30,000 Cases of Dengue Reported in US Territories From 2010-20

The United States territories of American Samoa, Guam, Puerto Rico and the U.S. Virgin Islands (USVI) reported 30,903 confirmed and probable cases of dengue virus (DENV) to CDC’s national arboviral surveillance system (ArboNET) between 2010 and 2020, according to new findings in Morbidity and Mortality Weekly Report.

Dengue is a transfusion-transmissible infection caused by a group of four related viruses spread by Aedes species (Ae. aegypti or Ae. albopictus) mosquito. It became nationally notifiable in ArboNET in 2010.

During the study period, Puerto Rico reported 29,862 cases (96.6%), followed by American Samoa (660, 2.1%), the USVI (353, 1.1%) and Guam (28, 0.1%). Results indicated that case counts in the territories were intermittent, with high case numbers reported in outbreak years and few or no cases reported in other years. Investigators noted that American Samoa, USVI and Guam reported no DENV cases in 8, 4 and 9 years of the study, respectively. Puerto Rico had historically low levels of DENV cases between 2016 and 2019 following outbreaks between 2010-13.

The findings also suggested that children and adolescents under the age of 20 are disproportionately affected by DENV. Approximately half of cases occurred among people younger than age 20 and the highest rate of cases and hospitalizations was among children aged 10–19 years.

The authors noted that a 2021 recommendation by the Advisory Committee on Immunization Practices for a safe and effective dengue vaccine (Dengvaxia, Takeda) offers a new option for preventing illness from dengue in these age groups. Takeda and the National Institutes of Health have two vaccines in late-stage vaccine trials.

Additional information about DENV is available on AABB’s dengue viruses fact sheet.