Infectious HIV can be detected at high levels in saliva during the early weeks of HIV infection (the ‘window’ period before antibodies appear), but levels fall rapidly after this point.
Free floating infectious viruses and virus-infected lymphocytes could be detected in saliva taken from individuals with primary HIV infection attending clinics in North Carolina. In 7 out of 8 cases, free floating infectious virus could be detected at an average level of 2,000 copies per ml, and in 5 out of 8 cases cell associated virus could be detected at an average level of 20,000 copies per ml.
The researchers also found high levels of HIV in the semen of infected men, and in two cases HIV levels remained high despite the initiation of antiretroviral therapy.
The researchers said that virus levels in blood and semen were much higher, and it is not clear how much of a transmission risk the virus levels in saliva might pose. However, some individuals in this study had virus levels as high as 500,000 copies in saliva, suggesting that during the early weeks of infection some individuals may be ‘super-excretors’ of HIV, and may play a significant role in the ongoing amplification of the HIV epidemic.
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Reference
Pilcher C et al. In subjects with primary HV infection, high levels of HIV RNA are present in oral fluids, genital secretions, peripheral blood and CNS and are rapidly reduced with combination antiretroviral therapy. Abstract 556, Seventh Conference on Retroviruses, San Francisco, 2000.