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3820: Microbiology & Immunology > Week 10 - GI > Flashcards

Week 10 - GI Flashcards

1
Q

What is Hepatitis

A

Liver inflammation - lead to fibrosis, cirrhosis, liver cancer

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2
Q

General Hep S/S

A
  • Jaundice
  • Dark urine
  • Fatigue
  • N/V
  • Abdominal pain
    *Sometimes no symptoms
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3
Q

Hepatitis A (HAV)

A
  • Present in feces of infected individuals
  • Infections often mild with full recovery
  • Does not cause chronic hepatitis/induce carrier state
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4
Q

HAV Structure

A
  • Nonenveloped
  • Single stranded RNA
  • Absence of lipid envelope - stable in bile facilitating fecal oral transmission
  • Replicates in liver
  • Excreted in bile
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5
Q

HAV Risk Factors

A
  • Poor sanitation
  • Lack of safe water
  • Living in household with infected person
  • Sexual partner to someone with acute Hep A infection
  • Use of recreational drugs
  • Sex between men
  • Travelling to areas of high endemicity without immunization
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6
Q

HAV Prevention

A
  • Improved sanitation
  • Food safety
  • Immunization
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7
Q

HAV Serology

A
  • Diagnosis confirmed by presence of IgM antibodies to HAV
  • IgM antibodies present 5-10 days before symptom onset
  • IgG antibodies begin to rise right before onset of clinical illness
  • IgG antibodies persist to provide lifelong immunity - produced with vaccine as well
  • ALT elevated 3-5 weeks post infection
  • Viremia appears soon after infection, proceeds to peak of liver enzyme elevation
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8
Q

Hepatitis B Transmission

A
  • Mother to child
  • Infected to uninfected child (under 5)
  • Needlestick injuries
  • Tattooing/piercing
  • Exposure to infected bodily fluids
  • Reuse of contaminated needles
  • Sexual contact
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9
Q

HBV Structure

A
  • Member of hepadnavirus group
  • Double stranded DNA virus
  • Replicated by reverse transcription
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10
Q

HBV Prevention

A
  • Safe sex practices
  • Avoid sharing needles
  • Wash hands after contact with blood, body fluids, contaminated surfaces
  • Hep B vaccine - healthcare workers
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11
Q

HBV Serology

A
  • HBsAg may be transiently positive 2-3 wks post vaccine
  • Abs levels decline overtime without re-exposure
  • Positive HBsAg indicated early acute infection if not recently vaccinated
  • Positive HBsAg, total anti-HBc, IgM anti-HBc = acute infection
  • Positive total anti-HBc & anti-HBs = past infection with recovery
  • Positive HBsAg & total anti-HBc = chronic infection
  • Positive anti-HBs = following vaccine & 3-6 months following HBIG
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12
Q

Hepatitis C (HCV) Transmission

A
  • Exposure to infected blood
  • Transfusions of HCV contaminated blood
  • Contaminated injections
  • Injection drug use
  • Sexual transmission - less common
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13
Q

HCV Structure

A
  • Single stranded RNA
  • Enveloped
  • Distantly related to flaviviruses
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14
Q

HCV Prevention

A
  • No vaccine
  • Antiviral meds if contracted
  • Avoid sharing personal care items
  • Avoid sharing needles
  • Wear gloves if in contact with other blood
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15
Q

HCV Serology

A
  • ALT levels peak 3 months post-exposure
  • Present anti-HCV 6 months following exposure
  • Anti-HCV remain positive for life
  • HCV RNA can be detected in blood as early as 1-2wks post-exposure
  • Resolved infection ALT & HCV RNA normal
  • Abs test can’t distinguish between recently acquired, chronic, resolved
  • Chronic: persistent presence of HCV RNA, fluctuating ALT levels
  • ALT can be intermittently normal with chronic infection
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16
Q

Hepatitis D

A
  • Only occur in those infected with HBV
  • HDV & HBV co-infection = most severe chronic viral hep
  • Rapid progression to hepatocellular carcinoma & liver related death
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17
Q

HDV Structure

A
  • Single stranded, circular RNA
  • Requires HBV helper functions for propagation
  • Presence of HBsAG required
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18
Q

Superinfection HDV

A
  • Must have chronic HBV
  • Accelerates progression to severe disease in 70-90% of people
  • Cirrhosis progression accelerated by 10y
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19
Q

