Genital Tract Shedding Differs for HIV-1 and HIV-2
Viral load in semen may explain why HIV-1 is more transmissible than HIV-2
FRIDAY, April 14 (HealthDay News) -- The difference in transmission rates of HIV-1 and HIV-2 may be partly due to a difference in the amount of virus shed in semen of infected individuals, according to a report in the April 4 issue of AIDS.
Geoffrey Gottlieb, M.D., Ph.D., from the University of Washington, Seattle, and colleagues from both Seattle and Dakar, Senegal, measured the viral load in both semen and plasma from 22 HIV-1 and 10 HIV-2 infected subjects at the University of Dakar.
HIV RNA was detected in semen from 95 percent of HIV-1 infected subjects and 70 percent of HIV-2 infected subjects, and the viral load in HIV-1 subjects was nearly two logs higher. A similar trend was seen in plasma viral load which, along with HIV type, was predictive of semen viral load.
"HIV-2 infection, in comparison with HIV-1, is characterized by lower plasma viral loads, slower CD4 cell count decline, decreased AIDS-related mortality, and lower rates of mother-to-child and sexual transmission," the authors write. "Interventions that decrease viral load may help decrease transmission of both HIV-1 and HIV-2."