Gastroenteritis Outbreaks

Question 1

Are gastro outbreaks nationally notifiable?

Answer 1

No.

Question 2

Are gastro outbreaks notifiable in Tasmania?

Answer 2

Yes if suspected in RCF, hospital, childcare facility

Question 3

What is the most common organism causing gastro outbreaks?

Answer 3

Norovirus (Norwalk virus)

Others: rotavirus, astroviruses, adenoviruses; bacteria, toxins and parasites - often food/waterborne

Question 4

What is the typical mode of transmission for gastro outbreaks?

Answer 4

Faecal-oral, person-to-person or via fomites

Question 5

What criteria would mean Norovirus is the most likely suspected pathogen?

Answer 5

Kaplan’s criteria
* > 50% of affected have vomiting
* mean incubation 24-48hr
* mean duration of illness 12-60hrs
* no bacterial pathogen in stool

Question 6

What are high-risk settings for gastro outbreaks?

Answer 6

• Childcare
• RACF, RCF
• Hospitals
• Camps
• Prisons
• Cruise ships
• Other close quarters
• Food premises

Question 7

What are the confirmed and probable case definitions for individual outbreaks?

Answer 7

Suspected: ≥3 loose bowel movements and/or ≥2 vomiting in 24 hours + epi association to outbreak

Confirmed: as above AND pathogen detection

3:2:1 E P

Question 8

What is the outbreak definition for a gastro outbreak?

Answer 8

CDNA: ≥2 linked cases of D/V within 24h/other timeframe.

Question 9

What is the peak period for gastro outbreaks?

Answer 9

Late winter to early summer

Question 10

How are gastro outbreaks prevented?

Answer 10

• Routine IPC and cleaning
• Hand hygiene
• Food hygiene
• Exclusion of unwell people from work/childcare
• Vaccination - rotavirus

Question 11

What is the guideline for gastro outbreaks?

Answer 11

CDNA Guidelines for public health management of gastro outbreaks due to norovirus or suspected viral agents

https://www.health.gov.au/resources/publications/norovirus-and-suspected-viral-gastroenteritis-cdna-national-guidelines-for-public-health-units

Question 12

Who are the key team members in an OMT for a gastro outbreak?

Answer 12

PHP, PHOs, EHOs, epi (OzFoodNet?), comms, IPC, facility IPC/manager

Question 13

What is an immediate control action for a gastro outbreak?

Answer 13

Urgent IPC advice, consider early site visit (inspection, samples, advice).

Question 14

How would you assess the likely mode of transmission in a gastro outbreak?

Answer 14

Sx, exposures, epi curve, lab tests

Question 15

What makes up the environmental investigation of a gastro outbreak?

Answer 15

ECEC/RCFs: council EHO visit to review IPC, cleaning, (supervise clean-up), give advice, escalate concerns. Hospital via IPC team

Question 16

What analytic studies can be considered for a gastro outbreak?

Answer 16

Case-control or cohort study

Question 17

What are general control measures for a gastro outbreak?

Answer 17

• Hand hygiene (washing with soap and water preferred) - scrupulous
• Signage
• Limit visitors (and inform of outbreak)
• Reduce transfers in/out
• Close or restrict common areas
• No sandpits or play doh (childcare)

Question 18

How are cases managed in a gastro outbreak?

Answer 18

• Ill staff/children home until 48h post Sx
• RCF/hospital isolate/cohort until 48h post Sx, contact + droplet precautions, cohort staff (sick/well patients)

Question 19

For how long should cases be isolated in a gastro outbreak?

Answer 19

Until 48hours post symptom resolution

Question 20

How are contacts managed in a gastro outbreak?

Answer 20

Close monitoring for Sx, isolate and test if Sx

Question 21

What environmental management is required for a gastro outbreak?

Answer 21

• Rigorous cleaning/disinfection of case areas min 2x/day (detergent then bleach 1000ppm)
• Frequently touched surfaces/toys/change tables
• Frequent cleaning for common areas.
• Clean non-disposable equipment between residents.
• Steam clean contaminated carpets/soft furnishings.
• Terminal clean.

Question 22

When can a gastro outbreak be declared over?

Answer 22

48h after Sx resolve in final case