Development of AIDS
As HIV continues to proliferate and invade healthy cells in an infected person’s body, the immune system loses its capacity to defend the body against opportunistic infections. The incubation period for AIDS (i. e., the time between HIV infection and the onset of one or more severe, debilitating diseases associated with extreme impairment of the immune system) typically ranges from 8 to 10 years in adults. However, a small percentage of people infected with HIV remain symptom-free for much longer periods. Furthermore, as we will see, powerful new treatment strategies can dramatically slow the progress of HIV/AIDS in individuals who have access to these costly treatments.
People who experience progression to AIDS can develop a range of life-threatening complications. A common severe disease among HIV-infected people, and one that accounts for many AIDS deaths, is pneumonia caused by overgrowth of the protozoan Pneumocystis carinii, which normally inhabits the lungs of healthy people. Other opportunistic infections associated with HIV include tuberculosis, encephalitis (viral infection of the brain), severe fungal infections that cause a type of meningitis, salmonella illnesses (bacterial diseases), and toxoplasmosis (caused by a protozoan). Africa is currently plagued with an escalating tuberculosis epidemic fueled largely by the HIV/ AIDS pandemic (Karim et al., 2011; Lawn, 2012). Worldwide tuberculosis is the most common infectious cause of death in HIV-infected people, and of the approximately 2 million annual deaths worldwide attributable to AIDS, about 25% are associated with this disease (Friedrich, 2011b; Torok & Farrar, 2011). The body is also vulnerable to cancers, such as lymphomas (cancers of the lymph system), cervical cancer, and Kaposi’s sarcoma, a common cancer in male AIDS patients that affects the skin and can also involve internal organs (Shiels et al., 2011).
Before the advent of much-improved antiretroviral treatments, once people living with AIDS developed life-threatening illnesses, such as pneumonia, tuberculosis, or cancer, the disease tended to run a fairly rapid course. Death usually occurred within 2 years for both men and women (Suligoi, 1997). Furthermore, most people who have developed AIDS since the beginning of the epidemic in the United States have already died. However, a significant decline in the rate of AIDS deaths began in 1996 (the first year that the death rate declined since the onset of the epidemic) and has continued to
the present. This reversal in death trends was largely due to improvement in combination drug therapies, which we discuss in the next section. Even with this trend toward a lowering of the number of annual deaths from AIDS in the United States, an estimated 16,000 Americans died from AIDS in 2011 (Tasker, 2011).
A reduction in AIDS deaths is also occurring in other developed nations that have the resources to implement the more effective drug therapies. Unfortunately, this reversal in AIDS deaths is minimal or nonexistent in developing nations, especially those located in Africa, where HIV/AIDS continues to result in an unacceptable incidence of both infections and deaths. The high cost and difficulty of administering new and better therapies are barriers to the effective use of these treatments in poor, developing nations. Less than half of HIV – infected persons in the developing world receive antiretroviral drug therapy (Kelland, 2011). Drug therapy for infected people in the developing world is also negatively impacted by the recent downturn in the global economy, which resulted in a 10% drop in HIV/AIDS funding in 2010 compared to 2009 (Voelker, 2011).
Reduced accessibility to antiretroviral drugs is commensurate with a reduction in donor funds (Berkley, 2010). Significantly reduced donations to various African nations have resulted in funding cuts for HIV/AIDS treatment in many countries including South Africa, Kenya, Uganda, Zimbabwe, Congo, and Mozambique. The worldwide economic crisis has also resulted in decreased accessibility to antiretroviral medications in the United States. In 2010 long waiting lists for these drugs were the norm as many infected people lost health insurance along with their jobs. In addition, many states were forced to cut back on AIDS treatment programs due to the high cost of antiretroviral drugs.