The first confirmed outbreak of Barmah Forest virus in Tasmania - 2019.

OBJECTIVE: To describe the first outbreak of Barmah Forest virus (BFv) in Tasmania and identify potential vectors for BFv in Tasmania. METHODS: A retrospective descriptive study of BFv notifications in the Tasmanian Notifiable Diseases Database (TNDD) was conducted. Adult mosquitoes were sampled from areas near outbreak cases and pooled samples were tested for BFv. RESULTS: 27 cases of confirmed BFv were recorded in the TNDD between 12 March 1999 and 30 June 2019. Nine cases were recorded between 21 January and 10 May 2019 that were acquired in Tasmania, with eight included in this confirmed outbreak. All outbreak cases resided in or travelled to locations in the Break O'Day Local Government Area and reported no recent interstate travel. No virus was detected in pooled mosquito samples. CONCLUSIONS: This is Tasmania's first confirmed outbreak of BFv. Known BFv vector species were identified in both saltmarsh and urban-fringe brackish saltmarsh larval habitats. BFv was not detected from pooled mosquito samples. IMPLICATIONS FOR PUBLIC HEALTH: Clinicians should consider BFv as a possible diagnosis for presentations with fever and arthritis, and potential mosquito exposure in Tasmania. These findings will guide broadening of prevention-focussed public health messaging.

COVID-19: Integrating genomic and epidemiological data to inform public health interventions and policy in Tasmania, Australia.

OBJECTIVE: We undertook an integrated analysis of genomic and epidemiological data to investigate a large health-care-associated outbreak of coronavirus disease 2019 (COVID-19) and to better understand the epidemiology of COVID-19 cases in Tasmania, Australia. METHODS: Epidemiological data collected on COVID-19 cases notified in Tasmania between 2 March and 15 May 2020, and positive samples of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or RNA extracted from the samples were included. Sequencing was conducted by tiled amplicon polymerase chain reaction with ARTIC v1 or v3 primers and Illumina sequencing. Consensus sequences were generated, sequences were aligned to a reference sequence and phylogenetic analysis was performed. Genomic clusters were determined and integrated with epidemiological data to provide additional information. RESULTS: All 231 COVID-19 cases notified in Tasmania during the study period and 266 SARS-CoV-2-positive samples, representing 217/231 (94%) notified cases, were included; 184/217 (84%) were clustered, 21/217 (10%) were unique and 12/217 (6%) could not be sequenced. Genomics confirmed the presence of seven clusters already identified through epidemiological links, clarified transmission networks in which the epidemiology had been unclear and identified one cluster that had not previously been recognized. DISCUSSION: Genomic analysis provided useful additional information on COVID-19 in Tasmania, including evidence of a large health-care-associated outbreak linked to an overseas cruise, the probable source of infection in cases with no previously identified epidemiological link and confirmation that there was no identified community transmission from other imported cases. Genomic insights are an important component of the response to COVID-19, and continuing genomic surveillance is warranted.

Epidemiologic, Entomologic, and Virologic Factors of the 2014-15 Ross River Virus Outbreak, Queensland, Australia.

Australia experienced its largest recorded outbreak of Ross River virus (RRV) during the 2014-15 reporting year, comprising >10,000 reported cases. We investigated epidemiologic, entomologic, and virologic factors that potentially contributed to the scale of the outbreak in Queensland, the state with the highest number of notifications (6,371). Spatial analysis of human cases showed that notifications were geographically widespread. In Brisbane, human case notifications and virus detections in mosquitoes occurred across inland and coastal locations. Viral sequence data demonstrated 2 RRV lineages (northeastern genotypes I and II) were circulating, and a new strain containing 3 unique amino acid changes in the envelope 2 protein was identified. Longitudinal mosquito collections demonstrated unusually high relative abundance of Culex annulirostris and Aedes procax mosquitoes, attributable to extensive freshwater larval habitats caused by early and persistent rainfall during the reporting year. Increased prevalence of these mosquitoes probably contributed to the scale of this outbreak.

New and old hotspots for rickettsial spotted fever acquired in Tasmania, 2012-2017.

