Print An Overview of Sexually Transmitted Diseases By Elizabeth Boskey, PhD - Reviewed by a board-certified physician. Updated July 28, 2016 Sexually transmitted diseases, or STDs, are usually defined as those diseases that primarily spread through intimate contact. They're not the only diseases that can spread during sex. After all, kissing is a good way to give someone a cold. However, unlike other diseases, STDs aren't generally spread by casual contact.STDs are generally spread in one of three ways:They can be transmitted by body fluids like blood, saliva, semen, vaginal secretions, and breast milk. They can be transmitted by direct skin-to-skin contact.There are a few, like pubic lice, that can be transmitted by contact with clothing, towels, or sheets.It is easiest to prevent those diseases that are transmitted only by body fluids, such as HIV and chlamydia. Consistent use of barriers during sex is very effective in preventing these diseases.It's much harder to completely prevent those diseases that spread from skin-to-skin, like herpes. List Think You Might Have an STD? Here Are Some Answers to Common Questions Article Asking Yourself, "Do I Have an STD?" The Only Way to Know Is a Test. Barriers help, but it simply isn't practical to cover all potentially infectious skin. It also wouldn't be much fun.The Most Common STDsSTDs That Spread by Skin-to-Skin ContactHow Common Are STDs?STDs are far more common than most people think. Here are some interesting statistics from the U.S. Centers for Disease Control and Prevention:In 2014, 456 out of every 100,000 people in the U.S. became infected with chlamydia. Almost 1.5 million new cases were reported over the course of the yearPrior to the introduction of the HPV vaccine, a national survey found that 42.5 percent of women between the ages of 15 and 59 were infected with HPV. Some estimates have suggested that as many as 80 percent of sexually active adults will be infected with HPV at some point during their lives. If young people were consistently vaccinated, that number could decrease a lot. Data from 2007 to 2010 found that 49.9 percent of 14 to 49-year-old Black females and 15.2 percent of White females were infected with HSV-2. In 2011, scientists estimated that 14 percent of HIV-positive individuals in the U.S. did not know that they were infected. Universal HIV testing is a goal, but it's far from a reality. Could I Get an STD?If you're sexually active, you're at least at some risk of getting an STD. The only time when that is not true is if you're in a mutually monogamous relationship in which both people have tested negative. Furthermore, even that isn't perfect. There are some STDs that doctors can't, or don't, test for. Not all sex is equally risky. Anal intercourse is generally considered the riskiest. That's followed by vaginal intercourse and oral sex. Fingering and fisting also pose some risks as does the use of sex toys, potentially. Fortunately, all of these activities can be made safer by consistently and correctly practicing safe sex. Not all partners are equally at risk either. List What to Expect After an STI Article Some STDs Can Cause Infertility. Learn More About Which Ones. However, there's no simple way to determine a person's level of risk by looking at them. Risk is based far more on geography, history, and behavior than age, race, sexual orientation, or gender. That's one of the many reasons it's a good idea to sit down and talk with your partner before having sex. Top 5 Things to Know About STDsThere are a lot of different STDs. Each one is different. So is each person's STD risk. However, there are five things I think everyone should know about STDs:Many STDs have no symptoms. The vast majority of people with STDs have no symptoms. That doesn't mean that they can't pass their infection to a partner. And it doesn't mean that the STD isn't potentially causing long-term damage. It just means... The only way to know if you have an STD is to get tested. It's impossible to diagnose most STDs by looking at yourself even if you do have symptoms. That's why regular STD screening is so important for anyone having sex outside of a mutually monogamous relationship. Barrier methods are really effective. Having safe sex isn't a guarantee you won't get or give an STD. However, consistently using appropriate barriers greatly reduces the odds. You just have to make a point of using them all the time. You can't just use them for intercourse because... Oral sex can easily pass on certain STDs. For example, it's thought that a growing number of genital herpes cases are caused by unprotected oral sex. Unprotected fellatio is also linked to the rise