Foodborne disease surveillance and outbreak investigations in Western Australia, third quarter 2015

OzFoodNet, Communicable Disease Control Directorate

Enhancing foodborne disease surveillance across AustraliaCommunicable Disease Control Directorate

Acknowledgments

Acknowledgement is given to the following people for their assistance with the activities

described in this report: Mr Damien Bradford, Ms Lyn O’Reilly, Ms Jenny Green, Dr Niki

Foster and the staff from the enteric, PCR and food laboratories at PathWest Laboratory

Medicine WA; staff from the Food Unit of the Department of Health, Western Australia;

Public Health Nurses from the metropolitan and regional Population Health Units; and

Local Government Environmental Health Officers.

Contributors/Editors

Nevada Pingault and Barry Combs

Communicable Disease Control DirectorateDepartment of Health, Western AustraliaPO Box 8172Perth Business CentreWestern Australia 6849

Email: OzfoodnetWA@health.wa.gov.au

Telephone: (08) 9388 4999

Facsimile: (08) 9388 4877

Web: OzFoodNet WA Health www.public.health.wa.gov.au/3/605/2/ozfoodnet_enteric_infections_reports.pmOzFoodNet Department of Healthwww.ozfoodnet.gov.au/

Disclaimer:

Every endeavour has been made to ensure that the information provided in this document

was accurate at the time of writing. However, infectious disease notification data are

continuously updated and subject to change.

This publication has been produced by the Department of Health, Western Australia.

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Executive summary During the third quarter of 2015, the Western Australian (WA) OzFoodNet team conducted

surveillance of enteric diseases, undertook investigations into outbreaks and was involved

with ongoing enteric disease research projects.

The most common notifiable enteric infections in WA were campylobacteriosis (n=648),

salmonellosis (n=301), rotavirus infection (n=198) and cryptosporidiosis (n=21).

Notifications of campylobacteriosis, salmonellosis and rotavirus infection were higher than

the five-year third quarter mean, while cryptosporidiosis notifications were lower.

One foodborne outbreak was investigated in the third quarter, while the investigation into

the increase in S. Typhimurium PFGE 0001 cases continued.

OzFoodNet also conducted surveillance of 28 non-foodborne outbreaks. Of these, the

most common mode of transmission was person-to-person (23 outbreaks), with a total of

629 people ill. Norovirus was the most common agent responsible for infection (identified

in 10 outbreaks), and most outbreaks were in aged care facilities.

Figure 1 Notifications of the four most common enteric diseases by quarter from 2010 to 2015, WA

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Table of Contents

Executive summary.......................................................................................2

1 Introduction..............................................................................................5

2 Incidence of notifiable enteric infections..............................................6

2.1 Methods..................................................................................................................62.2 Campylobacteriosis.................................................................................................62.3 Salmonellosis..........................................................................................................72.4 Rotavirus infection...................................................................................................92.5 Cryptosporidiosis.....................................................................................................92.6 Other enteric diseases and foodborne illness.......................................................10

3 Foodborne and suspected foodborne disease outbreaks.................12

3.1 After school care, Salmonella Typhimurium PFGE 0001, MLVA 03-10-15-11-496 outbreak (outbreak code 042-2015-007)........................................................................12

4. Cluster investigations...........................................................................13

4.1. S. Typhimurium PFGE 0001, phage type 9...........................................................13

5. Non-foodborne disease outbreaks and outbreaks with an unknown mode of transmission..................................................................................14

5.1. Person-to-person outbreaks..................................................................................145.2. Outbreaks with unknown mode of transmission....................................................155.3. Probable water-borne outbreak.............................................................................15

6. Site activities..........................................................................................16

7. References.............................................................................................16

List of Tables

Table 1 Number of campylobacteriosis notifications, 3rd quarter 2015, WA, by region...................7Table 2 Number of salmonellosis notifications, 3rd quarter 2015, WA, by region...........................8Table 3 Number of rotavirus notifications, 3rd quarter 2015, WA, by region..................................9Table 4 Number of cryptosporidiosis notifications, 3rd quarter 2015, WA, by region....................10Table 5 Summary of number of notified cases of enteric notifiable diseases in WA in the third quarter 2015 compared to historical means..............................................................................12Table 6 Outbreaks with non-foodborne transmission, 3rd Quarter 2015, WA...............................14

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List of Figures Figure 1 Notifications of the four most common enteric diseases by quarter from 2010 to 2015, WA............................................................................................................................................. 2Figure 2 Notifications of Salmonella Typhimurium PFGE 0001 in WA, May 2013 to September 2015....................................................................................................................................13

Notes:

1. All data in this report are provisional and subject to future revision.

2. To help place the data in this report in perspective, comparisons with other reporting periods are provided. As no formal statistical testing has been conducted, some caution should be taken with interpretation.

