Cases of three sexually transmitted diseases increased in Allegheny County last year, with two of them -- chlamydia and syphilis -- reaching their highest totals in more than a decade.

		Graphic: STDs: Trends in numbers of local, national cases

The county Health Department said yesterday that 4,341 chlamydia cases were reported in 2005, the highest number since the county began recording the cases in October 1991.

Seventy-five syphilis cases were reported, nearly triple the number from the previous year and the highest total since 1991, when 92 cases were reported.

In addition, 1,807 gonorrhea cases were reported, the most since 2002.

For all three diseases, more than half the cases occurred among blacks, officials said.

Overall, cases of chlamydia, which have increased steadily in the county in recent years, rose 1.8 percent in 2005. Gonorrhea cases increased 18 percent, though the totals were much smaller than in the early 1990s, when more than 4,000 cases were reported annually.

Statistics on reported cases of chlamydia and gonorrhea so far this year were not available yesterday. But health officials said 17 syphilis cases already have been reported for 2006, putting the county on pace to surpass last year's total.

Health officials said the increase in the three diseases appeared to be driven by several factors, including a shortage of disease intervention specialists employed by the county. The specialists contact the sexual partners of people with the infections and encourage them to seek treatment.

Budget constraints prompted the county to reduce the number of those workers from seven in the 1990s to three, officials said.

One of them, Mary Dea Johnston, said yesterday that the syphilis cases alone "are enough to keep the three of us busy."

Dr. Bruce Dixon, the Health Department's director, said the department planned to hire another staffer and also may use contract workers to help.

Trading sex for drugs also has contributed to the increase in cases, Dr. Dixon said, along with sexual encounters resulting from contacts made over the Internet.

"People look at that as an anonymous way to make contacts," he said.

Better reporting and testing also may be a factor in the increase, particularly in chlamydia cases, said Dr. Anthony Robins, a Health Department epidemiologist.

While the increase in all three diseases is a concern, the sharp increase in syphilis cases is especially troubling, he said.

Syphilis "was a disease we thought we had under control," he said, noting that only a few cases were reported in 1998 and 1999.

State Department of Health data, which include all counties except Philadelphia, also show a recent increase in syphilis cases, though whether an increase has occurred in the other two diseases is less clear, said Beth Butler, the department's infertility prevention project coordinator.

While syphilis has been reported mainly in men who have sex with men in recent years, the disease is being diagnosed in more heterosexuals, including women, county health officials said. Last year, 43 of the 75 syphilis cases occurred in men, 15 of whom reported having sex with other men, Dr. Robins said.

Reported gonorrhea cases in the county last year primarily occurred among heterosexuals. Sixty-two percent were in people ages 15 to 24 and 75 percent were among blacks.

Similarly, 75 percent of chlamydia cases occurred in people 15 to 24 and 64 percent occurred among blacks.

All three diseases are caused by bacteria. Gonorrhea and chlamydia can cause a discharge or burning during urination, especially in males, and can cause pelvic inflammatory disease in women, which can lead to sterility.

Untreated syphilis can be fatal. A pregnant woman can transmit it to her unborn child, resulting in stillbirth, blindness or other permanent disabilities.

County health officials said they did not know why so many reported cases occurred among blacks.

Dr. Stephen Thomas, director of the University of Pittsburgh's Center for Minority Health, noted that other diseases, such as diabetes and cardiovascular disease, also take a disproportionate toll on blacks.

Free, confidential testing and treatment is available at the Health Department's clinic at 3441 Forbes Ave., Oakland.