STDs

1
STDs Etiology and Symptoms

• HPV
• Gonorrhea
• Genital Herpes
• Chlamydia
• Trichomoniasis
• Hepatitis B
• Syphilis
• AIDS

2
HPV

• Double-stranded DNA virus that belongs to the
  Papovaviridae family
• Small and non-enveloped virions
• Over 100 characterized types
• Genital types have specific tropism (affinity)
  for genital skin and mucosa.
• Very limited animal models and no widely
  available system for in vitro cultivation
• Infection is identified by the detection of HPV
  DNA or capsid protein. Types are distinguished by
  different DNA sequences (gt10 difference) at L1
  capsid (surface) protein.

3
HPV, contd

• Genital HPV types are generally characterized in
  terms of their oncogenic potential (ability to
  cause cervical cancer).
• Low-risk types
• Associated with genital warts and benign or
  low-grade cervical cell changes (mild Pap test
  abnormalities).
• Most visible genital warts are caused by HPV
  types 6 and 11.
• Recurrent respiratory papillomatosis, a rare
  condition, is usually associated with HPV types 6
  and 11.
• High-risk types
• Associated with low grade cervical cell changes,
  high-grade cervical cell changes that are
  precursors to cancer (moderate to severe Pap test
  abnormalities), and, in rare cases, anogenital
  (i.e., cervix, vulva, anus, and penis) cancers.
• HPV types 16 and 18 account for more than half of
  HPV types found in anogenital cancers.
• Most women infected with high-risk HPV types have
  normal Pap test results and never develop
  precancerous (high-grade) cervical cell changes
  or cervical cancer.

4
HPV Symptoms

• In most cases genital HPV infection is transient
  and has no clinical manifestations or sequelae.
• Clinical manifestations of genital HPV infection
  include
• Genital warts
• Cervical cell abnormalities
• Anogenital squamous cell cancers
• Recurrent respiratory papillomatosis
• The two most common clinically significant
  manifestations of genital HPV infection are
• Genital warts that are visualized without
  magnification
• Cervical cell abnormalities that are detected by
  Pap test screening (with or without HPV DNA
  testing) or colposcopy

5
Vulvar Warts
Source Reprinted with permission of Gordon D.
Davis, MD.
6
Penile Warts
Source Cincinnati STD/HIV Prevention Training
Center
7
Gonorrhea

• Microbiology
• Etiologic agent is Neisseria gonorrhoeae
• Gram-negative intracellular diplococcus,
  oxidase-positive, utilizes glucose, but not
  sucrose, maltose, or lactose. Infects
  mucus-secreting epithelial cells.
• Divides by binary fission (every 20-30 minutes)
• Pathology
• N. gonorrhoeae attaches to different types of
  mucus-secreting epithelial cells via a number of
  structures located on the surface of gonococci.
• N. gonorrhoeae has ability to alter these surface
  structures, which helps the organism evade an
  effective host response.
• N. gonorrhoeae employs several mechanisms to
  disarm the complement system, which may result in
  a survival advantage in the human host.

8
Clinical Symptoms

• Urogenital, pharyngeal, and rectal infections in
  males and females
• Conjunctivitis in adults and neonates.
• If untreated, gonorrhea is a major cause of
  pelvic inflammatory disease (PID), tubal
  infertility, ectopic pregnancy, and chronic
  pelvic pain.

9
Cervicitis/Urethritis

• Cervicitis (50 of women have no symptoms)
• Symptoms may be nonspecific such as abnormal
  vaginal discharge, intermenstrual bleeding,
  dysuria, lower abdominal pain, or dyspareunia
• Clinical findings may exhibit mucopurulent or
  purulent cervical discharge and easily induced
  cervical bleeding
• Incubation period unclear, but symptoms may occur
  within 10 days of infection
• Urethritis (most women asymptomatic)
• Symptoms dysuria (difficulty in urination)
• 40-60 of women with cervical gonococcal
  infection may have urethral infection

10
Gonococcal Cervicitis
Clinical Manifestations
Source CDC/NCHSTP/Division of STD Prevention,
STD Clinical Slides
11
Urethritis/Epididymitis

• Urethritis
• Most male patients develop overt, symptomatic
  urethritis.
• Symptoms typically purulent or mucopurulent
  urethral discharge often accompanied by dysuria
• Clinical presentation purulent or mucopurulent
  urethral discharge is common, but discharge may
  be clear or cloudy
• Asymptomatic (unrecognized) infection may occur
  in approximately 10 of male cases. Asymptomatic
  gonorrhea may act as a reservoir in the community
  that perpetuates transmission from men to women.
• Incubation period usually 1-14 days for
  symptomatic disease. Most become symptomatic in
  2-5 days after exposure.
• Epididymitis
• Symptoms unilateral testicular pain and
  swelling
• Infrequent, but most common local complication of
  gonorrhea infection in males
• Usually associated with overt or subclinical
  urethritis
• Can result in infertility due to blockage

12
Gonococcal Urethritis Purulent Discharge
Source Seattle STD/HIV Prevention Training
Center at the University of Washington Connie
Celum and Walter Stamm
13
Swollen or Tender Testicles (Epididymitis)
Source Seattle STD/HIV Prevention Training
Center at the University of Washington
14
HSV Herpes Simplex Virus

• Genital herpes is a recurrent, lifelong viral
  infection.
• Two HSV serotypes HSV-1
• HSV-2 most genital symptoms due to HSV-2, but
  also possible with
• HSV-1
• 50 or more of new cases are asymptomatic or
  unrecognized.

