Abstract
Beginning in 2017, cases of canine leptospirosis started to be reported from the City of Sydney council area, the highly urbanized centre of the Greater Sydney Area, Australia (Griebsch et al., 2022). Prior to this, the most recent cases had been reported in 1976. The reasons for the appearance of canine leptospirosis after a period of more than 30 years of absence are unknown. Some suggested reasons included local construction activities, flooding events, and rodent problems (Gong et al., 2022). The aim of this research program is to identify the drivers of the current canine leptospirosis epidemic in Sydney, and specifically the role played by the urban landscape.
To date, using passive surveillance of veterinary practices, case ascertainment has been carried out. Using demographic information generated by dog registration and microchip data, the population at-risk has been modelled. Statistical areas have been used to calculate disease incidence. For each of these areas, information on a range of urban landscape factors have been extracted; these include parks, recreational areas, water bodies, vegetation coverage, and housing density.
Between 2017 and 2023, 20 cases of canine leptospirosis have been detected in the two central local government areas of Sydney and Inner West. The greatest number of cases (n=8) were detected in 2019. Cases were reported from a total of 18 out of 906 statistical areas. Clustering of cases was identified in an area on the periphery of the central business district of Sydney in 2019. Both a statistical area matched case-control study analysis and an area-based incidence Poisson regression are being used to identify the landscape factors associated with canine leptospirosis.
Most of our knowledge of landscape factors that influence leptospirosis outbreaks and epidemic are derived from the human literature and are often anecdotal. Results of the current study are expected to assist dog owners and veterinarians to control and prevent canine leptospirosis within this region.
References
Griebsch, C., Kirkwood, N., Ward, M.P., So, W., Weerakoon, L., Donahoe S., Norris, J.M. (2022). Emerging leptospirosis in urban Sydney dogs: a case series (2017-2020). Australian Veterinary Journal 100: 190-200.
Gong, J., Griebsch, Kirkwood, N., Norris, J.M, Ward, M.P. (2022). Emerging canine leptospirosis in Sydney and the role of population demographics. Transboundary and Emerging Diseases 69: 2485-2494.