OBJECTIVE: To describe the epidemiology and clinical characteristics of Tasmania-acquired rickettsial disease notified to the Department of Health in Tasmania from 2012 to 2017 inclusive. METHODS: Data on rickettsiosis cases acquired and notified in Tasmania between 1 January 2012 and 31 December 2017 were analysed descriptively. RESULTS: Eighteen cases of rickettsial infection notified in Tasmania 2012-17 and likely acquired in the state met one of three case definitions: 12 confirmed (67%), four probable (22%), and two possible (11%). The mean number of cases per year was 3.0 (population rate 0.6 per 100,000 population/year); 60% of cases occurred in November and December. Cases were more commonly older males. Fever, lethargy, and rash were commonly reported symptoms. Thirteen cases were likely acquired on Flinders Island, three around Great Oyster Bay and two in the Midlands. CONCLUSIONS: This study extends our knowledge of the epidemiology of rickettsial disease in Tasmania. This is the first account including confirmed cases acquired in the Midlands of Tasmania. Implications for public health: Increased knowledge and awareness of epidemiology of rickettsial infection in Tasmania is essential for timely diagnosis and appropriate treatment. These findings bear wider relevance outside Tasmania because visitors may also be at risk.

A novel public health threat - high lead solder in stainless steel rainwater tanks in Tasmania.

OBJECTIVE: We identified two water tanks in Tasmania with water lead concentrations exceeding the Australian Drinking Water Guidelines (ADWG) limit; they had been constructed with stainless steel and high-lead solder from a single manufacturer. An investigation was initiated to identify all tanks constructed by this manufacturer and prevent further exposure to contaminated water. METHODS: To identify water tanks we used sales accounts, blood and water lead results from laboratories, and media. We analysed blood and water lead concentration results from laboratories and conducted a nested cohort study of blood lead concentrations in children aged <18 years. RESULTS: We identifed 144 tanks constructed from stainless steel and high lead solder. Median water lead concentrations were significantly higher in the stainless steel tanks (121µg/L) than in the galvanised tanks (1µg/L). Blood lead concentrations ranged from 1 to 26µg/dL (median 5µg/dL); of these, 77% (n=50) were below the then-recommended health-related concentration of 10µg/dL. Concentrations in the 15 people (23%) above this limit ranged from 10-26µg/dL, with a median of 14µg/dL. The median blood lead concentration in the nested cohort of children was initially 8.5µg/dL, dropping to 4.5µg/dL after follow-up. CONCLUSIONS: Lead concentrations in the water tanks constructed from stainless steel and high-lead solder were up to 200 times above the recommended ADWG limits. Implications for public health: This investigation highlights the public health risk posed by use of non-compliant materials in constructing water tanks.

Invasive pneumococcal disease in Australia, 2009 and 2010.

Enhanced surveillance for invasive pneumococcal disease (IPD) was conducted in all Australian states and territories in 2009 and 2010 with comprehensive comparative data available since 2002. There were 1,556 cases of IPD notified to the National Notifiable Diseases Surveillance System in Australia in 2009, a notification rate of 7.2 cases per 100,000 population. In 2010 there were 1,640 cases, a notification rate of 7.4 cases per 100,000. The overall rate of IPD in Indigenous Australians was almost 6 times the rate in non-Indigenous Australians in both 2009 and 2010. In 2009 and 2010, notification rates of IPD caused by serotypes included in the 7-valent pneumococcal conjugate vaccine (7vPCV) continued to decrease across all age groups. Rates of IPD caused by non-7vPCV serotypes continued to show an increasing trend in both Indigenous and non-Indigenous children aged less than 5 years. In Indigenous adults (≥50 years), rates of IPD caused by both 23-valent pneumococcal polysaccharide vaccine (23vPPV) serotypes and non-23vPPV serotypes continued to show an overall increase, particularly in 2010. There were 110 deaths attributed to IPD in 2009 and 137 in 2010, although it should be noted that deaths may be under-reported. The number of invasive pneumococcal isolates with reduced penicillin susceptibility remained low and reduced susceptibility to third generation cephalosporins was rare.

An outbreak of norovirus linked to oysters in Tasmania.

Norovirus is the most commonly reported virus in shellfish related gastroenteritis outbreaks. In March 2013 an investigation was conducted following the receipt of reports of gastroenteritis after the consumption of oysters at private functions in Tasmania. Cases were ascertained through general practitioners, emergency departments, media releases and self-reporting. Of the 306 cases identified in Tasmania, ten faecal specimens were collected for laboratory testing and eight were positive for norovirus (GII.g). The most common symptoms were vomiting (87%), diarrhoea (85%), myalgia (82%) and fever (56%). The implicated oysters were traced to a single lease from which they were harvested and distributed locally and interstate. Nationally 525 cases were identified from Tasmania (306), Victoria (209), New South Wales (8) and Queensland (2). This report highlights the consequences of norovirus outbreaks in shellfish, even with rapid identification, trace back and removal of the implicated product from the market.