Diseases of the Digestive System Flashcards
Chapter 25 (143 cards)
1
Q
How do microbes enter the digestive system?
A
fecal-oral route
2
Q
What are examples of the fecal-oral route?
A
contaminated food & water (microbes + toxins)
3
Q
How can we prevent microbes from entering
humans via the fecal-oral route? (3)
A
- good sewage treatment
- disinfection of drinking water
- proper food handling & cooking
4
Q
Describe the microbes found in the mouth:
A
over 400 species of normal flora
5
Q
Describe the microbes and pH of the stomach and small intestines (2):
A
- low pH
- few microbes
6
Q
The lower the pH….. (the < or > the microbes)
A
the less (<) microbes
7
Q
Describe the microbes in the large intestine (3):
A
- large # of bacteria
- anaerobes
- facultative anaerobes
8
Q
What are the Bacterial Diseases of the Lower GI Tract? (4)
A
- Staphylococcal Food Poisoning
- Typhoid Fever
- Cholera
- Traveler’s Diarrhea (E. coli gastroenteritis)
9
Q
What are the Viral Diseases of the Lower GI Tract? (2)
A
- Hepatitis
- Viral Gastroenteritis
10
Q
Define Food Infection:
A
pathogen enters GI tract & multiplies
11
Q
What happens if a microbe remains in the GI Tract?
A
infection becomes systemic
12
Q
Define Food Intoxication:
A
ingestion of an exotoxin
13
Q
What is another name for food intoxication?
A
food poisoning
14
Q
What is another name for food poisoning?
A
food intoxication
15
Q
Are symptoms in food intoxication caused by the microbe or by the toxin?
A
the toxin
16
Q
What causes the symptoms of food poisoning?
A
the toxin
17
Q
Define Gastroenteritis:
A
inflammation of stomach & intestinal mucosa
18
Q
What are the common symptoms of microbes in the GI tract? (3)
A
- diarrhea or dysentery (diarrhea with blood & mucus)
- abdominal cramps
- nausea, vomiting
19
Q
Which Bacteria causes Staphylococcal Food Poisoning?
A
Staphylococcus aureus
20
Q
What is Staphylococcus aureus relatively resistant to?
A
drying
21
Q
Describe Staphylococcus aureus (3):
A
- found in nasal passages & skin lesions
- tolerate high salt, organic compounds, & higher temps
- grows in custards, creamy salad dressing, sauces, ham
22
Q
What is the incubation time for Staphylococcal Food Poisoning?
A
~2-6 hours
23
Q
What are the Symptoms of Staphylococcal Food Poisoning? (3)
A
- diarrhea
- stomach cramps
- vomiting
24
Q
How long does Staphylococcal Food Poisoning last in a healthy person?
A
24 hours
25
What does Staphylococcus aureus secrete?
an exotoxin that is an enterotoxin
26
What is an enterotoxin?
a toxin that affects the intestines
27
How are enterotoxins inactivated?
heat stabile: boil food 30 minutes
28
What Bacteria causes Salmonellosis?
Salmonella sp.
29
Describe Salmonella sp. (2):
- gram (-)
- rod
30
Where is Salmonella sp. found? (4)
- intestines of many animals
- eggs + egg products
- poultry
- pet reptiles (turtles & iguanas)
31
What does Salmonella enteritica cause?
salmonellosis
32
What does S. typhi cause?
typhoid fever
33
What bacteria causes Typhoid Fever?
S. typhi
34
How do we differentiate between different species of bacteria?
cell surface antigens
35
What is Vi Ag?
Capsule Ag
36
What is H Ag?
Flagella
37
What is the incubation period for a Food Infection?
12-36 hours
38
What are the steps of a Food Infection? (3)
- microbe enters GI and epithelial cells lining intestines
- multiplies within cells + enters lymphatics
- moves to blood + other organs
39
What are the symptoms of Food Infection? (4)
- fever
- nausea
- abdominal cramps
- diarrhea
40
How long do Food Infections typically last?
a few days
41
What bacteria causes Typhoid Fever?
Salmonella typhi
42
Where is Salmonella typhi found?
In humans only (no animals)
43
What are the Virulence Factors of Salmonella typhi? (3)
- endotoxins
- can replicate within macrophages
- can enter intestinal epithelial cells
44
How is Typhoid Fever spread? (2)
- ingested
- fecal-oral route
45
What is the incubation period for Typhoid Fever?
