INFECTIONS - Medicine for Mountaineering and Other Wilderness Activities - page 313

More information is available at www.cdc.gov/flu .
Infectious Mononucleosis
Infectious mononucleosis is a common viral infection of young adults spread through
close personal contact. Approximately 95 percent of adults forty years old have been in-
fected. Although sometimes incapacitating, it is usually a mild illness; fatal complications
such as splenic rupture, secondary bacterial infections, severe anemia, and low platelet
counts are rare.
Themostcharacteristicsymptomofinfectiousmononucleosisisapersistent,severesore
throat. Other complaints are not specific: fever, fatigue, and loss of energy. Lymph nodes
in various portions of the body are usually enlarged, especially those in the neck.
The triad of sore throat, lymph node enlargement, and fever is classic, but infectious
mononucleosis is notorious for its great variability. A skin rash, headache, weakness, loss
of appetite, and generalized aching may be present. Mild liver involvement is frequent;
more severe involvement with jaundice occasionally occurs.
No specific treatment is available. Antiviral and antibacterial drugs are of no benefit.
Serious complications, such as hepatitis or an obstructed airway due to enlarged lymph
nodes can be treated with a five-day course of prednisone. Saltwater gargles may help the
sore throat. An adequate fluid intake should be stressed since the sore throat may discour-
age oral intake. Rest is important, andthe person'sactivity should belimited until fever re-
solves. Since minor abdominal trauma could easily rupture the enlarged and fragile spleen,
climbing with a waist loop and other activities in which such injury is likely should be
avoided. Recovery in most cases takes two to four weeks. If jaundice or skin hemorrhage
is present, the individual should be evacuated.
More information is available at www.cdc.gov/ncidod/diseases/ebv.htm .
Dengue Fever
Dengue is another febrile illness that is associated with a rash and is transmitted to hu-
mansby Aedes mosquitoes,thesamevectorthattransmitsmalaria.Thediseaseiscausedby
avirusinthesamefamilyastheyellow-fevervirus.Inrecentyears,denguehasemergedas
a major public health problem, particularly in the Americas. The disease has the same geo-
graphicdistributioninthetropicsasmalariaandisthemostimportantmosquito-borneviral
infection affecting humans. Because Aedes mosquitoes are most commonly found near hu-
man habitation, the disease is more common in urban than rural environments, and the risk
of infection for wilderness travelers is smaller. After an incubation period of four to sev-
en days, infected individuals develop the sudden onset of high fever, headache, joint pain,
nausea, vomiting, and a blotchy, red rash. After a brief period of improvement, fever and
symptoms may recur. Almost everyone recovers, but bleeding, hepatitis, and neurologic