HDV Serology

A
  • Anti-HDV detectable in 85% of co-infections
  • No marker persisting to indicate HDV
  • Total anti-HBc remain high post-infection
  • Anti-HBs rise 32 weeks post exposure
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20
Q

Superinfection Serology

A
  • HBsAg remain high
  • Total anti-HBc remain high
  • Anti-HVD persist indefinitely
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21
Q

Hepatitis E (HEV) Transmission

A

Consumption of contaminated food/water

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22
Q

HEV Structure

A
  • Non-enveloped
  • Single stranded RNA
  • 4 different genotypes
  • Genotypes 1&2 found in humans
  • Genotypes 3&4 occasionally infect humans, also several animals
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23
Q

Fulminant Hepatitis

A
  • Acute liver failure
  • Rarely Hep E leads to this
  • Risk of teach
  • Pregnant women (2nd/3rd trimester) increased risk
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24
Q

HEV Prevention

A
  • Quality of public water supply
  • Proper disposal of human faeces
  • Maintain hygienic practice
  • Avoid water/ice consumption of unknown purity
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25
Q

HEV Serology

A
  • 15-60 day incubation
  • ALT elevation 4-5 weeks post-exposure persists 3-13 weeks
  • Symptoms occur when ALT elevated
  • Virus excretion in stool 4-7 weeks post-exposure
  • Viremia detected 3 weeks following exposure
  • IgM & IgG anti-HEV positive 3-4wks after exposure
  • IgG persists
  • IgM usually negative by 13 weeks
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26
Q

Infectious Enterocolitis

A
  • Caused by viruses, bacteria, protozoa
  • Common cause of death for children in developing countries
  • Highly prevalent - 2nd to common cold
  • Spread through oral-fecal route - contaminated water/food
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27
Q

Viral Infection Target

A
  • Superficial epithelium of small intestine
  • Lead to cell destruction & osmotic diarrhea
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28
Q

Bacterial Enterocolitis

A
  • Ingestion of preformed toxins in contaminated food
  • Infection by toxigenic organisms producing enterotoxins in gut
  • Infection by enteroinvasive organism - destroy mucosal epithelial cells
  • More severe symptoms than viral infection
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29
Q

Diarrhea Definition

A
  • Passage of 300+ grams of stool per day
  • Mainly caused by excretion of excess fecal water
  • Acute 2wks or less - associated with infectious causes
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30
Q

Gastroenteritis

A

Vomiting associated with diarrhea

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31
Q

Rotavirus Structure

A
  • Non-enveloped
  • Double stranded RNA
  • Group A serogroup most prevalent
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32
Q

Rotavirus Progression

A
  • Incubation 1-3 days
  • Virus shed before & after symptoms
  • Onset of vomiting & watery diarrhea
  • Vomiting lasts 1-3 days, diarrhea continues 1wk
  • Malabsorption 3-8wks
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33
Q

Norovirus Structure

A
  • Small round viruses of diarrhea
  • RNA - caliciviridae family
  • 4 serotypes
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34
Q

Norovirus Progression

A
  • Incubation 10-51h
  • Sudden onset of V/D lasting 1-2 days
  • Common in older children & adults
  • Often cause large outbreaks
  • 50% adults seropositive by 5th decade
  • Viral shedding continues 3-4 days after symptom onset
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35
Q

Listeria Monocytogenes

A
  • Causes foodborne illness listeriosis
  • Facultatively anaerobic bacteria
  • 5 flagella - tumbling motility
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36
Q

Listeria Prevention

A
  • Pasteurization
  • Meat processing - strict sanitation policies
  • Keeping food refrigerated below 4 degrees
  • Cooking meats to 73 degrees
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37
Q

Clostridium Structure

A
  • Anaerobic
  • Rods
  • Secrete potent exotoxins & enzymes
38
Q

Clostridium Complications

A
  • Botulism
  • Tetanus
  • Gas gangrene
  • Pseudomembranous colitis
39
Q

Clostridium Botulism

A
  • Produces lethal neurotoxin causing fatal food poisoning
  • Blocks acetylcholine release - flaccid muscle paralysis
  • Linked to eating contaminated food - botulinum spores
  • Thrive in jars/bags (anaerobic) producing neurotoxin
40
Q

