The NSW Arbovirus Surveillance and Mosquito Monitoring Program (ASMMP), led by NSW Health, plays an important role in protecting the public from viruses spread by mosquitoes (arboviruses). The program provides early warnings about arbovirus risks. This information is then used by NSW Health to advise the public about how they can protect themselves from mosquitoes. The program also prompts other agencies to take action at the local level including mosquito control activities.

The ASMMP runs from spring to autumn each year, when mosquitoes are most active. It monitors mosquito populations across coastal and inland areas of NSW and Greater Sydney. Each week mosquitoes are trapped and sent to the Department of Medical Entomology at NSW Health Pathology, at the Institute of Clinical Pathology and Medical Research (ICPMR). They are then counted and tested for the presence of arboviruses of concern like Ross River, Barmah Forest, Kunjin, Murray Valley encephalitis (MVE), and Japanese encephalitis (JE).

The program also monitors special flocks of chickens in inland NSW. Each week, the chickens are bled, and the blood samples are sent to the Arbovirus Emerging Diseases Unit at NSW Health Pathology, at the Institute of Clinical Pathology and Medical Research (ICPMR), for testing. The blood samples are tested for antibodies directed at three arboviruses: Kunjin, MVE and JE.

__ Important notes for interpretation of data__

Factors influencing exposure: High mosquito numbers do not always lead to an increase in human arbovirus cases. Other factors, such as weather, human behaviour, and the use of protective measures, can affect the risk of exposure to mosquito-borne viruses.

Trapping locations: Locations on maps reflect the mid-point of sites within a broader location, not exact mosquito trap sites (as some trapping sites are located on private properties).

Seasonal variation: Some locations may consistently experience higher mosquito numbers throughout a season while others may have lower numbers and others may have sudden increases in mosquito numbers at points during the season. There is may also be variability in mosquito numbers between seasons.

Positive test results: For mosquito traps, a detection represents the presence of virus in at least one mosquito in a sample of trapped mosquitoes. For sentinel chickens, a positive test result means that one or more chickens in a flock have tested positive for antibodies directed against a particular virus for the first time, suggesting a newly acquired infection. Infection in chickens gives an indication that there is enough virus to transmit to humans.