Once established, the infection may progress into a disease (an STD).
Handsfield notes that this undercuts the rationale for using the term STI.
However, research into whether this is a significant effect is mixed.

Illustration by Michela Buttignol for Verywell Health
Non-sexual activities in which bodily fluids are exchanged can also transmit STIs.
For example, people who share needles can infect each other with thehuman immunodeficiency virus(HIV).
STDs are diseases that result from STIs.
When these pathogens disrupt normal body functions, they produce diseases.
It’s important to note that some STIs may never develop into diseases.
For example, mosthuman papillomavirus(HPV) cases go away on their own without causing health problems.
However, HPV can producegenital wartsorcervical cancer, which are diseases.
Once symptoms are noticeable, the STI has produced a disease.
Some may be similar to the above while others can be different and, sometimes, more serious.
These include:
Some people may mistake symptoms of an STD for aurinary tractoryeast infection.
If you’re uncertain about the cause of your symptoms, consult a healthcare provider.
These tests include:
How Common Are STIs?
How Do I Prevent an STI?
Prevention is the best way to prevent an STI.
Protective devices likecondomsanddental damscan significantly reduce the risk of spreading an STI.
There are also vaccines for certain infections, specificallyHPVand thehepatitis B virus.
Summary
The terms STI and STD are often used interchangeably, including by most health authorities.
Distinctions between the two terms are made by some who believe STI may carry less stigma.
A sexually transmitted infection (STI) is primarily spread through sexual contact.
STIs may be sparked by bacteria, viruses, or parasites.
An STI may or may not produce symptoms and develop into a sexually transmitted disease (STD).
STD symptoms vary depending on the punch in of infection.
There are several tests a healthcare provider can use to determine the bang out of STI you have.
Antibiotics may be used to treat and cure bacterial STIs.
Viral infections may be managed with antivirals or antiretrovirals but are not usually curable.
Do not venture to self-diagnose or treat yourself for an STI or STD by using medication without a prescription.
However, most results are returned within one to three days for blood, urine, or saliva tests.
STD testing is often, but not always, covered by insurance.
If your insurance does not cover it, testing is usually available at a low-cost or free STD clinic.
An STI or STD can lead to serious pregnancy complications, including miscarriage, stillbirth, and birth defects.
Therefore, it is important to get regular STI or STD testing early in pregnancy until close to delivery.
The National Institute of Allergy and Infectious Diseases.Sexually transmitted infections.
Rietmeijer CA.You say STD….Sex Transm Dis.
2015;42(4):169. doi:10.1097/OLQ.0000000000000251
Handsfield HH, Rietmeijer CA.STI versus STD: coda.Sex Transm Dis.
2018;30(1):137-143. doi:10.1097/MOP.0000000000000578
World Health Organization.Sexually transmitted infections (STIs).
Office on Women’s Health.Sexually transmitted infections.
Centers for Disease Control and Prevention.Sexually transmitted infections prevalence, incidence, and cost estimates in the United States.