Foodborne Campylobacteriosis

in New ZealandEvidence rather than prejudice

Donald Campbell Principal Advisor (Public Health)

Science Group

Statistics are the triumph of the

quantitative method, and the

quantitative method is the victory of

sterility and death.

Hillaire Belloc 1870 -1953

The burden of acute gastro-intestinal disease pyramid

Human disease surveillance in

New Zealand

• Ministry of Health

• Environmental Services and Research Ltd

• Public Health Units

• New Zealand Food Safety Authority

Disease Investigations

Enteric

• Purpose

• Disease Control

• Attribution

• Monitoring

• Methods

• Outbreaks

• Sporadic

Foodborne

• Detecting, controlling and

preventing outbreaks

• Priorities / setting policy for

control (risk assessment)

• Estimating burden of disease

• Identifying emerging issues

• Data source

• Evaluation and monitoring

Campylobacteriosis 2006

• Cases• 15,873

• 383.5/100,000

• Hospitalisations• 677 (969)

• 7.3%

• Mortality

• 1

Campylobacteriosis Jan 03 - May 07

0

250

500

750

1000

1250

1500

1750

2000

2250

Annual by month

Cas

es

Notification RatesCampylobacteriois notification rates 1997 - 2006

0

50

100

150

200

250

300

350

400

450

Year

/ 100

,000

est

imat

ed m

id-y

ear

po

pu

lati

on

Campylobacter 2005

Disease Notifications

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Cas

es

Campylobacter

Cryptosporidiosis

Giardiasis

Salmonellosis

Monthly Campylobacteriosis2004 - 2007

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12

Months

Cas

es

Enteric Outbreaks 2006

No of outbreaks

% of outbreaks

No of cases

% of cases

Norovirus 156 31.5 3945 62.6

Campylobacteriosis 47 9.5 223 3.5

Giardia 32 6.5 98 1.6

Cryptosporidium 25 5.1 116 1.8

Salmonella 22 4.4 74 1.2

C perfringens 12 2.4 62 1.0

Others 34 6.6 217 3.4

Unidentified 153 30.9 1415 22.5

Case-case Analysis 2006 (%)

Food premise

Untreated drinking

water

Recreational

water

Farm Animal

Overseas Travel

Campylobacteriosis 52.4 16.4 10.7 28.6 6.0

Cryptosporidiosis 26.0 34.7 29.8 53.2 8.2

Giardiasis 27.0 36.4 27.8 27.6 26.6

Salmonellosis 46.0 20.2 16.7 25.2 19.3

Shigellosis 48.9 13.3 22.2 4.4 60.5

Yersiniosis 34.6 20.1 11.6 21.6 6.7

Case-control studies

• MAGIC 1997

• PAR chicken 50%+

• Home protective

• Christchurch 1994

• Poultry outside home

• Auckland 1996

• Barbecued, undercooked chicken

Published campylobacteriosis investigation reports

Likely Cause No. of Outbreak Reports

Likely foodborne 2

Limited for foodborne 2

Likely waterborne 5

Limited for waterborne 1

Possibly food or water 2

Unclear 1

Total 13

Overall evidence for causality in New Zealand

• Foodborne transmission• Evidence of association

• Strength of association

• Biologic gradient

• Consistency

• Biological plausibility

• Coherence

• Temporality

• Food dominant cause

The government is very keen on amassing

statistics. They collect them, add them, raise

them to the nth power, take the cube root and

prepare wonderful diagrams. But you must

remember that every one of these figures

comes in the first instance from the Chowty Dar

who just puts down what he damn well pleases.

Sir Josiah Stamp 1929

Good surveillance does not necessarily

ensure the making of right decisions

but it reduces the chances of making

wrong ones.

Alexander Langmuir 1963