Final answer:
CMV and trachoma can cause blindness in patients with weakened immune systems, like those with HIV/AIDS. CMV leads to progressive retinitis, while trachoma results from Chlamydia trachomatis. Both are preventable, yet pose a significant risk in developing countries.
Step-by-step explanation:
CMV, or Cytomegalovirus, is a significant viral pathogen that can cause severe health complications, particularly in individuals with compromised immune systems, like transplant recipients or patients with HIV/AIDS. In patients with AIDS, active CMV infections can result in serious conditions such as encephalitis or progressive retinitis, which may lead to blindness. The suppression of the immune system, either due to medical interventions for transplant or because of the effects of HIV, can reactivate dormant CMV infections, or facilitate new infections, resulting in symptomatic disease.
Another infectious agent, Chlamydia trachomatis, is responsible for trachoma, a preventable cause of blindness more prevalent in developing regions. Although rare in the United States, it is transmitted via direct contact with infected individuals or through contaminated objects like towels, and by flies that have been in contact with infected eyes. Both CMV and trachoma illustrate the broader point that certain pathogens can lead to severe ocular complications, potentially resulting in blindness especially in patients with weakened immune systems.