Coordinated surveillance and response activities to investigate the first locally acquired human DENV infections in Maricopa County

About the Program

Category: Health (Best in Category)

Year: 2023

Maricopa County Department of Public Health (MCDPH) Division of Epidemiology and Informatics (DEI) has built a partnership with Maricopa County Environmental Services Department Vector Control Division (MCESD-VCD) to monitor for and respond to mosquito-borne diseases in Maricopa County, Arizona. Dengue virus (DENV), a mosquito borne disease, is not endemic in the continental United States. MCESD-VCD mosquito surveillance has identified Aedes aegypti mosquitoes in Maricopa County. MCDPH-DEI investigates suspected DENV infection in residents. In 2017, this partnership drafted an “Aedes Arboviral Coordinated Response Protocol” to be enacted if local DENV transmission is suspected. Both human and mosquito thresholds were established, and a tiered joint response plan was developed. On November 7, 2022, DENV-3 infection was identified in a resident; MCESD-VCD tested Aedes aegypti mosquitos trapped near the case. Mosquitoes trapped on October 5th tested positive for DENV-3, suggesting potential local transmission. As per the response plan, teams canvassed residences within the affected area to collect human specimens for DENV testing and assess properties for mosquito breeding. Teams approached 241 households; 72 (29.9%) consented to environmental assessments, and 10 (13.9%) properties had evidence of active mosquito breeding. One person had confirmed recent DENV-3 infection with no travel prior to symptom onset. Coordinated surveillance and response activities identified the first locally acquired human DENV infections in Maricopa County.