MICRO Infections of the GIT - Week 5/6

Question 1

Transmission of H. pylori gastric ulcers

Answer 1

Person-to-person, ingestion of contaminated food/water.

Question 2

Symptoms of gastric ulcers

Answer 2

o Symptoms: dyspepsia, upper abdo pain, nausea, frequent burping, bloating
 NB: infections are, however, commonly asymptomatic.

Question 3

Complications of H. pylori gastric ulcers

Answer 3

Gastric & duodenal ulcers, acute & chronic gastritis, gastric adenocarcinoma, mucosa-associated lymphoid tissue (MALT) lymphoma.

Question 4

Diagnosis of H. pylori gastric ulcers

Answer 4

Urea breath tests, faecal H. pylori antigen testing, endoscopy w biopsy specimens, histopathology, rapid urease test of biopsy, PCR.

Question 5

Transmission of non-typhoidal salmonella

Answer 5

o Transmission/sources: large animal reservoirs (transferred to humans via contaminated food)

Question 6

Diagnosis of non-typhoidal salmonella

Answer 6

o Diagnosis: Culture on selective media, rapid molecular methods, blood cultures.

Question 7

Treatment of non-typhoidal salmonella

Answer 7

o Treatment : usually self-limiting & resolves without treatment, fluid & electrolyte replacement.

Question 8

Complications of non-typhoidal salmonella

Answer 8

Invasive infection, septicaemia

Question 9

Causative agents of typhoid & paratyphoid salmonella/enteric fever

Answer 9

Salmonella typhi & salmonella paratyphi

Question 10

Transmission of typhoid & paratyphoid salmonella/enteric fever

Answer 10

o Transmission: person-to-person via contaminated food/water

Question 11

Diagnosis of typhoid & paratyphoid salmonella/enteric fever

Answer 11

o Diagnosis: stool, blood culture or culture from another body fluid/tissue

Question 12

Symptoms of typhoid & paratyphoid salmonella/enteric fever

Answer 12

o Symptoms: fever, malaise, aches, diarrhoea & constipation, rose spots

Question 13

Treatment & prevention of typhoid & paratyphoid salmonella

Answer 13

Antibiotics
Vaccine developed.

Question 14

Causative agents of shigellosis

Answer 14

o Causative agents: Shigella sonnei , S. flexneri, S. boydii , S. dysenteriae.

Question 15

Transmission of shigellosis

Answer 15

o Transmission: person-to-person via faecal-oral route (highly infectious).

Question 16

Symptoms of shigellosis

Answer 16

o Symptoms: mild-severe gastroenteritis, initial watery diarrhoea which later worsens to contain mucous & blood , lower abdominal cramps.

Question 17

Diagnosis of shigellosis

Answer 17

Culture or rapid molecular tests.

Question 18

Treatment of shigellosis

Answer 18

Antibiotics for severe cases, rehydration.

Question 19

Causative agents of campylobacter

Answer 19

Campylobacter jejuni.

Question 20

Transmission of campylobacter

Answer 20

o Transmission: large animal reservoir via contaminated food consumption (highly infectious).

Question 21

Treatment of camylobacter

Answer 21

Antibiotics for invasive infections.

Question 22

Causative agents of cholera

Answer 22

V. cholerae.

Question 23

Transmission of cholera

Answer 23

Contaminated food/water.

Question 24

Symptoms of cholera

Answer 24

o Symptoms: severe watery non-bloody diarrhoea (rice water stools), massive fluid loss & electrolyte imbalance.

Question 25

Diagnosis of cholera

Answer 25

o Diagnosis: culture, PCR tests.

Question 26

Treatment & prevention of cholera

Answer 26

o Treatment: oral or IV fluids, antibiotics. Vaccine developed.

Question 27

Causative agent of C. difficile antibiotic-associated diarrhoea.

Answer 27

o Causative agent: C. difficile (antibiotic disruption of normal gut flora -> C. difficile multiplication).

Question 28

C. difficile symptoms

Answer 28

o Symptoms: diarrhoea, abdominal pain, fever after antibiotic treatment.

Question 29

Complications of C. difficile infection.

Answer 29

Toxic megacolon.

