BOSTON — Massachusetts health officials are alarmed by a steady rise in sexually transmitted diseases, with cases reaching record levels in recent years.

Chlamydia, gonorrhea and syphilis — three of the most common STDs — are becoming more prevalent in the state and nationally, especially among young people and minority groups more at risk, health officials say.

Nearly 24,000 cases of chlamydia were reported to the state Department of Public Health in 2015, about 60 percent more than a decade ago.

“The increase in chlamydia rates, especially among young people, is really alarming,” said Jennifer Childs-Roshak, president and CEO of the Planned Parenthood League of Massachusetts. “If it were anything else it, I think it would be a public health crisis.”

Gonorrhea infections have risen, as well, with 3,688 cases reported in 2015. That was a 52 percent increase from 2006.

Meanwhile, syphilis cases are also rising. In 2015, the state received word of 792 new cases, nearly four times the amount reported in 2006.

There’s no consensus about what’s causing a resurgence of diseases that just a decade ago had leveled out, if not declined.

Some health officials attribute it to more screenings that are revealing cases with little or no symptoms. Others suggest younger people and other at-risk groups are ignoring the dangers of unprotected sex.

Kevin Cranston, the health department’s assistant commissioner and director of the Bureau of Infectious Disease and Laboratory Sciences, said the three more common STDs are usually treatable with antibiotics. But most cases go undiagnosed, he said, which can lead to infertility and other problems.

“Chlamydia is a primary cause of pelvic inflammatory disease, as well as infertility in women,” he said. “So it has long-term effects that can be quite serious.”

Nearly 40 percent of babies born to women with syphilis may be stillborn, or die from the infection, according to the Centers for Disease Control and Prevention.

Syphilis rates are rising among men and women, but disproportionately affect gay men.

“While most gay men are very clear about their risk for HIV infection, they may not be as clear about the risks for syphilis infection,” Cranston said. “It’s made a very strong comeback.”

The diseases are also spreading among young people who are reluctant to use condoms — considered the most effective protection against STDs — and who have sex with multiple partners, some health officials say.

“We continue to preach the use of condoms, but sometimes it feels like we’re shoveling against the tide,” said Dr. Zandra Kelley, medical director at the Greater Lawrence Family Health Center, which has clinics in Methuen, Haverhill and Lawrence.

“The use of condoms among young people is still largely frowned upon,” she said.

Kelley said a lack of sex education in schools also contributes to the problem. Health officials say sex ed programs that emphasize abstinence, such as the curriculum in Lawrence, contribute to the problem.

The city had one of the highest rates of chlamydia in the state in 2015, with about 500 cases per 100,000 people. Rates for gonorrhea were also among the state’s highest.

“Our population is at a significantly higher risk than other parts of the state,” Kelley said.

High rates of STDs in Massachusetts and other New England states mirror trends nationally.

Syphilis cases for the United States rose most sharply in the past year, by 19 percent, according to the CDC. Reported chlamydia cases grew 5.9 percent, with more than 1.5 million cases last year, and gonorrhea cases increased 12 percent to 395,216.

While chlamydia disproportionately affects women, cases among men grew more sharply last year, as well.

Chlamydia rates are highest among 15- to 24-year-olds, who accounted for nearly two-thirds of diagnoses last year, and among blacks, according to the CDC.

The federal agency points out that more than half of state and local programs that provide testing and treatment have had budgets pared during the economic downturn.

The growing popularity of dating apps could contribute to elevated rates, as well, since they encourage sexual activity with multiple partners, the federal agency said.

Health officials say people who are sexually active should get tested regularly.

In some cases, confidentiality issues, such as concerns about parents finding out, prevent young people from seeking sexual health care services.

Cranston, of the Department of Public Health, said the state has made regular screenings for women up to age 26 a key part of its strategy to reduce STD infections. It has set up testing locations at community centers, public health facilities and hospitals.

Under a provision in the Affordable Care Act, which just survived a repeal attempt by the Republican-controlled Congress, most government-subsidized and commercial insurers are required to cover routine screenings for STDs and other diseases.

A 2015 state law requires health care providers and pharmacies to fill a prescription for the partner of someone diagnosed with chlamydia, gonorrhea and syphilis.

“The thing with STDs is that everybody got it from somebody,” Cranston said. “If there’s one infected person, chances are there’s a partner out there who is also infected.”

Christian Wade covers the Massachusetts Statehouse for the North of Boston Media Group’s newspapers and websites. Reach him at cwade@cnhi.com.