Stephen L. Doggett Senior Hospital Scientist Department of Medical Entomology, ICPMR, Westmead Hospital, Westmead NSW 2145

Overview Factors driving arbovirus activity Methods of surveillance NSW Arbovirus Program Enhanced surveillance! Information dissemination How to use surveillance data Case study: MVEV in 2008 A little challenge…

Factors Driving Arbovirus Activity Temperature drives mosquito activity Water drives mosquito abundance Water – rain, tides, humidity Distribution of vectors & reservoir hosts Host/herd immunity Reservoirs & humans Low immunity – pot. larger outbreaks Virus & virus strain Various human behaviours

Arbovirus Surveillance in NSW Predictive Weather patterns Vector populations Virus infected mosquitoes (Computer modeling) Transmission Sentinel animals (MVEV & KUNV) Humans Program must be tailored to the virus, the virus ecology and the human population

NSW Virogeographic Regions RRV, MVEV, KUNV Culex annulirostris RRV, BFV Aedes vigilax

NSW Surveillance Locations

Weather Patterns Rainfall Level of mosquito abundance Climatic indicators (El Nino/SO) Long term mosquito/arbovirus activity MVEV hypotheses: Forbes, Nichols

Weather - MVE models Forbes’ hypothesis Catchment Basin Oct-Dec 2014 Jan-Mar 2015 Oct-Dec 2015 Jan-Mar 2016 Darling River 0.80 0.65 0.48 Lachlan/ Murrumbidgee/ Murray Rivers 0.97 1.05 0.29 Northern Rivers 0.94 0.67 0.33 North Lake Eyre system 1.07 0.11

Nicholls’ Hypothesis Southern Oscillation

Weather Patterns Rainfall Level of mosquito abundance Climatic indicators (El Nino/SO) Long term mosquito/arbovirus activity MVEV hypotheses: Forbes, Nichols, Bennett Tidal Level of saltmarsh mosquito abundance

Tide & Mosq. Populations Tide height (m) Mosquito Numbers

Tide & Mosq. Populations

Weather Patterns Rainfall Level of mosquito abundance Climatic indicators (El Nino/SO) Long term mosquito/arbovirus activity MVEV hypotheses: Forbes, Nichols, Bennett Tidal Level of saltmarsh mosquito abundance Advantage: Cheap! Disadvantage: Least sensitive method

Vector Populations Determine species composition Examine seasonal abundance Arbovirus detection Quarantine Long term Mosquito population monitoring Arbovirus monitoring Changes in vector distribution Control Programs

EVS Trap (Encephalitis Vector Surveillance Trap) Adult monitoring

Vector Population Monitoring

Virus Isolation from Vectors Provide information on ‘normal’ activity (long term) Early indication of virus activity/type identify potential outbreaks Identify new vectors Monitor new virus incursions Traditionally via ‘cell culture’

Virus Identification Times

Honey-Baited Cards

Honey-Baited Cards FTA cards coated with honey Placed into mosquito trap Mosquitoes spit virus Cards tested via molecular tests Advantages

Virus Identification Times

Honey-Baited Cards FTA cards coated with honey Placed into mosquito trap Mosquitoes spit virus Cards tested via molecular tests Advantages Rapid: 1-2 days Sensitivity: > cell culture, > animals Labour savings!!!

But can we do even better?

Sugar Bait Stations Lark Coffey, UC Davis

Advantages/Disadvantages Mosquito Population Monitoring Highly significant relationship between mosquito populations & human disease Field equipment cheap & portable Traps can be placed in viral ‘hot spots’ Laboratory labour intensive Virus Isolation Good early indicator of epidemic activity Need to process many mosquitoes (1 virus in 2-4,000 mosquitoes)

Human Cases Advantages Most sensitive but… Provide epidemiological information Provide information on ‘risk’, e.g. geographic exposure, time of exposure determine when health warnings are needed Modify existing surveillance programs Disadvantage Too late for health interventions

Information Dissemination NSW Arbovirus Surveillance Web Site http://medent.usyd.edu.au/arbovirus Weekly reports Annual reports Special reports

So how can the data be used? Base mosquito warnings on the data The timing & degree Use the data in media campaigns It’s mosquito season: Take Precautions! Mosquito numbers 8x normal Increased Disease Risk! Virus detected in mosquitoes Disease Outbreak Feared!

Case Study MVEV 2008

MVEV 2008: Background Forbes: not fulfilled Nichols: not fulfilled Summer rainfall: >average Low irrigation allocation Mosquito numbers: low MVEV activity unlikely

MVEV Activity 2008 26/Feb/08 5/Feb/08 18/Feb/08 3/Mar/08 24/Mar/08

Low Pressure Cell Mid-Jan 2008 Dr Andrew Read, DPI, Menangle Follow the Low over central QLD. Passed through western NSW into Vic and into the Tasman Dr Andrew Read, DPI, Menangle

Health Actions Media releases/Fact Sheets/Radio/TV EDs, GPs contacted Telephone Hotline (1800 064 400) Weekly teleconferences Extended chicken/mosquito season Established further flocks & traps Opportunistic testing Dept. Agriculture opportunistic testing

Surveillance Requires Appropriate number of sites Intelligently located Multitude of methods Continuous Timely sample analysis & response Review locations/techniques Must consider vector!!!

Aedes albopictus Asian Tiger Mosquito (ATM)

Honey-Baited Cards FTA cards coated with honey Placed into mosquito trap Mosquitoes spit virus Cards tested via molecular tests Advantages Rapid: 1-2 days

FTA vs CC Viral Assay BFV RRV EHV KOKV STRV Total FTA 12 68 2 82 CC 6 82 CC 6 17 3 1 28 No. traps = 903