Infant Botulism

A
  • Infants ingest spores
  • Commonly from honey - release toxins in intestines
  • Infants should avoid honey
41
Q

Campylobacter Structure

A
  • Slender spiral
  • Single polar flagellum - corkscrew through fluids fast
  • Microaerophilic & capnophilic - no grow in air
  • Incubation 1-7 days
42
Q

Campylobacter Causes

A
  • Wild birds - reservoir
  • Present in all surface water
  • Infections result from undercooked poultry, meat, fish, cross-contamination
  • Pasteurization of milk eliminates bacteria
  • Common in store bought poultry - automated processing
43
Q

E Coli

A
  • Facultative anaerobic bacterium
  • Normally resides in intestines of healthy people/animals
  • Most strains harmless & aid in digestion
44
Q

E Coli Contamination

A
  • Meats - during slaughter, bacteria from intestines contacts meat
  • Raw milk, soft cheeses
  • Unpasteurized apple cider, juices
  • Fruits & veg - animal feces runoff
45
Q

Shinga

A
  • Toxin produced by E coli infection
  • Causes STEC infection
  • Damage lining of small intestine & cause diarrhea
46
Q

Shigella

A
  • Facultative anaerobic
  • Nonmotile
  • Rod shaped
  • Closely related to E.coli
  • Can survive in intestinal tract proteases & acids
47
Q

Shigellosis

A
  • Intestinal infection
  • Caused by shigella bacteria
48
Q

Shigella Transmission

A
  • Ingest small amounts of bacteria from infected stool
  • Contaminated food/water
  • Swimming in unsafe water - swallow it
49
Q

Shigella Process

A
  • Penetrate colonic mucosa
  • Degrading epithelium
  • Causing acute inflammatory colitis
  • Leads to blood, inflammation, mucus in intestines
50
Q

Shigella Risk Factors

A
  • Children under age 5
  • Living in group housing, group settings/activities
  • Living/traveling to areas that lack sanitation
  • Men having sex with men
51
Q

Yersinia

A
  • Coccobacilli bacteria
  • Facultative anaerobes
52
Q

Yersinosis Transmission

A
  • Eating raw/undercooked pork - contaminated with yersinia enterocolitica
  • Contaminated milk
  • Untreated water
  • Contact with infected animals or their feces
  • Person to person contact rare
53
Q

Yersinosis Complications

A
  • Skin rash
  • Joint pains
  • Spread of bacteria to blood stream
54
Q

Yersinia Pestis

A

Causative agent of bubonic plague

55
Q

Salmonella Typhi

A
  • Infect intestinal tract & blood
  • Typhoid fever
  • Common in developing countries - poor water treatment
  • Spread via fecal-oral route
  • Consuming contaminated food/drink - prepared by infected person/carrier
56
Q

Salmonella Structure

A
  • Rod shaped
  • Flagellated
  • Obligate anaerobe
  • Produce endotoxin inactivated by gastric acids - large amount of bacteria required
57
Q

Helminths Transmission

A
  • Soil
  • Oral ingestion of larvae infected tissue - undercooked meats
58
Q

Pinworm (roundworm)

A
  • Small, thin, white
  • Nematode class
  • Most common nematode infection
59
Q

Pinworm Risk Populations

A
  • Children
  • Institutionalized persons
  • Household members & caretakers of infected individual
60
Q

Enterobius Vermincularis (roundworm)

A
  • Female leaves intestine through anus & deposit eggs on surrounding skin
  • Causes itching around anus - restlessness
  • Benign
61
Q

Pinworm Transmission

A
  • Fecal-oral transmission direct/indirect
  • Infection by swallowing infective eggs
  • Eggs can be airborne & ingested while breathing - small size
62
Q

Ascaris Lumbricoides (roundworm)

A
  • Adult worms live in upper small intestine
  • Females produce many eggs - become infective in 2-3wks in soil
  • Problems: migration of adult works & hypersensitivity to larvae in lungs
63
Q

Hookworm

A
  • Infect human via nematode parasites
  • Live in small intestine
  • Eggs passed in feces
  • Eggs hatch into larvae that can penetrate human ski
64
Q

Hookworm Transmission

A
  • Human feces used as fertilizer or defecation on soil
  • Walking barefoot on contaminated soil
  • 1 type ingestion of larvae
65
Q

