Second Local Dengue Fever Case Identified in Guam

The mosquito-borne dengue fever is the most common vector-borne viral disease in the world. (Flickr)

Guam’s Department of Public Health and Social Services (DPHSS) confirmed the second locally-acquired case of dengue fever in roughly 75 years of the territory’s medical history on September 17. The diagnosis follows the detection of locally-acquired dengue fever in another patient less than a week prior, the Guam Public Health Laboratory said. 

Dengue fever is a mosquito-borne illness caused by dengue viruses, which are endemic to tropical and subtropical regions, including the Pacific Islands. The Center for Disease Control (CDC) estimates roughly 40 percent of the world’s population lives in areas prone to dengue, and over a hundred countries report dengue-related incidents. 

Dengue has seen an astronomical increase in infections over the last few decades, and is now considered the most common vector-borne viral disease in the world, with up to 100 million infections each year. The Pacific has been particularly hard-hit in this outbreak, with infections in Yap, the Philippines, Palau, and the Marshall Islands, among others. Guam’s newest cases of locally acquired dengue fever indicate that it may be the next victim in a long list of other dengue-prone territories.

The World Health Organization (WHO) credits increased urbanization across the South Pacific as perhaps the most compelling contributing factor for dengue in the region. Dengue is only transmitted by direct mosquito-bite and is not infectious from person-to-person contact. Due to its dependence on mosquito vectors, dengue only emerges in areas with a great deal of still water, as these sites serve as primary mosquito-breeding grounds. Urban environments naturally contain more breeding sites for mosquitoes with the extensive prevalence of automobiles, nonbiodegradable plastic containers, cisterns, and other substantial water containers. Moreover, researchers consider Aedes aegypti, the mosquito species responsible for dengue transmission, a highly domesticated and urban-oriented insect. Aedes prefers domestic environments and lays eggs in artificial human-made containers, making urban environments particularly adept at breeding Aedes.

According the World Bank, roughly 95 percent of Guam’s population lives in urban areas. Accordingly, public health officials find the two newfound cases of local dengue particularly worrying.

Various arms of Guam’s local government and executive agencies, including the Office of the Governor, the DHPSS, and Guam Homeland Security, have rushed to execute containment programs to restrict disease transmission. A DHPSS press release highlights a public education campaign to eliminate mosquito-breeding sites in daily citizen life. DHPSS’ Division of Environmental Health has also initiated insecticide application at local schools and certain residential areas to deter continued mosquito development and limit the risk of transmission. 

Dengue poses an increased public health risk in other countries in the Western Pacific and beyond. The Philippines declared a national dengue epidemic in August, and Bangladesh experienced record-high dengue-related predicaments this summer. Scientists have linked the epidemic to the climate crisis as the tropics get warmer and wetter, creating ideal conditions for mosquitoes.