The emergence of Leptospira borgpetersenii serovar Arborea in Queensland, Australia, 2001 to 2013

Lau, Colleen L., Skelly, Chris, Dohnt, Michael and Smythe, Lee D. (2015) The emergence of Leptospira borgpetersenii serovar Arborea in Queensland, Australia, 2001 to 2013. BMC Infectious Diseases, 15 1: 1-11. doi:10.1186/s12879-015-0982-0

Author Lau, Colleen L.
Skelly, Chris
Dohnt, Michael
Smythe, Lee D.
Title The emergence of Leptospira borgpetersenii serovar Arborea in Queensland, Australia, 2001 to 2013
Formatted title
The emergence of Leptospira borgpetersenii serovar Arborea in Queensland, Australia, 2001 to 2013
Journal name BMC Infectious Diseases   Check publisher's open access policy
ISSN 1471-2334
Publication date 2015-06-14
Sub-type Article (original research)
DOI 10.1186/s12879-015-0982-0
Open Access Status DOI
Volume 15
Issue 1
Start page 1
End page 11
Total pages 11
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2016
Language eng
Formatted abstract
Background: Leptospirosis is an emerging infectious disease, with increasing frequency and severity of outbreaks, changing epidemiology of populations at risk, and the emergence of new serovars. Environmental drivers of disease transmission include flooding, urbanisation, poor sanitation, changes in land use and agricultural practices, and socioeconomic factors. In Queensland, human infection with Leptosira borgpetersenii serovar Arborea was first reported in 2001. This study aims to report the emergence of serovar Arborea in Queensland from 2001 to 2013, and investigate potential risk factors for infection and drivers of emergence.

Methods: Data on laboratory-confirmed cases of human leptospirosis in Queensland were obtained from the enhanced surveillance system at the WHO/FAO/OIE Collaborating Centre for Reference and Research on Leptospirosis in Brisbane, Australia. The changing epidemiology of serovar Arborea from 2001 to 2003 was described with respect to case numbers, proportion of leptospirosis cases attributed to the serovar, and geographic distribution. Differences in risk factors for the most common serovars were compared.

Results: During this period, 1289 cases of leptospirosis were reported, including 233 cases attributed to serovar Arborea. Risk factors for infection include male gender (91 % of cases), occupation, and recreational exposure. Most common occupations recorded were banana workers (28.4 %), meat workers (7.2 %), dairy farmers (5.8 %), graziers/stockmen (5.5 %), ‘other agricultural/rural workers’ (16.4 %), and tourists or tourism operators (4.6 %). Time trend analysis showed that while non-Arborea cases decreased over the study period, Arborea cases increased by 3.4 cases per year. The proportion of annual cases attributed to Arborea peaked at 49 % in 2011 after unprecedented flooding in Queensland. Mapping of cases by residential location showed expansion of the geographic range of serovar Arborea, concentrating mostly around Brisbane, Cairns and Innisfail. Serovars varied significantly between ages and occupational groups, and serovar Arborea was most strongly associated with ‘other agricultural/rural workers’.

ConclusionsLeptospira borgpetersenii serovar Arborea has been emerging in Queensland since 2001, with increase in case numbers, the proportion of leptospirosis infections attributed to the serovar, as well as expansion of its geographic distribution. Reasons for this emergence are unknown, but climatic factors and environmental change are likely to have played important roles.
Keyword Eco-epidemiology
Emerging infectious diseases
Environmental health
Infectious disease epidemiology
Infectious disease outbreaks
Tropical medicine
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Medicine Publications
Child Health Research Centre Publications
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