Which of the following is the pathogen responsible for blindness in advanced HIV infections?
a. The predominant causes of morbidity and mortality among patients with late-stage HIV infection are opportunistic infections. These are defined as severe infections induced by agents that rarely cause disease in immune-competent individuals. Opportunistic infections usually do not occur until CD4 T cell counts drop from normal (1000 cells per microliter) to less than 200 cells per microliter.
b. The common opportunistic infections in untreated AIDS patients are caused by protozoa, fungi, bacteria, and other viruses. Coinfection with DNA viruses are reported to lead to enhanced expression of HIV in cells in vitro.
c. Herpesvirus infections are common in AIDS patients, and Cytomegalovirus (CMV) has been shown to produce a protein that acts as a chemokine receptor and is able to help HIV infect cells. CMV retinitis is the most common severe ocular complications of AIDS.