Hepatitis A outbreak in Australia linked to imported Medjool dates, June-September 2021.

Abstract: Imported, minimally processed food products have been historically associated with several hepatitis A outbreaks in Australia. Here, we report the first known hepatitis A outbreak in Australia linked to consumption of imported fresh Medjool dates. Between June and September 2021, six genetically identical hepatitis A cases were notified in New South Wales and the Australian Capital Territory. All cases reported date consumption during their exposure period. The implicated dates were positive for hepatitis A virus (HAV) by reverse transcription polymerase chain reaction. Rapid detection of this outbreak and the swift implementation of control measures was facilitated by two key factors. Firstly, Australian international border closures implemented in response to the COVID-19 pandemic meant that a common locally-acquired, as opposed to travel-acquired, source for cases was strongly suspected. Secondly, prompt awareness of a hepatitis A outbreak in the United Kingdom (which was found to be associated with date consumption) allowed for early hypothesis generation and investigation. This paper details the epidemiological and microbiological factors involved in this outbreak investigation and the actions taken to mitigate public health risk.

Salmonellosis in Australia in 2020: possible impacts of COVID-19 related public health measures.

BACKGROUND: More than seventy per cent of salmonellosis in Australia is thought to be due to contaminated food. Rates of salmonellosis vary across the Australian states and territories, with the highest rates in the Northern Territory. In 2020, to control coronavirus disease 2019 (COVID-19), Australia implemented public health measures including border closures, physical distancing and hygiene advice. This study analyses salmonellosis notification rates in 2020 and considers possible impacts of COVID-19 measures. METHODS: Monthly and annual salmonellosis notifications per 100,000 population, for each of Australia's eight states and territories for the years 2015 to 2020, were extracted from Australia's publicly accessible National Notifiable Diseases Surveillance System. For each jurisdiction, the salmonellosis rate each month in 2020 was compared with the previous 5-year median rate for that calendar month. The possible impacts of COVID-19 public health measures on salmonellosis notifications in the respective states and territories were examined. RESULTS: The annual Australian salmonellosis notification rate was 27% lower in 2020 than the previous 5-year median. The reduction in salmonellosis rate varied throughout Australia. States and territories with more stringent, more frequent or longer COVID-19 public health measures had generally greater salmonellosis rate reductions. However, Tasmania had a 50% deeper reduction in salmonellosis rate than did the Northern Territory, despite similar restriction levels. CONCLUSIONS: Salmonellosis notifications decreased in Australia during the global COVID-19 pandemic. The reduction in notifications corresponded with the implementation of public health measures. Persistence of high rates in the Northern Territory could indicate the overarching importance of demographic and environmental factors.

Monitoring the incidence and causes of disease potentially transmitted by food in Australia: Annual report of the OzFoodNet network, 2016.

ABSTRACT: In 2016, a total of 44,455 notifications of enteric diseases potentially related to food were received by state and territory health departments in Australia. Consistent with previous years, campylobacteriosis (n = 24,171) and salmonellosis (n = 18,060) were the most frequently-notified infections. Notable increases in incidence were observed for shiga toxin-producing Escherichia coli (n = 343; 166% increase), shigellosis (n = 1,408; 93% increase), campylobacteriosis (33% increase) and salmonellosis (30% increase) when compared with the historical five-year mean. The extent to which the introduction of culture-independent testing as a method of diagnosis has contributed to these increases remains unclear. In total, 188 gastrointestinal outbreaks, including 177 foodborne outbreaks, were reported in 2016. The 11 non-foodborne outbreaks were due to environmental or probable environmental transmission (nine outbreaks) and animal-to-person or probable animal-to-person transmission (two outbreaks). No outbreaks of waterborne or probable waterborne transmission were reported in 2016. Foodborne outbreaks affected 3,639 people, resulting in at least 348 hospital admissions and four deaths. Eggs continue to be a source of Salmonella Typhimurium infection across the country: 35 egg-related outbreaks, affecting approximately 510 people, were reported across six jurisdictions in 2016. Three large multi-jurisdictional Salmonella outbreaks associated with mung bean sprouts (n = 419 cases); bagged salad products (n = 311 cases); and rockmelons (n = 144 cases) were investigated in 2016. These outbreaks highlight the risks associated with fresh raw produce and the ongoing need for producers, retailers and consumers to implement strategies to reduce potential Salmonella contamination.

