australian mosquitoes take a bite out of california

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An Australian mosquito in California: Public health risks and control options Dr Cameron E. Webb Department of Medical Entomology University of Sydney & Pathology West – ICPMR Westmead Email: [email protected] Twitter: @mozziebites Greater Los Angeles County Vector Control District, California, Wednesday 15 November 2014

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Page 1: Australian mosquitoes take a bite out of California

An Australian mosquito in California: Public health risks and control options

Dr Cameron E. WebbDepartment of Medical Entomology

University of Sydney & Pathology West – ICPMR WestmeadEmail: [email protected] Twitter: @mozziebites

Greater Los Angeles County Vector Control District, California, Wednesday 15 November 2014

Page 2: Australian mosquitoes take a bite out of California

During an expanded search in the summer of 2014 for the invasive

Asian tiger mosquito, staff from the San Gabriel Valley Mosquito and

Vector Control District (SGVMVCD) and the Greater Los Angeles

County Vector Control District (GLACVCD) collected unusual

specimens from a couple of Californian homes.

.

After some initial research, photographs of the mosquito were sent to

Dr. Cameron Webb and John Clancy with the Marie Bashir Institute of

Infectious Diseases and Biosecurity at the University of Sydney,

Australia and they confirmed it to be the Australian backyard mosquito,

Aedes notoscriptus.

Page 3: Australian mosquitoes take a bite out of California

Aedes notoscriptus

Page 4: Australian mosquitoes take a bite out of California
Page 5: Australian mosquitoes take a bite out of California

Where is it?

Source: Landcare Research http://www.landcareresearch.co.nz

Page 6: Australian mosquitoes take a bite out of California

Natural and artificial water-holding containers Rock pools, tree holes and water-holding plants Artificial containers From bird baths to blocked roof gutters Rainwater tanks Rubbish and “backyard junk” Not subterranean

Habitat associations

Page 7: Australian mosquitoes take a bite out of California
Page 8: Australian mosquitoes take a bite out of California

Approximately 200m Brisbane study in 2000

reported: Mean 105.2 and 179.9m Max 195 and 238m

Compared to Ae. aegypti study in 2005 reporting: Mean 78m Max 200m

Vegetation critical Human assisted movement

Dispersal

Page 9: Australian mosquitoes take a bite out of California

Host Feeding

Host Bullians & Cowley

2001

Jansen et al 2005

Derraik et al 2007

Kay et al 2007

Johansen et al 2013

Human Yes Yes Yes Yes

Dog Yes Yes

Cat Yes

Possum Yes Yes Yes Yes Yes

Rodent Yes

Horse Yes

Flying fox Yes

Bird Yes Yes

Page 10: Australian mosquitoes take a bite out of California

Vector competence: Laboratory studiesPathogen Infection Transmission Reference

Ross River virus Yes Yes (No?) Watson & Kay 1998, Ryan & Kay 2000

Barmah Forest virus Yes Yes Watson & Kay 1999, Kramer et al 2011

Murray Valley encephalitis virus No No Kramer et al 2011

Japanese encephalitis virus No No van den Hurk et al 2003, Kramer et al 2011

West Nile virus Yes Yes Jansen et al 2008

Dengue virus No No Watson & Kay 1999, Kramer et al 2011

Chikungunya virus Yes Yes (No?) van den Hurk et al 2003,Kramer et al 2011

Yellow Fever virus Yes Yes Van den Hurk et al 2011

Rift Valley Fever virus Yes Yes Turell & Key 1998

Whataroa virus Yes Yes Holder et al 1999

Dog heartworm Yes Yes Russell & Geary 1997

Page 11: Australian mosquitoes take a bite out of California

Field isolations RRV, BFV plus other “minor risk” arboviruses

Brisbane 1994 13/63 RRV isolations from Aedes notoscriptus

Western Sydney 1999 Small cluster RRV cases Kangaroo populations but no substantial wetlands Aedes notoscriptus most common mosquito No RRV from field collected mosquitoes Subsequent isolation BFV Southern Sydney Small cluster RRV cases Aedes notoscriptus along with estuarine species Isolation of RRV, BFV

Surveillance and outbreak investigations

Page 12: Australian mosquitoes take a bite out of California

Surveillance options

Adult populations Carbon dioxide baited traps BG Sentinel traps Ovitraps (sticky or paddle) Human bait (afternoon) Gravid not effective

Larval surveys

Page 13: Australian mosquitoes take a bite out of California

Control options

Education Source reduction

Cleanup Screening

Methoprene Bti Monomolecular film

Page 14: Australian mosquitoes take a bite out of California

Endemic and exotic mosquito interactions

How does Aedes notoscriptus interact with other species? Aedes aegypti

No competitive exclusion in laboratory studies, minor advantage to Ae.notoscriptus in temperate climates (Russell 1986)

No competitive displacement in field studies but (?) Ae.notoscriptus selects non-Ae.aegypti containers (Tun-Lin et al 1999)

Aedes albopictus No significant impact on survivorship or population

performance indices (Nicholson et al 2015)

Russell (1986) Australian Journal of Zoology 34: 527-534Tuni-Lin et al (1999) Dengue Bulletin 23: 73-79

Nicholson et al (2015) Journal of Medical Entomology [in press]

Page 15: Australian mosquitoes take a bite out of California

How many species of Ae. notoscriptus?

Endersby et al (2013) Infection, Genetics and Evolution, 18: 191-201Foley et al (2004) Medical and Veterinary Entomology, 18:180-190

High levels of genetic divergence (Foley et al 2004)

Complex of species, some showing strong genetic isolation in two lineages (Endersby et al 2013)

Supportive of inconsistent vector competence studies?

More research required

Page 16: Australian mosquitoes take a bite out of California

Summary

Does Aedes notoscriptus pose a public health risk? Minor risk compared to Ae.aegypti and Ae.albopictus Comparable geographic spread to Ae.albopictus Unlikely to displace other container-inhabiting species “Collateral damage” associated with current control Reminder of ease of exotic mosquito spread Great example of international networks of expertise

Page 17: Australian mosquitoes take a bite out of California

Thank you!

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