*1 in 6 Americans infected with herpes

*Highest rates found among blacks, women

*

WASHINGTON, March 9 (Reuters) - About 16 percent of Americans between the ages of 14 and 49 are infected with genital herpes, making it one of the most common sexually transmitted diseases, U.S. health officials said on Tuesday.

Black women had the highest rate of infection at 48 percent and women were nearly twice likely as men to be infected, according to an analysis by the U.S. Centers for Disease Control and Prevention.

About 21 percent of women were infected with genital herpes, compared to only 11.5 percent of men, while 39 percent of blacks were infected compared to about 12 percent for whites, the CDC said.

There is no cure for genital herpes, or herpes simplex virus type 2 (HSV-2), which can cause recurrent and painful genital sores and also increases the likelihood of acquiring and transmitting the AIDS virus. It is related to herpes simplex virus 1, or oral herpes, which causes cold sores.

Several drugs are available to treat herpes symptoms and outbreaks, including acyclovir, which is available generically or under the Zovirax brand name, and valacyclovir, known generically as Valtrex -- both made by GlaxoSmithKline PLC GSK.L. Ganciclovir, sold as Zirgan, is made by privately-held Sirion Therapeutics, Inc.

The CDC estimates that more than 80 percent of people with genital herpes do not know they are infected.

“The message is herpes is quite common. The symptoms can be often very innocuous,” Dr. John Douglas of the CDC said in a teleconference.

“Because herpes is so prevalent it becomes ... a really important reason to use condoms on a consistent and correct basis with all of your partners,” Douglas said.

Douglas said the increased rate of infection in blacks is not do to increased risk behavior but likely due to biological factors that make women more susceptible as well as the higher rate of infection within black communities.

The CDC estimates that there are 19 million new sexually transmitted disease infections every year in the United States, costing the health care system about $16 billion annually.