This document discusses sexually transmitted infections (STIs). It begins by defining STIs as infections that can be transmitted through sexual activity, noting they may be caused by bacteria, viruses, fungi or other organisms. It then provides details on specific STIs like chlamydia, gonorrhea, herpes, HIV/AIDS, and HPV. For each STI, it discusses the causative agent, prevalence, transmission, symptoms, potential complications if left untreated, diagnosis, and treatment. The document aims to educate about common STIs by providing an in-depth overview of infectious agents, transmission, clinical presentation, and management.

1. “Sexually Transmitted
Infections”
DR. HANY LOTFY
ASS. PROFESSOR OF MEDICAL MICROBIOLOGY
AND IMMUNOLOGY
SULAIMAN AL RAJHI COLLEGES
2018

2. STIs
 Infections that can be transmitted through sexual
activity.
 May be caused by a bacteria, virus, fungus, or other
organisms.
 Some are curable, some are not.
 If left untreated, STIs can cause pain, sickness,
infertility, birth defects, and sometimes, death.
 STIs are very common.

3. Incidence of STIs
 ~ 1/2 of the STIs diagnosed annually in the US occur among
people under 25 years.
 ~ 19,000,000 new cases each year in US.
 ~ 3 million teenagers are infected with STIs each year.
 25% of U.S. population acquired single STI by the age 35.

4. Factors contributing to high rates of STIs
1. Multiple sexual partners and unprotected sex.
2. Use of oral contraceptives.
3. Limited access to health care.
4. Practitioners do not ask questions about patients’
sexual behaviors.
5. Some diseases have no obvious symptoms.
6. Difficulty talking to partner.

5. I. Bacterial infections
1. Chlamydia.
2. Gonorrhea.
3. Non-gonococcal urethritis (NGU).
4. Syphilis.

6. 1. Chlamydia
Caused by:
◦ Chlamydia trachomatis that infects the urogenital system.
Prevalence:
◦ The most common bacterial STI in the US (3-4 million new cases
/ year).
Transmission:
◦ Primarily penile-vaginal, oral-genital, oral-anal, or genital-anal
contact; can also be spread by fingers from one body site to
another.
Symptoms:
◦ In majority of cases, none.
◦ Women: mild irritation or itching, burning urination, slight
vaginal discharge.
◦ Men: urethral discharge, burning urination.

7. Women: Pelvic Inflammatory Disease (PID)
◦ Bacterial infection spreads from cervix → fallopian tubes →
ovaries.
◦ Symptoms: Disrupted menstruation, chronic pelvic and back pain,
fever, nausea, vomiting, and headache.
◦ Even after treatment, scar tissue from PID can block fallopian
tubes and cause infertility or ectopic pregnancy .
Men: Epididymitis or urethritis
◦ Symptoms of epididymitis: heaviness in testis; small, hard, painful
swelling in testis.
◦ Symptoms of urethritis: penile discharge, burning urination.
Consequences if left untreated:

8. Trachoma:
◦ A chronic form of conjunctivitis caused by chlamydia infection.
◦ World’s leading cause of preventable blindness.
◦ Newborns can become infected as they pass through birth canal.
Consequences for babies born to infected mothers:
◦ Babies of infected mothers can also develop pneumonia.
◦ Chlamydia infection can lead to premature delivery.

9. 9
Diagnosis:
 Serology:
◦ Direct immunofluorescence assays (DFA).
◦ Enzyme immunoassay (EIA).
 Chlamydia culture.

10. Treatment:
 7-day treatment of doxycycline.
 OR one dose of azithromycin.
 All exposed sexual partners should be treated.

11. 2. Gonorrhea
Caused by: Neisseria gonorrheae.
Prevalence:
◦ ~700,000 new cases / year in US.
Transmission:
◦ Penile-vaginal, oral-genital, oral-anal, or genital-
anal contact.
Symptoms:
◦ Male early symptoms:
◦ Cloudy penile discharge,
◦ Burning urination.
◦ Symptoms may clear up, but does not necessarily
mean bacteria are gone.
◦ Female early symptoms:
◦ Usually go undetected.
◦ Inflamed cervix, mild discharge.
◦ Burning urination.

