By Pooja Toshniwal PahariaJul 5 2023Reviewed by Benedette Cuffari, M.Sc. In a recent study published in Emerging Infectious Diseases, researchers reported a dengue epidemic among Key Largo residents between February and August 2020. This outbreak coincided with the early months of the coronavirus disease 2019 , which affected the dengue epidemic's investigations and the need to raise physician understanding of dengue virus testing protocols.
Health authorities informed the Florida Department of Health of a probable locally transmitted case of DENV infection in Key Largo in February 2020. On March 9, the FDOH published a countywide population health mosquito-borne disease advisory in Monroe County to increase the availability of non-essential services and businesses. Additional regionally transmitted dengue cases were not detected till June 16, after which numerous Florida residents reported possible dengue illness to the FDOH.
During the two-week incubation period through the prospective one-week viremic phase following the onset of symptoms, FDOH informed FKMCD of possible locations of Aedes Aegypti mosquito exposure for probable cases. The FKMCD increased vehicular and aerial spraying, surveyed neighborhoods, performed vector monitoring, eliminated or treated mosquito larvae sites, and educated residents regarding mosquito control.
Following CDC recommendations, FDOH used immunoglobulin M testing, and DENV reverse transcription-polymerase chain reaction on acute samples obtained within a week of symptomatic onset. Convalescent sera were tested for antibodies a week after the onset of symptoms. The CDC helped with serological verification, serotyping RT-PCR-confirmed DENV-positive specimens, and performing RT-PCR tests for the FKMCD mosquito populations.
Sequence information from 96 Aedes aegypti mosquito populations obtained between June 18 and September 21 was obtained through a phylogenetic study of the DENV-1 subtype V clustering from the Caribbean strain. Sequencing results were uploaded to GenBank, revealing clear distinctions between the Caribbean DENV strain and the Central African strain detected in Key West between 2009 and 2010.