of syphilis among men who have sex with men. The stigma is worse than the reality. People are often terrified that others will judge them for having an STD. Many are so afraid that they'll refuse even a free STD test. The thing is, most of the time it's a lot easier to find out your status and deal with the consequences than to spend a lot of time worrying about"what if?" If You Think You Might Have an STDThere are several common reasons that people think they might have an STD:They may have symptoms, such as genital itching, that they assume are STD related. Article Not All Warts Caused by HPV Are Genital Warts Article The Incubation Period of Common STDs They may have learned that a current or former sexual partner has been diagnosed.They may have engaged in unprotected sex and become worried about the risks.Fortunately, the steps you should take are similar no matter why you're worried. First things first—find out whether or not you're right.Think you might have an STD? This is what you should do. A brief guide to asking your doctor for an STD test.How long to wait before an STD test will be accurate.If You've Recently Been Diagnosed With an STDFinding out that you have an STD can be pretty stressful. That's why my main advice is DON'T PANIC. Take a deep breath and get some information. Learn what treatments are recommended for your condition. Figure out how you can protect yourself and your partner(s) from any serious consequences. Get to a place where you feel comfortable talking about what's going on. Then, talk to your partner(s)Sitting down with a partner after an STD diagnosis isn't an easy thing to do. Many people want to either lie or place blame. Unfortunately, neither of these things are helpful. What you want to do is have a discussion about what you know, what you don't know, and what you want to do.If you've been diagnosed, any current partners should be tested. They should also be treated if doing so is relevant. You might also talk to recent partners who you might have exposed or who might have exposed you. Things you might want to consider include:Whether you want to or need to take a break from sex during the testing and/or treatment period.If you want to change your safer sex practices.Whether suppressive therapy or other forms of treatment could help reduce the risk of passing on your condition to each other or other partners.What you don't want to do is assume you've been lied to. There is a tendency to blame the person who most likely infected you for knowingly putting you at risk. However, they may have neither known their status nor how to discuss it.That's another reason I always suggest people get tested and talk about results before they have sex. Someone may have no idea that doctors don't screen everyone for STDs. They may assume they'd know if they were at risk. A Word From VerywellPeople are often terrified of an STD diagnosis. In fact, they may be so afraid of being told they have an STD that they avoid doctors and testing like the plague. The truth is, however, that STDs aren't the end of the world. They're something that you can live with. They're also incredibly common.Do you want to get an STD? Probably not, if you can avoid it. That's why I encourage everyone to regularly practice safe sex. Still, if you do end up with an STD diagnosis, don't fret. You can still have a happy and healthy life.Although some people may be prejudiced against those with STDs, that's not everyone. Education about STDs can open minds and open hearts. After all, having an STD isn't that much different than having any other medical problem. It's just that the association with sex makes it a lot harder to talk about. Sources:Bernstein DI, Bellamy AR, Hook EW 3rd, Levin MJ, Wald A, Ewell MG, Wolff PA, Deal CD, Heineman TC, Dubin G, Belshe RB. Epidemiology, clinical presentation, and antibody response to primary infection with herpes simplex virus type 1 and type 2 in young women. Clin Infect Dis. 2013 Feb;56(3):344-51. doi: 10.1093/cid/cis891. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2014. Atlanta: U.S. Department of Health and Human Services; 2015.Champenois K, Cousien A, Ndiaye B, Soukouna Y, Baclet V, Alcaraz I, Choisy P, Chaud P, Velter A, Gallay A, Yazdanpanah Y. Risk factors for syphilis infection in men who have sex with men: Results of a case-control study in Lille, France. Sex Transm Infect. 2013 Mar;89(2):128-32. doi: 10.1136/sextrans-2012-050523.Hall HI, An Q, Tang T, Song R, Chen M, Green T, Kang J; Centers for Disease Control and Prevention (CDC). Prevalence of Diagnosed and Undiagnosed HIV Infection—United States, 2008-2012. MMWR Morb Mortal Wkly Rep. 2015 Jun 26;64(24):657-62.