Question 30

Diagnosis of C. difficile

Answer 30

C. difficile toxin in stools.

Question 31

Treatment of C. difficile

Answer 31

FMT, anti-anaerobic (e.g., metronidazole) or vancomycin.

Question 32

Causative agents of E. Coli

Answer 32

o Causative agents: enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC), enteroinvasive (EIEC), enteroaggregative (EAEC).

Question 33

Causative agents of staphylococcal food poisoning

Answer 33

S. aureus.

Question 34

Transmission of staphylococcal food poisoning

Answer 34

Contaminated food.

Question 35

Symptoms of staphylococcal food poisoning.

Answer 35

Vomiting or diarrhoea 1-6hrs post consumption.

Question 36

Treatment of staphylococcal food poisoning

Answer 36

Usually self-limiting.

Question 37

Bacillus cereus causative agent.

Answer 37

B. cereus.

Question 38

Transmission of B. cereus

Answer 38

o Transmission: spores (present in soil/food ) survive cooking, germinate upon cooling.

Question 39

Symptoms of 2 x types of bacillus cereus.

Answer 39

o Symptoms:  Emetic form: vomiting 15min-4hrs post consumption (due to ingestion of enterotoxin).  Diarrhoeal form: watery diarrhoea within 8-12hrs post consumption (due to production of enterotoxin in the gut).

Question 40

Causative agent botulism.

Answer 40

C. botulinum.

Question 41

Transmission of botulism.

Answer 41

Toxins in food (often canned food) ingested.

Question 42

Symptoms of botulism.

Answer 42

Descending paralysis.

Question 43

Complications of botulism.

Answer 43

Death.

Question 44

Clostridium gastroenteritis causative agents.

Answer 44

C. perfringens.

Question 45

Clostridium gastroenteritis transmission.

Answer 45

o Transmission: ingestion of spore-containing or inadequately cooked food.

Question 46

Clostridium gastroenteritis symptoms.

Answer 46

Abdominal pain, diarrhoea.

Question 47

Clostridium gastroenteritis complications.

Answer 47

Necrosis of the small bowel.

Question 48

Clostridium gastroenteritis treatment.

Answer 48

Usually self-limiting.

Question 49

Norovirus causative agent.

Answer 49

Norovirus virus.

Question 50

Norovirus transmission.

Answer 50

Food/water-borne (highly infectious - w short 24h incubation period).

Question 51

Norovirus symptoms.

Answer 51

Nausea, abdo pain, vomiting (projectile), diarrhoea.

Question 52

Norovirus diagnosis.

Answer 52

PCR, electron microscopy, ELISA.

Question 53

Norovirus treatment.

Answer 53

Usually self-limiting.

Question 54

Rotavirus causative agents.

Answer 54

Rotavirus virus.

Question 55

Rotavirus transmission.

Answer 55

Faecal-oral route or contaminated food/water.

Question 56

Rotavirus symptoms.

Answer 56

o Symptoms: vomiting, diarrhoea , respiratory symptoms (e.g., cough, coryza).

Question 57

Rotavirus treatment.

Answer 57

o Treatment: fluid & electrolyte replacement (particularly for at risk populations).

Question 58

Rotavirus diagnosis.

Answer 58

PCR, ELISA.

Question 59

Rotavirus prevention.

Answer 59

Vaccine.

Question 60

Hep A symptoms

Answer 60

Usually asymptomatic.

Question 61

Hep B symptoms

Answer 61

Usually asymptomatic.

Question 62

Hep C symptoms.

Answer 62

Usually asymptomatic.

Question 63

Hep D symptoms.

Answer 63

Usually asymptomatic.

Question 64

Hep E symptoms.

Answer 64

Usually asymptomatic.

Question 65

Hep A treatment.

Answer 65

Usually self-limiting.

Question 66

Hep A complications.

Answer 66

Serious or fatal fulminant hepatitis.

Question 67

Hep B treatment.

Answer 67

Usually self-limiting.

Question 68

Hep B complications.

Answer 68

Cirrhosis, liver failure, liver cancer.

Question 69

Hep C treatment.

Answer 69

Usually self-limiting.

Question 70

Hep C complications.

Answer 70

Cirrhosis, liver failure, liver cancer.

Question 71

Hep D treatment.

Answer 71

Usually self-limiting.

Question 72

Hep E treatment.

