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Buruli ulcer (BU) is a necrotizing disease of skin and soft tissue caused by the bacterium Mycobacterium ulcerans (MU). In Australia, where the disease is emerging in new geographic areas and human case numbers are increasing, native possum species act as reservoir hosts. To better understand the life history of MU in one of its natural hosts, we conducted intra-dermal challenge of six wild caught, MU-naïve common ringtail possums (Pseudocheirus peregrinus). All six animals developed BU disease consistent with that observed in naturally infected ringtail possums. Time to ulceration varied between 49 and 77 days (mean = 61.8 days). Molecular evidence of systemic infection was detected in five animals and was supported by consistent histopathological findings in four animals. Pathological findings included random, multifocal, granulomatous hepatitis in four possums, one of which also had a mild, multifocal, interstitial granulomatous pneumonia. Acid-fast bacilli were only evident in inflammatory foci beyond the primary inoculation site in one possum. The ringtail possum model of MU infection is an important tool for the investigation of bacterial transmission dynamics, pathogenesis and immune response in a natural host. Data from this model may improve disease risk modelling and help identify intervention points to stop zoonotic transmission and disease spread., (© 2024. Crown.)

Understanding vapor intrusion (VI) temporal variability is key for the design of sampling strategies intended to assess reasonable maximum exposure of indoor air concentrations of volatile organic compounds (VOCs) as well as risk evaluation and mitigation planning. VI temporal variability has previously been shown to be dependent on the complex interactions of multiple independent variables-meteorological, hydrogeological, and human behavioral. Several meteorological variables, including barometric pressure, wind speed, and rainfall, are linked during tropical and extratropical storm events. High-frequency meteorological and indoor VOC data from a series of seven tropical storms and four extratropical storms were collected at a single industrial building with multiple heating, ventilation, and air conditioning (HVAC) zones. The storms and sampling zones showed a variety of effects on trichloroethylene (TCE) concentrations in indoor air. In one zone (supply room), increases in TCE concentrations often, but not always, closely coincided with decreasing barometric pressure, sustained wind speeds over 32 km/h (20 mph), and differential pressures indicating subslab to indoor flow. A second zone, in a restroom, did not show a consistent pattern of temporal correlation between meteorological factors and indoor air concentrations. While peak indoor air concentrations may be associated with the passage of cyclonic storms at some sampling locations, this does not appear to be generalizable to all sampling locations. The observed increase in indoor air concentration potentially attributable to these storms is typically less than an order of magnitude and the duration ranges from a day to a week.