12. Consequences if left untreated:
Men:
◦ Prostatitis, epididymitis.
◦ Possible sterility due to scar tissue in epididymis after
epididymitis
Women:
◦ PID (often more severe than Chlamydial infection),
◦ Ectopic pregnancy.
Both sexes:
◦ Can spread throughout body in ~2% of cases, causing fever,
loss of appetite, arthritic pain, can invade heart, liver, CNS
◦ Blindness in infants.

13. 13
Diagnosis
 Clinical exam.
 Gram stain: Pus cells with Gram negative intracellular
diplococci.
 Cervical culture.
 Polymerase chain reaction (PCR).

14. Treatment:
 Dual therapy of two antibiotic regimens.
 Often, Chlamydia accompanies gonorrhea infection, dual
therapy will treat both infections.
 All exposed sexual partners should be treated.

15. 3. Non-Gonococcal Urethritis
= Any urethral inflammation not caused by gonorrhea
Main infecting organisms:
1. Chlamydia trachomatis.
2. Mycoplasma.
3. From other infectious agents, allergic reactions to vaginal secretions.
4. Irritation from soaps, contraceptives, or deodorant sprays.
Prevalence:
◦ Quite common in men.
◦ Symptoms in women are usually undetected.
Symptoms:
◦ Men: penile discharge, burning urination.
◦ Women: Mild itching, burning urination, vaginal discharge of pus.

16. 4. Syphilis
Caused by: Treponema pallidium.
Prevalence:
◦ ~700,000 new cases / year in US.
Transmission:
◦ Penile-vaginal, oral-genital, oral-anal, or
genital-anal contact
Symptoms:
1. Primary syphilis:
◦ Single, painless sore (chancre)
◦ Women: on inner vaginal walls or cervix,
sometimes on labia
◦ Men: glans of penis, shaft, or scrotum
◦ Can also occur on lips or tongue (orally) or in
rectum/anus (through anal intercourse)
Glans of penis

17. 2. Secondary syphilis:
◦ Skin rash.
◦ Often on palms, soles.
◦ Does not itch.
◦ Person may feel flu-like symptoms
◦ If not treated, symptoms will subside, but disease is not
eliminated.
3. Latent syphilis:
◦ No symptoms; no longer contagious after 1 year of
latent stage (except pregnant woman to fetus--at
all stages).
4. Tertiary syphilis:
◦ Severe symptoms anywhere--such as heart failure,
blindness, paralysis, liver damage, mental
disturbance, death.

18. 18
Diagnosis
Requires demonstration of:
1. Organisms on microscopy using dark field
2. Positive serology on blood or cerebrospinal fluid (CSF)
◦ Non-specific (Non-treponemal) tests:
a) Venereal Disease Research Laboratory (VDRL).
b) Rapid Plasma Reagin (RPR).

19. 19
◦ Specific (Treponemal) Test:
a) Fluorescent Treponemal Antibody (FTA)
b) Treponema pallidum Haemagglutination (TPHA)
c) Treponema pallidum Immobilization (TPI)
Organism may not be cultured but diagnosis cannot be
determined by clinical findings only

20. Treatment:
 Penicillin.
 All exposed sexual partners should be treated.
 Treated patients need blood tests at 3-month intervals
to make sure they are free of bacterium.

21. II. Viral infections
1. Herpes Simplex Virus (HSV-II).
2. Human papillomavirus (HPV).
3. Hepatitis B virus.
4. Human immunodeficiency virus (HIV).

22. 1. Herpes Simplex
Caused by: Herpes simplex virus (HSV):
◦ Two sexually transmitted types: HSV-1 and HSV-2
◦ HSV-1 is usually oral herpes (cold sores), but can infect genitals.
◦ HSV-2 usually causes genital lesions, but can also infect the mouth
Prevalence:
◦ >100 million Americans have oral herpes.
◦ > 45 million Americans (20-25%) have genital herpes.
Transmission:
◦ Genital herpes: penile-vaginal, oral-genital, oral-anal, or genital-anal
contact.
◦ Oral herpes: through kissing, or oral-genital contact.
◦ Herpes sores are highly contagious, need to avoid contact between
lesions and someone else’s body.
◦ Can still transmit herpes even if no lesions are present.

23. Recurrence:
◦ After lesions heal, virus enters up nerve fibers and stays latent in
nerve cells in the spinal column.
◦ Flare-ups occur when virus moves back down along fibers to
genitals or lips.
◦ Triggered by wide variety of factors, such as stress, anxiety,
depression, acidic food, UV light, fever, poor nutrition, fatigue…
◦ Symptoms during recurrent attacks tend to be milder than primary
episode, heal more quickly.