Describing the Epidemiology of Foodborne Outbreaks in New South Wales from 2000 to 2017.

Foodborne disease causes an estimated 4.1 million cases of illness in Australia each year and is responsible for causing many significant common source outbreaks. We analyzed 18 years of foodborne outbreak data collected in New South Wales (NSW), and classified the likely pathogen type responsible for outbreaks of unknown etiology, to track broad trends over time. A total of 869 outbreaks were reported in NSW from 2000 to 2017. The majority (53%) of outbreaks did not have a pathogen identified and underwent pathogen type categorization based on the epidemiology of the outbreak. The proportion of outbreaks due to toxin producing bacteria decreased over time, whereas the proportion of outbreaks due to other bacterial pathogens increased. The proportion of outbreaks due to viral gastroenteritis pathogens had no overall changing trend over time. Bacterial outbreaks had significantly more identified cases and had more hospitalizations than other pathogen type causes. Other features associated with high case numbers, hospitalizations, and deaths in foodborne outbreaks included being due to food contaminated in primary production, involving consumption of raw products, and having evidence of poor sanitation in the food preparation areas. Eggs were the most commonly determined pathogen food source, occurring in 12% of outbreaks; however, most outbreak investigations (77%) did not have a pathogen food source identified. This analysis demonstrates a changing landscape of foodborne outbreaks over time. Increases in outbreaks due to bacterial and viral pathogens coincide with increases in sporadic notifications of the same pathogens, whereas decreases in toxin caused outbreaks followed the introduction of mandatory food safety training in retail food businesses. Recognizing issues in food production and implementing improvements that reduce the number of pathogens in food will be key to reducing the incidence of foodborne outbreaks.

Seven Salmonella Typhimurium Outbreaks in Australia Linked by Trace-Back and Whole Genome Sequencing.

Salmonella Typhimurium is a common cause of foodborne illness in Australia. We report on seven outbreaks of Salmonella Typhimurium multilocus variable-number tandem-repeat analysis (MLVA) 03-26-13-08-523 (European convention 2-24-12-7-0212) in three Australian states and territories investigated between November 2015 and March 2016. We identified a common egg grading facility in five of the outbreaks. While no Salmonella Typhimurium was detected at the grading facility and eggs could not be traced back to a particular farm, whole genome sequencing (WGS) of isolates from cases from all seven outbreaks indicated a common source. WGS was able to provide higher discriminatory power than MLVA and will likely link more Salmonella Typhimurium cases between states and territories in the future. National harmonization of Salmonella surveillance is important for effective implementation of WGS for Salmonella outbreak investigations.

Shigella species epidemiology and antimicrobial susceptibility: the implications of emerging azithromycin resistance for guiding treatment, guidelines and breakpoints.

OBJECTIVES: To examine antimicrobial susceptibility patterns and predictors of resistance among Shigella isolates in New South Wales (NSW), Australia during 2013-14 with emphasis on azithromycin. METHODS: Cross-sectional analysis of all shigellosis cases (160) notified to public health authorities in NSW, Australia was performed. RESULTS: Among 160 Shigella isolates tested, 139 (86.9%) were susceptible to azithromycin, 104 (65.0%) to ciprofloxacin and 38 (23.7%) to co-trimoxazole. Ciprofloxacin resistance was 1.9 times more common in infections acquired in Australia compared with those acquired overseas, while azithromycin resistance was 8.5 times more common in males. CONCLUSIONS: We recommend ongoing reconsideration of guidelines for the treatment of shigellosis based on emerging resistance patterns. First-line therapy may need to be reconsidered based on local resistance rates due to common resistance to co-trimoxazole and ciprofloxacin. We recommend culture and susceptibility testing for suspected and proven shigellosis. Azithromycin susceptibility breakpoints for Shigella species may need to be species specific.

Re-testing for chlamydia at sexual health services in Australia, 2004-08.

