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Mosquito and Disease Surveillance History

Mosquito Surveillance

In 1953 Dr. Don Rees ran a mosquito surveillance survey in parts of Davis County to get an idea of the mosquito population. In 1976 we find records of a fully established surveillance program which utilized New Jersey Light traps which were set at 12-16 locations throughout the county. These traps were maintained through the summer months helping to monitor the population of mosquitoes in the county. New Jersey light traps ran yearly through 2015, when they were replaced with CDC light traps.

With the appearance of West Nile virus (WNV) in New York, the district added 5-6 CDC light traps baited with dry ice to the surveillance program in 2002. The number of traps increased to 24 by 2006. Between 2002 and 2006, they were used at different locations around the county to provide a quick snapshot of what the mosquito population was doing and to trap mosquitoes to use in monitoring for WNV. In 2016 the district moved over to using CO2 baited traps for the complete surveillance program.

Disease Surveillance

Disease surveillance started in 1983 with a focus on Western equine encephalitis (WEE) and St. Louis encephalitis (SLE). Surveillance was done with sentinel chicken flocks, which were maintained by the district. Between 1983 and 1993 the district maintained 2 flocks, in 1993 the number of flocks increased to 12 with a total of 60 chickens being maintained. These flocks were actively used in disease surveillance until 2014 when the cost of testing and maintenance became a challenge.

As West Nile virus (WNV) spread across the United States, it was added to the list of tested viruses in the district. WNV was first detected in Davis County in 2004 and has been routinely found in mosquito pools since then.

In 2014 the district started the process of bring the testing for diseases in house to help improve the response timeframe. From 2014 to 2018 a process called RAMP was used to test specific mosquito species for the viruses. In 2018 the district moved to the more sensitive and accurate RT-PCR testing procedures.

The district still currently monitors for WEE, SLE and WNV throughout the summer months and report our findings to the state department of health.