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In the late 1970s, patients suspected of having the sexually transmitted disease chlamydia needed a physician to diagnose the condition. A specimen was obtained during a pelvic examination for women and a urethral swab for men. Today a patient may be diagnosed with chlamydia from a urine test that uses polymerase chain reaction or other similar DNA amplification screening tests.
"When I first started working with the bacterium Chlamydia trachomatis, cultures used by researchers were cumbersome and expensive," said Dr. Walter Stamm, professor of medicine and head of the Division of Allergy and Infectious Diseases at UW. "Now a urine specimen is used to diagnose chlamydia. This does not require the time, expense, and patient discomfort associated with a pelvic exam or urethral swab."
Stamm became interested in infectious disease research as a medical student at Harvard Medical School. After two years of residency at the UW, Stamm went to the Centers for Disease Control and Prevention , where he directed the hospital infections program and studied nosocomial infections, antibiotic resistance, and urinary tract infections. He joined the UW faculty in 1979 and has led the Division of Allergy and Infectious Diseases since 1994.
"The interplay between clinical infectious disease, laboratory research, and public health was appealing," said Stamm. "In infectious diseases, there are always new things coming along, new infections or problems needing new solutions. At that time, chlamydia was an emerging pathogen."
Chlamydia is the most frequently reported infectious disease in the United States, according to the Centers for Disease Control and Prevention. Approximately 75 percent of women and 50 percent of men with the disease are asymptomatic and may not seek treatment for infection. As a result, only one-sixth of chlamydia cases are diagnosed and reported, out of an estimated three million cases annually.
Despite the lack of symptoms, unrecognized chlamydia infection of the lower genital tract may persist and progress. The main complication of chlamydia occurs when it travels to a woman's upper genital tract and causes pelvic inflammatory disease. The inflammation may lead to tubal scarring, ectopic pregnancy, and infertility. About half of women infected during pregnancy may also pass on the infection to their infants.
"We think about 25 percent of women who have chlamydia pelvic inflammatory disease will eventually become infertile or have an ectopic pregnancy," said Stamm. "The idea is to recognize the infection early, treat it, and prevent these serious complications."
More than 20 years ago, Stamm and his UW colleagues designed a 96-well microtiter plate methodology to identify chlamydia inclusions. Compared with previous techniques, this method made it possible to undertake large-scale studies and assess the epidemiology of chlamydia in young men and women. UW researchers have gone on to develop and test more sensitive, nonculture tests utilizing polymerase chain reaction, ligase chain reaction, and other forms of DNA amplification. These techniques are capable of detecting only a few copies of chlamydia genes in a patient specimen.
"Because patients frequently do not demonstrate clinical manifestations of infection, it's imperative to have an accurate diagnostic test that can be easily administered," explained Stamm. "Developing and implementing these new molecular tests has been a major part of our work. We've also applied these tests in various populations to identify who is infected, and have developed selective screening approaches to more efficiently apply testing."
In 1996, Stamm and colleagues at the UW and Group Health Cooperative in Seattle published a study in the New England Journal of Medicine that demonstrated chlamydia screening reduced the risk of pelvic inflammatory disease by approximately 50 percent. In the study, women at Group Health were randomized to receive either chlamydia screening or routine care, which at that time did not include chlamydia screening. After one year, patients who had been screened for chlamydia were half as likely to have pelvic inflammatory disease compared to the unscreened patients.
"Chlamydia screening, in part as a result of this study, is now widely recommended by the Centers for Disease Control and Prevention, the U.S. Preventive Services Task Force and others, and is considered normal care," said Stamm.
In recognition of his accomplishments in chlamydia research, Stamm received the 27th Thomas Parran Award from the American Sexually Transmitted Diseases Association during the 2001 International Congress on Sexually Transmitted Infections. The association's highest honor, the award recognizes lifetime career achievement in the fields of sexually transmitted diseases and HIV research. In May 2003, Stamm was appointed to a four-year term on the Board of Scientific Counselors of the National Center for Infectious Diseases. The board advises the secretary of Health and Human Services and the directors of the Center for Disease Control and Prevention and the National Center for Infectious Diseases.
"The ability to develop rapid, highly accurate diagnostic tests based on gene amplification is the future goal for a lot of infectious disease research," said Stamm. "Molecular tests are particularly important when the conventional, culture-based system is as slow, insensitive, expensive , as were previous tests for chlamydia. With the continued emergence of infectious diseases, there will be no shortage of problems to study."
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