Copyright to this material is vested in the State of Western Australia unless otherwise indicated. Apart from any fair dealing for the purposes of private study, research, criticism or review, as permitted under the provisions of the Copyright Act 1968, no part may be reproduced or re-used for any purposes whatsoever without written permission of the State of Western Australia.

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1 IntroductionIt has been estimated that there are 5.4 million cases of foodborne illness in Australia

each year at a cost of $1.2 billion per year1. This is likely to be an underestimate of the

total burden of gastrointestinal illness as not all enteric infections are caused by foodborne

transmission. Other important modes of transmission include person-to-person, animal-to-

person and waterborne transmission. Importantly, most of these infections are preventable

through interventions at the level of primary production, commercial food handling,

households and institution infection control.

This report describes enteric disease surveillance and investigations carried out during the

third quarter of 2015 by OzFoodNet WA, other WA Department of Health (WA Health)

agencies and local governments. Most of the data are derived from reports to WA Health

of 16 notifiable enteric diseases by doctors and laboratories. In addition, outbreaks caused

by non-notifiable enteric infections are also documented in this report, including norovirus,

which causes a large burden of illness in residential care facilities (RCF) and the general

community.

OzFoodNet WA is part of the Communicable Disease Control Directorate (CDCD) within

WA Health, and is also part of the National OzFoodNet network funded by the

Commonwealth Department of Health2. The mission of OzFoodNet is to enhance

surveillance of foodborne illness, including investigating and determining the cause of

outbreaks. OzFoodNet also conducts applied research into associated risk factors and

develops policies and guidelines related to enteric disease surveillance, investigation and

control. The OzFoodNet site, based in Perth, is responsible for enteric disease

surveillance and investigation in WA.

OzFoodNet WA regularly liaises with staff from Public Health Units (PHUs), the Food Unit

in the Environmental Health Directorate of WA Health; and the Food Hygiene, Diagnostic

and Molecular Epidemiology laboratories at PathWest Laboratory Medicine WA.

PHUs are responsible for public health activities, including communicable disease control,

within their respective administrative regions. The PHUs monitor RCF gastroenteritis

outbreaks and provide infection control advice. The PHUs also conduct follow-up of single

cases of important enteric diseases including typhoid, paratyphoid and hepatitis A.

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The Food Unit liaises with Local Government (LG) Environmental Health Officers (EHO)

during the investigation of food businesses. The Food Hygiene, Diagnostic and Molecular

Epidemiology laboratories at PathWest Laboratory Medicine WA provide public health

laboratory services for the surveillance and investigation of enteric disease.

2 Incidence of notifiable enteric infections2.1 Methods

Enteric disease notifications were extracted from the Western Australian Notifiable

Infectious Diseases Database (WANIDD) by optimal date of onset (ODOO) for the time

period 1st July 2010 to 30th September 2015. The ODOO is a composite of the ‘true’ date of

onset provided by the notifying doctor or obtained during case follow-up, the date of

specimen collection for laboratory notified cases, and when neither of these dates is

available, the date of notification by the doctor or laboratory, or the date of receipt of

notification, whichever is earliest. Rates were calculated using estimated resident

population data for WA from Rates Calculator version 9.5.5 (WA Health, Government of

Western Australia), which is based on 2011 census data. Rates calculated for this report

have not been adjusted for age.

2.2 Campylobacteriosis

Campylobacteriosis was the most commonly notified enteric disease in WA during the third

quarter of 2015 (3Q15), with 648 notifications (Table 1) and a rate of 100 per 100 000

population per year. There was a 19% increase in campylobacteriosis notifications in the

3Q15 compared with the five year 3rd quarter mean (3QM). The increase appeared to be

due to sporadic disease, as there were no identified Campylobacter outbreaks during the

3Q15. At least some of the increase is likely to be due to the introduction by one large

private pathology laboratory of polymerase chain reaction (PCR) testing of faecal

specimens, which has greater sensitivity than culture techniques.