15
Transmission
Epidemiology

• HSV-2 is transmitted sexually and perinatally.
• Most sexual transmission occurs while source case
  is asymptomatic.
• Efficiency of sexual transmission is greater from
  men to women than from women to men.

16
Transmission, contd

• Likelihood of transmission to others declines
  with increased duration of infection.
• Incubation period after acquisition is 2-12 days
  (average is 4 days).
• Genital HSV-2 infection facilitates both
  acquisition and transmission of HIV infection.

17
HSV - Etiology

• HSV-1 and HSV-2 are members of the human herpes
  viruses (herpetoviridae) that includes EBV and
  CMV.
• HSV-1 and HSV-2 are double-stranded DNA viruses
  surrounded by an envelope of lipid glycoprotein.
• 50 DNA homology exists between HSV-1 and HSV-2.
• All members of this species establish latent
  infection in specific target cells (for HSV, this
  would be CNS cells, specifically, ganglia of
  peripheral nerves).
• Infection persists despite the host immune
  response, often with recurrent disease.

18
Etiology, contd

• The virus remains latent indefinitely.
• Precipitation of viral replication due multiple
  known and unknown factors (eg., trauma, fever,
  stress)
• The re-activated virus may cause a cutaneous
  outbreak of herpetic lesions.
• Up to 90 of persons seropositive for HSV-2
  antibody have no clinical history of anogenital
  herpes outbreaks.

19
Signs and Symptoms

• First outbreak characterized by multiple lesions
  that are more severe, last longer, and have
  higher titers of virus than recurrent infections
• Lesion progression
• papules ? vesicles ? pustules ? ulcers ? crusts ?
  healed
• Illness lasts 2-4 weeks
• Often associated with systemic symptoms including
  fever, headache, malaise

20
Signs and Symptoms, contd

• Local symptoms include pain, itching, dysuria,
  vaginal or urethral discharge, and tender
  inguinal lymph node swelling
• Numerous, bilateral painful genital lesions last
  an average of 11-12 days
• Median duration of viral shedding (from the onset
  of lesions to the last positive culture) is 12
  days
• HSV cervicitis occurs in most primary HSV-2
  (90) and primary HSV-1 (70) infections

21
HSV Diagnosis

• Clinical diagnosis is insensitive and
  nonspecific. Lesions may or may not be present,
  must be confirmed as to origin
• Clinical diagnosis should be confirmed by lab
  testing
• Virologic tests (viral culture from lesions)
• Type-specific serologic tests (to differentiate
  between HSV 1 and HSV 2)
• Acyclovir (antiviral) Recommended therapy (no
  cure, but decreases symptom duration and
  quantity of viral shedding)

22
Herpes Genitalis Clinical Periurethal Lesions on
Vestibule
Clinical Manifestations
Source Cincinnati STD/HIV Prevention Training
Center
23
Herpes Primary Complex
Clinical Manifestations
Source Cincinnati STD/HIV Prevention Training
Center
24
Chlamydia

• C. trachomatis is an obligate intracellular
  bacterium with a Gram-negative-like cell wall.
• C. trachomatis infects columnar epithelial cells
  of cervix or urethra
• C. trachomatis survives by replication that
  results in the death of the cell. (Alternative
  modes of replication and persistence of organisms
  are important research topics.)
• Chlamydia takes 2 forms in the cycle elementary
  body (EB) and reticulate body (RB). Life cycle
  72 hrs

25
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26
Clinical Syndromes Caused by C. trachomatis
Clinical Manifestations
Local Infection Complication Sequelae
Conjunctivitis Urethritis Prostatitis Reiters syndrome Epididymitis Chronic arthritis Infertility (rare)
Conjunctivitis Urethritis Cervicitis Proctitis Endometritis Salpingitis Perihepatitis Reiters syndrome Ectopic pregnancy Chronic pelvic pain Chronic arthritis
Conjunctivitis Pneumonitis Pharyngitis Rhinitis Chronic lung disease? Rare, if any
27
C. trachomatis Infection in Men
Clinical Manifestations

• Urethritis
• Majority (gt50) asymptomatic
• Symptoms/signs if present mucoid or clear
  urethral discharge, dysuria
• Incubation period unknown (probably 5-10 days in
  symptomatic infection)
• Epididymitis
• Reiters Syndrome

