Worldwide, more than 40 million people are infected with human immunodeficiency virus (HIV). About 40,000 new infections occur every year in the United States.

HIV infects and destroys cells of the immune system. Over time, people with HIV develop infections and cancers due to their weakened immune systems. These include pneumonia, tuberculosis, dementia, meningitis, liver disease, chronic diarrhea, arthritis, herpes, Kaposi's sarcoma, lymphoma, and other disorders.

Transmission of HIV occurs through sexual intercourse, intravenous drug use, mother-to-infant infection (during pregnancy or during breast-feeding), blood transfusions, or open wounds.

When someone becomes infected, the initial symptom is a flu-like or mononucleosis-like syndrome (headache, fever, chills, cough, and muscle aches) with a rash that occurs within four to 14 days of infection and lasts less than three weeks. Patients then return to their normal state of health for two to 10 or more years, while the virus slowly grows within the cells of the immune system.

Risk Factors

• High-risk sexual intercourse: This includes heterosexual and homosexual contact. Nearly 90 percent of cases occur through heterosexual transmission. Condom use reduces, but does not eliminate, the risk.
• Blood transfusion: Since 1985, screening of blood products has significantly decreased the HIV transmission rate. The risk of transmission due to blood transfusion is now about one in two million.
• Injection drug use: Drug injection is a particularly important source of the HIV epidemics in Eastern Europe, Asia, and the Middle East.
• Transmission from mother to child: Children are at risk while in utero, during delivery, and during breast-feeding. However, the combination of antiviral therapy, cesarean delivery, and avoidance of breast-feeding in HIV-positive mothers has reduced the risk significantly.
• Occupational exposure: Risk of transmission after an accidental needle stick exposure is less than 1 percent.

 Human Immunodeficiency Virus: Diagnosis and Treatment

Diagnosis

• Several blood tests are available to identify HIV infection.
• After diagnosis, further blood testing is recommended every three to six months to evaluate the progression of the disease and the need for antibiotics to prevent other infections. In addition, routine follow-up testing is important to assess the adequacy of treatment and to monitor for medication side effects.
• All individuals diagnosed with HIV should be tested for other sexually transmitted diseases, including gonorrhea, chlamydia, syphilis, herpes, hepatitis B, and hepatitis C.

Treatment

• Antiviral medications are the standard therapy for HIV. Combination therapy, in which three or more medications are prescribed simultaneously, is used to attack the HIV virus from multiple angles. To prevent the virus from becoming drug resistant, it is essential to follow the antibiotic regimen precisely.
• As the immune system becomes progressively weakened, antibiotics are given to prevent further infections from occurring.
• Regular exercise can reduce some side effects of antiviral treatment. Combinations of aerobic exercise and progressive resistive exercise (done for at least 20 minutes at least three times per week) may also lead to significant reductions in depression and improvements in heart and lung function.
• Psychological treatments can provide benefits for persons with HIV. Some evidence suggests that excessive stress can increase the risk for infections in HIV-positive persons. In women with HIV, higher stress has been shown to increase the odds of developing cervical cancer, compared with women experiencing the least life stress.

Human Immunodeficiency Virus: Nutritional Considerations

Nutritional issues in HIV infection relate to providing for calorie needs, avoiding nutrient deficiencies, and controlling cholesterol levels. A combination of medications and a healthful diet can improve immune function and decrease the risk for infections.

• Meeting Calorie Needs: Studies of HIV-infected men have shown increased resting energy expenditure and protein use, compared with non-HIV-infected individuals. HIV-infected individuals require increased calorie and protein intake to prevent wasting.
  
  Protein supplementation with amino acids (L-arginine and L-glutamine) and related compounds (such as beta-hydroxy beta-methylbutyrate, which is a metabolite of the amino acid leucine) may help prevent or reduce wasting in HIV-positive individuals, according to some studies. However, additional clinical trials are required before these supplements can be routinely recommended.
  
  Unless they are obese, patients should not be encouraged to lose significant amounts of weight. Studies have consistently shown that HIV-infected patients with a body mass index (BMI) higher than 25 are healthier than thinner HIV-infected patients. Loss of excess weight may be helpful, however, for overweight patients at a higher risk for heart disease.

• Ensuring Nutrient Adequacy: Preliminary evidence reveals that higher intakes of fruits, vegetables, and juices improve the immune system in HIV-positive patients. Fruits and vegetables also provide many nutrients that are deficient in persons with HIV and help reduce the side effects of antiviral therapy.
  
  Nutrient supplements may be helpful. Low blood levels of many nutrients occur in HIV-positive individuals and are associated with worsened disease. Although some reviews suggest that multivitamin supplements are helpful, others have found no such advantage. Preliminary evidence suggests that selenium supplementation (200 mg a day) may reduce the need for hospitalization by lowering the frequency of infections. Magnesium deficiency has also been found in roughly 60 percent of HIV-infected individuals. However, routine magnesium supplementation is not recommended except for persons on a medication called foscarnet, which frequently causes low magnesium levels.
• Controlling Cholesterol: Individuals with HIV often have elevated levels of cholesterol and triglycerides (particles of fat in the body), as a result of antiviral medications. Ten to 50 percent of patients on antiviral medications have high cholesterol and 40 to 80 percent of these individuals have high triglyceride levels. A diet that helps control cholesterol and triglycerides and addresses other cardiovascular risk factors is appropriate for people with HIV.