Disease & Vector Studies II
Disease & Vector Studies II
Dengue is not endemic in the contiguous US. Maricopa County Department of Public Health (MCDPH), Maricopa County Environmental Services Department Vector Control Division (MCESDVCD), and Arizona Department of Health Services (ADHS) monitor dengue virus (DENV) presence in Maricopa County. MCDPH and MCESD maintain a joint locally acquired mosquito-borne disease response plan. DENV infection was identified in a Maricopa County resident on November 8, 2022. The individual reported < 4 hours travel to Mexico on October 12th with febrile illness onset October 19th. In response, MCESDVCD conducted targeted mosquito pool testing. Both the patient and one mosquito pool collected October 5th tested positive for DENV-3, a DENV not known to be circulating in the travel region.
Per the response plan, MCDPH and MCESDVCD canvassed residences within a 150-meter radius of the case and positive mosquito pool November 17–19 to interview residents, collect human specimens for DENV testing, and assess properties for mosquito breeding. ADHS conducted DENV testing for participating residents. CDC confirmed IgM-positive samples by plaque reduction neutralization and PCR-positive samples with whole genome sequencing. MCESDVCD tested mosquito traps countywide for DENV by PCR.
DENV testing of 4,320 mosquito pools collected September 18–November 19 were PCR-negative. MCDPH and MCESDVCD approached 241 households; 72 (29.9%) consented to environmental assessments and 59 (24.5%) were interviewed. DENV IgM testing was done on 53/73 interviewees (72.6%). Thirteen respondents (24.5%) reported recent dengue-like symptoms; all were PCR-negative. One (1.9%) person had confirmed DENV-3 by PRNT and reported no travel in the 2 weeks prior to symptom onset. Environmental assessment of this residence identified Aedes aegypti mosquitoes.
We report the first probable locally acquired human DENV infection in Maricopa County. Response activities identified 2 likely autochthonous DENV infections. Established partnerships and pre-existing exercised plans were essential to mount a rapid, coordinated response to nonendemic arboviral transmission.