28
C.trachomatis Urethritis Mucoid Discharge
Source Seattle STD/HIV Prevention Training
Center at the University of Washington/UW HSCER
Slide Bank
29
Swollen or tender testicles (epididymitis)
Clinical Manifestations
Source Seattle STD/HIV Prevention Training
Center at the University of Washington
30
C. trachomatis Infections in Women
Clinical Manifestations

• Cervicitis
• Majority (70-80) are asymptomatic
• Local signs of infection, when present, include
• Mucopurulent endocervical discharge
• Edematous cervical ectopy with erythema and
  friability
• Urethritis
• Usually asymptomatic
• Signs/symptoms, when present, include dysuria,
  frequency, pyuria

31
Sequelae, female

• Pelvic Inflammatory Disease (PID)an acute
  clinical syndrome associated with ascending
  spread of microorganisms from the vagina or
  cervix to the endometrium, fallopian tubes,
  ovaries, and contiguous structures.
• PID is defined as any combination of
  endometritis, salpingitis, tubo-ovarian abscess,
  or pelvic peritonitis.
• Signs and symptoms when present lower abdominal
  pain, cervical motion tenderness, and uterine
  tenderness on pelvic exam.
• A substantial proportion of chlamydia-associated
  PID is clinically silent, but still results in
  tubal scarring which may lead to infertility and
  ectopic pregnancy.
• It is estimated that up to 40 of women with
  untreated C. trachomatis infection will develop
  PID. Of those with PID, 20 will become
  infertile, 18 will experience debilitating
  chronic pelvic pain, and 9 will have a
  life-threatening ectopic pregnancy.
• Endometritis (inflammation of the endometrium)
• Salpingitis (inflammation of the fallopian tubes)
• Perihepatitis (Fitz-Hugh-Curtis syndrome)

32
Normal Cervix
Clinical Manifestations
Source STD/HIV Prevention Training Center at the
University of Washington/Claire E. Stevens
33
Chlamydial Cervicitis
Clinical Manifestations
Source STD/HIV Prevention Training Center at the
University of Washington/Connie Celum and Walter
Stamm
34
Normal Human Fallopian Tube Tissue
Clinical Manifestations
Source Patton, D.L. University of Washington,
Seattle, Washington
35
C. trachomatis Infection (PID)
Clinical Manifestations
Source Patton, D.L. University of Washington,
Seattle, Washington
36
Acute Salpingitis
Clinical Manifestations

Source Cincinnati STD/HIV Prevention Training
Center
37
Trichomonis vaginalis

• Protozoan parasite
• Anaerobic, lack mitochondria, must adhere to host
  epithelium to survive
• No cyst enclosed form, but may survive 1-2 hrs on
  moist surfaces (thus, toilet seat transfer
  possible, but not likely)

38
                                                
                  Trichomonas vaginalis resides
in the female lower genital tract and the male
urethra and prostate    , where it replicates
by binary fission    .  The parasite does not
appear to have a cyst form, and does not survive
well in the external environment.  Trichomonas
vaginalis is transmitted among humans, its only
known host, primarily by sexual intercourse    .
39
Symptoms - Female

• Often asymptomatic
• When symptomatic
• Foul smelling or frothy green discharge from the
  vagina, vaginal itching or redness.
• Other symptoms can include painful sexual
  intercourse, lower abdominal discomfort, and the
  urge to urinate.
• Much more common in women than in men
  transmitted male to female, female to female
  (vulvar contact) 5-28 days post exposure

40
Symptoms - Male

• Often asymptomatic
• May have painful urination, discharge from
  urethra
• Symptoms (and transmission) less in males than in
  females
• Female to male transmission most likely

41
Sequelae

• Untreated female, may lead to abdominal pain,
  PID, pregnancy complication
• Untreated male, may lead to epididymitis,
  prostatitis, infertility
• Treated no complications

42
Diagnosis and Treatment

• Verified only by presence of parasite
• Microscopic observation diagnostic, but
  relatively imprecise. Can be cultured in vitro to
  verify in cases of low parasite numbers
• Treatment Metronidazole (although resistance
  has been reported in literature)
• No host immunity possible, therefore re-infection
  problematic
• Increases risks of HIV transmission by increasing
  numbers of lymphocytes in genital tract (these
  cells are susceptible to HIV infection). Effusion
  in relation to this parasite may also increase
  rates of HIV shedding

43
AIDS

• Single Stranded RNA virus
• Incapable of long-term survival outside the host
• Encapsulated virus host specific

44
Figure 14.AIDS_01
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46
AIDS Timecourse
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49
Syphilis - Treponema pallidum on darkfield
50
Syphilis Signs and symptoms

• Chancre appearing at site of infection
• 1o, 2o, 3o
• Treated Curable
• Untreated May lead to dementia and death

51
Primary syphilis - chancre
52
Primary syphilis - chancre
53
Secondary syphilis - papulosquamous rash
54
Late syphilis
55
Neurosyphilis - spirochetes in neural tissue