Over 30 million people have HIV, or have already developed AIDS, and it is believed that close to 2 million people die from AIDS every year, according to Avert, an international AIDS charity. HIV and AIDS are often confused, but the primary distinction is that HIV is a virus and AIDS is a disease. There are subtle yet distinct differences between HIV and AIDS.
Virus vs. Disease
HIV infection is a viral infection, while AIDS is a disease that can result from this virus.
The HIV virus targets the immune system. HIV usually spreads through unprotected sex, exposure to contaminated blood and sharing tainted syringes. It can also be passed from mothers to their babies during birth. It hinders the function of the immune system, leading to disease. Essentially, a disease is a condition that affects the body or some part of it. Diseases typically manifest specific symptoms, and certain diseases are caused by viruses. AIDS is such a disease, and is accompanied by various symptoms.
CD4+ Lymphocyte Count
HIV targets the immune system by invading cells called CD4+ lymphocytes. These are the cells responsible for defending against disease. HIV systematically infects and destroys these cells throughout the course of its development, according to the San Francisco AIDS Foundation.
One of the key signs that a patient has developed AIDS is CD4+ lymphocyte cell count below 200 per cubic millimeter of blood. This indicates that the number of CD4+ lymphocytes has dropped to 14 percent of normal levels. If the patient tests positive for HIV in addition to the low CD4+ lymphocyte count, then that person has AIDS, according to Avert.
Symptoms
HIV may sometimes produce symptoms very similar to the flu during its early phase of infection. Any symptoms that manifest during this early phase are either similar to less serious illnesses or not severe enough to prompt more thorough testing, explains the San Francisco AIDS Foundation. Unlike AIDS, HIV can be present without producing overt symptoms for years.
Once HIV has reached an advanced state of infection, more serious symptoms may manifest, including constant exhaustion, enlarged lymphatics, recurring diarrhea and fever that exceeds 100 degrees Fahrenheit and lasts longer than one week, according to the Mayo Clinic.
AIDS manifests specific symptoms because by this time the disease develops, the immune system is no longer able to provide an adequate defense for the body due to the low CD4+ lymphocyte count. Symptoms that may manifest are pale spots or sores in the mouth and on the tongue, impaired vision and weight loss. AIDS may also manifest similar symptoms to advanced stage HIV such as fever and diarrhea, according to the Mayo Clinic.
Opportunistic Infections
HIV can continue to develop without manifesting any symptoms. As such, people with HIV may appear perfectly healthy.
As the virus weakens the immune system, other diseases such as Kaposi sarcoma, toxoplasmosis, tuberculosis, varicella zoster and herpes simplex may develop. These diseases are known as opportunistic infections because they take advantage of the weakened immune response. When opportunistic infections set in, HIV has progressed into AIDS, according to Avert.
HIV-positive patients are rarely infected with these opportunistic infections before the virus develops into the disease. This is because the virus has yet to severely damage the immune system.
Once certain opportunistic infections, such as toxoplasmosis or tuberculosis, are diagnosed in HIV-positive patients, physicians usually return with a diagnosis of AIDS.