The place of acquisition of infection was reported for 60% (n=392) of cases, of which 68%

(268 cases) were locally acquired and 30% were acquired overseas (118 cases).

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Table 1 Number of campylobacteriosis notifications, 3rd quarter 2015, WA, by region

Region 2015 3rd Quarter

5 Year Mean for 3rd Quarter

3rd Quarter

% change*

North Metro 275 248 11South Metro 234 176 33South West 50 47 7Great Southern 21 16 35Midwest 19 11 76Pilbara 14 9 59Wheatbelt 12 17 -29Goldfields 9 9 2Kimberley 8 12 -32WA address not specified 6 3 NATotal 648 546 19© WA Department of Health 2015

Number of notifications

*Percentage change in the number of notifications in the current quarter compared to the historical five year mean for the same quarter. Positive values indicate an increase when compared to the historical five year mean of the same quarter. Negative values indicate a decrease when compared to the historical five year mean of the same quarter. Percentage change should be interpreted with caution when the number of cases is small.NA: Not applicable

2.3 Salmonellosis

Salmonellosis was the second most commonly notified enteric disease in WA in the 3Q15,

with 301 notifications (Table 2) and a rate of 46 per 100 000 population per year. The

number of salmonellosis notifications in the 3Q15 was 18% higher than the 3QM (n=254).

Place of acquisition of infection was reported for 71% (n=215) of cases, of which 50% (108

cases) were locally acquired, 48% were acquired overseas (103 cases) and 2% were

acquired interstate (4 cases).

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Table 2 Number of salmonellosis notifications, 3rd quarter 2015, WA, by region

Region 2015 3rd Quarter

5 Year Mean for 3rd Quarter

3rd Quarter % change*

North Metro 135 100 34South Metro 96 82 18South West 18 22 -19Kimberley 15 15 0Pilbara 11 9 20Wheatbelt 10 6 67Midwest 6 7 -14Goldfields 6 4 36Great Southern 3 8 -62WA address not specified 1 1 NATotal 301 254 18© WA Department of Health 2015

Number of notifications

*Percentage change in the number of notifications in the current quarter compared to the historical five year mean for the same quarter. Positive values indicate an increase when compared to the historical five year mean of the same quarter. Negative values indicate a decrease when compared to the historical five year mean of the same quarter. Percentage change should be interpreted with caution when the number of cases is small. NA: Not applicable

The most commonly reported Salmonella serotype was S. Typhimurium (STM) (n=93),

and of those cases with information on place of acquisition (n=66, 71%), 54 cases (82%)

were locally acquired. Pulsed-field gel electrophoresis (PFGE) is used in WA for the

subtyping of STM and the most common PFGE types were type 0001 (n=33, 35%), type

0043 (n=7, 8%) and type 0602 (n=7, 8%). Cases with type 0001 were interviewed as part

of an on-going cluster investigation (see section 4); and cases with type 0602 were

investigated as part of a probable waterborne outbreak.

S. Enteritidis was the second most common Salmonella serotype (n=68), and of those

cases with information on place of acquisition (n=67, 98%), nearly all (n=66, 98%)

acquired their infection overseas, primarily after travel to Indonesia (n=38, 58%), and

almost exclusively to Bali.

The next most commonly notified Salmonella serotype was S. Paratyphi B bv Java (n=20),

which is traditionally acquired overseas. Salmonella notifications that did not have a

serotype were the next most common group (n=15). Approximately half of these

notifications were from PCR positive, culture negative samples from one laboratory that

uses PCR screening for enteric pathogens.

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2.4 Rotavirus infectionIn the 3Q15 there were 198 notifications (Table 4) of rotavirus infection (30 per 100 000

population per year). There was a 49% increase in rotavirus notifications in the 3Q15

compared with the mean of the previous three years for the third quarter. This increase

was in all Western Australian regions except the Kimberley. The cases were mainly

(n=166, 84%) non-Aboriginal people with an average age of 18 years (range <1 years to

97 years). There were two RCF outbreaks and a single outbreak in a childcare centre due

to rotavirus in this quarter (see section 5).

