Page 126 - Journal of Special Operations Medicine - Winter 2014

perhaps with pharmacologic options outside the typical The illness is usually self-limiting, and treatment is sup-
US-approved protocols, but these case-by-case decisions portive. There is no specific antiviral therapy. Acet-
should be made in consultation with higher headquar- aminophen should be used to treat the pain and fever.
ters medical authorities. A valuable resource is the US If there is a question of whether the patient has dengue,
Centers for Disease Control and Prevention (CDC) Ma- nonsteroidal anti-inflammatory drugs (NSAIDs) should
laria Hotline: during duty hours +1-770 488-7788 or not be used until the patient has been afebrile for longer
after hours +1-770 488-7100. 7 than 48 hours and has no warning signs of severe den-
gue fever (discussed in the following section). Because
The need for terminal prophylaxis with primaquine for the clinical findings of both CHIKV and dengue fever
P. vivax or P. ovale in Africa is controversial. Experts are similar, patients with suspected CHIKV should be
agree that most travelers to Africa do not need terminal managed as having dengue fever until dengue has been
prophylaxis, because the overall risk of developing ma- ruled out. There is no vaccine or medication available to
laria caused by P. vivax or P. ovale is very low. Terminal prevent CHIKV infection. This, again, stresses the im-
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prophylaxis should be considered for those who have portance of reducing mosquito exposure through FHP
lived 6 months or longer in high-risk areas with intense measures.
exposure to P. vivax, such as can be found along the
Omo River in Ethiopia. The recommended adult dose Dengue
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of primaquine for terminal prophylaxis based on clinical Dengue fever and dengue hemorrhagic fever are caused
trials and expert opinion is 30mg base daily for 14 days, by the transmission of one of four dengue viruses
started on the return from a malarious region. Persons through the bite of an A. aegypti mosquito. Unlike ma-
with glucose-6-phosphate dehydrogenase (G6PD) defi- laria, there is no chemoprophylaxis available for den-
ciency must not take primaquine for malaria prophy- gue and no cure. The only way to prevent the disease is
laxis. Both the AFRICOM and SOCAsFRICA policy through bite avoidance.
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for primaquine use reflect this recommendation.
According to the CDC, there are nearly 400 million
Chikungunya people infected with dengue fever yearly worldwide.
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Chikungunya virus (CHIKV) is a mosquito-borne viral The principal symptoms of dengue fever are high fever
disease characterized by acute onset of fever and severe sustained for 5 to 6 days, severe headache with retro-
polyarthralgia. CHIKV is a single-stranded RNA virus orbital pain, photophobia, arthralgias, myalgias, rash,
whose primary vectors are the Aedes aegypti and A. al- and mild bleeding (e.g., nose or gums, easy bruising).
bopictus mosquitoes. Both are aggressive daytime bit- The course of dengue fever is self-limited, and treatment
ers, which makes them a serious threat to troops who is supportive. Laboratory samples may be sent to the
have been accustomed only to using personal protective UVRI in Entebbe, as mentioned, for definitive diagnosis.
measures (e.g., DEET, sleeves down) at dusk or dawn. This is important to provide feedback to commanders
who may assist with the enforcement of FHP measures.
The incubation period of CHIKV is typically 3 to 7
days, and the majority of those infected are symptom- Dengue hemorrhagic fever (DHF) is a more severe form
atic. CHIKV infection presents with acute onset of fe- of dengue infection, with a mortality rate of approxi-
ver and debilitating symmetric arthralgias, often in the mately 20%. DHF is usually associated with secondary
hands and feet. Associated signs and symptoms in- dengue infection. An infection with one of the four den-
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clude: headache, myalgia, conjunctivitis, nausea, vom- gue virus serotypes produces immunoglobulin antibod-
iting, and maculopapular rash. Symptoms of CHIKV ies that provide lifeling immunity against that serotype.
infection usually resolve in about a week; however, there During the second infection with a different serotype,
may be relapses of arthralgias for months to years fol- these preexisting antibodies from the first infection may
lowing this acute infection. fail to neutralize and instead enhance viral uptake and
replication in the phagocytes. Such infected cells be-
Blood samples should be collected for diagnostic test- come the target of an immune elimination mechansim
ing at the closest reliable laboratory. Testing reveals with activation of complement and the clotting cascade,
lymphopenia, thrombocytopenia, and elevated levels of and eventually produce DHF. DHF is characterized by
creatinine and liver transaminases. There is no rapid di- a fever that lasts from 2 to 7 days and in addition to
agnostic test available; however, CHIKV testing is avail- dengue fever symptoms, patients experience petechiae,
able at the CDC Uganda Viral Research Institute (UVRI) purpura, gingival bleeding, hematemesis, melena, he-
in Entebbe. Definitive testing can be accomplished here maturia, hepatomegaly, and shock, due to plasma leak-
using polymerase chain reaction (PCR) testing on the age (dengue shock syndrome). Once the fever subsides,
patient’s blood sample. This can be coordinated through symptoms include persistent vomiting, severe abdomi-
the SOCAFRICA Surgeon’s office. nal pain, and dyspnea. Laboratory tests in DHF reveal

116 Journal of Special Operations Medicine Volume 14, Edition 4/Winter 2014