The seroprevalence of antibodies to Japanese encephalitis virus in five New South Wales towns at high risk of infection, 2022: a cross-sectional serosurvey.

OBJECTIVES: To determine the proportion of people in New South Wales towns at high risk of Japanese encephalitis virus (JEV) infections during the 2022 outbreak; to identify risk factors for JEV infection. STUDY DESIGN: Cross-sectional serosurvey study of the seroprevalence of JEV-specific antibodies in NSW. SETTING, PARTICIPANTS: Convenience sample of people (all ages) from five regional NSW towns deemed to be at high risk of JEV infections after first outbreak of Japanese encephalitis in southeastern Australia in early 2022 (Balranald, Corowa, Dubbo, Griffith, Temora), 21 June - 22 July 2022. MAIN OUTCOME MEASURES: Proportion of people seropositive for JEV total antibody, assayed by defined epitope-blocking enzyme-linked immunosorbent assay; prevalence odds ratios for exposure risk factors and protective behaviours. RESULTS: Eighty of 917 eligible participants (559 girls or women, 61%; 42 Aboriginal and Torres Strait Islander people, 4.6%; median age, 52 years [IQR, 37-62 years]) were seropositive for JEV-specific total antibody (8.7%); the median age of seropositive people was 61 years (IQR, 48-70 years). The seropositivity proportion was largest for people aged 65 years or more (30 of 192; weighted proportion, 13.7%) and larger for male than female participants (30 of 358, 10.6% v 50 of 559, 7.5%). Five of 42 samples from Aboriginal and Torres Strait Islander participants were seropositive (12%). We found mixed associations with a range of potential risk factors. CONCLUSION: We found evidence for a substantial number of JEV infections in five regional NSW towns during a single arbovirus season in 2022. Public health responses, including effective surveillance, vaccination against JEV, and mosquito management, are critical for controlling outbreaks. Promoting behaviours that reduce exposure to mosquitoes is a core component of prevention, particularly when the vaccine supply is limited.

An outbreak of gastroenteritis linked to a buffet lunch served at a Canberra restaurant.

In 2013, an outbreak of gastrointestinal illness occurred following a buffet lunch at a restaurant in Canberra. An investigation was conducted to identify the cause of illness and to implement appropriate public health measures to prevent further disease. We conducted a retrospective cohort study via telephone interviews, using a structured questionnaire developed from the restaurant buffet menu. A case was defined as someone who ate the buffet lunch at the restaurant on the implicated date and developed any symptoms of gastrointestinal illness (such as diarrhoea, abdominal pain and nausea) following the consumption of food. A total of 74% (225/303) of known attendees were interviewed, of whom 56% (125/225) had become ill. The median incubation period and duration of illness were 13 and 19 hours respectively. The most commonly reported symptoms were diarrhoea (94%, 118/125) and abdominal pain (82%, 103/125). A toxin-mediated gastrointestinal illness was suspected based on the incubation period, duration of illness and the symptoms. The environmental health investigation identified a lack of designated hand washing facilities in the kitchen, an absence of thermometers for measuring food temperatures and several maintenance and minor cleaning issues. A number of food samples were taken for microbiological analysis. Multivariable analysis showed that illness was significantly associated with consuming curried prawns (OR 18.4, 95% CI 8.6-39.3, P < 0.001) and Caesar salad (OR 3.6, 95% CI 1.8-7.5, P 0.001). Enterotoxin-producing Staphylococcus aureus and Bacillus cereus were identified in leftover samples of cooked buffet food, but this food was not epidemiologically implicated. The investigation suggested that a breakdown in cleanliness, temperature control and food handling practices may have resulted in contamination of the buffet food. In order to prevent such outbreaks in the future, caterers and restaurateurs need to ensure they have the appropriate facilities and procedures in place if planning to cater for large groups.

EpiReview: tuberculosis in NSW, 2008.

AIM: To describe the epidemiology of tuberculosis cases notified in NSW in 2008. METHOD: Data on tuberculosis cases resident in NSW that were reported in 2008 were extracted from the Notifiable Diseases Database. Demographic, microbiological, clinical and other characteristics of cases were described. Incidence rates per 100 000 were calculated. RESULTS: In 2008, 498 tuberculosis cases were notified in NSW (7.1 cases per 100 000 population). Most cases were newly diagnosed (n = 479, 96%). The lung was the most common site of disease (n = 304, 61%). Eight of 269 tested cases (1.6%) had a HIV-tuberculosis co-infection. One case had multidrug-resistant tuberculosis. Most cases reported past residence (n = 429, 86%) or birth (n = 378, 76%) in a country with a high incidence of tuberculosis. CONCLUSION: The incidence of tuberculosis in NSW increased slightly in 2008. Most cases had links to countries with a high tuberculosis incidence.

Estimate of the number of Campylobacter infections in the Hunter region, NSW, 2004-2007.