Table 3 Number of rotavirus notifications, 3rd quarter 2015, WA, by region

Region 2015 3rd Quarter

3 Year Mean for 3rd Quarter**

3rd Quarter % change*

North Metro 77 46 67South Metro 55 39 40Pilbara 22 18 20South West 15 3 355Kimberley 13 19 -33Wheatbelt 6 1 362Great Southern 4 2 100Midwest 3 2 50Goldfields 3 1 131Total 198 133 49© WA Department of Health 2015

Number of notifications

*Percentage change in the number of notifications in the current quarter compared to the historical three year mean for the same quarter. Positive values indicate an increase when compared to the historical three year mean of the same quarter. Negative values indicate a decrease when compared to the historical three year mean of the same quarter. Percentage change should be interpreted with caution when the number of cases is small.**Rotavirus: comparison to three years (2012-2014) of data only because laboratory testing and notification practices (increased use of more specific PCR over antigen testing) have changed since the beginning of 2012.

2.5 Cryptosporidiosis

In the 3Q15, there were 21 cryptosporidiosis notifications (Table 3) (3 per 100 000

population per year), which was a 34% decrease compared to the 3QM.

The place of acquisition of infection was reported for 81% of cases (n=17) of which 76%

(13 cases) were locally acquired.

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Table 4 Number of cryptosporidiosis notifications, 3rd quarter 2015, WA, by region

Region 2015 3rd Quarter

5 Year Mean for 3rd Quarter

3rd Quarter % change*

South Metro 9 9 2North Metro 6 8 -25Kimberley 4 4 -9South West 2 4 -52Midwest 0 1 -100Great Southern 0 1 -100Pilbara 0 1 -100Wheatbelt 0 2 -100Goldfields 0 1 -100Total 21 32 -34© WA Department of Health 2015

Number of notifications

*Percentage change in the number of notifications in the current quarter compared to the historical five year mean for the same quarter. Positive values indicate an increase when compared to the historical five year mean of the same quarter. Negative values indicate a decrease when compared to the historical five year mean of the same quarter. Percentage change should be interpreted with caution when the number of cases is small.

2.6 Other enteric diseases and foodborne illness

During the 3Q15, other enteric disease notifications included:

Shigellosis: There were 17 shigellosis notifications in 3Q15 (see Table 5) that were

culture positive, which was 21% higher than the 3QM (n=14). Shigella sonnei was

the most commonly notified species (14/17), with S. sonnei biotype A the most

common subtype (11/14). Single cases of S. flexneri, S. boydii and unspeciated

Shigella were notified in 3Q15. The same proportion of Aboriginal and non-

Aboriginal people were notified (47%), with Indigenous status unknown for one

case. The place of acquisition of infection was reported for 65% of cases (n=11)

and most (n=7) of these cases were locally acquired infections. Most cases (n=13)

were in rural regions.

Hepatitis A infection: Three hepatitis A cases were notified in 3Q15, all of whom

acquired their infection overseas, in Cambodia, Afghanistan and the Philippines.

Yersiniosis infection: There were six yersiniosis notifications in 3Q15 that were

culture positive, comprising 4 male and 2 female cases with an average age of 49

years (range 30 to 68 years). Three cases acquired their infection overseas.

Listeria: Four cases were notified in 3Q15. These infections were thought to be

sporadic as the isolates were of different molecular types and no common

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exposures were identified. Case 1 was a 21 day old male, whose mother had a

clinically compatible illness during pregnancy. Case 2 was a 94 year old male with

chronic renal disease. Case 3 was an 8 month old male who likely acquired the

infection overseas. Case 4 was a 31 year old pregnant female whose pregnancy

continued despite the infection. The mother of case 1, plus cases 3 and 4 all

reported consumption of high risk foods during the incubation period.

Haemolytic uraemic syndrome (HUS): A single case was reported in a 12 year

old female, who presented with bloody diarrhoea, vomiting and lethargy, with HUS

diagnosed 10 days after onset of symptoms. Stool and rectal swab specimens

collected after HUS diagnosis were negative for shiga toxin E. coli. Risk factors

were limited, but included horse riding and hamburger consumption at a pony club.

Paratyphoid fever: Single case of Salmonella Paratyphi A in a 27 year old male

who had travelled to Bangladesh.

Typhoid fever: Two cases, both male, aged 22 and 24 years, who had acquired

their infections in India and Indonesia, respectively.

There were no notifications for Vibrio parahaemolyticus, botulism, cholera, hepatitis E or

shiga toxin E. coli in this quarter.

