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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
HEV Serology
- 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
26
Infectious Enterocolitis
- 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
27
Viral Infection Target
- Superficial epithelium of small intestine - Lead to cell destruction & osmotic diarrhea
28
Bacterial Enterocolitis
- 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
29
Diarrhea Definition
- Passage of 300+ grams of stool per day - Mainly caused by excretion of excess fecal water - Acute 2wks or less - associated with infectious causes
30
Gastroenteritis
Vomiting associated with diarrhea
31
Rotavirus Structure
- Non-enveloped - Double stranded RNA - Group A serogroup most prevalent
32
Rotavirus Progression
- 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
33
Norovirus Structure
- Small round viruses of diarrhea - RNA - caliciviridae family - 4 serotypes
34
Norovirus Progression
- 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
35
Listeria Monocytogenes
- Causes foodborne illness listeriosis - Facultatively anaerobic bacteria - 5 flagella - tumbling motility
36
Listeria Prevention
- Pasteurization - Meat processing - strict sanitation policies - Keeping food refrigerated below 4 degrees - Cooking meats to 73 degrees
37
Clostridium Structure
- Anaerobic - Rods - Secrete potent exotoxins & enzymes
38
Clostridium Complications
- Botulism - Tetanus - Gas gangrene - Pseudomembranous colitis
39
Clostridium Botulism
- 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
Infant Botulism
- Infants ingest spores - Commonly from honey - release toxins in intestines - Infants should avoid honey
41
Campylobacter Structure
- Slender spiral - Single polar flagellum - corkscrew through fluids fast - Microaerophilic & capnophilic - no grow in air - Incubation 1-7 days
42
Campylobacter Causes
- 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
E Coli
- Facultative anaerobic bacterium - Normally resides in intestines of healthy people/animals - Most strains harmless & aid in digestion
44
E Coli Contamination
- Meats - during slaughter, bacteria from intestines contacts meat - Raw milk, soft cheeses - Unpasteurized apple cider, juices - Fruits & veg - animal feces runoff
45
Shinga
- Toxin produced by E coli infection - Causes STEC infection - Damage lining of small intestine & cause diarrhea
46
Shigella
- Facultative anaerobic - Nonmotile - Rod shaped - Closely related to E.coli - Can survive in intestinal tract proteases & acids
47
Shigellosis
- Intestinal infection - Caused by shigella bacteria
48
Shigella Transmission
- Ingest small amounts of bacteria from infected stool - Contaminated food/water - Swimming in unsafe water - swallow it
49
Shigella Process
- Penetrate colonic mucosa - Degrading epithelium - Causing acute inflammatory colitis - Leads to blood, inflammation, mucus in intestines
50
Shigella Risk Factors
- Children under age 5 - Living in group housing, group settings/activities - Living/traveling to areas that lack sanitation - Men having sex with men
51
Yersinia
- Coccobacilli bacteria - Facultative anaerobes
52
Yersinosis Transmission
- 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
Yersinosis Complications
- Skin rash - Joint pains - Spread of bacteria to blood stream
54
Yersinia Pestis
Causative agent of bubonic plague
55
Salmonella Typhi
- 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
Salmonella Structure
- Rod shaped - Flagellated - Obligate anaerobe - Produce endotoxin inactivated by gastric acids - large amount of bacteria required
57
Helminths Transmission
- Soil - Oral ingestion of larvae infected tissue - undercooked meats
58
Pinworm (roundworm)
- Small, thin, white - Nematode class - Most common nematode infection
59
Pinworm Risk Populations
- Children - Institutionalized persons - Household members & caretakers of infected individual
60
Enterobius Vermincularis (roundworm)
- Female leaves intestine through anus & deposit eggs on surrounding skin - Causes itching around anus - restlessness - Benign
61
Pinworm Transmission
- Fecal-oral transmission direct/indirect - Infection by swallowing infective eggs - Eggs can be airborne & ingested while breathing - small size
62
Ascaris Lumbricoides (roundworm)
- 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
Hookworm
- Infect human via nematode parasites - Live in small intestine - Eggs passed in feces - Eggs hatch into larvae that can penetrate human ski
64
Hookworm Transmission
- Human feces used as fertilizer or defecation on soil - Walking barefoot on contaminated soil - 1 type ingestion of larvae
65
Hookworm Risks
- Warm, moist climates - Sanitation & hygiene poor
66
Cestodes (tapeworm)
- Flat segmented worms - Head, neck, chain segment (proglottids) - Live in intestines of some animals
67
Tapeworm Transmission
- Grazing/drinking contaminated water infects animals - Humans infected eating raw/undercooked meats from infected animal
68
Tapeworm Infection Process
- 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
Trematodes (flukes)
- Parasitic flat worm - Infects vessels, GI tract, lungs or liver - Infection via raw fish, crabs from areas with flukes endemic
70
Giardia
- Not a helminth - Microscopic parasite - Causes giardiasis
71
Giardiasis
- Protected by outer shell - survive outside body for long periods - Tolerant to chlorine disinfection
72
Giardiasis Transmission
- Swallowing - Untreated water - most common - Lakes, rivers - Uncooked food - Contact with ill person - Travel
73
Function of Liver
- Process food - Remove harmful stuff from blood - Makes bile to help digest fats - Stores sugar - Helps blood clot
74
ALT (alanine aminotransferase) Function
- Convert amino acids into energy - Regulate liver's metabolism
75
ALT Significance
Elevated levels indicate liver damage/inflammation
76
AST Function
- Assists in conversion of amino acids - Crucial for energy production in cells
77
AST Significance
- Elevated levels may suggest liver damage - Elevated can suggest heart issues, muscle injuries, medications
78
ALP Function
- Removing phosphate groups from molecules - Bile production & transport
79
ALP Significance
- Elevated levels associated with liver/bone disease - Obstructed bile ducts, gallstones, liver tumours = elevated
80
Bilirubin Function
- Yellow pigment produced when old RBCs break down - Processed by liver & excreted in bile - Gives stool brown color
81
Bilirubin Significance
- Elevated levels = liver's ability to process bilirubin problem - Jaundice common symptom
82
Stool C&S Purpose
- Presence of harmful microorganisms in GI tract - Pinpoint specific pathogens responsible for symptoms - Targeted treatment
83
Rotavirus Testing
- Stool sample - symptoms of V/D - ELISA method - RT-PCR
84
ELISA
- 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
RT-PCR
- Confirm presence of rotavirus genetic material - Accurate & rapid diagnosis
86
Norovirus Testing
- Collection of stool/vomit sample - ELISA - PCR - outbreak situations
87
PCR
- 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
E. coli Testing
- 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
Botulism Testing
- Examination of symptoms - weakness, paralysis, resp distress - Stool, blood, wound analysis - ELISA identify strain
90
Salmonella Testing
- Stool sample - diarrhea & fever - Cultured - will grow into colonies - Confirm colonies via special tests
91
Listeriosis Testing
- Blood/CSF cultures - PCR detect bacteria's genetic material
92
Helminths Testing
- 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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