Rates of sexually transmitted diseases (STDs) in the U.S. continue to rise.
If that sounds familiar, well, it is: Last year, Live Science reported the same trend. In fact, this is the fourth consecutive year of rising STD rates, the Centers for Disease Control and Prevention (CDC) said.
CDC researchers discussed the new statistics — based on preliminary data from 2017— today (Aug. 28) at the National STD Prevention Conference. They found that doctors diagnosed nearly 2.3 million cases of chlamydia, gonorrhea and syphilis in the U.S. that year. That's 200,000 more cases than were reported the year before. [Quiz: Test Your STD Smarts]
"We are sliding backward," Dr. Jonathan Mermin, the director of the CDC's National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, said in a statement.
The most common STD in 2017 (and the one most commonly reported to the CDC in general) was chlamydia, with over 1.7 million cases identified in 2017, according to the report. This infection, which is caused by the bacterium Chlamydia trachomatis, can infect both men and woman who have unprotected vaginal, anal or oral sex, according to the CDC.
Sexually active young people are particularly at risk of a chlamydia infection, the CDC says. Of the reported cases in 2017, 45 percent were among females between the ages of 15 and 24.
This is also true of gonorrhea, according to the CDC. Gonorrhea is another bacterial infection, in this case, caused by the bacterium Neisseria gonorrhoeae. Like chlamydia, this STD can infect both men and women. Diagnoses of gonorrhea increased 67 percent from 2013 to 2017, with infection rates nearly doubling among men from 169,130 cases to 322,169 cases, according to the preliminary data.
Both chlamydia and gonorrhea, if left untreated in women, can lead to a condition called pelvic inflammatory disease, which can damage the reproductive system and may lead to infertility. In men, though less likely to cause health problems, can sometimes spread to the tubes that carry sperm from the testicles and cause pain and fever, according to the CDC. Rarely, it can also lead to sterility.
Syphilis infections have also increased, the preliminary data showed. This infection is caused by the bacterium Treponema pallidum, and the infection is divided into four stages, depending on the severity. Diagnoses for the first two stages — when the infection is most contagious — increased 76 percent from 2013 to 2017. Of the more 30,000 syphilis cases diagnosed in 2017, the majority (70 percent) occurred in gay and bisexual men and other men who have sex with men. People can get syphilis through direct contact with a syphilis sore during vaginal, anal or oral sex.
All three infections can be treated with antibiotics, as of now. However, like with all bacterial infections, the STDs run the risk of becoming resistant to the antibiotics that treat them.
In fact, the bacteria that cause gonorrhea have become resistant to every class of antibiotics used to treat the disease except for one. The last remaining shield, ceftriaxone, is now prescribed along with another oral antibiotic, called azithromycin, to help delay the resistance, according to the statement.
Though treatment is still effective, laboratory testing has found that the gonorrhea bacteria are becoming resistant to azithromycin: 1 percent of samples tested in 2013 were resistant to the drug, and over 4 percent were resistant in 2017. Researchers are concerned this could eventually lead to a strain of gonorrhea that's entirely antibiotic-resistant.
"We expect gonorrhea will eventually wear down our last highly effective antibiotic, and additional treatment options are urgently needed," Dr. Gail Bolan, the director of CDC's Division of STD Prevention, said in the statement. "We can't let our defenses down — we must continue reinforcing efforts to rapidly detect and prevent resistance as long as possible."
The risk of STD infections can decrease by using protection during sex.
The CDC recommends STD screening and timely treatment. "Most cases go undiagnosed and untreated," the organization wrote in the statement. This "can lead to severe adverse health effects," such as infertility, ectopic pregnancy (in which a fertilized egg begins to grow outside the uterus), stillbirth and increased HIV risk.
Originally published on Live Science.
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Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.