Sexually transmitted infections (STIs) usually pass from one person to another through sexual contact. Most are fairly common, and effective treatment is available — especially in the early stages.
Some STIs are benign, but others can lead to severe complications without treatment.
HIV has other routes of transmission. For example, this STI can spread through the use of unsterilized drug needles as well as sexual contact.
STIs can affect anyone, regardless of the individual’s sexual orientation or hygiene standards. Many STIs can spread through nonpenetrative sexual activity.
Most Common STDs
The herpes simplex virus (HSV) is a common virus that affects the skin, cervix, and genitals, as well as some other parts of the body.
HSV-1 usually affects the mouth. It can spread through saliva or if there is a herpes-related sore around another person’s mouth. It can pass to the genital area during oral sex.
HSV-2 can affect the genital area, the anal area, and the mouth. It transmits through vaginal, oral, and anal sex.
Herpes cannot spread via utensils, toilet seats, swimming pools, soaps, or bedding. However, if a person touches a body part where herpes is present and then touches another part of their body, herpes can spread to that area.
Once herpes is present, it stays in the body. It usually remains dormant, however, and many people will never develop symptoms.
The main symptoms are blisters around the mouth, anus, or genital area. These blisters can break, causing a painful sore that takes a week or longer to heal.
Some symptoms of initial infection include:
- body aches
- swollen lymph nodes
Some people never have symptoms, some have only an initial outbreak, and some have repeated outbreaks.
The first bout is usually the most severe, but people with compromised immune systems — due, for example, to HIV — have a higher risk of experiencing severe symptoms overall. Having herpes can also increase the chance of contracting or transmitting HIV.
A person might never know that they have the herpes virus, but it can still spread to others.
There is currently no cure, but medication can help relieve any symptoms. Daily antiviral medications can help prevent the spread of herpes.
Wearing a condom will not completely prevent the transmission of herpes.
Hepatitis B can cause a long-term infection and result in liver damage. Once a person has the virus, it can remain in their semen, blood, and other bodily fluids.
Transmission is possible through:
- engaging in sexual contact
- using nonsterile equipment for injections
- puncturing the skin with a sharp object where the virus is present
This infection can pass to a baby during pregnancy or delivery. However, a doctor can advise on ways to prevent this.
As long as the nipples are not cracked, the risk of transmitting the virus through breast milk is negligible, according to the Centers for Disease Control and Prevention (CDC).
People at high risk of contracting hepatitis B should ask their doctor about a vaccine, which can offer some protection. The vaccine may not provide long-term immunity, however, and the person may need booster doses for continued protection.
HIV is a virus that attacks the immune system. It can spread through sexual contact and some other means.
HIV makes a person more prone to certain other infections. People with HIV also have a higher risk of contracting other STIs. Without treatment, this susceptibility to infection worsens and may lead to life-threatening complications.
Once a person has HIV, the virus will be present in their bodily fluids, including semen, blood, breast milk, and vaginal and rectal fluids. If these fluids enter another person’s body, that person can also contract HIV.
This can happen through sexual contact, sharing needles, contact with broken skin, giving birth, and breastfeeding.
Treatment can reduce the amount of the virus present in the body to an undetectable level. This means that the amount of the virus within the blood is so small that blood tests cannot detect it. It also means that it cannot spread to other people.
A person with undetectable HIV must continue to follow their treatment plan exactly as the doctor prescribes to keep virus levels low.
Some other ways to prevent transmission include:
- using a condom or other barrier method of contraception during vaginal or anal sex
- not sharing needles
- using gloves and disposing of sharps carefully, such as when working in a healthcare setting
Scabies is a contagious skin condition that develops due to Sarcoptes scabiei, which is a mite. This condition can cause a pimple-like rash to appear anywhere on the body.
The first time a person has scabies, the symptoms may appear after 2–6 weeks of exposure. If they have scabies again, symptoms can appear 1–4 days after exposure. Scabies can spread before a person even knows that they have it.
Transmission usually occurs through skin-to-skin contact and due to sharing items such as towels and bedding.
A doctor can prescribe topical creams that kill the mites. While a person has scabies, they should avoid skin-to-skin contact with others. Once it has cleared up, they should decontaminate any personal items, including all bedding and clothes.
When to see a Doctor
Many STIs will not cause symptoms, so a person should not wait until symptoms appear before seeing a doctor.
Instead, people should seek medical advice if they think that they have had exposure to an STI.