Page 120 - Journal of Special Operations Medicine - Fall 2014

subsequently initiates an immunologic cascade of events locations in 2001–2010. 23–27 Most recently, confirmed
that produces cytotoxins and other vasoactive media- dengue cases were diagnosed in USASOC personnel
tors, ultimately leading to DHF and/or DSS. DHF is deployed to various locations in Southeast Asia, South
1,2
a severe febrile disease characterized by abnormalities America, the Caribbean, and Africa every year from
of homeostasis and increased vascular permeability that 2008 to 2014 (unpublished data). The increase in den-
can lead to hypovolemia and hypotension DSS, often gue endemicity worldwide raises the likelihood of mul-
complicated by severe internal bleeding. The case-fatal- tiple exposures to different dengue serotypes among US
ity rate of DHF can be as high as 10% without therapy, Special Operations personnel. The related possibility of
although it is below 1% in most centers with modern immune enhancement increases the risk for contract-
intensive supportive therapy. However, the potential im- ing DHF and/or DSS and subsequently rendering small
pact of a single DHF case on a small team in an austere teams operationally ineffective.
environment is significant and can ultimately compro-
mise the mission. An understanding of dengue exposure With the conclusion of the war in Iraq and scaling down
prevalence in the USASOC population coupled with of operations in Afghanistan, more Special Operations
knowledge of the behavior of the virus and vector arms personnel will return to traditional Special Forces mis-
commanders and medical personnel with the ability to sions working far forward in austere environments
avoid catastrophic outcomes. where medical support is limited and medical evacua-
tion frequently inadequate or delayed. Because there is
Mosquito vectors for dengue viruses, Ae. aegypti and no curative treatment for DHF, Special Operations med-
Ae. albopictus, are now present in all tropical and sub- ical personnel* who have knowledge of team members’
tropical areas of the world and in some temperate areas exposure status are armed to take appropriate steps
of the United States (US), Europe, Africa, Australia, and toward medical evacuation versus delaying the action
the Middle East. An estimated 100 million cases of DF and experiencing a catastrophic outcome. Gaining in-
3
and 500,000 cases of DHF occur worldwide annually. formation about the seroprevalence rate of dengue in
4
According to the World Health Organization (WHO), USASOC personnel is critical to achieving the appropri-
one third of the world’s population lives in dengue- ate level of knowledge of the risk to this population and
endemic areas in more than 100 countries. In the past emphasizing the need for effective use of personal pro-
5
20 years, epidemic DF and DHF have expanded geo- tective measures and field diagnostics. Very little is cur-
graphically from Southeast Asia to the South Pacific rently known about the epidemiology of dengue among
Islands, the Caribbean, and the Americas. The increas- US Army personnel, particularly the frequently deployed
ing dengue burden is driven by several factors, includ- USASOC population.
ing increased urbanization, world population growth,
increased international trade and travel, and changes in In an effort to quantify the risk of multiple exposures,
human behavior that increase mosquito breeding sites. the USASOC Surgeon’s Office, in conjunction with the
6
Primarily due to vector expansion, dengue viruses are Viral Diseases Branch, Walter Reed Army Institute of
also endemic in some parts/territories of the US (Texas, Research (VDB, WRAIR), Silver Spring, Maryland,
Florida, Puerto Rico, Hawaii), as well as in some French conducted two separate studies looking at the serop-
7
overseas territories (Martinique, Guyana, New Caledo- revalence of dengue in deployed USASOC personnel.
nia). 8–12 Although the majority of the dengue infections The first was a retrospective seroprevalence study of ar-
occur among residents of dengue-endemic areas, dengue chived serum samples collected from USASOC person-
is increasingly diagnosed among travelers to these desti- nel deployed to Asia and Central and South America
nations, 13–15 as well as in localized outbreaks within the during 2006–2008. The second, which is ongoing, is a
US. 18–22 Dengue fever is not only an important vector- multicenter, prospective serosurveillance study examin-
borne disease in civilian travelers but also a disease of ing sera obtained from USASOC personnel before or
importance among deployed troops in endemic areas. after deployment to USASOC areas of operation in den-
DF is considered to be a potential cause of febrile ill- gue-endemic areas for the presence of neutralizing anti-
ness in troops deployed in tropical areas since World bodies (an antibody that reacts with the infectious agent
War II. DF has been reported in French forces in New and destroys or inhibits its infectiveness and virulence) to
16
Caledonia (1989), French Polynesia, and the West In- dengue serotypes 1–4. The results from these studies will
dies (1997); among US forces in Somalia (1992–1993) provide important information on the epidemiology of
and Haiti (1997); and among Australian forces and Ital- dengue in deployed troops, guide commanders’ medical
ian troops in East Timor (1999–2000) and worldwide threat planning for endemic areas, support consistent use

*18D Special Forces Medic; 68WW1 Special Operations Combat Medic; 68WW4 and 38BW4 Special Operations Civil Affairs
Medical Sergeant. 28

112 Journal of Special Operations Medicine Volume 14, Edition 3/Fall 2014