Some Strains Worse on the Brain?

Are you at greater risk for developing HIV-related dementia? It may depend on the strain of HIV you're infected with, say researchers at Johns Hopkins University School of Medicine. Their study of HIVers with advanced HIV disease at a Ugandan clinic has shown that 24% of participants infected with HIV subtype A (a viral strain most common in West and Central Africa) developed dementia, but an alarming 89% of those infected with subtype D (found in East and Central Africa) suffered from the condition. HIV subtype B is the strain most prevalent in the United States and Western Europe. "These findings provide the first evidence, to our knowledge, to demonstrate that HIV subtypes may have a pathological factor with respect to their capacity to cause cognitive impairment," the researchers conclude in the September 1, 2009 issue of Clinical Infectious Diseases. Because the researchers aren't sure exactly why HIV subtype D is linked with greater risk of dementia -- or if other viral subtypes are similarly associated with cognitive disorders -- they're planning additional studies.