1.77. Sexually Transmitted Infections http://www.ck12.org
TABLE1.9:(continued)
Myth Fact
If you don’t have any symptoms, then you don’t have
an STI.Many STIs do not cause symptoms, especially in fe-
males.
Getting STIs is no big deal, because STIs can be cured
with medicine.Only some STIs can be cured with medicine; other STIs
cannot be cured.Most STIs are caused by bacteria or viruses. STIs caused by bacteria usually can be cured with drugs called
antibiotics. But antibiotics are not effective against viruses. Therefore, STIs caused by viruses are not treated
with antibiotics. Other drugs may be used to help control the symptoms of viral STIs, but they cannot be cured.
Once you have a viral STI, you are usually infected for life.
Bacterial STIs
In the U.S.,chlamydiais the most common STI caused by bacteria. Females are more likely than males to develop
the infection. Rates of chlamydia among U.S. females in 2006 are shown below (Figure1.141). Rates were much
higher in teens and young women than in other age groups.
Chlamydia may cause a burning feeling during urination. It may also cause a discharge (leaking of fluids) from the
vagina or penis. But in many cases it causes no symptoms. As a result, people do not know they are infected, so
they don’t go to the doctor for help. If chlamydia goes untreated, it may cause more serious problems in females. It
may cause infections of the uterus, fallopian tubes, or ovaries. These infections may leave a woman unable to have
children.
FIGURE 1.141
This graph shows data on the number
of cases of chlamydia in U.S. males and
females in 2009. Which two age groups
had the highest rates of chlamydia? Why
do you think rates were highest in these
age groups?Gonorrheais another common STI. Gonorrhea may cause pain during urination. It may also cause a discharge
from the vagina or penis. On the other hand, some people with gonorrhea have no symptoms. As a result, they don’t
seek treatment. Without treatment, gonorrhea may lead to infection of other reproductive organs. This can happen
in males as well as females.
Syphilisis a very serious STI. Luckily, it is less common than chlamydia or gonorrhea. Syphilis usually begins with
a small sore on the genitals. This is followed a few months later by a rash and flu-like symptoms. If syphilis is not
treated, it may damage the heart, brain, and other organs. It can even cause death.
Viral STIs
Genital warts are an STI caused by human papilloma virus, orHPV. They are one of the most common STIs in
teens. HPV infections cannot be cured. But a new vaccine called Gardasil® can prevent most HPV infections in