OBJECTIVE: To describe the frequency of the 3-month test for re-infection among sexual health service patients in Australia. METHODS: We assessed the re-testing rates at 30-120 days after chlamydia infection in men who have sex with men (MSM), heterosexual males and females attending sexual health services across Australia between 2004 and 2008. A χ(2)-test was used to determine significant differences in re-testing rates according to demographic characteristics and trends over time. RESULTS: In the 5-year period, 10207 MSM, 28530 heterosexual males and 31190 heterosexual females were tested for chlamydia. Of those tested, 9057 (13.0%) were positive. The proportion of patients with chlamydia infection who were re-tested in 30-120 days was 8.6% in MSM, 11.9% in heterosexual males and 17.8% in heterosexual females. Among MSM, chlamydia re-testing rates were lower in men aged <30 years (8.4%) than ≥30 years (12.5%) (P=0.04) and lower in travellers and migrants (2.9%) than non-travellers (9.9%) (P=0.002). In heterosexual males, chlamydia re-testing rates were lower in men in regional and rural areas (10.5%) than metropolitan areas (13.5%) (P=0.017). There was no increasing trend in re-testing rates between 2004 and 2008 (P=0.787). Of the patients re-tested, 44.1% of MSM were positive, 21.0% of heterosexual males and 16.1% of females. DISCUSSION: The high chlamydia positivity at 30-120 days support recommendations that call for a 3-month test for re-infection following a positive test. The low re-testing rates highlight the need for innovative strategies to increase re-testing.

Chlamydia trends in men who have sex with men attending sexual health services in Australia, 2004-2008.

BACKGROUND: In most Australian settings, chlamydia notifications do not contain information on the gender of sexual partners. We assessed trends and predictors of chlamydia testing and positivity among men who have sex with men (MSM), attending sexual health services in Australia. METHODS: The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) program was established in 2008 to collate demographic and chlamydia testing information from 25 sexual health services. We calculated the proportion tested and chlamydia positivity among MSM and assessed trends from 2004 to 2008 using a χ2 test and predictors using logistic regression. RESULTS: In the 5-year period, 11,777 MSM attended as new patients (first visit ever to the service) and the proportion tested for chlamydia increased significantly from 71% in 2004 to 79% in 2008 (P < 0.01). Independent predictors of chlamydia testing were younger age, residing in a metropolitan area (adjusted prevalence ratio [APR] = 1.23; 95% confidence interval [CI]: 1.19, 1.27), being Australian-born (APR = 1.03; 95% CI: 1.01, 1.06), being a traveler or migrant (APR = 1.09; 95% CI: 1.06, 1.12), and sex overseas in the past year (APR = 1.05; 95% CI: 1.03, 1.07). Overall chlamydia positivity was 8.6% (95% CI: 8.0%-9.2%). There was no significant trend in chlamydia positivity between 2004 and 2008. Independent predictors of chlamydia positivity were younger age, being a traveler or migrant (APR = 1.52; 95% CI: 1.26-1.84), and exclusive same-sex contact (APR = 1.28; 95% CI: 1.05-1.55). CONCLUSIONS: This new national surveillance program demonstrates that the majority of MSM attending sexual health services was offered chlamydia testing and testing has increased over time. The MSM at highest risk of chlamydia were more likely to be tested. Chlamydia transmission was frequent but stable among MSM accessing clinical services.

Quadrivalent human papillomavirus vaccination and trends in genital warts in Australia: analysis of national sentinel surveillance data.

BACKGROUND: Quadrivalent human papillomavirus (HPV) vaccine has high efficacy in clinical trials but no reports describe its effects at a population level. From July, 2007, Australia was the first country to fund a vaccination programme for all women aged 12-26 years. We established a national surveillance network in Australia and aimed to identify trends in diagnoses of genital warts in 2004-09. METHODS: We obtained standardised data for demographic factors, frequency of genital warts, HPV vaccination status, and sexual behaviour for new patients attending eight sexual health services in Australia between January, 2004, and December, 2009. We used χ² analysis to identify significant trends in proportions of patients diagnosed with warts in periods before and after vaccination began. Our primary group of interest was female Australian residents who were eligible for free vaccination, although data were assessed for patients ineligible for free vaccination, including women older than 26 years of age, non-resident women, and men. FINDINGS: Among 112 083 new patients attending sexual health services, we identified 9867 (9%) cases of genital warts. Before the vaccine programme started, there was no change in proportion of women or heterosexual men diagnosed with genital warts. After vaccination began, a decline in number of diagnoses of genital warts was noted for young female residents (59%, p(trend)<0·0001). No significant decline was noted in female non-residents, women older than 26 years in July, 2007, or in men who have sex with men. However, proportionally fewer heterosexual men were diagnosed with genital warts during the vaccine period (28%, p(trend)<0·0001), and this effect was more pronounced in young men. By 2009, 65·1% of female Australian residents who were eligible for free vaccine reported receipt of quadrivalent or unknown HPV vaccine. INTERPRETATION: The decrease in frequency of genital warts in young Australian women resulting from the high coverage of HPV vaccination might provide protective effects in heterosexual men through herd immunity. FUNDING: CSL Biotherapies.

