Human immunodeficiency virus, or HIV, weakens patients' immune systems. MedlinePlus says that even though HIV patients may not have symptoms for up to 10 years after initial infection, they can pass the virus to other people. When HIV progresses to its last stage, acquired immune deficiency syndrome or AIDS, patients can die from the infection.
Prevalence of HIV and AIDS
The World Health Organization notes that in 2008, 33.4 million people in the world had HIV. Of those 33.4 million people, 31.3 million people were adults and 2.1 million people were children under the age of 15. The WHO adds that in 2008, 2.7 million people in the world contracted HIV. That number of new cases includes 2.3 million adults and 430,000 children under the age of 15.
Modes of Transmission
MedlinePlus explains that people can contract HIV through sexual contact, from mother to child through breast milk or shared blood circulation, through needle sharing or blood transfusion, though few people get HIV through blood transfusions as donated blood gets tested. The Centers for Disease Control and Prevention notes that in 2007, an estimated 16,749 AIDS cases resulted from male-to-male sexual contact. The organization adds that in the same year, an estimated 6,010 AIDS cases came from sharing drug needles.
Symptoms
MayoClinic.com points out that with an early HIV infection, patients may have no symptoms or they may see flulike symptoms that last two to four weeks. Examples of the flulike symptoms include a rash, sore throat, headache, fever and swollen lymph glands. As the infection progresses, patients can start having shortness of breath, fever, diarrhea and weight loss. When patients have AIDS, they can develop opportunistic infections, or infections that occur due to a weakened immune system. Symptoms from opportunistic infections include weight loss, soaking night sweats, chronic diarrhea, lesions on the tongue or mouth, dry mouth, shaking chills and headaches.
Methods of Testing
Doctors test for HIV and AIDS by checking patients' blood for HIV antibodies, a protein produced by the immune system. MedlinePlus explains that for a doctor to diagnose a person with HIV, that person must have positive results on both the HIV Western blot and the HIV ELISA tests, the two HIV tests. Both tests involve drawing blood from the patient, then running that sample through the tests for the presence of HIV antibodies. If a person has a negative test but has a high risk for HIV, he should have another blood test three months later.
Death
MedlinePlus notes that among people ages 25 to 44 in the United States, AIDS is the sixth leading cause of death, though it was the first leading cause back in 1995. The World Health Organization notes that in 2008, 2 million people throughout the world died from AIDS. Those 2 million people include 1.7 million adults and 280,000 children under the age of 15.
