Effective control of egg-associated salmonellosis remains a challenge in Australia, with Salmonella Typhimurium dominating as the causative serotype in outbreak events. Although outbreaks predominantly occur in the settings of restaurants, the high recovery rate of indistinguishable Salmonella on epidemiologically implicated egg farms suggests that further efforts to minimize infection pressure at the primary production level are needed in Australia.

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An outbreak of 26 cases of Salmonella Litchfield infection occurred in the states of Western Australia and Queensland between October 2006 and January 2007. A case-control study was conducted with 12 cases and 24 controls, and a significant association was found between illness and consumption of papaya (odds ratio, 32.8; 95% confidence interval, 2.71 to 883.5). Papaya samples were collected from 26 stores in Western Australia, and 9 of 38 samples were contaminated with Salmonella Litchfield. These samples had pulsed-field gel electrophoresis patterns and multilocus variable-number tandem-repeat analysis profiles indistinguishable from the outbreak strain. Three farms in Western Australia supplied the contaminated papaya, and two of these farms were inspected. Salmonella Litchfield was not detected in papaya samples, fungal sprays, or water samples from the farms; however, at one farm other serotypes of Salmonella were detected in untreated river water that was used for washing papaya. Only treated potable water should be used for washing fresh produce that is to be eaten raw.

Background: A variety of infectious diseases can cause outbreaks on board vessels, with both health and economic effects. Internationally, Coronavirus Disease 2019 (COVID-19) outbreaks have occurred on numerous cruise and cargo vessels and the containment measures, travel restrictions, and border closures continue to make it increasingly difficult for ship operators world-wide to be granted pratique, effect crew changes, and conduct trade. An effective outbreak management strategy is essential to achieve the outcome triad – healthy crew, clean vessel, and set departure date – while maintaining the safety of the on-shore workers and broader community and minimizing disruption to trade. This report describes the principles of COVID-19 outbreak responses on four cargo vessels, including the successful use of one vessel as a quarantine facility. Methods: Established principles of management and the experiences of COVID-19 outbreaks on cruise ships elsewhere informed a health-lead, multi-agency, strict 14-day quarantine (Q) regime based on: population density reduction on board; crew segregation; vessel cleaning and sanitation; infection risk zones, access, and control measures; health monitoring; case identification and management; food preparation and delivery; waste management control; communication; and welfare and security. Findings: Sixty-five crew were diagnosed with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection (range 2-25; attack rate 10%-81%; 15 asymptomatic). No deaths were recorded, and only one crew was hospitalized for COVID-19-related symptoms but did not require intensive care support. Catering crew were among the cases on three vessels. All non-essential crew (n-EC) and most of the cases were disembarked. During the vessel’s Q period, no further cases were diagnosed on board, and no crew became symptomatic after completion of Q. The outbreak response duration was 15-17 days from initial decision. No serious health issues were reported, no response staff became infected, and only two Q protocol breaches occurred among crew. Interpretation: Despite increasing risk of outbreaks on cargo vessels, maritime trade and crew exchanges must continue. The potential consequences of COVID-19 outbreaks to human life and to trade necessitate a balanced response. The principles described can offer health, financial, operational, and safety advantages.

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Background: Multiple instances of flight-associated SARS-CoV-2 transmission during long-haul flights have been reported during the COVID-19 pandemic. However, comprehensive investigations of passenger risk behaviours, before, during, and after the flight, are scarce. Methods: To investigate suspected SARS-CoV-2 transmission during a flight from United Arab Emirates to Australia in July 2020, systematic, repeated PCR-testing of passengers in hotel quarantine was linked to whole genome sequencing. Epidemiological analyses of in-depth interviews covering behaviours during the flight and activities pre- and post-boarding were used to identify risk factors for infection. Results: Seventeen of the 95 passengers from four different travel origins had PCR-confirmed infection yielding indistinguishable genomic sequences. Two of the 17 passengers were symptomatic within two days of the flight, had travelled together, and classified as co-primary cases. Seven secondary cases were seated within 2-rows of the co-primary cases, but five economy passengers seated further away, and three business class passengers were also infected (attack rate = 16% [15/93]). In multivariable analysis, being seated within 2-rows of a primary case (OR 7.16; 95% CI 1.66–30.85) and spending more than an hour in the arrival airport (OR 4.96; 95% CI 1.04–23.60) were independent predictors of secondary infection, suggesting travel-associated SARS-CoV-2 transmission may have occurred both during and after the flight. Self-reported increased hand hygiene, wearing gloves, frequent aisle walking and using the bathroom on the plane did not independently affect the risk of SARS-CoV-2 acquisition. Conclusions: This investigation identified substantial in-flight transmission among passengers seated both within and beyond two-rows of the primary cases, the standard applied to contact tracing on flights. Infection of passengers in separate cabin classes also suggests transmission occurred outside the cabin environment, likely at the arrival airport. Recognising that transmission may occur pre- and post- boarding may inform contact tracing advice and improve efforts to prevent future travel-associated outbreaks.

Aims:  Three molecular typing techniques were examined to determine which method was the most discriminatory in order to perform epidemiological typing of Moraxella catarrhalis. Methods and Results:  Twenty‐five Mor. catarrhalis isolates obtained from nasopharyngeal aspirates collected from Aboriginal and non‐Aboriginal children were subjected to random amplified polymorphic DNA (RAPD) analysis, automated ribotyping and pulsed field gel electrophoresis (PFGE). RAPD analysis determined two Mor. catarrhalis types, automated ribotyping with PstI determined four Mor. catarrhalis ribogroups and PFGE analysis with NotI determined 21 pulse field groups within the 25 isolates examined. Conclusions:  Analysis of discrimination index and typeability demonstrated that PFGE is the most discriminatory method for typing Mor. catarrhalis. Significance and Impact of the Study:  This study confirms that PFGE is the most appropriate molecular tool for the epidemiological study of Mor. catarrhalis.