Much to the worry of public health officials, new national data show that cases of chlamydia, gonorrhea and syphilis are climbing in the United States and have reached an all-time high.

A report released this week from the U.S. Centers for Disease Control and Prevention shows that though rates of these sexually transmitted diseases fluctuated over the last five years, all three spiked in 2014. The center called the increases “alarming.”

“America’s worsening STD epidemic is a clear call for better diagnosis, treatment and prevention,” said Dr. Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and Tuberculosis Prevention.

The volume of chlamydia cases last year was particularly staggering. Nationwide, there were about 1.4 million cases, which is the highest number of annual cases of any condition ever reported to the CDC.

Here’s the prevalence of those diseases in the U.S. in 2014:

—Chlamydia: 456 cases per 100,000 people

—Gonorrhea: 111 cases per 100,000 people

—Primary and secondary syphilis: Six cases per 100,000 people

“STDs are a substantial health challenge facing the United States,” a CDC report summary says. “Each of these infections is a potential threat to an individual’s immediate and long-term health and well-being.”

Chlamydia and gonorrhea are common and curable diseases, but if not treated can cause serious problems such as infertility in women. Officials estimate that undiagnosed STDs cause 20,000 women in the country to become infertile each year.

More than half of chlamydia and gonorrhea cases are among people between the ages of 15 and 24. Officials recommend that sexually active women under 25 be tested annually for these diseases.

Syphilis, which is also curable, can lead to complications such as blindness if allowed to progress.

Health officials recommend using condoms during sex to prevent the spread of these diseases.