HIV in Saliva – Transmission Risk through Open Wound and Blood

Dental Health Care Guide on AIDs Infection from Saliva to Blood, Cut, spit & Kissing in word/ .doc Format (CDC)

SALIVA AND HIV TRANSMISSION:

There is only a very slim responsibility that HIV may be transmitted by saliva, for the following reasons.

Only a small minority of HIV infected individuals harbour the virus in whole saliva (e.g. in one study HIV was detected in mixed saliva of 5% of infected individuals and only in one of 15 parotid saliva samples). In any case HIV virions cannot exist in cell free State in saliva, and estimates are that there is less than one infectious particle of HIV per milliliter of mixed saliva.

Saliva contains IgA group antibodies to HIV proteins (p24, gp120, gp160) which may neutralize the infectivity of the virus and are the basis of salivary kits used for HIV testing in epidemiological studies.

Other HIV inhibitory factors in saliva include high molecular weight mucins thought to entrap the virus, proline rich proteins, and a serine protease inhibitor termed salivary leucocyte protease inhibitor (SLPI). The latter possibly blocks cell surface receptors needed for entry of HIV into the cells.

The virus loses its infectivity when exposed to when exposed to mixed saliva for 30 minutes.

Animal studies have shown that it is not possible to transmit HIV by surface application of the virus on the oral mucosa, although it was transmitted in this manner through vaginal mucosa.

The dose of HIV required for infection is far higher than that for hepatitis B virus (the risk of acquiring hepatitis B infection from a contaminated needle stick injury is 6-30%, compared with a 0.4% risk of contracting HIV infection.  

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