Kishen Lachireddy Senior Policy Analyst Health Protection NSW December 2015 Overview of NSW Arbovirus Surveillance Program

Brief History  1974 MVE outbreak  Program started in 1979 with sentinel chicken surveillance.  RRV outbreak in Riverina  Mosquito monitoring commenced in 1984/85 – Mosquito population counts.  Arbovirus isolations from mosquitoes started in 1988/89 season.

Arboviral Surveillance Program Two parts to the Program: 1. Sentinel Chicken Surveillance: The aim – to provide early warning on presence of Murray Valley Encephalitis (MVE) and Kunjin. Reduce potential for human disease. 2. Mosquito Monitoring: Detect underlying causes for seasonal fluctuations in arbovirus activity and abundance of mosquito vector species. Potential to effect human health.

Overview of season  Usually duration of the surveillance season is from November to end of April (mid-spring to mid-autumn).  Sentinel chicken flocks are bled weekly and tested for specific viruses (MVE and Kunjin).  Mosquitoes are collected weekly for species identification and quantification, and processed for isolation of viruses.  End of season – total mosquito numbers low and two consecutive weeks of negative results for arboviral isolation. In addition, rainfall and temperature is taken into consideration.

Sentinel Chicken Surveillance  Sentinel flocks are located in inland areas (Southwestern NSW) stretching from Deniliquin to Moree.  15 birds per flock.  Flocks are bled prior to deployment to the test sites and then at weekly intervals.  Tested for Kunjin and Murray Valley Encephalitis using ELISA (Enzyme Linked Immunobsorbent Assay).  Current season - 10 sites across the state.

Mosquito Monitoring Mosquito Monitoring:  Trapping locations around the NSW – Major centres along the coast, Sydney suburbs, and inland NSW towns along principal river systems.  Current season – there are 20 different locations across NSW.

Mosquito Collection and Identification  Mosquitoes are collected overnight in dry-ice baited mosquito traps.  Live mosquitoes are sent to the Pathology West, Institute for Clinical Pathology and Medical Research, Westmead for identification and processing for arbovirus isolation.  The mosquitoes are identified according to keys and illustrations. Mosquito Monitoring

Arbovirus Isolation Methodology  Mosquitoes are sorted into pools of 25.  Mosquitoes are ground up.  Supernatants from these pools are inoculated into cell cultures.  After a number of passages on different cell lines (screened for cytopathic effects) - plates are fixed and screened for different viruses using monoclonal antibodies. Mosquito Monitoring

Participants  Health Protection NSW  Public Health Units  Local Councils  Pathology West, ICPMR, Westmead

 Provides funding for the surveillance program.  Coordinates running of the program along with pathology west and training needs for the participants. Health Protection NSW

PHU’s:  Liaise with councils on any health advisories as required.  Some PHU’s coordinate invoices from contractors and submit to NSW Health.  Some PHU’s undertake mosquito trapping and maintain chicken flocks.  Collect samples and dispatch to Pathology West, Westmead. Public Health Units

Local Councils:  Undertake mosquito trapping and maintain chicken flocks.  Collect samples and dispatch to Pathology West, Westmead. Local Councils

 Provides advice to the Health Protection NSW on length of season, extension, public health messaging and mosquito control methods.  Provides support to the sites in terms of supply of collection kits, sample collection and any queries on day to day running of the program.  Provides testing services for different arboviruses and prepares summary reports.  Preparation of weekly reports during the active season and annual report. Pathology West, Institute for Clinical Pathology and Medical Research

  Results from sentinel chickens and mosquito monitoring available and can be accessed through the above link.  Weekly reports available online.  Annual report, which summarises the whole season results including human notifications is also available online.  Great resource for information on mosquito species and public health messaging. Program Website