Hookworm Risks

A
  • Warm, moist climates
  • Sanitation & hygiene poor
66
Q

Cestodes (tapeworm)

A
  • Flat segmented worms
  • Head, neck, chain segment (proglottids)
  • Live in intestines of some animals
67
Q

Tapeworm Transmission

A
  • Grazing/drinking contaminated water infects animals
  • Humans infected eating raw/undercooked meats from infected animal
68
Q

Tapeworm Infection Process

A
  • Head adheres to intestinal wall
  • Proglottids grow & produce eggs
  • Can live up to 30years in host
  • Usually mild - 1-2 adults
  • Invasive larval infections - serious complications
69
Q

Trematodes (flukes)

A
  • Parasitic flat worm
  • Infects vessels, GI tract, lungs or liver
  • Infection via raw fish, crabs from areas with flukes endemic
70
Q

Giardia

A
  • Not a helminth
  • Microscopic parasite
  • Causes giardiasis
71
Q

Giardiasis

A
  • Protected by outer shell - survive outside body for long periods
  • Tolerant to chlorine disinfection
72
Q

Giardiasis Transmission

A
  • Swallowing
  • Untreated water - most common
  • Lakes, rivers
  • Uncooked food
  • Contact with ill person
  • Travel
73
Q

Function of Liver

A
  • Process food
  • Remove harmful stuff from blood
  • Makes bile to help digest fats
  • Stores sugar
  • Helps blood clot
74
Q

ALT (alanine aminotransferase) Function

A
  • Convert amino acids into energy
  • Regulate liver’s metabolism
75
Q

ALT Significance

A

Elevated levels indicate liver damage/inflammation

76
Q

AST Function

A
  • Assists in conversion of amino acids
  • Crucial for energy production in cells
77
Q

AST Significance

A
  • Elevated levels may suggest liver damage
  • Elevated can suggest heart issues, muscle injuries, medications
78
Q

ALP Function

A
  • Removing phosphate groups from molecules
  • Bile production & transport
79
Q

ALP Significance

A
  • Elevated levels associated with liver/bone disease
  • Obstructed bile ducts, gallstones, liver tumours = elevated
80
Q

Bilirubin Function

A
  • Yellow pigment produced when old RBCs break down
  • Processed by liver & excreted in bile
  • Gives stool brown color
81
Q

Bilirubin Significance

A
  • Elevated levels = liver’s ability to process bilirubin problem
  • Jaundice common symptom
82
Q

Stool C&S Purpose

A
  • Presence of harmful microorganisms in GI tract
  • Pinpoint specific pathogens responsible for symptoms
  • Targeted treatment
83
Q

Rotavirus Testing

A
  • Stool sample - symptoms of V/D
  • ELISA method
  • RT-PCR
84
Q

ELISA

A
  • Detects specific antibodies/antigens present
  • Known antigen/abs immobilized on solid surface
  • Any matching abs/antigens will bind to immobilized molecules when sample added
  • Rapid, sensitive, specific results
85
Q

RT-PCR

A
  • Confirm presence of rotavirus genetic material
  • Accurate & rapid diagnosis
86
Q

Norovirus Testing

A
  • Collection of stool/vomit sample
  • ELISA
  • PCR - outbreak situations
87
Q

PCR

A
  • Takes tiny piece of DNA & makes lots of copies
  • Identify infections, check for genetic issues, DNA research
  • Crucial in COVID19 diagnosis from nose swabs
88
Q

E. coli Testing

A
  • Stool samples - symptoms of diarrhea, fever, abdominal pain
  • Routine stool culture
  • Then identify bacterial strains through biochemical testing
  • STEC - PCR to detect presence of virulence genes
89
Q

Botulism Testing

A
  • Examination of symptoms - weakness, paralysis, resp distress
  • Stool, blood, wound analysis
  • ELISA identify strain
90
Q

Salmonella Testing

A
  • Stool sample - diarrhea & fever
  • Cultured - will grow into colonies
  • Confirm colonies via special tests
91
Q

Listeriosis Testing

A
  • Blood/CSF cultures
  • PCR detect bacteria’s genetic material
92
Q

Helminths Testing

A
  • Analyzing stool samples
  • Detect presence of worm eggs, larvae, segments
  • Microscopy/fecal flotation - identify type of worm

3820: Microbiology & Immunology (11 decks)

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