Can Saliva Transmit Hepatitis C?
As the most common chronic blood borne infection in the United States, the concentration of Hepatitis C virus in a drop of infected blood is exponentially higher than the concentration of HIV in a drop of infected blood. This explains why it is important to avoid anything that could possibly be tainted with any amount of blood. While not normally found in urine, semen, vaginal/cervical fluids, feces or saliva, injury or illness may cause some of these substances to be contaminated with blood.
In nearly half the cases of Hepatitis C, the infected individuals cannot identify the source for their infection. While it is believed most cases are due to risk factors involving contaminated blood, there remain unidentified modes of Hepatitis C transmission. Salivary transmission is one potential explanation for many unexplained viral causes.
Tiny and Infectious
Measuring only about 50 nanometers in diameter, Hepatitis C is an extremely small virus. A nanometer is one billionth of a meter; 200,000 Hepatitis C viruses placed end to end would only measure a single centimeter. Smaller than the wavelength of visible light, viral particles have no color. In those who are infected, Hepatitis C may produce approximately one trillion new viral particles every day.
Unlike many other viruses (like HIV), any potential source of blood to blood contact seems capable of carrying the Hepatitis C virus. This is true, even if the source is indirect, such as a used razor, making HCV far more transmissible than most other blood borne viruses. As documented by occupational exposure statistics, Hepatitis C is approximately seven times more infectious than HIV.
People with chronic Hepatitis C are advised not to share toothbrushes, razors, nail clippers or other personal articles that may have potentially been in contact with their blood. While there is very little emphasis on saliva as a vehicle of Hepatitis C transmission, under the right circumstances there is some evidence to the contrary:
- As published in the September 2006 issue of Journal of Viral Hepatitis, German researchers investigated the transmission of Hepatitis C via a toothbrush. A team from the University of Regensburg examined 30 patients with Hepatitis C to see whether they had contaminated their toothbrushes with the virus. They collected saliva samples from infected patients both before and after tooth brushing. Figures showed that 30 percent of infected patients tested positive for traces of the virus in their saliva before brushing their teeth, while 38 percent tested positive in their saliva after brushing. Additionally, about 40 percent of the water used to rinse the infected toothbrushes tested positive for the virus. This information confirms the caution against toothbrush sharing, and also sounds a possible Hepatitis C transitory alarm.
- In September of 2003, evidence that saliva contains the Hepatitis C virus was disclosed at the Interscience Conference on Antimicrobial Agents and Chemotherapy. Scientists from the University of Washington in Seattle concluded that while saliva may be infectious, the strongest predictor of viral presence in the saliva is serum viral load. Researchers found that Hepatitis C was not found in saliva if the person’s viral load was under one million. Additionally, any risk of acquiring infection through salivary contact existed only in the presence of gum disease. Investigators attribute this risk to microscopic amounts of blood in the saliva and visually undetectable open mouth wounds present in gum disease.
All possibilities must be considered in trying to determine how unknown sources of Hepatitis C infection took place. Although Hepatitis C has been detected in saliva, the necessary conditions render it unlikey—but not impossible—to be transmitted by kissing or through the sharing of a toothbrush. Before anybody panics about these potential risks, remember that there are conditions accompanying these possible modes of transmission:
- The person with the virus must have a viral load over one million.
- Both parties involved have gum disease.
While experts view the risk of transmitting this disease through saliva as extremely low, it is recommended to maintain good oral hygiene, and toothbrushes be used solely by their owners.
Jancin, Bruce, Hepatitis C virus may be spread through saliva: avoid toothbrush sharing, OB/GYN News, November 2003.
Hepatitis C – contamination of toothbrushes: myth or reality?, Journal of Viral Hepatitis, September 2006.
www.cdc.gov, Hepatitis C FAQ, US Department of Health and Human Services, 2006.
www.epidemic.org, The Hepatitis C Virus, Trustees of Dartmouth College, 2006.
www.hcvadvocate.org, HCV: Important Study on Dried Blood Stability, Hepatitis C Support Project, January 2004.
www.hcvets.com, Saliva may have infectious amounts of HCV in presence of high HCV viral load and gum disease, Michael Carter, HCVets.com, September 2003.
www.hepnet.com, Stopping the Spread of the Virus, Molly Colin, Schering Canada Inc., 2006.
www.medicalnewstoday, Kissing Could Spread Hepatitis C, MediLexicon International, Ltd., September 2003.
www.pafp.com, Hepatitis C Virus can Live in Dried Blood, Pennsylvania Academy of Family Physicians, 2003.