A new national Chlamydia Sentinel Surveillance System in Australia: evaluation of the first stage of implementation.

The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) was established with funding from the Department of Health and Ageing to trial the monitoring of the uptake and outcome of chlamydia testing in Australia. ACCESS involved 6 separate networks; 5 clinical networks involving sexual health services, family planning clinics, general practices, antenatal clinics, Aboriginal community controlled health services, and 1 laboratory network. The program ran from May 2007 to September 2010. An evaluation of ACCESS was undertaken in early 2010, 2 years after the program was funded. At the time of the evaluation, 76 of the 91 participating sites were contributing data. The jurisdictional distribution of the 76 sites generally matched the jurisdictional distribution of the Australian population. In 2008, the chlamydia testing rates in persons aged 16-29 years attending the 26 general practices was 4.2% in males and 7.0% in females. At the 25 sexual health services, the chlamydia testing rates in heterosexuals aged less than 25 years in 2008 was 77% in males and 74% in females. Between 2004 and 2008, the chlamydia positivity rate increased significantly in heterosexual females aged less than 25 years attending the sexual health services, from 11.5% to 14.1% (P < 0.01). Data completeness was above 85% for all core variables except Aboriginal and/or Torres Strait Islander status and country of birth, which ranged from 68%-100%, and 74%-100%, respectively, per network. There were delays in establishment of the system due to recruitment of 91 sites, multiple ethics applications and establishment of automated extraction programs in 10 different database systems, to transform clinic records into a common, pre-defined surveillance format. ACCESS has considerable potential as a mechanism toward supporting a better understanding of long-term trends in chlamydia notifications and to support policy and program delivery.

Chlamydia at an inner metropolitan sexual health service in Sydney, NSW: Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) Project.

BACKGROUND: Australia has a widely dispersed network of public sexual health services that test large numbers of people from high prevalence populations for genital Chlamydia trachomatis infection. These populations include young sexually active heterosexuals, men who have sex with men, sex workers and Aboriginal and Torres Strait Islander people. The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) Project was established to monitor chlamydia testing rates and positivity rates at a national level, which in turn will help interpret trends in chlamydia diagnoses reported through passive surveillance. The ACCESS Project is the first time that chlamydia-related data including priority population and testing denominators has been collated at a national level. The present paper reports on chlamydia testing and positivity rates in a sexual health service in the inner west of Sydney between 2004 and 2008 and compares these to published national data from the ACCESS Project in sexual health services. METHODS: Chlamydia positivity and testing rates at an inner western Sydney sexual health service were compared with aggregate data from the ACCESS Project obtained from 14 sexual health services across Australia. Using a standardised extraction program, retrospective de-identified line-listed demographic and chlamydia testing data on all patients were extracted from patient management systems. RESULTS: Over the 5-year period, 5145 new patients attended the inner-west sexual health service. Almost 66% had a chlamydia test at first visit and there was no significant difference in this testing rate when compared with the ACCESS Project national rate for sexual health services (67.0%; odds ratio [OR] 0.94, 95% confidence intervals 0.88-1.00). The testing rate increased over time from 61% in 2004 to 70% in 2008. There were 281 chlamydia diagnoses at this service, giving an overall chlamydia positivity rate of 9.3%, significantly higher than the ACCESS Project national rate of 8.2% (OR 1.16, 95% confidence intervals 1.02-1.32). DISCUSSION: Testing rates were similar and positivity rates for Chlamydia trachomatis were higher in this sexual health service in Sydney than national trends.