Chapter 18 STDs

  1. Why are STD's so prevalent?
    People underestimate the prevalence of STDs and the personal risk of acquiring an STD.

    Many STDs are aymptomatic, strong social stigma about people with STDs prevents open discussion of the problem.

    25% of women and 30% of men say they NEVER use a condom with a new partner.
  2. STDs caused by bacteria
    • Chlamydia "Silent Epidemic"
    • Gonorrhea "Clap"
    • Syphilis
  3. STDs caused by protists
  4. STDs caused by invertebrates
    Pediculosis Pubis "crabs"
  5. STDs caused by viruses

    • zoonis: - transfer of virus in animals to humans (lyme disease, rabies, catch scratch disease, african sleeping sickness)
    • VIRAL STDS: tiny, non-living infectious particiles consisting of DNA or RNA enclosed in protein coat capsid.

    Highly specific with regard to species and type of cell they infect

    Able to reproduce only inside cells.

    Responsible for majority of STD infections

    Genital Herpes (DNA)

    Human papillomaviruses (HPVs genital warts and genital cancers) (DNA)

    Hepatitis B (A C D were also mentioned)(DNA)

    HIV-1 *central Africa and HIV 2 *west Africa Disease (human immunodeficiency virus)  (RNA)

    AIDs (acquired immunodeficiency syndrome)(RNA)
  6. Overview of transmission
    • Genital- genital
    • Anal-genital
    • Oral -genital
    • Parenteral infection (blood -> blood)
    • Perinatal infection (mother -> baby during pregnancy or delivery)

    Protection is not always highly effective for all the different kinds of STDs
  7. Chlamydia "Silent Epidemic" Overview
    • Most common bacterial STD
    • Caused by: Chlamydia trachomatis

    Incubation: 7-10 days in men 7-28 days in women

    Transmission: sexual; hand-eye transfers of genital secretions, oral (less likely), perinatal during vaginal delivery

    • Symptoms: male: 50% asymptomatic penile discharge, frequent burning during urination, epididymitis
    • female: 75% asymptomatic yellowish vaginal discharge; frequent burning on urination, lower abdominal pain, ectopic pregnancy

    Effect on Fertility: causes infertility in men and women. Pelvic inflammatory in women and ectopic pregnancy

    Newborn Effect: premature birth / low birth weight, lung and eye infection pneumonia

    Diagnosis: tissue culture, enzyme test and highly sensitive nucleic acid amplification test performed on urine


    Treatment: antibiotics like azithromycin, doxycycline and there are antibiotic eye drops (newborns)
  8. Gonorrhea "Clap" Overview
    Caused by: Neisseria gonorrhoeae (BACTERIAL)

    Incubation: 2-5 days

    Transmission: 50-90% chance of infection for women and 20% for men after exposure: sexual; oral sex,  perinatal (crosses placenta and during vaginal delivery)

    • Symptoms: *infected people 3-5xs more likely to get HIV and pass it to partner* shows symptoms after 2-30 days of infection
    • male: 1-3% asymtomatic, painful urination, milky discharge
    • female: 75% asymptomatic, clear or whitish vaginal discharge that changes to yellow/green puss disrcharge, irregular bleeding, painful urination, lower abdominal pain

    Effect on Fertility: infertility noted in males. Untreated women can lead to infertility and PID after 2-10 wks

    Newborn Effect:miscarriage; eye infection; blindness; menigitis

    Diagnosis: Seems difficult. Symptoms DO NOT distinguish it from other STDs. No reliable blood test.Sample of discharge from penis is more accurate for men. Swabs of urethra and cervix have to be taken for biochemical test. ONLY 15-20% who have the disease are not visible in culture so repeat cultures are recommended.

    • Prevention: condoms, foams, jellies
    • spermicide (nonxynol-9) reduces transmission by 60%

    • Treatment: cephalosporin classed-drugs. follow-up cultures are needed after treament. newborns receive silver nitrate antibiotic eye drops
    •  quinolone-resistant Neisseria gonorrhoeae (QRNG) in '06 led to changes in notional guidelines
  9. Syphilis Overview
    Caused by: Treponema pallidum

    Incubation:10-70 days

    • Transmission: 1/10 exposed will contract, sexual, contact with syphilis sores; perinatal (crosses placenta) blood
    • Symptoms: Phases: Prmary: chancre (cain-core) develops (10-90 days) at site of infection (disappears after 3-6 weeks)
    • Secondary: 2wks - 6 months after primary the bacteria  spread to blood and lymphatic system: fatigue, weight loss, fever, muscle ache, non-itchy rash. (disappear after 2-6 weeks and can recur for 1-2 yrs)
    • Latent: (yrs with or without symptoms) no longer infectious to fetus or others
    • Tertiary (15-30 years after infection)
    • person no longer infectious, gummas develop. Liver, lung, eye, digestive damage. cardiovascular damage; heart attack and stroke. Neurological damage: dementia, spinal cord damage (paralysis, blindness)

    Effect on Fertility: miscarriages if that counts

    Newborn Effect: primary and secondary phases affect fetus after 6 months of pregnancy. 40% miscarriages, 70% born with congenital syphilis (biological birth defects) premature birth or stillbirth. Damaged eyes, deafness, nose defect, teeth defect, notochord defect.

    Diagnosis: anitbodies in blood. venereal disease reasearch lab test, rapid plasm reagin test, Syphla-check test for 1 stage. 25% flase negatives and 1/3000 false positives. Dark-field microscope to confirm.

    Prevention: condoms, avoid contact with sores or rashes

    Treatment: benzathine penicillin G, injection every 8 days for 1 stage and higher doses for longer advanced stages. Tetracycline or erthromycin. Increasing antibiotic resistance.
  10. Trichomoniasis
    Caused by: Trichonomas vaginalis

    Incubation: 4-28 days

    Transmission: sexual, washcloths, towels

    • Symptoms: men: burning urination, mild penile discharge, most men asymptomatic
    • women: itching and burning, odorous vaginal discharge, burning urination, painful intercourse, many women are aymptomatic

    Newborn Effect: premature birth / low birth weight

    Diagnosis: Not covered on slide

    Prevention: Not covered on slide

    Treatment: Not covered on slide
  11. Pediculosis Pubis "Crabs" Overview
    Caused by: Pediculosis pubis

    Incubation: Not covered

    Transmission: Direct body, hair, bed, clothing contact eggs hatch in 7-9 days

    Symptoms: Crazy ass itching

    Diagnosis: Not covered on slide

    Newborn Effect:Not covered on slide

    Prevention: Not covered on slide

    Treatment: repeated application of cream, lotion, or shampoo version of gamma benzene hexachloride (Kwell) to disrupt hatch cycle. All clothing and linens should be washed in HOT bleach water. All household members should be treated.
  12. Genital Herpes Overview
    1/5  (45 million) infected

    Caused by:Herpes simplex virus HSV-1 or HSV-2

    Incubation: 4-7 days (1 week)

    Transmission: sexual, oral sex, perinatal (during vaginal delivery)

    Symptoms:  itching, burning pain at infection site, painful urination, round painful sores, tiny blisters underlying redness that heal without scarring. Establish latency in nerve cells after sores heal. Symptoms recur 4-5 times a year HSV-2 more often than HSV-1

    Newborn Effect: fatal for newborns, miscarriage or low birth weight if woman has 1st outbreak during prenancy, skin lesions, encephalitis, CNS destruction

    Diagnosis: smear from cervix and blood test

    Prevention: safer sex. you can still contract herpes even with a condom

    Treatment: NO CURE Viralprin, Vir-L-Lysine, QuickClerarm Acyclovirand Famiclovier relieves symptoms of primary infection and suppresses recurrent episodes to some extent.
  13. HPV: Genital Warts and Genital Cancers
    Non-enveloped DNA viruses (easier to treat?)

    Caused by: Human papillomaviruses

    Incubation: 3-8 months

    Transmission: sexual, perinatal (during vaginal delivery)

    • Symptoms: painless warts on penis and scrotum, labia, vagina, cervix, and anus.
    • establishes latency; recurrences occur. cancer-associated types integrate into host chromosome; usually cause abnormal pap smears

    Newborn Effect: develops warts in genital area or respiratory tract (can obstruct airway)

    • Diagnosis: females regular pap smears from cervix and antibody test for HPV have to specifically ask for one. Women under the age of 30 are not test during routine STD checks by doctors because the body may rid the virus on its own.
    • No FDA-approved test for men.

    Prevention: condoms provide LITTLE TO NO PROTECTION. Abstain from infect person. Annual pap smears for women. HPV vaccine

    Treatment: warts removed by chemicals, freezing, laser therapy or surgery (may reoccur). Immunosuppressant drugs and antimitotic agent can also help to treat.
  14. Hepatitis B Overview
    • *enveloped DNA virus
    • attachment proteins envelope, capside, DNA, DNA polymerase

    Caused by: Hepatitis B Virus (HBV)

    Incubation:1-5 months

    Transmission: sexual, parenteral (IV drug use), transfursion, shared toothbrushes, razors, or towels, perinatal (during birth)

    Symptoms: infects liver cells, 30% are asymptomatic, flu-like symptoms, abdominal pain, jaundice, dark urine, most recover completely [immune to reinfection], 6% develop chronic hepatitis and die from cirrhosis or liver cancer

    Newborn Effect: Not covered on slide

    Prevention: Hep A and B have vaccines. No vaccine for Hep C, safer sex,give nerbowns HBIG (hepatitis B immune globulin) and vaccine within 12 hours of birth, avoid IV drug use and the tattoo parlor, do NOT share personal care items that might have blood on them

    Treatment: NO CURE interferon and lamivudine use to treat persons with chronic hepatits B, alcohol avoidance.
  15. HIV Disease & AIDs
    • enveloped RNA virus
    • infect helper T cells

    Caused by: Human immunodeficiency virus HIV-1 *central African HIV-2 *west Africa

    Incubation:1-6 weeks for intial symptoms. 7-15 years for post-infection

    Transmission: sexual; parenteral; pernatal (crossess placenta and during breastfeeding)

    • Symptoms: Stages: Stage 1 Primary Acute HIV: flu-like symtpoms, enlarged lymph nodes, rash, disappear within 6 weeks, virus becomes latent. 30% of people are asymptomatic. Stage 2 Secondary Chronic HIV Disease: CD4 T cell count 200-499 / ml. Persistent swollen lymph nodes. Severe fatigue, unexplained weight loss. Recurrent fevers and night sweats. Recurrent non-life-threatening infections like PID and oral thrush
    • Stage 3 AIDs: HIV positive and CD4 T cell count < 200/ml or presence of one or more 26 clinical conditions

    Diagnosis: Blood test to check for HIV antibodies. takes 2-6 weeks for detectable antibody levels. follow-up test more than 3 months after last potential exposure to HIV may be required. Approved HIV test extremely reliable. Saliva test available at doctor's offices or clinics. Western Blots follow saliva test.

    Newborn Effect: Born with virus, also can be passed through breastfeeding

    Prevention: Strap up. Vaginal dams and condoms. Don't share needles. Don't breast feed with HIV.

    • Treatment: NO CURE
    • HAART (highly active antiretroviral therapy)
    • uses a combination of several antiviral drugs with different modes of action to disable HIV replication.

    Two classes of drugs available: Reverse transcriptase (RT) inhibitors AZT and Protease inhibitors (PIs) Crixivan
Card Set
Chapter 18 STDs