- HAV. Can cause Jaundice. - Mollusks are a reservoir. Fecal oral route. - Single stranded RNA - No chronic form. Only acute. Takes 3 - 5 weeks to incubate. - Vaccine: There is one for travelers. Its an inactivated virus.

- Double stranded DNA virus, and is a spherical, filamentous, & entire virion (Dane particle). - Transmission: Blood, vertical transmission from mom to fetus, Semen. - Sometimes chronic. Incubates 5 - 6 wks. Vaccine is available.

- HCV. Single strand RNA. - Transmission: Blood and maybe sexually - Incubates 6 - 7 wks. - Up to 85% of those infected have it turn into chronic hepatitis. - Variable viruses. Hard to study.

- Caused by: Giardia Lamblia - Acquire it from contaminated water supplies - Symptoms might include watery diarrhea alternating with greasy stools. Fatigue, cramps, and belching gas also may occur.

- Many microbes in the mouth - Stomach and duodenum have very few species d/t extreme acidity of HCl in stomach - Many microbes in large intestine and part of small intestine (once HCl has been absorbed) - Est fecal mass 1/3 bacteria

Ch. 25 Microbial Diseases of the GI tract Flashcards by Aine Schmidt

Clostridium Perfingens Gastroenteritis

Obligate anaerobe
Meats/meat stews contaminated with intestinal contents
Caused my temperature abuse: Foods held at room temp, inadequate cooling
Prevention is key

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Clostridium Difficile

Toxins cause: diarrhea, inflammatory colitis, can last a long time
Has resistant endospores
Causes: HAI (Pathogen). Antibiotics eliminate normal intestinal microbiota leading to this infection.
Can be community acquired as well.

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Treatment of C. Difficile

Discontinue precipitating antibiotic
Metronidazole (Targets anaerobes)
PO hydration therapy
Fecal transplants. They take donor stool and filter it out till they just have gut microbiota. Then they administer it via enema.

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Viral diseases of GI - Mumps virus

Portal: Respiratory tract
Affects parotid gland (on side of face)
Orchitis (inflammation of one or both testicles) can cause sterility.
MMR –> its the middle “M”

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Viral - Hepatitis

Inflammation of liver

- There are different kinds. We talk about Hep A, B, C. All different viruses that cause these.

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Hepatitis A

HAV. Can cause Jaundice.
Mollusks are a reservoir. Fecal oral route.
Single stranded RNA
No chronic form. Only acute. Takes 3 - 5 weeks to incubate.
Vaccine: There is one for travelers. Its an inactivated virus.

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Hepatitis A Treatment

Immune globulin. Passive immunity, via antibodies from others who have recovered from Hep A.

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Hepatitis B

Double stranded DNA virus, and is a spherical, filamentous, & entire virion (Dane particle).
Transmission: Blood, vertical transmission from mom to fetus, Semen.
Sometimes chronic. Incubates 5 - 6 wks. Vaccine is available.

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Hepatitis C

HCV. Single strand RNA.
Transmission: Blood and maybe sexually
Incubates 6 - 7 wks.
Up to 85% of those infected have it turn into chronic hepatitis.
Variable viruses. Hard to study.

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Hepatitis C treatment

Protease and polymerase inhibitors
Interferon
Ribavirin
No vaccine
Best approach: Prevention, precaution and blood testing.

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Fungal diseases - Ergot poisoning

Caused by: Claviceps purpurea
Mycotoxin (ergot) causes hallucinations, and restricts blood flow
Found in improperly milled wheat etc. Modern milling removes fungus.
Suspected causative agent of Salem witch trials.
LSD derivative. In a purified state, its used as a vasoconstrictor med.

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Aflatoxin Poisoning (Fungal)

Caused by: Aspergillus Flavus
Produces a toxin
Potential carcinogen

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Giardiasis

Caused by: Giardia Lamblia
Acquire it from contaminated water supplies
Symptoms might include watery diarrhea alternating with greasy stools. Fatigue, cramps, and belching gas also may occur.

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i messed up and these cards arent in perfect order

Gi diseases are …….

Most common infectious diseases in developing countries

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Normal Microbiota

Many microbes in the mouth
Stomach and duodenum have very few species d/t extreme acidity of HCl in stomach
Many microbes in large intestine and part of small intestine (once HCl has been absorbed)
Est fecal mass 1/3 bacteria

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Bacterial - Dental Caries

Caused by Streptococcus mutans
Breaks down sucrose into glucose and fructose
Glucose is synthesized into dextran (polysaccharide) –> capsule for Strep. Mutans
Fructose –> lactic acid (strict fermenter)
Plaque = biofilm of variety of species (dentist scrapes this off to get rid of S. mutans)
Lactic acid next to enamel leads to break down

Periodontal Disease

Progression: Healthy gingivae -> gingivitis (plaque at base) -> periodontal pockets -> periodontitis (breaking down bone; teeth loose; trench mouth is very severe form of this)

Lower Digestive System diseases ( bacteria) - Most of em have these –>

Transmission in most cases: fecal-oral route
Symptoms of all: nausea, vomiting, diarrhea (severity varies w disease)
Types: infection (growth of bacteria) or intoxication (not bacteria itself, but a toxin)
Symptoms of infection: 12+ hours
Symptoms of intoxication: 1-6 hr
Treatment: Oral rehydration therapy (main concern; electrolyte balance out of whack). Only very few cases are antibiotics recommended

Staphylococcal Food Poisoning

Caused by: S. aureus
Facultative halophile
Produces Staphylococcal enterotoxins (exotoxins)
Seen in foods with high osmotic psi (e.g. potato salad)

Course of staph infection:

Food containing protein is cooked (bact usually killed)
Food handled by contaminated worker (staph on hands)
Food is left at room temp (MAIN PROBLEM); organisms incubate in food long enough to form and release toxins (reheating will eliminate staph, but NOT the toxins
Food containing toxins is eaten
In 1-6 hrs, Staphylococcal intoxication occurs.

Salmonellosis

Caused by: Salmonella enterica
Many serotypes
Reservoirs: animal intestinal tracts (may contaminate chicken eggs); reptiles
Oral rehydration therapy; but BEST is…
Prevention: cleanliness; adequate cooking (no raw eggs; cook meat well)

Typhoid Fever

Caused by: Salmonella typhi

Reservoir: only HUMANS (carriers e.g. Typhoid Mary)

Recover –> immunity

Prevention: cleanliness; adequate cooking.

Cholera

Caused by: Vibrio cholerae
Exotoxin
Rice-water stools (extreme dehydration)
Ingesting contaminated water
Treatment: fluid and electrolyte replacement
Recovery –> immunity (but only to the same strain)
Big problem after natural disasters

E. coli Gastroenteritis

Various strains of E. coli, but only a few are pathogenic
Pathogenicity:
Fimbriae and/or production of Toxins
Severity of symptoms vary by strain
Treat the symptoms, try not to become too dehydrated
“Travellers Diarrhea”

Helicobacter Peptic Ulcer Disease

- Caused by Helicobacter pylori - Continual ulcer flare-ups with cause not found for many years - Finally discovered that it was an infectious disease! - Fecal-oral route - Treatment: antibiotics; pepto-bismol

Helicobacter Peptic Ulcer Disease - Disease mechanism

- Very acidic pH in your stomach - Helicobacter pylori can live in stomach because it produces urease, which breaks down urea into ammonia; this neutralizes the HCl of the stomach - Neutral enviro so bacteria can grow - Damage is due to inflammation - Organism tries to grow; inflammatory response to remove (or attempt removal of) organism depletes mucus-secreting cells; HCl then continues the damage