Surveillance
Regular monitoring of mosquito populations in both the larval and adult stages provides the data necessary to support treatment decisions and evaluate program results. The four components of AHS’s surveillance program are larval breeding inspections, New Jersey light trap monitoring, CDC live trap monitoring and standing bite counts.
Larval Breeding Inspections
Periodic inspection of all catch basins and storm drainage areas, woodland and vernal pools, freshwater swamplands and meadows, wastewater treatment and settling ponds, ditches, and other man-made or natural depressions and containers will determine which habitats are suitable for mosquito breeding. Areas identified as supporting breeding mosquitoes are targeted for source reduction methods.
The inspection schedule begins in the spring and continues until October. A monthly inspection cycle is recommended, although additional inspections should be performed during any week in which local rainfall is approximately 3⁄4 “ or more. AHS will provide inspection reports to the Natural Resources Protection Department.
New Jersey Light Trap Monitoring
This device uses a photo electrically operated AC powered light source to attract adult mosquitoes toward a fan generated air current which is directed into a kill jar. Weekly collection and analysis of a trap’s contents indicate adult population densities and the species present. This information is in turn used to monitor the effectiveness of source reduction activities, identifying possible breeding sources, and determining if adulticide spray treatments are necessary. An adulticiding treatment is usually indicated when a trap’s density consists of 30 or more female mosquitoes.
The placement of 3-4 traps is recommended for a monitoring period of 24 weeks. They should be installed by May 1st and remain in service until the program year ends. Trap counts are reported weekly to the Natural Resources Protection Department along with any recommendations for adulticide spray treatments, if necessary.
CDC Live Trap Monitoring
This trap is set up for a 12-16 hour period to determine if arbor viruses are present in the local mosquito populations. It uses solid CO2 as a bait to attract adult mosquitoes toward the DC powered light source and fan generated air current which is directed into a containment area. Trapped mosquitoes remain alive until they are collected the next morning and immediately frozen. The female mosquitoes are separated by species and delivered to the Connecticut Agricultural Experiment Station for arbor virus testing conducted by Yale University. The presence of arbor virus isolations indicates a potential public health threat whereupon more extensive trapping is recommended.
The placement of 3-6 traps every week is recommended over a monitoring period of 18 weeks. They should be installed by June 1st and remain in service until the program year ends. The trap contents analysis is reported to the Natural Resources Department after samples are submitted. Test results are communicated immediately upon notification from Connecticut Agricultural Experiment Station.
Standing Bite Counts
Bite counts are a simple field test used to measure adult mosquito population densities in a specific area. Inspectors survey the target area by capturing and identifying adult mosquitoes attempting to land on them. Mosquitoes are considered at nuisance levels when 4 or more landings per minute are recorded. This is useful for investigating and verifying complaints.
