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CDC CO2 trap hanging in tree
CDC CO2 trap hanging in a tree in Davis County.

Mosquito surveillance is the process of collecting mosquitoes in larval and adult forms to get an idea of the mosquito population size, reach and human disease risk. Surveillance is key to MAD-D fulfilling our mission of enhancing public health and comfort of those living in Davis County. Multiple surveillance methods exist for monitoring mosquitoes this is because there is not a perfect surveillance method for that captures all mosquito types. Different surveillance methods are used based on the type of mosquitoes in the environment as well as the potential health risks to the human population.

Larval Surveillance

This type of surveillance occurs in the field, with our field technicians. Inspections start in the early Spring and go through September. Field technicians are checking sites throughout the county looking for locations which have the proper conditions for larvae to occur. They inspect by using a “dipper” which is a white one-pint cup attached to a handle. The “dipper” allows the technicians to get into the water source and determine if larvae is in the water. They are then able to treat the source in the best manner possible to decrease the larval mosquito potential.

Active Adult Surveillance

Is a large driving force of our program. It helps us know which species of mosquitoes are present as well as allowing us to collect mosquitoes for West Nile virus testing. We start regularly trapping mosquitoes in May and continue through September. This surveillance is done by setting CDC- CO2 baited traps throughout the county. Traps are placed out overnight and are brought into the lab the next morning where the mosquitoes are identified and counted.

Passive Adult Surveillance

Is only possible with the help of the public. This type of surveillance is through those in the community who are reporting mosquito issues to us. These come in the form of service requests. These requests help us find locations where there can be mosquito problems in areas which are not always easily accessible by our field technicians.