Table 5 Summary of number of notified cases of enteric notifiable diseases in WA in the third quarter 2015 compared to historical means

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Notifiable Disease Notified Cases 3Q 2015

5yr mean 3Q (2010-2014)

Botulism 0 0Campylobacteriosis 647 546Cholera 0 0Cryptosporidiosis 21 32HUS 1 0Hepatitis A 3 3Hepatitis E 0 1Listeriosis 4 1Paratyphoid 1 2Salmonellosis 301 254Shigellosis 17 14STEC/VTEC 0 1Typhoid 2 3Yersiniosis 6 1V. parahaemolyticus 0 4Total 1201 1001© WA Department of Health 2015

3 Foodborne and suspected foodborne disease outbreaks

There was one foodborne outbreak investigated in this quarter.

3.1 After school care, Salmonella Typhimurium PFGE 0001, MLVA 03-10-15-11-496 outbreak (outbreak code 042-2015-007)

Two cases of the same type of S. Typhimurium (PFGE 0001, MLVA type 03-10-15-11-

496) (centremanager and female student) at an after school care facility. Both cases ate

raw cake mixture on 7/8/2015 at 2 pm and became ill on 8/8/2015 and 9/8/2015,

respectively. No other food was shared between the cases. Eggs used in the cake mixture

were from home hens. The manager of the facility was advised not to use home hen eggs

at the facility and not to offer students raw cake mixture to eat.

4. Cluster investigationsThere was one ongoing cluster investigation during the third quarter of 2015.

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4.1. S. Typhimurium PFGE 0001, phage type 9

There has been an ongoing community-wide increase in notifications of STM PFGE 0001

(see figure 2) in WA since late 2013. There were 35 cases of PFGE type 0001 infection

notified with specimen dates between July and September 2015 and of these, 2 cases

were part of a small defined outbreak (see section 3). The remaining 33 cases, comprising

52% males and 48% females, ranged in age from 1 to 91 years (average 30 years), and

most (88%) resided in the Perth metropolitan area. Retail chicken meat sampled in

September 2014 was also positive for PFGE type 0001. In the first three quarters of 2015,

there have been three identified foodborne outbreaks due to PFGE type 0001, with the

implicated foods being raw or undercooked eggs. Previous interviews of sporadic cases

support the hypothesis that the cause of illness was consumption of free range eggs

and/or chicken meat. From the 25/2/15 onwards, non-outbreak cases have been

investigated as part of a case-control study of community acquired STM PFGE 0001

illness, with 79 cases enrolled to date. The investigation is ongoing.

Figure 2 Notifications of Salmonella Typhimurium PFGE 0001 in WA, May 2013 to September 2015

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5. Non-foodborne disease outbreaks and outbreaks with an unknown mode of transmission

There were 28 outbreaks of enteric disease in this quarter that appeared to be non-foodborne (see Table 6). Of these, 23 outbreaks were ascribed to person-to-person transmission and four outbreaks had an unknown mode of transmission.

Table 6 Outbreaks with non-foodborne transmission, 3rd Quarter 2015, WA

Mode of transmission Setting Exposed Agent responsible

Number of outbreaks

Number of cases

Number hospitalised

1 Number died

Person to person Residential Care Norovirus 8 214 1 0Residential Care Rotavirus 2 26 0 0Residential Care Unknown 3 27 0 0Residential Care 13 267 1 0

Child care Rotavirus 1 10 0 0Unknown 6 52 0 0

Child care total 7 62 0 0Hospital Unknown 1 8 0 0Cruise Norovirus 2 292 0 0

Total 23 629 1 0Unknown Residential Care Unknown 3 24 0 0

Private residence S. Typhimurium 1 3 3 0Total 4 27 3 0Probable Waterborne Resort S. Typhimurium 1 18 0 0Grand total 28 674 4 0© WA Department of Health 2015

Outbreaks with non-foodborne transmission

1 Deaths temporally associated with gastroenteritis, but contribution to death not specified

5.1. Person-to-person outbreaks

In the 23 non-foodborne outbreaks that were suspected to be due to person-to-person transmission, 13 outbreaks (52%) occurred in RCFs, 7 were in child care centres (30%), two were on cruise ships and one occurred in a hospital. The causative agent for 10 (43%) outbreaks was confirmed as norovirus and three (13%) were caused by rotavirus. The remaining 10 (43%) outbreaks were of unknown aetiology, as specimens were either not collected (n=7), were negative for common viral and bacterial pathogens (n=2) or viral testing was not requested (n=1).

