Why the CDC stopped saying STD and started saying STI

The two terms are not synonyms, and the difference explains the switch.

**The primary goal of public health and healthcare is to prevent and treat
infections before they develop into disease. As a result, many — including
CDC — are using the term STI more often.**

The older word named the failure case. Most of the work happens before that
point. (**STD is still used when referring to data or information from sources
that use the term**, so both appear.)

Which makes this the central fact

**Many STIs have no symptoms or may only cause mild symptoms, so people can
have an infection but not know it.**

If the disease is what you notice and the infection is what you have, then
waiting to notice something is not a strategy. **That is why getting an STI
test matters if you are having sex** — the test is the only way to find the
thing the definition says is silent.

And the news at the other end is better than people expect: **all are treatable
with medicine and some are curable entirely.**

The list

There are dozens of STIs. Spread mainly by sexual contact:

Bacterial vaginosis (BV) · Chlamydia · Genital herpes ·
Gonorrhoea · Human papillomavirus (HPV) · **Mycoplasma genitalium
(Mgen)** · Pelvic inflammatory disease (PID) · Syphilis ·
Trichomoniasis

Often transmitted sexually: chancroid, lymphogranuloma venereum (LGV),
pubic lice, scabies.

Sometimes but not always: HIV/AIDS and viral hepatitis.

Can be spread sexually, but usually are not: Zika and Ebola — worth
knowing precisely because they are not what anyone means by the term.

How they spread

Through vaginal, oral and anal sex. Also **through intimate physical
contact like heavy petting, though this is not very common.**

STIs are preventable. **Millions of new infections occur every year in the
United States** — which is the other reason the vocabulary is worth getting
right: this is not a rare category of illness.

Source: Centers for Disease Control and Prevention.