11. Major bacterial and viral pathogens causing enteric infections

Question 1

Gastroenteritis

Answer 1

Syndrome including:
 nausea
 vomiting
 diarrhoea
 abdominal discomfort

Question 2

Dysentery

Answer 2

Inflammation of GI Tract
small stool with blood/pus
pain
fever

Question 3

Enterocolitis

Answer 3

Inflammation of the mucosa of both large & small intestine

Question 4

Enteritis

Answer 4

inflammation of the small intestine

Question 5

Colitis

Answer 5

inflammation of the large intestine, especially the colon

Question 6

Toxic Shock Syndrome (TSS)

Answer 6

Body temperature > 38.9 °C (102.02 °F)

Systolic blood pressure < 90 mmHg

Diffuse rash,erythroderma, blanching

Question 7

6 types of Pathogenic Ecoli

Answer 7

1) EPEC
2) ETEC
3) EHEC
4) EIEC
5) EAEC
6) DAEC

Question 8

EPEC

Answer 8

Bind to epithelial cells

disrupt microvilli

Question 9

ETEC

Answer 9

colonize the intestinal epithelium

secrete toxins

Question 10

EHEC

Answer 10

Shiga toxin

binds to Verotoxin* receptors on renal cells

causes :

1) haemolytic-uremic syndrome (HUS)
2) Haemorrhagic colitis (HC)

Question 11

EIEC

Answer 11

Invade cells by endocytosis

multiply in intestinal epithelial cells

ulceration of the intestinal lining

Question 12

DAEC

Answer 12

Sometimes cause diarrhoea

recurrent urinary tract infections

Question 13

Haemolytic-Uremic Syndrome HUS

Answer 13

Acute renal failure

Anaemia, neurological complications

Dialysis/fluid replacement

Question 14

Salmonella

Answer 14

Gram –ve
rod bac

O (cell wall)

H (flagella)

2000 serotypes

Causes secretion of fluid into gut

Question 15

Cholera

Answer 15

Curved bac
gram negative rod

Diarrhoea

Dehydration

Hypovolemic shock

Question 16

Treatment of cholera

Answer 16

prompt rehydration

salt replacement required

Question 17

Viral causes of diarrhoea

Answer 17

1) Rotavirus

2) Norovirus

Question 18

Rotavirus

Answer 18

Double stranded RNA Virus
double shell, non-enveloped

Loss of microvilli = less S.A to absorb nutrients

Question 19

Rotavirus treatment

Answer 19

fluids and salt replacement

Question 20

Rotavirus and Norovirus diagnosis

Answer 20

EM or ELISA

Question 21

Incubation time of rotavirus

Answer 21

24-48 hr

Vomiting and diarrhoea for 4-7 days

Question 22

Noroviruses

Answer 22

Small Round Structured Viruses (SRSV)

Question 23

Incubation time of Norovirus

Answer 23

12-24 hours

Question 24

Symptoms of Norovirus

Answer 24

Projectile vomiting/diarrhoea

Fever, chills

Abdominal pain (acute Gastroenteritis)

Question 25

Preventing spread of Noroviruses

Answer 25

Cooking shell fish >65oC Removing and washing contaminated clothing/bedding Barrier nursing/quarantine

Question 26

Cryptosporidium Incubation period

Answer 26

average of 7 days

Question 27

Symptoms of Cryptosporidium

Answer 27

watery diarrhoea dehydration weight loss abdominal pain fever nausea and vomiting

Question 28

Treatment of Cryptosporidium

Answer 28

fluid and electrolyte replacement   Nitazoxanide For persons with AIDS, anti-retroviral therapy

Question 29

Clinical Features of Taenia saginata (beef tapeworm)

Answer 29

mild abdominal symptoms  proglottids Occasionally, appendicitis or cholangitis can result from migrating proglottids

Question 30

Clinical features of Taenia solium (pork tapeworm)

Answer 30

proglottids | cysticercosis

Question 31

Clinical Features of Ascaris lumbricoides

Answer 31

may cause stunted growth abdominal pain haemoptysis oral expulsion cough

Question 32

Treatment of Human nematode hookworms

Answer 32

anthelmintics

Question 33

Hepatitis A Virus

Answer 33

Non-enveloped | positive sense RNA virus

Question 34

HAV Transmission

Answer 34

Mainly Fecal-Oral Route Close personal contact Contaminated food, water Blood exposure

Question 35

Incubation period of HAV

Answer 35

Average 30 days

Question 36

Hepatitis B Virus – HBV

Answer 36

Double stranded DNA virus + strand not complete Replication involves a reverse transcriptase Classified into 8 genotypes (A-H)

Question 37

HBV Incubation period

Answer 37

Average 60-90 days

Question 38

Transmission of HBV

Answer 38

Mother to child in utero High Risk sexual activity The eye is route for entry

Question 39

Treatment of HBV

Answer 39

Entecavir Interferon Lamivudine Adefovir

Question 40

Incubation period of Hepatitis C

Answer 40

Average 6-7 wks

Question 41

HCV Transmission

Answer 41

Transfusion from infected donor IV drug use Haemodialysis needlestick injury Multiple sex partners Birth to HCV-infected mother

Question 42

HCV treatment

Answer 42

Interferon Ribavirin

Question 43

Ecoli causing Bloody diarrhoea

Answer 43

1) EIEC | 2) EHEC

Question 44

Ecoli causing watery diarrhoea

Answer 44

1) EPEC | 2) ETEC

Question 45

Taenia Saginata

Answer 45

Beef tapeworm

Question 46

Taenia Solium

Answer 46

Pork tapeworm