Lessons from the re-emergence of imported measles cases following the COVID-19 pandemic in Victoria, Australia.

Introduction: Australia was declared to have eliminated endemic measles in 2014; however, imported cases continue to pose a threat of outbreaks. International travel restrictions during the coronavirus disease 2019 (COVID-19) pandemic led to a rapid decline in measles cases. The re-opening of the Australian international border to measles endemic regions returns the threat of outbreaks, which may be further compounded by disruptions in routine vaccinations during the COVID-19 pandemic. We consider lessons learned from the public health response to recent measles cases. Methods: This case series includes all confirmed measles cases meeting the national case definition reported to the Victorian Government Department of Health (the Department) between 1 January and 31 December 2022. The Department conducted active case finding and contact tracing of all cases in line with national guidelines. Cases were descriptively analysed. Results: In 2022, six of the seven measles cases reported in Australia occurred in Victoria, all of whom resided in Australia and acquired their infection overseas. Three cases were unlinked, and three formed an epidemiologically-linked household cluster. One case was partially vaccinated, one was not eligible for vaccination, one had unknown vaccination status, and three were unvaccinated, one of whom was under 12 months old but would have been eligible for vaccination prior to travel to endemic regions. None of the cases led to secondary transmission within Australia. Discussion: Following the COVID-19 pandemic, measles importations have re-commenced in Victoria. Although few measles cases occurred in 2022 and none resulted in onwards transmission, imported measles cases remain complex and require substantial public health follow-up. Delays in case diagnosis and flight contact tracing pose a significant risk for outbreaks of measles. Public health interventions are needed to maintain high vaccination rates, improve contact tracing, and ensure public health authorities and healthcare providers can rapidly identify and respond to imported measles cases.

Buruli ulcer: a new case definition for Victoria.

ABSTRACT: Laboratory-confirmed infection with Mycobacterium ulcerans is currently notifiable to health departments in several jurisdictions. Accurate surveillance is imperative to understanding current and emerging areas of endemicity and to facilitate research into a neglected tropical disease with poorly-understood transmission dynamics. The state of Victoria currently reports some of the highest numbers of M. ulcerans cases in the world each year, with 340 cases notified in 2018 (an incidence of 5.5 per 100,000 population). In May 2019, a group of clinical, laboratory and public health experts met to discuss a new case definition for the surveillance of M. ulcerans disease in Victoria, incorporating clinical and epidemiological elements. The new case definition supports important public health messaging and actions for residents and visitors to popular tourist areas in Victoria.

Challenges in managing a school-based measles outbreak in Melbourne, Australia, 2014.

OBJECTIVE: To identify barriers to control of a Victorian primary school-based measles outbreak. METHODS: Confirmed measles cases notified in Victoria in 2014 were reviewed. Surveillance data, correspondence, and investigation notes for the school-based outbreak were assessed regarding timeliness of diagnosis and notification, and adequacy of school-based immunisation records. RESULTS: Twenty-three (31%) of the 75 measles cases notified in 2014 were school-aged (5-18 years); three had documentation of measles vaccination, 17 were unvaccinated, and three had unknown vaccination history. Eight measles outbreaks were identified, including a primary school-based outbreak with ten cases. Of the six unvaccinated pupils in the affected school, five (83%) contracted measles. The proportion of the school's prep students with documented vaccination records, as required by law, ranged from 39% in 2013 to 97% in 2014. CONCLUSIONS: Inadequately vaccinated students constitute a vulnerable population and schools are a potential site for measles outbreaks. Inadequate enforcement of school-based immunisation records impact the management and control of school-based measles outbreaks. Implications for Public Health: There is a need to educate clinicians on measles diagnosis and notification, and schools on the requirement to maintain up-to-date vaccination records. School entry is an opportunity to review student vaccination history and offer immunisations.

Effects of polysaccharide intercellular adhesin (PIA) in an ex vivo model of whole blood killing and in prosthetic joint infection (PJI): A role for C5a.

BACKGROUND: A major complication of using medical devices is the development of biofilm-associated infection caused by Staphylococcus epidermidis where polysaccharide intercellular adhesin (PIA) is a major mechanism of biofilm accumulation. PIA affects innate and humoral immunity in isolated cells and animal models. Few studies have examined these effects in prosthetic joint infection (PJI). METHODS: This study used ex vivo whole blood modelling in controls together with matched-serum and staphylococcal isolates from patients with PJI. RESULTS: Whole blood killing of PIA positive S. epidermidis and its isogenic negative mutant was identical. Differences were unmasked in immunosuppressed whole blood pre-treated with dexamethasone where PIA positive bacteria showed a more resistant phenotype. PIA expression was identified in three unique patterns associated with bacteria and leukocytes, implicating a soluble form of PIA. Purified PIA reduced whole blood killing while increasing C5a levels. In clinically relevant staphylococcal isolates and serum samples from PJI patients; firstly complement C5a was increased 3-fold compared to controls; secondly, the C5a levels were significantly higher in serum from PJI patients whose isolates preferentially formed PIA-associated biofilms. CONCLUSIONS: These data demonstrate for the first time that the biological effects of PIA are mediated through C5a in patients with PJI.