24. Complications:
Women:
◦ Increased incidence of cervical cancer (women with herpes
should get Pap smears every 6-12 months).
◦ Newborn baby can be infected by passage through birth canal →
can cause severe damage or death.
Both sexes:
◦ Ocular herpes infection can occur if virus is transferred from a
sore to the eye.
◦ Must be treated quickly to avoid eye damage.

25. Diagnosis:
1. Clinical presentation
2. Viral culture
3. Giemsa smear
4. Skin biopsy

26. Treatment:
Antiviral drugs which reduce viral shedding and the
duration and severity of outbreaks:
◦ Acyclovir (Zovirax®).
◦ Valacyclovir (Valtrex®).
◦ Famiclovir (Famvir®).

27. 2. Genital warts
Caused by: Human papilloma virus (HPV)
◦ There are over 100 strains, ~1/2 cause genital infections
Transmission:
◦ Penile-vaginal, oral-genital, oral-anal, or genital-anal contact
◦ Condoms do provide some protection, but don’t prevent
transmission of viral infections on vulva, base of penis, scrotum,
and other genital areas not covered by condoms.
◦ HPV is most commonly transmitted by people who are
asymptomatic.

28. Symptoms:
◦ Most people don’t develop symptoms and are
unaware that they are infected.
◦ In women, genital warts usually appear on lower
vaginal opening, perineum, labia, inner vaginal
walls and cervix.
◦ In men, usually on glans, or shaft of penis.
◦ Both sexes: can also occur on anus. In moist areas,
appear pink or red and soft, with cauliflower-like
appearance; in dry areas, appear hard and yellow-
gray

29. Consequences:
 Certain strains of HPV are associated with cancers of the
cervix, vagina, vulva, urethra, penis and anus.
 HPV infections account for 85-90% of risk for development
of cervical cancer.
 Risk of HPV-induced cervical cancer is minimal if regular
Pap testing and treatment of precancerous lesions is done.
 Pregnant women that are + for HPV can transmit the virus
to their babies during birth.

30. Treatment:
 Visible genital warts are removed by either cryotherapy (freezing)
or chemical treatment.
 Larger warts may require minor surgery to remove.
Prevention via vaccine:
 Gardasil: vaccine against 4 strains of HPV (6, 11, 16, and 18) that
together cause 70% of cervical cancers and 90% of genital warts.
 Most health officials believe vaccination before puberty is best,
before teens become sexually active.

32. 4. Hepatitis B (HBV)
Hepatitis B can cause liver damage and is considered the most
general and severe liver disease worldwide.
Transmission:
 Sexual contact *
 Sharing needles
 Mother-to-child

33. Symptoms:
Jaundice.
Fatigue.
Abdominal and joint pain.
Nausea.
Loss of appetite.
About 30% of persons have no signs or symptoms.

34. If left untreated …
 Transmission to sex partners and newborns.
 Cirrhosis.
 Liver failure.
 Liver cancer can develop.

35. Treatment:
• HBsAg.
• High risk people (HCWs, injection drug users, sexually active
people w/multiple sex partners, etc.) should be immunized.
• CDC recommends that children be immunized for HepB
• 3 injections given over 5-6 months.
• Medications slow down the virus
and reduce liver damage.
• In some cases, they may even rid of
the virus completely.
Prevention:

36. 5. Acquired immunodeficiency
syndrome (AIDS)
Caused by:
 Human immunodeficiency virus
(HIV).
 HIV-1, and HIV-2.
 HIV-1 is more virulent and causes
most cases in US.
 HIV-2 exists along with HIV-1 in
some African countries.

37. HIV = a retrovirus that
Targets & destroys helper T cells (CD4 T cells).
◦ T cells play a very important role in the immune system.
◦ Therefore, HIV infection leaves the body vulnerable to a variety of
opportunistic infections and cancers.
HIV becomes AIDS when:
◦ HIV is present, and CD4 T-cell count is <200 cells/microliter of
blood (normal: 600 - 1,200 cells/microliter)
CD4 T cell under
attack by HIV

38.  Estimated ~1.9 million people currently HIV+, and ~25 -50%
of these people are unaware of their HIV status.
 Overall rate of new HIV infections in US has slowed, but
number of new infections among teenagers, and women
continues to rise.

