What is an STI? Causes, Symptoms, and How to Stay Protected

Duly Care
5 days ago
9 min read

Sexually transmitted infections (STIs) are an important but often misunderstood aspect of sexual health. They can impact anyone who is sexually active, yet stigma and misinformation often prevent open conversations about them. STIs, which include conditions like syphilis, HPV, HIV/AIDS, and herpes simplex, are caused by bacteria, viruses, or parasites and are primarily transmitted through sexual contact.

STI (sexually transmitted infection) refers to the presence of an infection, which may not show symptoms. STD (sexually transmitted disease) is used when the infection causes noticeable symptoms or complications. STI is the broader, more accurate term.

This guide explores the causes, signs, symptoms, and prevention strategies for STIs.

Key Takeaways

STI stands for sexually transmitted infections. They are infections transmitted through sexual activity, caused by bacteria, viruses, or parasites, and can affect anyone who is sexually active.
STIs are common but preventable. Understanding symptoms like unusual discharge or skin rashes can help with early detection.
Routine testing and protective measures, such as condoms, can significantly reduce risks.
Effective treatments are available for most STIs, emphasizing the importance of seeking timely medical care.

What are STIs?

Sexually transmitted infections (STIs) are infections caused by bacteria, viruses, or parasites that are primarily spread through sexual activity, including vaginal, oral, and anal sex. They are a common health concern affecting individuals of all ages and genders. Common examples of STIs include chlamydia, gonorrhea, syphilis, human papillomavirus (HPV), herpes simplex virus, and human immunodeficiency virus (HIV).

While sexual contact is the primary mode of transmission, some STIs, such as HIV and syphilis, can also be spread through non-sexual means, including sharing needles or from mother to child during childbirth or breastfeeding. Understanding what STIs are is essential for recognising their potential impact and taking steps toward prevention and early detection.

Causes of STIs: How They Spread and Develop

STIs are caused by various microorganisms, including bacteria, viruses, and parasites, each with unique transmission methods and characteristics. Understanding the causes can help demystify these infections and encourage preventive measures.

Bacteria

Bacterial STIs are caused by bacteria that thrive in the warm, moist environments of the genital, anal, and oral areas. These infections include:

Chlamydia - caused by Chlamydia trachomatis and spreads through vaginal, oral, or anal sex. It often remains asymptomatic, making regular screening vital.
Gonorrhea - caused by Neisseria gonorrhoeae, is highly contagious and can infect the genitals, throat, or rectum through sexual contact.
Syphilis - caused by an infection by Treponema pallidum and spreads through direct contact with syphilitic sores (chancres), typically during sexual activity.

Virus

Viruses are another major cause of STIs, often requiring lifelong management:

Human Papillomavirus (HPV) - spreads through skin-to-skin contact during sexual activity. It can cause genital warts and increase the risk of cancers like cervical cancer.
Herpes Simplex Virus (HSV-1 and HSV-2) - transmitted through kissing or sexual activity, causing painful sores or blisters.
Human Immunodeficiency Virus (HIV) - spreads through unprotected sex, sharing needles, or from mother to child. It attacks the immune system, leading to AIDS if untreated.
Hepatitis B and C - spread through sexual contact or infected blood, potentially causing severe liver damage.

Parasite

Parasites also contribute to STIs, with direct contact or shared items leading to infection:

Trichomoniasis - caused by the protozoan Trichomonas vaginalis and spreads through sexual contact, often presenting symptoms like itching, discomfort, or discharge.
Pubic Lice or crabs - are tiny parasites that live on coarse hair and spread through close physical contact or shared personal items like towels.
Scabies - caused by Sarcoptes scabiei, spreads through prolonged skin contact, including sexual activity, resulting in intense itching and rash.

Non-Sexual Transmission

Though less common, some STIs can spread without sexual activity:

Sharing needles can transmit infections like HIV, syphilis, and hepatitis B.
Mother-to-child transmission occurs when infections like HIV, syphilis, and gonorrhea are passed during childbirth or breastfeeding.
Blood transfusions or organ transplants, though rare, may spread STIs if donor material is not adequately screened.

Each type of STI has a unique cause and transmission pathway, highlighting the need for targeted prevention and treatment strategies.

Signs and Symptoms of STIs

Sexually transmitted infections (STIs) can manifest in various ways, ranging from mild discomfort to severe health complications. In some cases, they may show no symptoms at all, making regular testing crucial. Common signs to look out for include unusual discharge, persistent odours, sores, skin rashes, or pain during urination or sexual activity. These symptoms can vary depending on the specific infection and its cause.

If you are experiencing the following symptoms, it is a call for concern. These could possibly indicate a STI and require a medical intervention.

Unusual discharge that may be thick, coloured, or foul-smelling.
Pain or burning sensation during urination.
Itching or irritation in the genital area.
Skin changes, such as rashes, blisters, or warts.
Discomfort during sex.

Now let’s dive into the specific signs and symptoms associated with different types of STIs.

Bacterial Infections

Chlamydia is often called a "silent" infection, as most people experience no symptoms. When symptoms occur, they may include abnormal discharge or pain during urination.
Gonorrhea can cause thick green or yellow discharge, painful urination, and abdominal or pelvic pain in advanced cases.
Syphilis typically starts with a single painless sore at the site of infection, progressing to rashes and, if untreated, severe complications affecting the brain and other organs.

Viral Infections

HPV may lead to genital warts or, in some cases, show no visible symptoms but increase the risk of cervical and other cancers.
Herpes simplex virus causes clusters of painful blisters or sores around the mouth, genitals, or anus, often accompanied by flu-like symptoms during outbreaks.
HIV often starts with flu-like symptoms, such as fever, fatigue, and swollen lymph nodes, and progresses to a weakened immune system if left untreated.
Hepatitis B and C can manifest through jaundice, fatigue, nausea, and dark urine, often indicating liver damage.

Parasitic Infections

Trichomoniasis may present as frothy, yellow-green discharge with a strong odour, along with genital itching or discomfort during urination or intercourse.
Pubic lice cause intense itching and visible lice or eggs in coarse body hair.
Scabies leads to red, itchy rashes or small bumps that worsen at night due to mite activity under the skin.

Testing for STIs: What You Need to Know

Regular testing is vital for identifying and managing STIs. Here is a detailed overview of when and how to get tested:

When to Get Tested

Testing should be considered under the following circumstances:

If symptoms such as unusual discharge, pain, or sores develop.
Before starting a new sexual relationship.
After engaging in unprotected sex or if a partner is diagnosed with an STI.

Types of Tests

Different tests are used to detect STIs, depending on the infection type.

Blood tests detect viral infections like HIV, syphilis, and hepatitis B by identifying antibodies or the virus itself in the bloodstream.
Swab tests collect samples from specific areas such as the cervix, throat, or rectum to detect infections like gonorrhea, chlamydia, or herpes simplex.
Urine tests are effective for diagnosing bacterial infections like chlamydia and gonorrhea by analyzing a urine sample for the presence of bacteria or genetic material.

These tests help identify infections early, even in the absence of symptoms.

Treatment Options for STIs

Effective treatment for STIs is essential to prevent complications and reduce the risk of transmission. The approach to treatment varies based on the type of infection: