One of the major problems society faces is the spread of sexually transmitted diseases, or STDs.

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Chapter 10
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Introduction

• One of the major problems society faces is the
  spread of sexually transmitted diseases, or STDs.
• Many of them are bacterial and some are viral.
• Of all the diseases we face STDs can disrupt our
  quality of life and even cut it short.
• Well consider several of these topics in the
  next two lectures.

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Fig. 10-01
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Bacterial Diseases

• Bacteria (pathogens) cause many diseases in
  humans.
• Chlamydia, Gonorrhea, and Syphilis are all caused
  by a bacteria.
• We also may call these diseases communicable
  since they are spread by host to host contact.
• Some are also found in soil, water, food, etc.

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Fig. 10Ab
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Fig. 10Aa
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How do we get around them?

• Most bacterial infections are treatable by simple
  antibiotics. Good for us!
• Antibiotics kill bacteria according to where they
  interfere in the bacterias metabolism.
• Resistance to treatment is always an issue.
• Antibiotics vs. bacteria will be a continuing war
  for us all.

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The Big Three

• Chlamydia
• Gonorrhea
• Syphilis

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Chlamydia

• Pathogen Chlamydia trachomatis
• This is the leading cause of STDs in the US!
• 18 of women have it, and dont know it!
• Nearly 50 infection rate on college campuses
  estimated!

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Chlamydia Symptoms

• Maybe none.
• Mild burning (18-21 days post sex) during
  urination.
• Vaginal discharge
• PID common side effect.
• Can affect babies during birth.

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Chlamydia Treatment

• Single dose of Azithromycin, tetracycline or
  erythromycin.

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Fig. 10-02
Infant with Chlamydia infection. Occurrence
post-birth.
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Gonorrhea

• Another popular bact. infection!
• Caused by Neisseria gonorrhoeae.
• Although the occurrence of this disease has
  declined drastically in reacent years, a rise in
  infection rates has been noticed since the late
  90s in adloescents, young adults, and African
  Americans.

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Gonorrhea

• Strangely enough, regular use of oral
  contraceptives in women increases their
  likelihood of contracting this disease. (Makes
  the birth canal more susseptable to infections by
  pathogens.)
• A double whammy? People diagnosed with G often
  also are diagnosed with C.
• Additionally, the presence of either (or both) of
  these diseases increases the likelihood of HIV
  infection.
• Why?

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Rates of Infection Gonorrhea (1981-1999)
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Gonorrhea Symptoms

• In men, this is relatively easy to detect. Why?
• Pain during urination, milky discharge 3-5 days
  post coitally (or after contact with pathogen).
• Women show lesser symptoms or are asymptomatic!
  May experience sever pain in the adbomial region
  due to PID.
• Women using IUDs are very succeptable to PID from
  the big G.

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More symptoms

• Gonorrhea of the anus?? Yep! Also known as
  gonorrhea proctitis. Pain, inflammation, blood
  or pus in the feces.
• Eye contact can also result in infection.
• Spreading to internal parts of the body is also
  possible.

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Treatment for Gonorrhea

• Ladies, if your partner is infected, then you
  might as well flip a coin if youre worried about
  having sex with them and becoming infected
  (Women 50-60, Men 20).
• Resistance is becoming more and more of an issue
  since many men and women dont realize they are
  carriers. (Sharing of antibiotics also an
  issuemore later.)
• New tests are being devleope, but most rely on
  blood samples.

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Syphilis

• Agent Treponema pallidum.
• This one has three stages! Chancre, body rash,
  and gummas.
• Chancre (right) is the site where the bacterium
  actually enters the body cavity.

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Syphilis

• Palms of the hand can also be used to identify
  carriers.
• Body rash in these locations is obvious, although
  the rash doesnt itch.

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Syphilis

• Tertiary syphilis (gummas) may not always evolve.
  
• This stage lasts until the patient dies. Cure??
• Symptoms include cardiovascular weakening,
  aneurysms. Nervous system disorders, blindness,
  confusion, insanity.

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Diagnosis and Treatment

• Diagnosis is often made by a blood test, or
  microscopically.
• Blood Reagin (antibody)
• Usually followed up by a microscopic evaluation,
  since blood test may result in a falso positive.
• Penicillin will cure all stages if given in time
  and of sufficient dosage!

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Viral Pathogens

• Herpes, HIV, Genital Warts, Hepatitis.

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What a Virus Isnt

• Not a bacterium
• Not an independently-living organism
• Cannot survive in absence of a living cell within
  which to replicate
• Antibiotics do no harm to a virus, unless
  indirectly
• Treatment of a flu virus with antibiotics is only
  the treatment of its symptoms
• You dont kill the organism that causes the flu!

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What are Viruses?

• Infectious agents composed mainly of nucleic acid
  with a protein coat (capsid)
• Can only be seen with an electron microscope
• Range in size from 10 to 200 nanometers (nM)
• Carry on normal cell-like function unless free,
  then infectious
• In infectious form, they neither grow nor respire
• Can enter living plant, animal or bacterial cell

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What do Viruses Look Like?

• Most viruses have a capsid, core and genetic
  material (DNA/RNA)
• Capsid outer shell of the virus which encloses
  genetic material (link chemical structure of
  capsid helps determine immune response to virus)
• Capsid is made of many identical individual
  proteins, precisely assembled
• Protein core under capsid protecting genetic
  material
• Sometimes an additional covering (lipid bilayer
  w/embedded proteins) on outside known as an
  envelope
• Resembles a baseball
• Various forms rods, filaments, spheres, cubes,
  crystals

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What do Viruses Actually Do?