A total of 629 people were affected in these 23 outbreaks, with one reported hospitalisation and no associated deaths. The number of person-to-person outbreaks in the 3Q15 was comparable to the 3QM (n=22).

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5.2. Outbreaks with unknown mode of transmissionThere were four outbreaks in this quarter with an undetermined mode of transmission, with

27 people ill, three hospitalisations and no deaths. Three of these outbreaks were in

RCFs, where the most common symptom reported was diarrhoea, and vomiting was

reported infrequently, which is not typical of norovirus outbreaks in RCF settings. In these

three outbreaks stool specimens were collected and tested, but were negative for common

bacterial and viral pathogens.

The fourth outbreak with an unknown mode of transmission involved three cases of S.

Typhimurium PFGE type 0057, MLVA type 03-14-17-10-523 in an extended family in a

rural town. One case who was PEG fed (no oral food intake) had an onset of 7/9/2015 and

lived with a sister who had an onset of 8/9/15. The son of one of the cases who lived in a

separate house but visited regularly had an onset on 17/9/2015. All three cases were

hospitalised.

5.3. Probable water-borne outbreakHoliday resort, Salmonella Typhimurium MLVA 04-16-11-15-000 outbreak (outbreak code 042-2015-005)

From the 2/7/15 to12/72015, four separate groups of people (approximately 65 people)

stayed at a remote holiday resort facility. At least 18 people became ill with diarrhoea or

fever plus one other symptom, with people affected in each group. Eight cases were

confirmed as having S. Typhimurium MLVA type 04-16-11-15-000 infection. Children had

a higher attack rate (15/36, 42%) compared to adults (3/29, 10%). The average duration of

diarrhoea was six days and the average incubation period was three days (from date of

arrival to becoming ill). Groups either stayed at a homestead where food was provided and

prepared by the management or another house where guests had to bring and prepare

their own food. Rainwater was provided to both sites and unboiled water was drunk by

guests. Bore water was plumbed into both sites and used for cleaning, showering, washing

hands and food preparation. Both rainwater and bore water samples were tested and the

same type of Salmonella as cases was identified in the rainwater. It was unclear how the

rainwater tank could have been contaminated. Interventions included providing guests with

bottled water for drinking and increasing the concentration of chlorine in the bore water.

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6. Site activitiesDuring the third quarter of 2015, the following activities were conducted at the WA OzFoodNet site:

Ongoing surveillance of foodborne disease in WA. Monitoring culture-independent nucleic acid amplification diagnostic testing in

private laboratories and impact on notification rates. Investigation of one foodborne outbreak and one waterborne outbreak. Investigation and monitoring of 23 person-to-person gastroenteritis outbreaks and

four outbreaks with unknown mode of transmission. Ongoing investigation of a community-wide increase in one Salmonella type. Responded to national OzFoodNet enteric disease surveillance requests. Attendance at the ‘Embracing the Genomic Revolution – Applied Microbial

Genomics in Public Health and Clinical Microbiology’ symposium in Melbourne in July.

Presentations and practical exercises on foodborne disease for masters level students.

Interviewing Salmonella Enteritidis cases regarding travel status and attempting to identify risk factors in locally acquired cases.

Continuing to work with PathWest on implementation of MLVA typing of S. Typhimurium isolates and PCR testing of bloody stools for STEC.

Chairing the Series of National Guidelines (SoNG) working group for Listeria infection.

Membership of OzFoodNet working groups on:o National STEC surveillanceo Outbreak registero Foodborne disease tool kito Egg-related outbreakso Culture-independent testing

Participation in monthly national OzFoodNet teleconferences.

7. References1 Hall G, Kirk MD, Becker N, Gregory JE, Unicomb L, Millard G, et al. Estimating

foodborne gastroenteritis, Australia. Emerg Infect Dis 2005;11(8):1257-1264.2 OzFoodNet Working Group. A health network to enhance the surveillance of

foodborne diseases in Australia. Department of Health and Ageing 2013. www.ozfoodnet.gov.au/internet/ozfoodnet/publishing.nsf/Content/Home-1 [14/03/2012].

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