ORCID Profile
0000-0001-9873-7163
Current Organisations
Austin Health
,
University of Melbourne
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-2018
DOI: 10.1126/SCITRANSLMED.AAR6115
Abstract: Alcohol-based disinfectants and particularly hand rubs are a key way to control hospital infections worldwide. Such disinfectants restrict transmission of pathogens, such as multidrug-resistant
Publisher: Cold Spring Harbor Laboratory
Date: 08-08-2023
DOI: 10.1101/2023.08.07.552371
Abstract: Ross River Virus and Barmah Forest Virus infections (alphaviruses) have short incubation periods and are transmitted to humans by mosquitoes. Mycobacterium ulcerans infection (Buruli ulcer) has a much longer incubation period and its mode of transmission is contested. We studied the relationship between month of notification of alphavirus infections and Buruli ulcer in the temperate Australian state of Victoria over the six-year period, 2017-2022. Using cross-correlation, a signal processing technique, we found that a five-month temporal shift in month of Buruli ulcer notification provided optimal alignment with month of alphavirus notification over the six-year period. This closely matches the previously determined 5-month Buruli ulcer incubation period. Inferred transmission of both conditions showed coordinated maxima in summer and autumn and coordinated minima in winter and spring. The close alignment in season of transmission of alphavirus infection and Buruli ulcer in Victoria supports mosquitoes as the primary local vector of M. ulcerans.
Publisher: Public Library of Science (PLoS)
Date: 18-08-2017
Publisher: Public Library of Science (PLoS)
Date: 12-10-2023
Publisher: Cold Spring Harbor Laboratory
Date: 29-03-2023
DOI: 10.1101/2023.03.29.534673
Abstract: Mycobacterium ulcerans (MU) causes Buruli ulcer (BU), a geographically restricted infection that can result in skin loss, contracture, and permanent scarring. Lesion-location maps compiled from more than 640 cases in south eastern Australia suggest biting insects are likely involved in transmission, but it is unclear whether MU is brought by insects to their target or if MU is already on the skin and inoculation is an opportunistic event that need not be insect dependent. We validated a PCR swab detection assay and defined its dynamic range using laboratory cultured M. ulcerans and fresh pigskin. We invited volunteers in Buruli-endemic and non-endemic areas to s le their skin surfaces with self-collected skin swabs tested by IS2404 quantitative PCR. Pigskin validation experiments established a limit-of-detection of 0.06 CFU/cm 2 at a qPCR cycle threshold (Ct) of 35. Fifty-seven volunteers returned their self-collected kits of 4 swabs (bilateral ankles, calves, wrists, forearms), 10 from control areas and 47 from endemic areas. Collection was timed to coincide with the known peak-transmission period of Buruli. All swabs from human volunteers tested negative (Ct ≥35). M. ulcerans was not detected on the skin of humans from highly BU endemic areas. Buruli ulcer (BU) incidence is increasing in temperate south eastern Australia. We have yet to develop public health programs to assist people avoid BU partly because the precise mode of transmission is contentious. Recent research has shown that environmental contamination with M. ulcerans (the cause of BU) is widespread in endemic areas as a result of faecal shedding from infected possums that live close to humans, although direct human-possum contact is rare. We investigated the possibility that the skin of humans in endemic areas could become transiently contaminated with M. ulcerans while outdoors. If this were the case then BU prevention programs could be developed around skin protection and regular washing/showering. To study this possibility, we developed a sensitive skin swab PCR-assay that we tested using a pigskin laboratory model so we could be confident in our results. We asked volunteers to collect their own skin swabs after spending at least 4 hours outside during the known period of peak Buruli transmission. Fifty seven volunteers returned swab sets for testing. Our results were negative. We did not find evidence that humans in our endemic zone have M. ulcerans contamination on their skin.
Publisher: Public Library of Science (PLoS)
Date: 20-04-2020
No related grants have been discovered for Paul D. R. Johnson.