"We have unequivocally observed that CMV retinitis is causing blindness in a young population in developing countries, even though the full scope of the problem remains to be defined," says an international team of 14 eye doctors, HIV specialists, and medical and humanitarian aid workers in PLoS Medicine.
Cytomegalovirus (CMV), a member of the herpesvirus family, was a familiar cause of blindness and death in patients with advanced AIDS in Western countries prior to the introduction of highly active antiretroviral therapy (HAART). In the era before HAART, about 1/3 of patients with AIDS in the West suffered potentially blinding CMV retinitis.
But in developing countries, CMV retinitis has been neglected, with little data describing the scope of the problem, and no strategy for management of the disease, say David Heiden (California Pacific Medical Center, San Francisco, California), Nathan Ford (Médecins Sans Frontières, Bangkapi, Bangkok, Thailand) and colleagues. CMV is absent from current and pending WHO guidelines for the management of HIV in resource-limited settings, they say, while the WHO's ambitious "Vision 2020" program, which seeks to provide guidance on the use of ophthalmologic resources until the year 2020, fails to mention CMV retinitis.
In order to assess the prevalence of CMV retinitis in HIV-infected patients in developing countries, the authors conducted retinal screening examinations at the primary care level in AIDS clinics in five countries of sub- Saharan Africa and Southeast Asia. They examined 325 HIV-infected patients with weakened immune systems (CD4 counts below 50 cells per micro liter). Twenty percent of patients had CMV retinitis, usually not previously diagnosed, and additional studies found 37% of individual eyes with CMV retinitis were blinded by the infection.
"The stark reality is that conditions favorable to the development of CMV retinitis--patients with low CD4 counts in the absence of HAART--are most common in impoverished rural areas where profound blindness will have a devastating impact on the entire family, and often a fatal outcome for the patient," say the authors.
Successful management of CMV retinitis is a realistic goal, say the authors, and must begin with decentralizing diagnostic capacity to the primary care level. They suggest that all high-risk patients (at minimum all patients with CD4 count below 50) must have properly conducted retinal screening examinations with the pupil fully dilated and using an indirect ophthalmoscope. Treatment with valganciclovir, an oral medication that is effective for both eye and systemic disease, is essential, say the authors. "Valganciclovir, a single-source monopoly product, is prohibitively expensive at present," they say, "but must be made available and affordable."
Citation: Heiden D, Ford N, Wilson D, Rodriguez WR, Margolis T, et al. (2007) Cytomegalovirus retinitis: The neglected disease of the AIDS pandemic. PLoS Med 4 (12): e334.
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