Answer 72

Usually self-limiting.

Question 73

Hep A transmission.

Answer 73

Contaminated food, water, objects, person-to-person.

Question 74

Hep B transmission.

Answer 74

Contact w infected body fluids.

Question 75

Hep C transmission.

Answer 75

Contact w infected body fluids.

Question 76

Hep D transmission.

Answer 76

Contact w infected blood.

Question 77

Hep E transmission.

Answer 77

Faecal-oral route (often via contaminated water or undercooked meat).

Question 78

+ve HBsAg indicates

Answer 78

Infection/recent vaccination.

Question 79

+ve HBeAg indicates

Answer 79

Acute phase infection.

Question 80

+ve HBsAb

Answer 80

Infection/previous vaccination.

Question 81

HBeAb +ve, but HBeAg -ve indicates

Answer 81

Been through active phase - immune response.

Question 82

When does the the HBeAg escape?

Answer 82

During infection.

Question 83

A higher HBeAg level indicates:

Answer 83

Higher infectivity level.

Question 84

IgM high titre indicates... IgM low titre indicates...

Answer 84

Acute infection. Chronic infection.

Question 85

IgG +ve, but HBsAg -ve indicates

Answer 85

Past infection.

Question 86

H. pylori microscopy

Answer 86

Gram -ve spiral bacterium.

Question 87

Campylobacter jejuni microscopy

Answer 87

Curved/S-shaped gram -ve.

Question 88

C. difficile toxin A and B.

Answer 88

Toxin A (enterotoxin) -> increased intestinal permeability & fluid secretion. Toxin B (cytotoxin) -> colonic inflammation, haemostasis & tissue necrosis in the colon.

Question 89

C. perfringens microscopy

Answer 89

Anaerobic gram +ve, spore-forming rod.

Question 90

Which Hep viruses are transmitted via faecal-oral route?

Answer 90

Hepatitis A and E are transmitted via faecal-oral route (often food-borne infections e.g., shellfish). (Non-enveloped/naked viruses tend to be very hardy and tough and can survive through acid of the stomach -> GIT infectious agents).

Question 91

Amoebiasis mode of transmission.

Answer 91

Contaminated food/water or person-to-person via faecal-oral route. NB: also involves cyst formation.

Question 92

Giardiasis mode of transmission.

Answer 92

Contaminated food/water or person-to-person.

Question 93

Amoebiasis signs, symptoms & complications.

Answer 93

Asymptomatic OR diarrhoea, dysentery, abdominal distension, fever. Complications – liver abscess (symptoms incl. fever, nausea, liver, intermittent diarrhoea, mucous, pain, flatulence, weight loss).

Question 94

Giardiasis signs & symptoms.

Answer 94

Asymptomatic OR weight loss, GI symptoms incl. diarrhoea, nausea, stomach cramps, gas, greasy stools, dehydration, malnutrition.

Question 95

Amoebiasis diagnosis.

Answer 95

Stool ova & parasite exam, immunoassay, serology, biopsy, molecular & antibody tests. MRI can be used to detect liver abscesses.

Question 96

Giardiasis diagnosis.

Answer 96

Stool ova & parasite exam, immunoassay, ELISA.

Question 97

Ascariasis/roundworm mode of transmission.

Answer 97

Eggs of worms are transmitted via contaminated food/water.

Question 98

Hookworm mode of transmission.

Answer 98

Eggs develop into larvae in soil contaminated by dog or cat faeces -> penetrate the skin -> reside in lumen of small/large intestine.

Question 99

Roundworm signs, symptoms, complications.

Answer 99

Shortness of breath, cough, nausea, diarrhoea, blood in the stools, abdominal pain, weight loss, fatigue. Complications – children w substantial infections may experience intestinal blockage.

Question 100

Hookworm signs, symptoms, complications.

Answer 100

Cough, itchy rash, loss of appetite, abdominal pain, diarrhoea., cutaneous larva migrans.

Question 101

Prevention of helminth infections.

Answer 101

Clean water, improving sanitation, improving hygiene, not walking barefoot, deworming.

Question 102

Roundworm diagnosis.

Answer 102

Eggs can be ID via microscopy. Worms via XRT, MRI, USS.

Question 103

Hookworm diagnosis.

Answer 103

Stool microscopy.