Russell Stafford

Estimating Foodborne Gastroenteritis, Australia

An estimated 4.0–6.9 million episodes of foodborne gastroenteritis occur in Australia each year.

Risk factors for campylobacter infection in infants and young children: a matched case-control study

Campylobacter infection has one of the highest rates of all the notifiable diseases in Australia, with a peak in children aged 0-35 months. A matched case-control study was conducted to investigate risk factors for campylobacter infection for children in this age group. Eighty-one cases and 144 controls were enrolled in the study that was conducted between 24 January 1996 and 21 January 1997. The following risk factors were found to be independently associated with illness: ownership of pet puppies (adjusted odds ratio [OR] 16.58, 95% confidence interval [CI] 3.73-73.65) and pet chickens (OR 11.80, CI 1.37-101.75), and consumption of mayonnaise (OR 4.13, CI 1.61-10.59). We propose that children aged less than 3 years are at risk of campylobacter infection if residing in a household which has puppies or chickens as pets.

Internationally Distributed Frozen Oyster Meat Causing Multiple Outbreaks of Norovirus Infection in Australia

BACKGROUND Between November 2003 and January 2004, outbreaks of norovirus in 3 Australian jurisdictions involving 83 cases of illness were associated with imported oyster meat. METHODS Cohort studies were conducted in 2 jurisdictions to identify relative risks of illness for the consumption of oysters. A case series was conducted in the third jurisdiction. RESULTS The cohort studies conducted in the first 2 jurisdictions identified relative risks of illness of 17 (95% confidence interval, 5-51) and 35 (95% confidence interval, 5-243), respectively, for the consumption of oysters. Multiple strains of norovirus were detected in fecal specimens from 8 of 14 patients and in 1 of the 3 batches of implicated oyster meat using seminested reverse-transcriptase polymerase chain reaction methods. Traceback investigations revealed that all oyster meat was harvested from the same estuary system in Japan within the same month. CONCLUSIONS These outbreaks demonstrate the potential of foodborne disease to spread internationally and the need for national and international collaboration to investigate such outbreaks. Foodborne illness related to norovirus is underestimated because of underreporting of human cases and challenges in laboratory detection of viruses in foods, both of which can delay public health action.

Frequency of infectious gastrointestinal illness in Australia, 2002: regional, seasonal and demographic variation

To estimate the frequency of infectious gastroenteritis across Australia, and to identify risk factors, we conducted a national telephone survey of 6087 randomly selected respondents in 2001-2002. The case definition was three or more loose stools and/or two or more vomits in a 24-hour period in the last 4 weeks, with adjustment to exclude non-infectious causes and symptoms secondary to a respiratory infection. Frequency data were weighted to the Australian population. Multivariate logistic regression was used to assess potential risk factors including season, region, demographic and socioeconomic status. Among contacted individuals, 67% responded. The case definition applied to 7% of respondents (450/6087) which extrapolates to 17.2 million (95% CI 14.5-19.9 million) cases of gastroenteritis in Australia in one year, or 0.92 (95% CI 0.77-1.06) cases/person per year. In the multivariate model, the odds of having gastroenteritis were increased in summer and in the warmest state, in young children, females, those with higher socioeconomic status and those without health insurance.

Population-Attributable Risk Estimates for Risk Factors Associated with Campylobacter Infection, Australia

One-sentence summary: Each year, an estimated 50,500 cases in persons >5 years of age can be directly attributed to consumption of chicken.

Foodborne Disease in Australia: The OzFoodNet Experience

In 2000, Australia improved national surveillance of gastrointestinal and foodborne illness by adapting the Centers for Disease Control and Prevention’s (CDC’s) FoodNet model of active surveillance. The OzFoodNet surveillance network applied concentrated effort at the national and local levels to investigate and understand foodborne disease, to describe more effectively its epidemiology, and to provide better evidence for minimizing the number of cases of foodborne illness in Australia. The Australian government funded each of Australia’s 6 states and 2 territories to employ 1 epidemiologist to enhance surveillance of foodborne disease, with a coordinating team based at the federal Department of Health and Ageing. OzFoodNet estimated that there are ∼5.4 million cases of foodborne disease per year, costing A

Low-Level Fluoroquinolone Resistance among Campylobacter jejuni Isolates in Australia

1.2 billion annually. In Australia, contaminated food results in ∼100 outbreaks of illness each year, with the incidence of outbreaks of illness caused by fresh produce and internationally distributed food increasing. In addition, OzFoodNet showed the value of aggregating national-level outbreak data for policy development and conducted successful multijurisdictional investigations of outbreaks; these investigations implicated a variety of foods, including alfalfa sprouts, chicken meat, eggs, peanuts, baby corn, tahini, and oysters. Foodborne diseases are globally important because of their high incidence and the costs that they impose on society. There is a great potential for large outbreaks of foodborne illness in both developing and developed countries. More than 200 different diseases may be transmitted through contaminated food or water [1]. Most foodborne diseases result in gastroenteritis, but other nongastroenteric illnesses are common. Prevention of foodborne disease occurs through interventions aimed at the

Surveillance for outbreaks of gastroenteritis in long-term care facilities, Australia, 2002-2008.

