by Tamar Nordenberg
Anna Lange (not her real name) had no symptoms when she went to a Wake County,
N.C., sexually transmitted diseases (STD) clinic earlier this year to pick up
her birth control pills. But a routine test revealed that the 20-year-old had
chlamydia. "She came in and had no complaints," says Peter Leone, M.D., the
clinic's medical director, "and then 'boom'?she was diagnosed with a sexually
transmitted disease."
The sexually transmitted disease chlamydia usually comes with no telltale
symptoms, so most people don't even know when they are infected. But left
untreated, the so-called "silent epidemic" of chlamydia threatens to cause
reproductive damage and infertility in many of the three million to four million
Americans who get it each year.
Routine chlamydia screening and early, effective treatment are the keys to
reducing chlamydia's toll, according to Penny Hitchcock, chief of the National
Institutes of Health's (NIH) sexually transmitted disease branch. She calls two
recent medical advances "very important breakthroughs" in controlling the
rampant disease: a new drug treatment recently approved by the Food and Drug
Administration (FDA) to cure chlamydia in a single oral dose, and a urine-based
screening test that does not require a swab sample of cells from the genital
area.
The price of sex
Chlamydia is the most common bacterial (and thus curable) sexually
transmitted disease in the United States, by far, ahead of gonorrhea and
syphilis. It is caused by the Chlamydia trachomatis bacteria and transmitted
during vaginal, oral or anal sexual contact with an infected partner.
"Far and away, the age group most affected are the 15- to 19-year-olds," says
Hitchcock. Studies show that young adults in Lange's age group, 20 to 24, are
the second most affected group.
Wearing a condom may help reduce the risk of contracting chlamydia, but
"protected" sex with a condom can't completely prevent transmission of chlamydia
or some other STDs, though experts recommend consistent condom use to reduce the
chances of getting an STD.
Symptoms of chlamydia
When they occur, symptoms of chlamydia usually appear within one to three
weeks of exposure. In women, signs can include unusual vaginal discharge or
bleeding, burning during urination, or lower abdominal pain. Men may also have
pain during urination, or they may notice a burning and itching around or
discharge from the penis or pain and swelling in the testicles.
More often, though, chlamydia lives up to its reputation for silence. Experts
estimate that up to 75 percent of women and 50 percent of men with chlamydia
have no symptoms or symptoms so mild that they don't seek medical attention.
Chlamydia is "a very insidious disease," says Hitchcock. "Because it rarely
causes symptoms, people don't know they're infected. So they don't get treated,
and they infect their partners, who also don't get treated." Without treatment,
the Centers for Disease Control and Prevention (CDC) estimates that in up to 40
percent of cases chlamydia can lead to pelvic inflammatory disease, a serious
infection of the woman's fallopian tubes that can also damage the ovaries and
uterus leading to infertility. It's not known whether chlamydia infection causes
fertility problems or other long-term consequences in men.
Simple screening and treatment
Because so many people are at risk for chlamydia and the disease can ravage a
woman's reproductive system without so much as a symptom, experts recommend
regular, widespread screening to detect the disease.
The old way
- Traditional methods of screening require a health professional to collect
a swab sample of genital secretions. For women, this can be done as part of a
pap smear with little or no discomfort. Male samples are obtained by inserting
a swab into the end of the penis.
- In the past, the sample had to be "cultured" in a laboratory, and it could
take three days or more for results to become available. Also, accuracy of
results could vary greatly based on the lab staff's level of expertise and
experience.
The new ways
Today, a number of tests are available to supplement or replace the relatively
expensive and slow traditional culture. The three major types of nonculture
tests are:
- Direct fluorescent antibody test (DFA)
- This test uses a scientific method called staining to make chlamydia
easier to spot under a microscope. DFA can give quicker results than culture
and can be performed on specimens taken from the eye, cervix or penis.
- Enzyme immunoassays
- This test comes in some forms that can be used in small, unsophisticated
laboratories that don't have special lab equipment. Because testing can be
done where the specimen is collected, results are more rapid than with
culture, access to testing is increased, and costs can be lower.
- Tests to detect the genes of C. trachomatis in urine and genital
samples
- These tests can accurately identify even very small numbers of genes in
a specimen. These tests can be expensive, but are becoming more popular
among public and other labs because of their accuracy and the relative ease
of collecting urine samples.
No one screening method is best, Leone says. "It's a tradeoff. We're
constantly balancing what is the cheapest test with what is the most sensitive,
what is easiest to get from the patient versus what will pick up the most
infections."
Should you get tested?
The CDC recommends annual chlamydia screening for all sexually active
adolescent girls and for other females who may be at high risk for chlamydial
infection, such as those who:
- are less than 25 years old
- don't use barrier contraceptives consistently
- have new or multiple sex partners
- have signs of a possible cervical infection
- have previously had an STD
"Females who are at risk because of their age and sexual activity need to get
screened at least once a year," says researcher Gale Burstein, M.D, a chlamydia
researcher at Johns Hopkins University. She and other chlamydia experts have
recently questioned whether that is even enough.
Routine screening is recommended for pregnant women, also, because of the risk
that their babies will become infected with chlamydia at birth.
There are no recommendations for routine screening among males, Burstein says.
"There is a lot of chlamydia in men that we're missing, and they are a major
reservoir of infection. We're really only putting a band-aid on the problem
because, even if we're screening the women, some are going back to their
partners and getting reinfected."
New medication: a one shot deal
Lange and her boyfriend both took the antibiotic azithromycin (Zithromax), a
prescription drug approved by the FDA in 1997 to cure chlamydia in one dose.
"It's a breakthrough because we can observe therapy rather than depending on
people to adhere to a more complicated regimen," Hitchcock says. Doxycycline
(sold under several brand names), the other antibiotic approved and commonly
used to treat chlamydia, is generally taken twice a day for seven days.
Is a vaccine next?
Recently, researchers at Stanford University and the University of California
at San Francisco uncovered new information about the chromosomes of C.
trachomatis, providing promising leads for developing new antibiotics and even a
vaccine. Hitchcock says she and other STD experts at NIH are "very excited about
the new opportunities for vaccine development."
Until the hope of a vaccine is realized, those who choose to be sexually active
should use condoms?for what they're worth. "Condom use clearly prevents HIV
infection and gonorrhea, as well as pregnancy," Hitchcock says. "Use a condom,
but not with blinders on, either. Don't kid yourself that condoms make sex
risk-free."
Tamar Nordenberg is a staff writer for FDA Consumer.