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.

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.

Objective: We undertook an integrated analysis of genomic and epidemiological data to investigate a large healthcare-associated COVID-19 outbreak and to better understand the epidemiology of all 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 SARS-CoV-2 samples or extracted RNA from those cases, were included. Sequencing was conducted by tiled amplicon PCR using ARTIC v1 or v3 primers and Illumina sequencing. Consensus sequences were generated, sequences were aligned to a reference sequence, and phylogenetic analysis performed. Genomic clusters were determined and integrated with epidemiologic data to assess any additional insights. Results: All COVID-19 cases notified in Tasmania during the study period (n=231) and 266 SARS-CoV-2 positive samples, representing 217/231 (94%) of notified cases, were included in the study; 182/217 (84%) were clustered, 21/217 (10%) were unique, 12/217 (6%) could not be sequenced. Genomics confirmed the presence of seven epidemiological clusters, clarified transmission networks where epidemiology was unclear and additionally identified another genomic cluster which had not been identified by epidemiology alone. Discussion: Genomic analysis provided useful additional information on COVID-19 in Tasmania including evidence of the probable source of infection in cases where epidemiological links had not been identified and that the source of a large healthcare-associated outbreak was an overseas cruise. Genomic analysis also confirmed there was no identified community transmission from other imported cases. Genomic insights are an important component in responding to COVID-19 and ongoing genomic surveillance is warranted.

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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 highlead 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.