BACKGROUND Ciprofloxacin-resistant Campylobacter jejuni isolates obtained from infected patients in Australia have not been detected in studies of isolates from specific geographic areas. The Australian government has prohibited the use of fluoroquinolone in food-producing animals. To assess the impact of this policy, we have examined the antimicrobial susceptibility of isolates from 5 Australian states. METHODS We conducted a period-prevalence survey of the susceptibility of C. jejuni isolates to 10 antimicrobial agents. C. jejuni isolates obtained from 585 patients from 5 Australian states (Queensland, South Australia, Tasmania, Victoria, and Western Australia) were identified by means of notifiable disease databases and were systematically selected from September 2001 to August 2002. RESULTS Among locally acquired infections, only 2% of isolates (range, 0%-8% in different states) were resistant to ciprofloxacin. The locally acquired isolates also exhibited resistance to sulfisoxazole (55%), ampicillin (46%), roxithromycin (38%), tetracycline (7%), nalidixic acid (6%), chloramphenicol (3%), erythromycin (3%), gentamicin (2%), and kanamycin (0.2%). Treatment with antimicrobial agents in the 4 weeks before onset was not associated with ciprofloxacin resistance. CONCLUSIONS The very low level of ciprofloxacin resistance in C. jejuni isolates likely reflects the success of Australias policy of restricting use of fluoroquinolones in food-producing animals.

Outbreaks of Shigella sonnei infections in Denmark and Australia linked to consumption of imported raw baby corn

BACKGROUND Each year in Australia, health departments investigate hundreds of gastroenteritis outbreaks. Long-term care facilities (LTCFs) for elderly persons are a common setting for these outbreaks and can result in potentially serious outcomes. METHODS We established surveillance for gastroenteritis outbreaks in 2001, and analyzed data on outbreaks occurring from 1 July 2002 through 30 June 2008 to estimate the incidence in Australian LTCFs and residents. We summarized outbreaks by mode of transmission and etiological agent. We used negative binomial regression to examine variation in the number of fecal specimens collected in outbreaks-a marker of investigation intensity. RESULTS During surveillance, 3257 (52%) of 6295 outbreaks of gastroenteritis and foodborne disease in Australia were reported in LTCFs. These outbreaks affected 84,769 people, with 1577 people hospitalized and 209 deaths. There were 0.19 (95% confidence interval, 0.14-0.26) residents affected per 1000 bed days and 16.8 (95% confidence interval, 12.4-22.7) outbreaks per 100 LTCFs annually. LTCF outbreaks were most commonly transmitted from person to person. Only 43 (1.3% ) of 3257 outbreaks were foodborne, although 47 (6.4%) of 733 residents were hospitalized and 20 (2.7%) of 733 died. Norovirus was responsible for 1136 (35%) of all 3257 outbreaks. Higher numbers of fecal specimens per outbreak were collected in 4 Australian States, in later years of surveillance, and where the etiology was identified. CONCLUSIONS Norovirus outbreaks spread from person to person are common in LTCFs, although clinicians should be alert for foodborne outbreaks with more serious consequences. There is a need to identify effective infection control measures to assist facilities in managing outbreaks of gastroenteritis.

An outbreak of Salmonella enterica serotype Litchfield infection in Australia linked to consumption of contaminated papaya.

We investigated an outbreak of Shigella sonnei infections in Denmark and Australia associated with imported baby corn from one packing shed in Thailand. We reviewed nationwide surveillance and undertook case finding, food trace-back and microbiological investigation of human, food and environmental samples. A recall of baby corn and sugar snaps was based on descriptive epidemiological evidence. In Denmark, we undertook a retrospective cohort study in one workplace. In total, 215 cases were laboratory-confirmed in Denmark, and 12 in Australia. In a multivariable analysis, baby corn was the only independent risk factor. Antibiotic resistance and PFGE outbreak profiles in Denmark and Australia were indistinguishable, linking the outbreaks. Although we did not detect S. sonnei in baby corn, we isolated high levels of other enteric pathogens. We identified a packing shed in Thailand that supplied baby corn to Denmark and Australia, and uncovered unhygienic practices in the supply chain. This outbreak highlights the importance of international communication in linking outbreaks and pinpointing the source.