Cases of some sexually transmitted diseases (STDs) have reached an all-time high, according to a new report from the Centers for Disease Control and Prevention (CDC).
From 2014 to 2015, there was a 6 percent increase in diagnosed cases of chlamydia and a 13 percent increase in gonorrhea.
The craziest part: The actual number of people with STDs is probably much higher than what the CDC is reporting, because many people have no clue they’re infected, the CDC says.
That’s because STDs often show no noticeable symptoms.
“Sexually transmitted infections (STIs) are often called a ‘silent epidemic’ for the very reason that they don’t typically have outward signs,” says Debby Herbenick, Ph.D., M.P.H., a sex researcher at the University of Indiana.
This means that you could be infected and not even know it—and same goes for your partner. Read on for four common STDs that might have already snuck up on you, and what you should do about it.
SEXUALLY TRANSMITTED DISEASE: GONORRHEA
This bacterial illness is spread through unprotected vaginal, oral, or anal sex. As a result, it can cause infections in your genitals, rectum, or throat.
Condoms are nearly 100 percent effective at preventing transmission of the disease, says Khalil Ghanem, M.D., Ph.D., associate professor of medicine and infectious disease at Johns Hopkins University School of Medicine. (Dental dams can be protective if you’re giving oral sex to a woman.)
Related: The New Rules Of Oral Sex
Signs of gonorrhea: Women often don’t have any symptoms, says Herbenick. And when they do, the signs are usually mild and may mimic a bladder infection—meaning she may not know she’s infected, and there’s no way for you to tell during sex.
As for guys: If the infection is in your throat or rectum, you probably won’t have any symptoms, says Dr. Ghanem.
If the bacteria is targeting your penis, you may see a greenish or yellowish penile discharge or a burning sensation when you pee, Dr. Ghanem says. Testicular pain is another possibility, although it’s rare. These problems usually creep up 3 to 5 days after an exposure.
Left untreated, gonorrhea can cause something called epididymitis, an inflammation of your testicles that may lead to infertility.
How to detect gonorrhea: The CDC recommends routine annual screenings for men. But ask your doctor what’s right for you, since it may depend on risk factors like how often you have new partners, says Herbenick.
How to treat gonorrhea: The good news is that gonorrhea can usually be cured with antibiotics.
But Some Gonorrhea Strains Are Resistant To Antibiotics, so make sure to follow up with your doctor to make sure all the bacteria has been killed, says Herbenick.
SEXUALLY TRANSMITTED DISEASE: CHLAMYDIA
Chlamydia, another bacterial infection, is spread through unprotected vaginal, oral, or anal sex, says Dr. Ghanem.
As with gonorrhea, condoms are nearly 100 percent effective at preventing the spread. And if you’re giving oral sex to a woman, dental dams can reduce your risk.
Signs of chlamydia: Chlamydia rarely has noticeable symptoms in either women or men, says Herbenick.
In the off-chance you do show signs of infection, the symptoms could include a penile discharge or burning when you pee, says Dr. Ghanem. These problems usually creep up about a week after an exposure.
Severe infections in men that are not treated quickly can cause scarring in your urethra, making it more difficult to pee—and it may even require surgery.
Related: What You Should Do If You Pee Blood
How to detect chlamydia: The CDC recommends annual screening for gay or bisexual men. However, straight men should ask their doctors about testing as well.
How to treat chlamydia: Chlamydia can be cured with antibiotics.
SEXUALLY TRANSMITTED DISEASE: HERPES
Genital herpes is caused by two viruses: Herpes simplex type 1 (HSV1), which usually affects your mouth as cold sores, and herpes simplex type 2 (HSV2), which mainly targets your genitals.
Sexual contact can spread your partner’s oral herpes to your genitals or her genital herpes to your mouth. The virus can be spread even if you—or your partner—don’t have any signs of it.
Wearing condoms can help protect you, but not completely: They’re only 80 percent effective for preventing herpes transmission, says Dr. Ghanem. That’s partly because the virus can live on parts of your skin that aren’t covered by the condom.
Signs of herpes: Up to 70 percent of people infected with the virus don’t have symptoms, Dr. Ghanem says.
If you do, you may notice blisters or ulcers on your genitals, or just feel some burning and itching.
When first infected, some patients will develop fevers, chills, swollen lymph nodes, headaches, and fatigue.
How to detect herpes: Have your doctor take a look at any suspicious sores.
How to treat herpes: There’s no cure for genital herpes, but antiviral drugs can ease your symptoms, according to the CDC.
SEXUALLY TRANSMITTED DISEASE: HUMAN PAPILLOMA VIRUS (HPV)
HPV, which comprises more than 150 related viruses, is the most common STI, according to the CDC.
There are two main types: low risk, which usually only cause genital warts, and high risk, which can lead to penile, anal, and cancers. You can catch it via intercourse, oral sex, or even skin-to-skin contact during sex.
Using condoms during sex can help reduce, but not eliminate, your chances of infection, says Michael Krychman, M.D., executive director of the Southern California Center for Sexual Health.
Signs of HPV: “HPV almost never has visible symptoms,” says Herbenick.
Most strains don’t cause warts, and when they do, they’re often tiny—not like the
“scare photos” from your high school’s health class
How to detect HPV: Unfortunately, there are no currently recommended tests to detect HPV in men, Dr. Ghanem says.
How to treat HPV: While warts can be frozen off, removing the lesion doesn’t cure your infection. The warts can recur and the infection can still be spread, Dr. Ghanem explains.
That’s why vaccination—which is recommended for straight men through age 21, or men who have sex with men through age 26—and wearing condoms is especially important to help reduce your risk, says Dr. Krychman.