2 Disease Topics Flashcards
Describe the organisms which cause GAS
Streptococcus pyogenes
Gram-positive, nonmotile chains of spherical cells or diplococcus
Typically, capsulated
Facultative anaerobic
Positive for beta-hemolysis
List and describe the mild illnesses associated with GAS.
No illness- 5 to 15% have bacteria.
Mild illness- strep throat, impetigo
Severe illness- scarlet fever. Necrotizing fasciitis (invasive GAS), streptococcal toxic shock syndrome (invasive GAS)
List and describe the severe illnesses associated with GAS.
Mild
Strep throat:
-Sore scratchy throat
-Postulates
-Swollen lymph glands
-Severe complications: heart valve damage
Impetigo signs
-One of the most common skin infections
-common in children
-bacterium enters in cuts and bites
-normally around the mouth
Severe
Scarlet fever:
-After or with strep
-Rash- strain makes erythrogenic toxin
-Throat and tongue covered by postulates strawberry tongue
-Complication: rheumatic fever
Necrotizing Fasciitis
-Flesh-eating disease
-Destroys muscle, fat, and skin tissue
-40% of patients die
-Makes exotoxin A
Streptococcal toxin shock syndrome
STSS
-Cascade of steps leads to rapid drop of blood pressure and organ failure (liver, kidneys)
-50% of patients die
Treatment:
-Penicillin and clindamycin
-Amputations for necrotizing fasciitis
Why a STI?
Sexually transmitted infection
Long periods with no signs and symptoms
Describe the derivation of the slang term for gonorrhea
French word clapper meaning brothel
Keeper of a brothel named mother clap (Margaret Clap)
Painful sting in male urethra feels like a clap
A clap was a traditional treatment to clear the blockage
Describe the organism which causes gonorrhea.
Neisseria gonorrhoeae
Gram-negative bacterium
Lots of fimbriae and opacity proteins (Opa Proteins)
diplococci
What are some symptoms in men and women which have gonorrhea?
Men:
Some can be asymptomatic for several months
Burning sensation when urinating
White, yellow, green discharge from the penis
If untreated, it can cause epididymitis, a painful condition of the testicles- lead to infertility
Women
Often mild; most women have no symptoms
Painful or burning sensation when urinating
Increased vaginal discharge or bleeding between cycles
If untreated- pelvic inflammatory disease
Not always signs/symptoms
Abdominal pain/fever
Internal abscesses
Damaged fallopian tubes- infertility
What is a major problem for women which have gonorrhea?
Gonococcal conjunctivitis.
What is a problem associated with gonorrhea and newborns
Pregnant women infect their babies as it passes through the birth canal during delivery
Causes blindness, joint infections blood infections.
What is the prevention for gonorrhea?
Abstain from sexual intercourse,
long-term monogamous relationship
Latex condoms with the correct use
Describe the three “schools” of thought for the origin of syphilis?
Pre Columbus
Present in Hippocrates writing
Some bible passages
Columbian theory
New world disease brought back by Columbus
First well-recorded outbreak of what we know as syphilis in Naples in 1494
Bot sides wrong-combination
Similar disease-yaws existed in Europe
Form of yaws that had evolved in the new world and was brought back to the old
Describe and list the causative agent of syphilis
Bacterium- treponema pallidum
Spiral shaped bacterium called spirochete
Axial filament- internal flagella- moves the whole organism “twist”
Does not survive well outside of host
Gram negative
Describe the four stages of the disease.
Primary stage
Marked by the appearance of a single sore called a chancre (can be multiple)
Chancre lasts 3-6 weeks, and it heals without treatment
No treatment then progresses
Secondary stage
Skin and mucous membrane rash with lesions
Rough red or reddish-brown spots mainly visible on palms and soles
Swollen lymph glands
Sore throat
Person most contagious in the secondary stage
Latent (hidden stage)
Secondary symptoms and signs disappear
Infection remains in the body- only mother-to-fetus transmission
Most cases end here (25% progress after years)
Tertiary stage
Tumor-like growth on skin-rubbing lesions
Neurological problems
Cardiovascular problems
Blindness
How is the disease important in medical ethics?