39. Women are more easily infected from heterosexual
intercourse with HIV+ partner than men are:
◦ Semen contains higher concentration of HIV than vaginal fluids.
◦ Female mucosal surface is exposed to HIV in ejaculate longer than a
man’s penis is exposed to HIV in vaginal secretions.
◦ Larger area of mucosal surface is exposed in vagina/on vulva than on
the penis.
◦ Female mucosal surface is exposed to greater potential trauma than
the penis and can cause small tears that allow virus to enter.
◦ Some women have unprotected receptive anal intercourse--the
single-most risky behavior in terms of HIV infection for both men and
women.
◦ Adolescent women are more vulnerable to HIV infection because
their reproductive tracts are immature--more susceptible to
infection.

40. Global HIV/AIDS, 2016
 19.5 million people were accessing antiretroviral therapy in 2016.
 36.7 million people globally were living with HIV in 2016.
 1.8 million people became newly infected with HIV in 2016.
 1 million people died from AIDS-related illnesses in 2016.
 76 million people have become infected with HIV since the start of the
epidemic.
 35 million people have died from AIDS-related illnesses since the start
of the epidemic.
 AIDS-related deaths have fallen by 48% since the peak in 2005.
 http://www.unaids.org/en/resources/fact-sheet

42. AIDS in Africa
AIDS has reached epidemic proportions in sub-Saharan Africa;
>15% of all adults are HIV+
◦ Over 80% of AIDS deaths have occurred in Africa.
◦ 75% of HIV infections in African youth are of females.
Factors contributing:
◦ Poverty, lack of medical care and ignorance about HIV prevention.
◦ Cultural factors.
◦ General feeling of hopelessness.

44. AIDS: Transmission
HIV in bodily fluids:
◦ Blood, semen, vaginal secretions, breast milk.
◦ NOTE: Saliva, urine, tears--concentration of virus (if any) way too low to
transmit infection.
Can be transmitted:
◦ Through vaginal or anal intercourse or oral-genital contact.
◦ Through contaminated blood (needles, blood transfusion).
◦ From mother to fetus before birth, infant during birth or after through
breastfeeding.
Likelihood of transmission during sexual contact:
◦ Depends on infected person’s viral load (virus particles /ml of blood).
◦ Is greater when HIV is transmitted directly into blood, (through small
tears in rectal tissues or vaginal walls).

45. HIV/AIDS: symptoms & complications
Within few weeks of infection, can cause flu-like
symptoms in some people.
As virus depletes immune system:
◦ Persistent or periodically repeating fevers, night
sweats, weight loss.
◦ Opportunistic infections:
◦ Oral candidiasis.
◦ Life-threatening pneumonia caused by Pneumocystis jirovecii,
which normally inhabits lungs of healthy people.
◦ Others: TB, encephalitis, toxoplasmosis.
◦ Cancers: lymphomas, Kaposi’s sarcoma.
Time from HIV infection to onset of AIDS
typically ranges from 8 - 11 yrs; new treatments can
dramatically slow progression of HIV to AIDS.

46. Treatment
HIV treatment drugs inhibit two major viral enzymes
1) Reverse transcriptase
◦ Enzyme that converts HIV RNA genome into DNA, so it can insert
into our own DNA.
2) Protease
◦ New HIV proteins are produced in the form of long chains that
need to be cut into smaller pieces to assemble into new HIV
viruses.
◦ Protease enzyme is the “scissors” for this process.

47. The search for a vaccine
Several attempts have been made to develop a vaccine
against HIV--so far, with disappointing results.
Many challenges confront vaccine researchers:
◦ Absence of ideal animal model for research.
◦ HIV is a very complicated virus with multiple strains.
◦ HIV can change rapidly through genetic mutation.

48. III. Protozoa (Trichomoniasis)
Common in women and men.
Primarily spread through sexual contact.
Symptoms (women):
◦ White or yellow-green discharge, frothy, with unpleasant odor.
◦ Irritated vaginal and vulval tissues.
◦ If untreated, can damage cervical cells, may lead to cervical cancer; in
pregnant women, can lead to premature rupture of amniotic sac and
preterm delivery.
Symptoms (men):
◦ Usually none, may have frequent or painful urination or slight urethral
discharge.
Treatment: metronidazole (Flagyl).
◦ All sexual partners should be treated.

