Sexually Transmitted Infections

Chlamydia

• Detected through nucleic acid amplification test (NAAT)
• Various commercial methods available for detection
• Treated with doxycycline, azithromycin, or erythromycin
• Contact tracing done by Public Health

Syphilis

• Caused by Treponema pallidum, a tightly coiled spirochaete
• Not easily cultured in the lab, so darkfield microscopy is used
• Increasing prevalence since 2000, especially among men with multiple/anonymous male partners
• Transmission occurs through sexual contact or transplacental (to the fetus)

Clinical Presentation of Syphilis

• Primary syphilis: presents 1-4 weeks post-infectious contact, produces a painless chancre, and heals spontaneously within weeks
• Secondary syphilis: skin rash, "flu-like illness", lymphadenopathy, and heals spontaneously
• Latent infection: asymptomatic
• Tertiary syphilis: cardiovascular (heart failure) and neurological (dementia, seizures, paralysis) symptoms, and gumma (late cutaneous, bony, or visceral masses)
• Congenital syphilis: bone, teeth, and brain damage

Diagnosis of Syphilis

• Dark field microscopy: used for primary disease only, in high volume areas, and on primary chancre
• Serology is the main route to diagnosis, using nonspecific tests (VDRL, RPR) and specific tests (EIA, TPPA)

Gonorrhea

• Caused by Neisseria gonorrhoeae, a gram-negative diplococcus
• Fastidious, susceptible to drying, and requires transport medium for culture
• Molecular methods (not culture-based) are commonly used for detection
• Clinical manifestations: mucopurulent urethritis, mucopurulent cervicitis, pelvic inflammatory disease, pharyngitis, conjunctivitis, and disseminated gonococcal infection

Diagnosis of Gonorrhea

• Nucleic acid amplification testing (NAAT): more sensitive than culture, and can detect from urine sample
• Can be used with non-specific tests, either first or second in order

Treatment of Syphilis and Gonorrhea

• Syphilis: penicillin is the treatment of choice, with doxycycline as an alternative (if allergy)
• Gonorrhea: treatment is dependent on stage of infection and antibiotic susceptibility

Genital Herpes

• Caused by herpes simplex virus (HSV) type 1 or 2
• Linear double-stranded DNA virus that invades nerves and becomes dormant
• Transmission occurs through close contact with a person shedding the virus
• Clinical manifestations: primary infection causes fever, headache, malaise, myalgia, painful lesions on genitalia, dysuria, and vaginal or urethral discharge

Genital Herpes - Recurrence and Congenital

• Recurrent infection: HSV-2 > HSV-1, usually less severe than primary infection, and usually localized to genital area
• Congenital infection: can be severe (life-threatening) if acquired during birth

Diagnosis and Treatment of Genital Herpes

• Swabs of local lesions: nucleic acid amplification test (NAAT) and culture on cells (less sensitive, laborious)
• Treatment: antivirals (acyclovir, valaciclovir, famciclovir) and long-term prophylaxis may be necessary in frequently recurrent disease

Genital Warts

• Caused by human papillomaviruses (HPV)
• Many serotypes, some found at different body sites (not all are STI)
• Certain serotypes are causative agents of cancers (cervical, anal, oral)
• Transmission occurs through direct sexual contact
• Skin growths on genitalia, perianal area, and may be asymptomatic
• Warts can be removed by chemical means, freezing, or surgery
• Vaccine prevents infection by more common cancer-related types

Diagnosis and treatment of chlamydia and syphilis, including detection methods and antibiotic treatments.