Syphilis Genome Sequence Offers Clues To Better Diagnosis, Prevention And...( diagnose treat and prevent: DIAGNOSI...)

DIAGNOSIS

Symptoms can be mild or absent in the early stages, and early symptoms mimic those of many other diseases. Moreover, interpreting blood tests can be difficult - the tests can give false negative results for up to three months after infection - and repeated tests are often needed to confirm the diagnosis. "For example, with the current screening test, people who have yaws will test positive for syphilis," says Dr. Hitchcock. "In addition, we need a specific test that will diagnose congenital syphilis."

Scientists can use the genetic blueprint for T. pallidum to devise diagnostic tests that are more specific, more accurate and easier to use.

TREATMENT

Syphilis is treated with injections of penicillin or other antibiotics. About 10 percent of the population is allergic to penicillin; others do not respond to the usual doses and may need repeated injections. Easy-to-administer treatments that do not require an injection are needed, especially for use in developing countries.

The genetic blueprint for the syphilis bacterium suggests targets for new, more specific antibiotics.

PREVENTION

As for other sexually transmitted diseases, preventing syphilis requires constant vigilance, such as using condoms during intercourse and avoiding contact with an infected person's open sores. Moreover, for syphilis as well as some other sexually transmitted diseases, the male condom is only partially protective. That is because the sores can be in places that are not covered by the condom.

Thus preventing syphilis requires extensive screening and treatment. A vaccine would be the easiest, most practical and effective method of prevention, and is especially needed to prevent new infections in high-risk U.S. populations and in developing countries.

The genome sequence for T. pallidum reveals the existence of 12 membrane (surface) proteins that could be tested in experimental vaccines. One o
'"/>

Contact: June R. Wyman
jwyman@nih.gov
301-402-1663
NIH/National Institute of Allergy and Infectious Diseases
16-Jul-1998