• All viruses only exist to make more viruses
• All, with the exception of some bacterial
  viruses, appear to be harmful
• Their replication leads to the death of the cell
  which the virus has entered
• Virus enters the cell by first attaching a
  specific structure on the cells surface
• Depending on the virus, either the entire virus
  enters the cell or only the genetic material is
  injected

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The Virus Invasion

• Phase 1 spike and fibers attach themselves to
  the walls of the cell or bacteria
• Phase 2 the sheath contracts and drives the
  core through the cell wall (injection)
• Phase 3 the nucleic acid passes through the
  core, from the capsid head, into the host cell
• Phase 4 nucleic acid disappears, afterwards
  (10m) hundreds of virions appear causing the cell
  to rupture, releasing hundreds of small viral
  replicates
• This is how it can replicate so quickly!!

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The Virus Invasion
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What Things Can Become Infected by a Virus?

• All living things have some susceptibility to a
  particular virus
• Virus is specific for the organism
• Within a species, there may be a 100 or more
  different viruses which can affect that species
  alone
• Specific for example, a virus that only affects
  one organism (humans and smallpox)
• Influenza can infect humans and two animals.

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Different Types of Viruses

• Major classification animal, plant, bacterial
• Sub-classified by arrangement and type of nucleic
  acid
• animal virus group double-stranded DNA,
  single-stranded DNA, double-stranded RNA,
  single-stranded RNA, retrovirus
• influenza SS-RNA
• for all viruses, regardless of the kind of
  arrangement of genetic material, the virus is
  capable of replicating within a living cell and
  can produce progeny

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Human Viruses

• Best way not get hit is not be there when punch
  arrive.
• -Mr. Miagi (The Karate Kid II)
• Good advice! Applies to viruses too. Prevention
  of transmission is the ultimate cure.
• Herpes, Genetal warts, and Hepatitis are
  problematic in this area as they are very
  difficult to control outbreaks.

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Herpes 1 and 2

• Herpes simplex virus 1 and 2 (HSV 1 and HSV 2)
  are difficult to deal with.
• HSV 1 Cold sores primarily
• HSV 2 Genital herpes
• Cross-over symptoms work both ways.
• 45 million people are estimated to be infected.

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Symptoms

• Tingling, itching followed by blisters on the
  genitals.
• Ruptured blisters are slow to heal (3 weeks) and
  painful.
• Fever and swollen lymph nodes in the groin also
  likely. (Copius vaginal discharge in women.)
• Healed ulcers dont mean cure! Only latent
  condition.
• Sun, stress, and menstrual cycles will trigger
  outbreaks.
• Newborns can also be affected when passing
  through the birth canal. (Cesarean section
  avoids this!!)

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Trasmission

• Transmission from infected individuals occurs
  primarily during lesion outbreaks.
• Monogamous relationships go a long way toward low
  risk.
• No cure. Multiple treatments for symptoms.

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Treatment (cont.)

• Acyclovir and vidarabine disrupt the viral
  reproduction, but dont stop it altogether.
• Ointment of acylovir works to relieve initial
  symptoms, while oral drug valaciclovir (Valtrex)
  is most often prescribed for treatment of
  recurrent symptoms.

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Genital Warts

• Caused by human papillomavirus (HPV)
• 5.5 million people infected each year.
• A large cooccurence of genital warts and cervical
  cancer in women.
• No cure once infected, although warts can be
  removed.
• Vaccines exist for some strains.

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Hepatisis

• Disease that attacks the liver.
• Hep A Sewage (aquired natural immunity
  possible)
• Hep B DNA virus spread by needle sharing
• Hep C infected blood (death)
• Hep E developing countries (rare in US)
• Vaccines available for Hep B (children get it
  now)

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Fig. 10-08
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HIV (AIDS)

• Aquired Immune Deficiency Syndrome (AIDS) is
  caused by the human immunodefficiency virus
  (HIV).
• Blood infection (64 million worldwide)
• While youve looked at this slide, at least 2 new
  cases have occurred in heterosexuals!

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HIV (AIDS)

• Most cases are reported in Africa, many due to
  unprotected sex with infected men.
• How does HIV work? Its complicated. Thats why
  our bodies havent developed an immunity, yet.

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How AIDS Works

• Lymphocytes in our blood fight infection.
• B-lymphocytes are pathogen specific in action.
• T-lymphocytes which kill cells directly (T-killer
  cells) or assist others work better (T-helper
  cells) are the primary line of cellular defense
  against pathogens
• HIV destroys T-helper cells ultimate
  resultimmune system compromised

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AIDS Stages

• AIDS has three phases Acute (Category A),
  Chronic Infection (Category B), and AIDS
  (Category C).
• Most people die of secondary diseases also known
  as opportunistic infections (ex. Pneumonia).
• HAART treatment used to fight disease involves
  expensive drugs which disrupt replication of
  virus or help to strengthen existing immune
  system.
• Newer drugs actually promote active immunity in
  humans (turn on T-killer cells).

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Other issues

• Vaginitis caused by bacteria (Gardnerella
  vaginalis), parasites (Trichomonas spp.) (L), or
  yeast (Candida albicans) (R).

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Crabs can also be problematic. Caused by a
louse, Phthirus pubis. Treated with Lindane.