5 Most Common Sexually Transmitted Infections (STIs): What You Should Know

For what were formerly called sexually transmitted diseases (STDs) or venereal diseases (VD), the correct term is now sexually transmitted infections (STIs). They develop due to bacteria, viruses, or parasites passing from person to person during sexual contact with the penis, vagina, anus, or mouth, or contact with any of the membranes that line the urinary or genital tracts. It’s important for all sexually active individuals to be aware of the various types of STIs, particularly the most common infections spread among the general population.

The symptoms of STIs vary between individuals, even for the same disease, and many people have no symptoms. Moreover, the consequences of contracting an STI can be great. Some STIs increase the risk of getting and transmitting HIV/AIDS and affect the progression of the disease. STIs can cause long-term health problems, especially in women and infants. Some of these health problems include pelvic inflammatory disease (PID), infertility, ectopic pregnancy, cervical cancer, and perinatal or congenital infections in infants.

StudyFinds takes a look at the five most common types of sexually transmitted infections. Better awareness and understanding of these STIs can certainly help to prevent the spread of these conditions.

1. Human Papillomavirus (HPV)

HPV is the most common STI. There are more than 40 HPV types. All of them can infect both men and women. The types vary in their ability to cause genital warts. They can also infect other regions of the body, including the mouth and throat. Infection can progress to cancers of the cervix, vulva, penis, anus, and mouth. 

There is no cure for HPV, but the disease is preventable with vaccines and controllable with medication. Genital warts due to the virus are also treatable. Regular screening with a Pap smear test can prevent or detect most cases of cervical cancer resulting from HPV at an early stage. 

Two available vaccines protect against most (but not all) HPV types that cause cervical cancer. The Centers for Disease Control and Prevention (CDC) recommends the vaccine for both boys and girls at 11 or 12 years of age.

Dr. Maryam Dadar and a research team at Razi Vaccine and Serum Research Institute in Iran are making important progress in immunotherapy, biotechnology, recombinant DNA technology, and the molecular biology of HPV. They have developed alternative medicinal systems, which are providing opportunities to develop more effective vaccines, drugs, and treatment approaches to fight the virus.

2. Chlamydia

Chlamydia is caused by the bacterium Chlamydia trachomatis. It is transmitted during vaginal, oral, or anal sexual contact with an infected person. Many people infected with chlamydia will have no symptoms, but it can cause fever, abdominal pain, and discharge from the penis or vagina. It is treatable with antibiotics.

In women, if the infection is left untreated, it can cause pelvic inflammatory disease throughout the female genital tract. This can lead to debilitating chronic pelvic pain and permanent impairment of fertility.

The infection is also transmittable to the fetus during pregnancy or to the infant during delivery, causing eye infections or pneumonia. At birth, healthcare professionals routinely apply antibiotic ointment to a baby’s eyes to treat undetected chlamydia.

Chlamydia and gonorrhea often occur together, so a healthcare provider will often treat for both when they detect either one. To prevent sexual transmission, prompt treatment is necessary for everyone testing positive for infection. That individual’s recent sexual contacts should also go for testing promptly to prevent reinfection. Infected individuals should follow their healthcare provider’s instructions about how long to abstain from sex after treatment, to avoid passing the infection back and forth. 

3. Gonorrhea

Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. It thrives in the warm, moist areas of the reproductive tract. The most common symptoms are discharge from the vagina or penis and painful urination. However, it is treatable with antibiotics.

A study finds that an investigational oral antibiotic called zoliflodacin is well-tolerated by patients and successfully cured most cases of uncomplicated gonorrhea during tests in a multicenter clinical trial, published in the New England Journal of Medicine. 

Like chlamydia, untreated gonorrhea can cause pelvic inflammatory disease, leading to chronic pelvic pain and permanent damage to a woman’s reproductive tract and infertility. It is also transmittable to the fetus during pregnancy.

In both men and women, gonorrhea can infect the mouth, throat, eyes, and rectum — spreading throughout the bloodstream and becoming a life-threatening illness. Gonorrhea and chlamydia often occur together. People who have one infection typically receive treatment for both simultaneously. Recent sexual partners should undergo testing at the same time as the patient.

People with gonorrhea are more prone to contract HIV, the virus that causes AIDS. HIV-infected people with gonorrhea are also more likely to transmit the virus to someone else. 

4. Genital Herpes

Genital herpes is caused by the herpes simplex virus (HSV). There are two different strains of HSV which cause genital infections: HSV type 1 (HSV-1) and type 2 (HSV-2). Most cases of genital herpes are the result of an HSV-2 infection.

HSV-1 lesions are usually blisters or cold sores on the lips, but this strain can also infect the genital region through oral-genital or genital-genital contact. Symptoms of HSV-2 are typically painful, watery skin blisters on or around the genitals or anus. Many people who carry these viruses, however, have no or minimal signs or symptoms.

This is currently no cure for herpes, but it is controllable using medication. Patients can take these drugs daily to make it less likely that the infection will pass on to sex partner(s) or to infants during childbirth. Some people will periodically experience outbreaks of new blisters in the genital area, which are highly contagious to other people.

If a pregnant woman has lesions when she goes into labor, she needs a cesarean section (C-section) to prevent the infant from getting the virus during birth. Neonatal HSV infection can be life-threatening, affecting the infant’s skin, brain, and other organs. 

5. Syphilis

Syphilis is caused by the bacterium Treponema pallidum. It passes from person to person during vaginal, anal, or oral sex through direct contact with syphilis sores.

In 2001, the number of cases of syphilis was at its lowest in 60 years. Since then, the number of cases has increased nearly every year up to 2016, the most recent year for which data is available. The number of infections is still climbing among both men and women, but men account for most cases.

The first sign of syphilis is a chancre — a painless genital sore that most often appears on the penis or in and around the vagina. Chancres typically heal on their own, but the infection does not clear from the body on its own.

Having the sores makes a person two to five times more likely to contract an HIV infection. If the person already has HIV, chancres also increase the likelihood that the HIV virus can pass to a sexual partner.

Syphilis is treatable with antibiotics. In the early stages, within the first year of infection, a single injection of an antibiotic will cure the disease. If not recognized or treated early, however, longer treatment with antibiotics may be necessary.

Without treatment, the disease spreads to other parts of the body, including the skin, heart, blood vessels, liver, bones, and joints – a condition called secondary syphilis. Other sores, such as a syphilis rash, can break out in later stages. Without treatment over years, the disease will progress to tertiary syphilis. It will involve the nerves, eyes, and brain, potentially causing death.

Pregnant women with syphilis, especially if untreated, are at greater risk of miscarriage and stillbirth. Syphilis can pass to the fetus during pregnancy, causing deformed bones, an extremely low red blood cell count (severe anemia), enlarged liver and spleen, jaundice (yellowing of the skin or eyes), nerve problems, blindness or deafness, meningitis, and skin rashes. 

Individuals being treated for syphilis must avoid sexual contact until the chancres completely heal or they can infect other people. People with syphilis should notify their sex partners so they can take an STI test and receive treatment if necessary.

YouTube video

Follow on Google News

About the Author

Dr. Faith Coleman

Dr. Coleman is a graduate of the University of New Mexico School of Medicine and holds a BA in journalism from UNM. She completed her family practice residency at Wm. Beaumont Hospital, Troy and Royal Oak, MI, consistently ranked among the United States Top 100 Hospitals by US News and World Report. Dr. Coleman writes on health, medicine, family, and parenting for online information services and educational materials for health care providers.

The contents of this website do not constitute advice and are provided for informational purposes only. See our full disclaimer