroviruses.
While HIV infection is required to develop AIDS, the actual definition of AIDS is the development of a low CD4 cell count (<200 cells/mm3) or any one of a long list of complications of HIV infection ranging from a variety of so-called "opportunistic infections", cancers, neurologic symptoms, and wasting syndromes.
HIV is present to variable degrees in the blood and genital secretions of virtually all individuals infected with HIV, regardless of whether or not they have symptoms. The spread of HIV can occur when these secretions come in contact with tissues such as those lining the vagina, anal area, mouth, eyes (the mucus membranes), or with a break in the skin, such as from a cut or puncture by a needle.
The most common ways in which HIV is spreading throughout the world include sexual contact, sharing needles, and by transmission from infected mothers to their newborns during pregnancy, labor (the delivery process), orbreastfeeding. See the section below on treatment during pregnancy for a discussion on reducing the risk of transmission to the newborn.
Sexual transmission of HIV has been described from men to men, men to women, women to men, and women to women through vaginal, anal, and oral sex. The best way to avoid sexual transmission isabstinence from sex until it is certain that both partners in a monogamous relationship are not HIV-infected.
Because the HIV antibody test can take months to turn positive after infection occurs, both partners would need to test negative for at least 12 and up to 24 weeks after their last potential exposure to HIV. If abstinence is out of the question, the next best method is the use of latex barriers.
This involves placing a condom on the penis as soon as an erection is achieved in order to avoid exposure to pre-ejaculatory and ejaculatory fluids that contain infectious HIV. For oral sex, condoms should be used for fellatio (oral contact with the penis) and latex barriers (dental dams) for cunnilingus (oral contact with the vaginal area). A dental dam is any piece of latex that prevents vaginal secretions from coming in direct contact with the mouth. Although such dams occasionally can be purchased, they are most often created by cutting a square piece of latex from a condom.
The spread of HIV by exposure to infected blood usually results from sharing needles, as in those used for illicit drugs. HIV also can be spread by sharing needles for anabolic steroids to increase muscle, tattooing, and body piercing. To prevent the spread of HIV, as well as other diseases including hepatitis, needles should never be shared.
At the beginning of the HIV epidemic, many individuals acquired HIV infection from blood transfusions or blood products, such as those used for hemophiliacs. Currently, however, because blood is tested for both antibodies to HIV and the actual virus before transfusion, the risk of acquiring HIV from a blood transfusion in the United States is extremely small and is considered insignificant.
There is little evidence that HIV can be transferred by casual exposure, as might occur in a household setting. For example, unless there are open sores or blood in the mouth, kissing is generally considered not to be a risk factor for transmitting HIV.
This is because saliva, in contrast to genital secretions, has been shown to contain very little HIV. Still, theoretical risks are associated with the sharing of toothbrushes and shaving razors because they can cause bleeding, and blood can contain large amounts of HIV. Consequently, these items should not be shared with infected people. Similarly, without sexual exposure or direct contact with blood, there is little if any risk of HIV contagion in the workplace or classroom.
The time from HIV infection to the development of AIDS varies. Rarely, some individuals develop complications of HIV that define AIDS within one year, while others remain completely asymptomatic after as many as 20 years from the time of infection.
However, in the absence of antiretroviral therapy the time for progression from initial infection to AIDS is approximately eight to10 years. The reason why people experience clinical progression of HIV at different rates remains an area of active research.
Within weeks of infection, many people will develop the varied symptoms of primary or acute infection which typically have been described as a "mononucleosis" or "influenza" like illness but can range from minimal fever, aches, and pains to very severe symptoms.
The most common symptoms of primary HIV infection are:
- aching muscles and joints,
- sore throat,
- swollen glands (lymph nodes) in the neck.
It is not known, however, why only some HIV-infected people develop these symptoms. It also is unknown whether or not having the symptoms is related in any way to the future course of HIV disease. Regardless, infected people will become symptom-free (asymptomatic) after this phase of primary infection.
During the first weeks of infection when a patient may have symptoms of primary HIV infection, antibody testing may still be negative, the so-called window period.
If there is suspicion of early infection based upon the types of symptoms present and a potential recent exposure, consideration should be given to having a test performed that specifically looks for the virus circulating in the blood, such as a viral load test or the use of an assay that identifies HIV p24 antigen, for example, the new fourth-generation antibody/antigen combination test. Identifying and diagnosing individuals with primary infection is important to assure early access into care and to counsel them regarding the risk of transmitting to others.
The latter is particularly important since patients with primary HIV infection have very high levels of virus throughout their body and are likely to be highly infectious. Once the patient enters the asymptomatic phase, infected individuals will know whether or not they are infected if a test for HIV antibodies is done.
Shortly after primary infection, most individuals enter a period of many years where they have no symptoms at all. During this time, CD4 cells may gradually decline, and with this decline in the immune system, patients may develop the mild symptoms of HIV such as vaginal or oral candidiasis thrush (a fungal infection), fungal infections of the nails, a white brush-like border on the sides of tongue called hairy leukoplakia, chronic rashes, diarrhea, fatigue, and weight loss.
Any of these symptoms should prompt HIV testing if it is not being done for other reasons. With a further decline in function of the immune system, patients are at increasing risk of developing more severe complications of HIV, including many more serious infections (opportunistic infections), malignancies, severe weight loss, and decline in mental function.
From a practical perspective, most physicians think about patients with HIV diseases as having no symptoms, mild symptoms, or being severely symptomatic. In addition, many would characterize a patient's level of immunosuppression by the degree and type of symptoms they have as well as the CD4 cell count.
The Centers for Disease Control and Prevention have defined the presence of a long list of specific diseases or the presence of less than 200 CD4 cells per mm3 as meeting a somewhat arbitrary definition of AIDS.
It is important to note that with effective antiretroviral therapy many of the signs and symptoms of HIV as well as severity of immunosuppression can be completely reversed, restoring even the most symptomatic patients to a state of excellent health.
HIV/AIDS is caused by infection with the human immunodeficiency virus (HIV). HIV/AIDS is most often contracted through sexual contact. Any person who engages in sexual activity, including vaginal, oral, or anal sex, can contract and pass on an HIV infection.
This includes heterosexual, homosexual, and bisexual men and women. The more sexual partners a person has, the greater the risk of catching and passing on HIV/AIDS.
HIV/AIDS can also be passed to another person through other means, such as contact with blood or bodily fluids. This can occur during blood transfusions or by sharing needles contaminated with HIV.
Contracting HIV/AIDs through transfusions of blood products has become very rare since 1985 because donated blood products are now tested for HIV.
HIV can also be passed from an infected mother to her baby during pregnancy, childbirth or breastfeeding.
Treatment of HIV starts with seeking regular medical care. This allows your health care professional to best evaluate your symptoms and risks and provide behavior counseling and regular testing for HIV infection as appropriate.
Regular medical care can increase your chances of catching and treating HIV in its earliest stages before serious complications occur. In some cases, rapid treatment with medication can prevent the development of HIV/AIDS after exposure to HIV. This prophylactic treatment needs to begin within 72 hours after exposure to HIV/AIDS.
HIV is not curable, but prompt diagnosis and treatment can help to reduce or delay the onset of serious complications, improve quality of life, and minimize the spread of the disease to others. You can best manage HIV/AIDS by consistently following your treatment plan.