Tuskegee syphilis experiment
1932 and 1972- US public health service conducted an experiment on 399 black men in the late stages of syphilis
Never told what disease they were suffering from
Doctors had no intention of curing them
28 men died and others passed the disease on
Start of IRB
Describe some features of the causative agent for TB.
Mycobacterium tuberculosis
Acid-fast bacterium (mycolic acid in the cell wall)
Rod-shaped
Obligate aerobe
List and describe the two forms of TB.
latent and active
latent tuberculosis infection
People are carriers (no symptoms of active)
Can’t spread bacteria
Can develop active form
Can be in this form for a lifetime
active tuberculosis infection
Only 10% of infected people develop the infection (weakened immune system)
Bad cough (with or without blood/sputum
Chest pain
Spread bacteria
Without treatment, very few survive
how is TB diagnosed
Mantoux PPD skin test
Inject tuberculin under skin of the forearm
Reacts with sensitive tcells
After 48-72 hours, measure welt
15 mm or more positive
Confirm with chest x-ray
concepts of TB history
1 killer of people during this time (20-30% of people)
Ancient disease- common in Greek (Hippocrates) and Egyptian writings
Epidemic in Europe and North America from the 18th and into the 20th century
Known as the white plague or consumption
Better ventilation in homes and at work sites and pasteurization of milk helped slow disease
List some Emerging Infectious Disease information (numbers) associated with TB
Ranks 4th in death due to infectious diseases worldwide (now)
Estimated that 1.5 million die each year (worldwide)
1/3 of people with latent infections (worldwide)
What is the main problem associated with the disease? Describe what happens. botulism
Flaccid paralysis
The botulism toxin interferes with nerve to muscle impulses
List and describe the three types of botulism.
Food borne
Eating foods contaminated with botulism toxin
Cause container lids to bulge and contents have an off odor
Very dangerous-many people can get sick
Infant botulism
Endospores of toxin growing in the intestinal tract of infants-releasing the toxin
Infants don’t have established normal flora
Dont feed infants under 1 honey
Wound botulism
Wounds infected endospores
Majority of cases in US linked with those who mainline or skin pop Mexican tar heroin
food borne botulism symptoms
Weaknesses of muscles, blurry vision, double vision, droopy eyelids, slurred speech, dry mouth, difficulty swallowing, nausea and vomiting
infant botulism
Weak poor muscle control, eat less, often become constipated, weak cry, nausea and vomiting
Describe the organism which causes botulism.
Clostridium botulinum
Rod shaped
Motile
Survive best in conditions where little oxygen is present
Gram positive
Noncontagious
Endospore former
What are some types of treatment for botulism?
Antitoxin
Vomiting or enemas
Wounds surgically cleaned
Breathing through ventilator
How can Botulism be prevented?
Boil home canned food for 10 minutes
Can denature protein toxin
Use proper canning techniques.
Do not inject street drugs
List and describe the three forms of anthrax
Cutaneous
-Most common 95% of cases
-Endospores enter cut or abrasion on the skin-germinated in macrophages.
-Starts as raised itchy bump
-Vesicle and then a painless ulcer
-Black necrotic (dying) area in the center
-20% of untreated cases=death
-Deaths are rare with appropriate antimicrobial therapy
Inhalation (better chance of bacteria reaching the bloodstream and proliferating)
-Person inhales microspores
-Like common cold
-Progresses to severe breathing problems and septic shock
-Usually fatal-close to 100%
Intestinal (rare)
-Consumption of contaminated/undercooked meat
-Nausea, loss of appetite, vomiting, fever are followed by abdominal pain, vomiting blood, and severe diarrhea
-Mortality- 50-60% of cases
What causes the disease (give some organism characteristics)?
Bacillus anthrax
Gram positive
Endospore forming
Soil bacteria
Obligate aerobe
Makes exotoxins
List vaccination and bioterrorism information.
Can be treated with antibiotics
Human vaccine available but only given to high risk individuals
Use a livestock vaccine in areas where there is a constant outbreaks called endemic
22 people infected in the US (2001)
Five died
Anthrax endospores were distributed via letter sent by US mail to media organizations and political offices
Need a better vaccine to prevent