49. 49
 Flagellated, motile trichomonads on wet mount
 Vaginal pH > 4.5
 Diagnosis confirmed by microscopy
 Other FDA approved tests:
◦ OSOM Trichomonas Rapid Test.
◦ Affirm VP III.
Diagnosis

50. IV. Ecto-parasitic infections
Ectoparasites: parasitic organisms that live on the
outer skin surfaces
2 common STIs caused by ectoparasites:
1) Pubic lice.
2) Scabies.

51. 1. Pubic lice
Caused by: biting louse called Phthirius pubis.
Prevalence: more prevalent among young (15-25 years) single people,
often associated with presence of other STIs.
Transmission: during sexual contact when two people bring their
pubic areas together.
◦ Lice can live away from the body for as long as 1 day, can drop off onto
underclothes, bedsheets, etc, and eggs deposited by female louse can survive for
several days
◦ Therefore, it is possible to get pubic lice by sleeping in someone’s bed or wearing
someone’s clothes

52. Symptoms:
◦ Itching (that’s not relieved by scratching)
◦ Can also leave bluish-grayish marks on the
thighs and pubic area from bites.
◦ Self-diagnosis is possible by locating a louse
on a pubic hair.
Treatment:
◦ medicinal lotion (1% permethrin or pyrethrin)
applied to all affected areas + ALL areas with
hair (genitals, axilla, scalp, even eyebrows).
◦ Boil all clothes and bedding that were
exposed.

53. 2. Scabies
Caused by: parasitic mite called Sarcoptes scabiei
◦ Female mite burrows beneath skin to lay eggs.
◦ The hatched egg grows into adult that on host’s skin.
◦ Too small to be seen by naked eye.
Prevalence: not reported to health agencies—worldwide.
Transmission:
◦ By close physical contact, both sexual and nonsexual.
◦ Can be transferred on clothing or bedding (can live away from host for up to 3
days).
◦ In addition to sexually active people, school children, nursing home residents,
and indigent people are at risk.
Scabies mite

54. Symptoms:
◦ Small vesicles or pimple-like bumps, red rash.
◦ Intense itching.
◦ Favorite sites of infestation: webs and sides of fingers, wrists,
abdomen, genitals, buttocks, and female breasts.
Treatment:
◦ Medicinal lotion applied at bedtime, then washed off after 8 hrs.
◦ Wash all clothes and bedding that were exposed.

55. Preventing STIs
 Only sure-fire way is abstinence, or
monogamous relationship between 2 uninfected
people.
 Get tested for STIs, insist that your partner do
too
◦ May want to wait for results before engaging in sexual
activity that can put you at risk.
 Communicate with partners about safe sex:
◦ Get to know potential sexual partners well enough to
develop trust and communication.
◦ Inform a partner if you have an STI.
 Avoid sex w/multiple partners or w/individuals
at high risk for STIs.
 Use condoms or oral dams.
 If you use injected drugs, do not share needles.

56. Condoms
 Latex condoms are highly effective in preventing
transmission of HIV, Chlamydia, Gonorrhea, NGU, and
trichomoniasis.
 Condoms are less effective in preventing infections
transmitted by skin-to-skin contact, such as Syphilis,
Herpes, HPV, and are ineffective in preventing pubic
lice and scabies
 Condoms from sheep’s membrane contain small
pores that may permit passage of viruses (HIV, HSV,
hepatitis)
 Studies on couples where one partner is infected
show that with consistent condom use, HIV
transmission rates for the uninfected partner are
below 1% per year.
 CDC recommends against using condoms containing
nonoxynol-9 (N9), which can cause genital lesions
that create an entry point for HIV.

57. Proper use of condoms
Condoms must be used correctly every time!

58. Still Think You Are Not At Risk???

59. Proper use of condoms
1. Store condoms in a cool, dry place away from direct sunlight.
2. Throw away condoms past expiration date or condoms in
damaged packages.
3. Put on a condom before any genital contact occurs.
4. Be sure that the condom is adequately lubricated.
5. Unroll condom directly onto erect penis.
6. After ejaculation, hold base of condom before withdrawal so
condom does not slip off.
7. Note: rates of condom slippage and breakage are higher during anal intercourse than
vaginal intercourse, so be extra careful during anal penetration.