Posted by Vector and Vector-borne Disease Committee
March 20, 2023
MMWR Morb Mortal Wkly Rep 2023;72:290–291. http://dx.doi.org/10.15585/mmwr.mm7211a5
A Maricopa County, Arizona resident was hospitalized with Dengue-like symptoms on October 19, 2022 after brief travel to Mexicali, Mexico 7 days prior. RT-PCR testing was positive for dengue virus (DENV). Twenty-one mosquito pools within 5 miles of patient’s residence were tested retrospectively. One pool collected on October 5 tested positive for DENV. Whole genome sequencing identified both to be a DENV-3 strain not closely related to known strains in the area of travel. Preexisting response plans were activated and residences within a 150-meter radius were canvassed and residents interviewed. Twelve residents reporting recent Dengue-like symptoms were tested, all of which were negative by RT-PCR. Antibody testing of one of 53 resident without travel history was positive for Dengue antibodies, which were confirmed as DENV-3 by plaque reduction neutralization assay. Retrospective testing of 4,299 mosquito pools were negative. Aedes aegypti collected in BG-Sentinel traps were negative for DENV. The outbreak (2 cases) was declared over on January 4, 2023, following >45 days without additional cases.
Note: This outbreak provides a case study of a local DENV outbreak in a new area and shows the benefits of having a preexisting response plan in the event of local transmission of an Aedes aegypti transmitted virus.