203 - Arbovirus Surveillance in Polk County Mosquito Control

Abstract: Polk County is the fourth largest county in Florida with a total area of 5,210 km², of which 550 km² (10.6%) is freshwater. According to the last census (2020), its population was 725,046. Arbovirus activity requires a surveillance program to monitor endemic viruses, such as West Nile viruses, Eastern Equine encephalitis, and St. Louis encephalitis. Other non-endemic viruses and mosquito transmitted diseases include Dengue, Chikungunya, Zika, Oropouche, California encephalitis group viruses, and malaria. These are typically travel assisted and necessitates a rapid response when suspected cases are reported.

Polk County Mosquito Control (PCMC) was established in 1958. PCMC’s integrated mosquito management (IMM) involves several components that includes, surveillance by regular trapping and collecting larvae and adult mosquitoes for identification, biological control methods, chemical control, use of sentinel chickens, insecticide resistance evaluation and public education, and source reduction.

Surveillance data was collected year-round from sixty-eight CDC- CO₂ baited traps. Other surveillance methods include the deployment of Biogents traps, Ovi-traps and Gravid traps. Chemical mosquito control methods used include larvicides (Bacillus thuringiensis, Bacillus sphaericus, Spinosad, and Methoprene) and adulticides (Permethrin, Malathion, Deltamethrin and Sumithrin). Chemical treatments were applied by rotary wing aircraft and truck mounted application. When applicable, Gambusia holbrooki serves as a biological control method. A total of eight sentinel chicken coops are strategical place to monitor avian associated pathogens. Blood samples are collected weekly and analyzed for pathogen activity.

Data obtained over the past ten years during surveillance of mosquito-borne pathogens in Polk County will be presented. Results such as the most common mosquito species (vectors and non-vectors), tools used in pathogen monitoring, most common viruses detected, Integrated Mosquito Management techniques used in the County, database systems, and recommendations to follow.