Wildlife reservoirs of mosquito borne diseases: Ross River virus, a case study Eloise Stephenson1, Cassie Jansen2, Alison Peel1, Simon Reid3 & Hamish McCallum1 1Environmental Futures Research Institute, Griffith University 2Metro North Public Health Unit, Queensland Health 3School of Public Health, University of Queensland Eastern grey kangaroo – Photographed 8th of July 2016 in Sherwood, Brisbane

Outline Zoonoses Human health Management Ross River virus Current challenges Systematic approach in light of Ross River virus Key conclusions

Zoonoses and human health Weaver & Barrett (2004) Zoonoses and human health OIE (2016)

Zoonoses and management challenges Human Environmental Animal = disease

Zoonoses and management challenges Human Mosquito Environmental Animal = disease

Ross River virus

Ross River virus Big problem in Australia - Widespread - ↑ public health costs - No vaccine or treatment - Average of 4800 cases/yr - Recent outbreak

> > Ross River virus Marsupials Placental Mammals Birds 2. Complex epidemiology - > 30 sp. mosquito - Human-mosquito-human  number of cases alone - Non-human reservoirs > > Marsupials Placental Mammals Birds

Where to begin?

Potential Reservoir Species Criteria Analyses (PCR, Serology) Research Question Methodology Status Phase 1: RRV Reservoir Knowledge (What do we really know?) 1. Collate Information Literature Review Draft in progress Phase 2: Vector-Host Relationships (Systematic approach to understanding) Potential Reservoir Species Criteria 2. Vector-Host Relationship Initial phases Analyses (PCR, Serology) 3. Sampling Samples in discussion Model Predicted Areas 4. Correlate Data Not yet commenced Phase 3: Management Strategies (in light of new findings) 5. Inform Strategies Current Strategy Gaps Not yet commenced

Total number of studies Experimental Infection Phase 1: RRV Reservoir Knowledge (What do we really know?) 1. Collate Information Literature Review Draft in progress Kay et al (1986) Different Methods Experimental Infection Study type Total number of studies Location of studies Date range of studies Strengths Limitations Experimental Infection 7 QLD 1969-2001 Controlled conditions (such as viral dose) Not indicative of natural epidemiology Virus isolation 4 QLD, VIC 1968-2003 Demonstrates presence of virus - Only a small window of opportunity to identify - Difficult to do in random wild animal samples Serology  35 QLD, NSW, WA, VIC, SA, NT, TAS, New Guinea, Fiji, New Zealand 1966-2015 Indicates previous infection No evidence for active amplification Blood meal analysis QLD, WA, NSW, SA 1997-2016 Indication of natural epidemiology Seroprevalence Virus Isolation 54.2% 43.9% x3 11% 14% x2 x15 Blood meal analysis

Potential Reservoir Species Criteria Phase 2: Vector-Host Relationships (Systematic approach to understanding) 2. Vector-Host Relationship Potential Reservoir Species Criteria Initial phases What defines a reservoir? Arboviruses = 3 criteria commonly used Virus isolation High antibody prevalence Demonstration of viremia Different definitions Important  Reservoir – Lacks greater ecology

Potential Reservoir Species Criteria Phase 2: Vector-Host Relationships (Systematic approach to understanding) 2. Vector-Host Relationship Potential Reservoir Species Criteria Initial phases Human Virus isolation High antibody prevalence Demonstration of viremia Environmental Animal = disease

Analyses (PCR, serology) Phase 2: Vector-Host Relationships (Systematic approach to understanding) Analyses (PCR, serology) 3. Sampling Samples in discussion 10-20 species Wildlife Health Networks Samples

Potential Reservoir Species Criteria Analyses (PCR, Serology) Research Question Methodology Status Phase 1: RRV Reservoir Knowledge (What do we really know?) 1. Collate Information Literature Review Draft in progress Phase 2: Vector-Host Relationships (Systematic approach to understanding) Potential Reservoir Species Criteria 2. Vector-Host Relationship Initial phases Analyses (PCR, Serology) 3. Sampling Samples in discussion Model Predicted Areas 4. Correlate Data Not yet commenced Phase 3: Management Strategies (in light of new findings) 5. Inform Strategies Current Strategy Gaps Not yet commenced

Key conclusions

Non-human vertebrate species are critical for the spread and maintenance of arboviruses Identifying wildlife reservoirs of arboviruses cannot be done without collaborations Better management strategies are needed which incorporate wildlife reservoir epidemiology

Rare -

References Ashford (2001) What it takes to be a reservoir host. Belgian Journal of Zoology. 127. Haydon et al (2002) Identifying reservoirs of infection: A conceptual and practical challenge. Emerging Infectious Diseases. 8(12): 1468-73 Kay et al (1986) Experimental infection of vertebrates with Murray Valley encephalitis and Ross River viruses. Arbovirus Research in Australia. 71-75 NNDS (2016) National Notifiable Diseases Surveillance System, Summary Tables. Available: http://www9.health.gov.au/cda/source/cda-index.cfm OIE (2016) One Health at a Glance. One Health. Available: http://www.oie.int/en/for-the-media/onehealth/ Viana et al (2014) Assembling evidence for identifying reservoirs of infection. Trends in Ecology and Evolution. 29(5): 270-9 Weaver & Barrett (2004) Transmission cycles, host range, evolution and emergence of arboviral disease. Nature Reviews Microbiology. 2(10):789-801

Acknowledgements Supervisors - Funding – Cassie Jansen: Queensland Health Alison Peel: Griffith University Hamish McCallum: Griffith University Simon Reid: The University of Queensland Funding – Environmental Futures Research Institute, Griffith University Clip art - Prawny Eastern grey kangaroo photo – St Aidan’s AGS

Questions? @elle_stephenson Eloise Stephenson eloise.stephenson@griffithuni.edu.au Eastern grey kangaroo – Photographed 8th of July 2016 in Sherwood, Brisbane