OBJECTIVES: Campylobacteriosis is not notifiable in NSW and the number of cases of Campylobacter disease is thus not well described. METHODS: De-identified campylobacteriosis records for 2004-2007 were requested from laboratories in the Hunter region of NSW. Based on notifying laboratory, a Salmonella notification weighting was applied to laboratory-confirmed campylobacteriosis cases to provide an overall estimate of Campylobacter disease in the area. RESULTS: The estimated median of the annual number of laboratory-confirmed campylobacteriosis cases was 788 (range 700-1022). The ratio of estimated Campylobacter cases to Salmonella notifications was 5.5 : 1. CONCLUSION: Campylobacter infection causes considerable disease in the Hunter, and likely in NSW. Regular review of Campylobacter laboratory results may be valuable.

Epidemiology of gonorrhoea notifications in Australia, 2007-12.

UNLABELLED: Background An increase in the notification rate of gonorrhoea was observed in the national surveillance system. In Australia, gonorrhoea is relatively rare, apart from among some populations of Aboriginal people and men who have sex with men. METHODS: Data about gonorrhoea cases reported between 2007 and 2012 from all Australian jurisdictions were extracted from the National Notifiable Diseases Surveillance System. Analyses were undertaken of the time trends in counts and rates, according to jurisdiction, gender, Aboriginal and Torres Strait Islander status, diagnosis method and sexual orientation. RESULTS: The largest increase in notifications between 2007 and 2012 was observed in both men and women in New South Wales (2.9- and 3.7-fold greater in 2012 than 2007, respectively) and Victoria (2.4- and 2.7-fold greater in 2012 than 2007, respectively), men in the Australian Capital Territory and women in Queensland. The highest notification rates remained in Indigenous people in the Northern Territory and Western Australia, and particularly in women, although rates may have decreased over the study period. Changes in age and sex distribution, antimicrobial resistance and patterns of exposure and acquisition were negligible. CONCLUSIONS: There is an ongoing gonorrhoea epidemic affecting Aboriginal and Torres Strait Islander people in Australia, but the increases in notifications have occurred primarily in non-Aboriginal populations in the larger jurisdictions. Interpretation of these surveillance data, especially in relation to changes in population subgroups, would be enhanced by laboratory testing data. Further efforts are needed to decrease infection rates in populations at highest risk.

Egg-associated Salmonella outbreak in an aged care facility, New South Wales, 2008.

Salmonellosis is a bacterial disease that causes acute gastroenteritis, with sudden onset of headache, abdominal pain, diarrhoea, nausea and sometimes vomiting. Infection is often associated with the consumption of foods prepared using raw eggs. During July to August 2008 an outbreak at an aged care facility (ACF) in New South Wales was confirmed as Salmonella Typhimurium phage type 44 (Stm 44) in eight of 45 residents. Two additional probable cases also occurred. Cases were located in each unit of the ACF and for 5 cases, onset of diarrhoea was between 45 to 64 hours (median of 46 hours) after consumption of a dessert containing raw eggs. Onset for 5 further cases occurred up to 9 days after this meal. Eggs were supplied to the ACF from a local farm. Stm 44 was detected on an egg in an unopened box at the ACF from this supplier. The raw-egg dessert was epidemiologically implicated as the likely source of the Salmonella and delayed onset cases may have resulted from ingestion of a smaller dose of Salmonella, or ongoing transmission through cross-contamination of kitchen machinery or surfaces. This outbreak demonstrates that inadequate cooking of eggs continues to pose a risk for Salmonella infection in settings with vulnerable populations. The findings of the investigation provide support for the importance of food safety regulations and demand further advocacy for measures to reduce the risks associated with the distribution, storage and preparation of shell eggs.

An evaluation of the Australian Rotavirus Surveillance Program.

The Australian Rotavirus Serotyping Program (ARSP) serotypes rotavirus isolates obtained from stool samples sent from Australian laboratories. In collaboration with ARSP the Australian Government Department of Health and Ageing evaluated the program for its utility and capacity to monitor effectiveness of the rotavirus vaccines recently introduced into the Australian National Immunisation Program. The system was described using ARSP annual reports and staff interviews. The attributes of the system were assessed by adapting standard guidelines for evaluating a surveillance system. Email surveys or face to face interviews were conducted with staff of ARSP, participating laboratories, rotavirus vaccine manufacturing companies and representatives of the Communicable Diseases Network Australia. The ability of the ARSP to monitor changes in rotavirus serotype epidemiology was assessed. ARSP serotypes rotavirus isolates received from participating laboratories at least bi-annually, with results being reported at least as often. Serotype analyses have informed formulation of rotavirus vaccines and contributed to forecasting the extent of outbreaks caused by novel serotypes. The ARSP will be able to monitor changes in rotavirus serotype epidemiology and identify probable vaccination failures. Enhancement of the representativeness and sensitivity of the system are needed for the data to remain useful in the public health context. Methods for transferring data between the program and state and territory health departments need to be developed.