~2 weeks
46
What is the path that Typhoid Fever takes in the body? (4)
- microbe enters intestines + penetrates intestinal lining
- enters lymphatic
- re-enters intestines + pierces intestinal wall leading to bleeding
- microbe shed in feces
47
What are the Symptoms of Typhoid Fever? (4)
- fever
- weakness
- "rose spots" on trunk
- diarrhea (appears weeks later)
48
How long does Typhoid Fever last for?
2-3 weeks
49
Is Typhoid Fever fatal?
It can be because of internal bleeding (intestinal wall)
50
Who are the typical carriers of Typhoid Fever?
food handlers
51
Where is Typhoid Fever found in the human body?
Gallbladder (1-3%)
52
Who is an example of a Typhoid Fever Outbreak?
Typhoid Mary: asymptomatic food handler that caused various outbreaks
53
What are the Four F's of Typhoid Fever?
- Feces
- Flies
- Fingers
- Food
54
How is Typhoid Fever Prevented? (3)
- proper sewage treatment
- proper water treatment
- proper food handling
55
What Vaccines are available for Typhoid Fever? (2)
- subunit vaccine
- live oral vaccine
56
What bacteria causes Cholera?
Vibrio cholera
57
Describe Vibrio cholera (3):
- gram (-)
- rod (comma shaped)
- high pH
58
What is the most common serotype of Vibrio cholera?
O:1
59
What is O:1 serotype divided into?
2 major biovars (based on biochemical properties)
60
What are the 2 biovars serotype O:1 is divided into?
- El Tor (South America)
- Classical
61
How is Cholera spread? (2)
- ingestion of contaminated water
- improperly cooked seafood
62
What is the path that Cholera takes in the body? ()
- microbe enters intestines (stays there)
- adheres to intestinal lining (exotoxin = choleragen)
63
Is Cholera an invasive pathogen?
No
64
Does Cholera release and endotoxin or an exotoxin?
Exotoxin
65
What is the Exotoxin that Cholera releases?
Choleragen
66
What does Choleragen do?
- activates Adenyl Cyclase (enzyme): increases cAMP production
67
What does Adenyl Cyclase do?
Increases cAMP production
68
What is c-AMP?
increases secretion of chloride + bicarbonate out of blood into lumen of intestines
69
What happens when sodium cannot leave intestines into blood?
Diarrhea
70
What are the Symptoms of Cholera? (5)
- vomiting
- severe "rice water" diarrhea
- coma
- convulsion
- fever
71
What is the Incubation period for Cholera?
few hours - few days
72
Why would someone die from Cholera?
Dehydration within 48 hours if untreated
73
What Treatments are there for Cholera? (2)
- replace electrolytes + water
- tetracycline
74
How is Cholera prevented? (2)
- proper water treatment
- proper food cooking + storage (seafood)
75
What Vaccines are there for Cholera? (2)
- killed cell vaccine (part of toxin)
- oral vaccine (not very effective)
76
What bacteria causes Traveler's Diarrhea?
E. coli
77
Describe E. coli (3):
- facultative anaerobic
- gram (-)
- rod
78
(T/F) E. coli is an Enterobacteriaceae
True
79
(T/F) Most E. coli are pathogenic
False
80
What do most pathogenic strains of E. coli contain?
Fimbriae (for attachment to intestinal cells)
81
Do all E. coli produce toxins?
No, only some
82
What are the symptoms of Enterotoxigenic E. coli?
watery diarrhea
83
What is the major cause of Enterotoxigenic E. colli?
contaminated water
84
Is Enterotoxigenic E. coli an invasive form?
No
85
What type of E. coli is in Enterohemorrhagic E. coli?
serotype O158:h7
86
What does Enterohemorrhagic E. coli (EHEC) release?
enterotoxin = Shiga like toxin
87
What is the cause of Enterohemorrhagic E. coli?
ingestion of undercooked meats or raw milk
88
What is the path of Enterohemorrhagic E. coli?
Vero toxin -> hemorrhage -> dysentery
89
What is dysentery?
bloody diarrhea
90
What is the major reservoir for Enterohemorrhagic E. coli?
Cattle
91
What is the major complication for Enterohemorrhagic E. coli?
hemolytic - uremic syndrome = leads to kidney failure
92
What is Hepatitis?
inflammation fo the liver
93
What are the 5 different types of hepatitis?
- A
- B
- C
- D
- E
94
Which virus causes Hepatitis A?
Picorna Virus (RNA)
95
Which virus causes Hepatitis B?
Hepadna Virus (DNA)
96
Which virus causes Hepatitis C?
Flaviviridae (RNA)
97
What virus causes Hepatitis D?
(RNA)
98
What virus causes Hepatitis C?
Caliciviridae (RNA)
99
What is the second most frequent reported infectious disease in the U.S.?
Hepatitis
100
Describe the Picorna Virus (5):
- hepatitis A
- naked
- icosahedral
- single stranded
- RNA
101
Where does the Picorna Virus replicate in?
the intestines
102
Which Hepatitis is known as the infectious Hepatitis?
Hepatitis A
103
How does Hepatitis A spread in the body?
intestines -> blood -> liver, spleen etc.
104
How is Hepatitis A spread?
fecal-oral route
105
What are the main causes of Hepatitis A? (2)
- contaminated water
- contaminated food (shellfish)
106
How is Hepatitis A shed from the body?
through feces
107
What are the Symptoms of Hepatitis A? (3)
- fever
- headache
- jaundice
108
What is the incubation period of Hepatitis A?
~ 2- 6 weeks
109
Is Hepatitis A chronic or acute?
Acute
110
What Vaccines are available for Hepatitis A?
killed vaccine (2 doses)
111
Describe Hepadnaviridae (5):
- hepatitis B
- enveloped
- icosahedral
- double stranded
- DNA
112
Which Hepatitis is known as the Serum Hepatitis?
Hepatitis B
113
How is Hepatitis B spread? (4)
- sexual intercourse (anal/oral)
- blood transfusions
- contaminated needles
- mother to child
114
How is Hepatitis B spread in the body?
virus -> liver replicates (also lymphoid tissues)
115
What are the Symptoms of Hepatitis B? (3)
- fever
- joint pain
- loss of appetite (leads to jaundice)
116
How long is the incubation period for Hepatitis B?
~4 - 26 weeks
117
Hepatitis B is Chronic in what percent of infected people?
10%
118
What characteristics do Chronic Carriers of Hepatitis B have? (2)
- virus source
- increased risk of liver cancer
119
What is Hepatocellular carnicoma?
liver cancer
120
What treatment is there for Hepatitis B?
alpha interferon
121
How is Hepatitis B prevented?
recombinant subunit vaccine (surface antigen)
122
Describe Flavivirdae (4):
- hepatitis C
- enveloped
- icosahedral
- RNA
123
Which Hepatitis is known as the NANB (non-A, non-B virus) Hepatitis?
Hepatitis C
124
How is Hepatitis C spread? (5)
- transfusions
- sexual
- needles
- razors
- tattoo
125
What are the Symptoms of Hepatitis C? (2)
- milder than other hepatitis in acute form
- causes high blood concentrations of alanine transferase
126
What is the Incubation Period for Hepatitis C?
2 - 4 weeks and 8 - 12 weeks
127
What percent of infected develop Chronic Hepatitis C?
50%
128
What is the Treatment for Hepatitis C?
combination of antivirals for various months (too expensive)
129
What Vaccines are there for Hepatitis C?
None (no immunity develops)
130
Describe Hepatitis D Virus (3):
- enveloped
- RNA
- defective
131
Can Hepatitis D cause infection by itself?
No, must co-infect with HBV
132
How is Hepatitis D spread?
similar to HBV
133
What are the Symptoms of Hepatitis D?
intensifies symptoms of HBV
134
What is the incubation period of Hepatitis D?
2 - 12 weeks
135
What can HBV and HDV do together?
extensive liver damage + higher mortality rate
136
Describe Caliciviridae (4):
- Hepatitis E
- naked
- single stranded
- RNA
137
Which Hepatitis is known as the Infectious NANB Hepatitis?
Hepatitis E
138
How is Hepatitis E spread?
fecal - oral route
139
Where is Hepatitis E found?
areas with poor sanitation
140
What are the Symptoms of Hepatitis E? (2)
- similar to HAV
- no chronic stage
141
In what group is Hepatitis E virus more common in?
adults
142
In what group does Hepatitis E have a higher mortality rate in?
pregnant women
143
What Vaccines are there for Hepatitis E?
None (no immunity produced)
