INFECTIONS - Medicine for Mountaineering and Other Wilderness Activities - page 312

fections a wide berth. However, such individuals sometimes are passengers in public con-
veyances, even aircraft, and staying a safe distance from them may be difficult.
Travelers must be alert to this risk and try to avoid contact with individuals who appear
possibly to be suffering with an active infection.
VIRAL INFECTIONS
Influenza
Influenza, or “the flu,” is a viral infection caused by influenza viruses A or B and pro-
duces an acute, self-limited disease that lasts five to six days. Spread occurs by sneezing,
coughing, or close contact with an infected person. Epidemics are common, particularly in
winter months. The incubation period is one or two days. The onset is heralded by chills,
fever, weakness, lassitude, headache, loss of appetite, and the characteristic aching muscle
pains. A dry, hacking cough is prominent and may be severe. The runny nose and sinus
congestion of the common cold are absent. Fever usually lasts two to three days and occa-
sionally reaches 104°F (40°C).
The signs and symptoms of respiratory tract involvement usually differentiate influenza
from other systemic infections; the fever, muscle aches, and cough distinguish it from a
common cold. A history of contact with other persons with influenza is helpful in making
a diagnosis. Gastrointestinal symptoms are usually absent, but diarrhea may occur.
Symptoms are partially relieved by rest, warmth, a light diet with abundant liquids, and
medications such as acetaminophen (Tylenol® and others) or ibuprofen (Motrin® and oth-
ers) to relieve discomfort. Medication to promote sleep and reduce cough may be helpful.
Specific antiviral treatment with oral oseltamivir (Tamiflu®) or inhaled zanamivir (Relen-
za®) is expensive, is effective only if started within forty-eight hoursofthe onset ofsymp-
toms, and shortens the length of illness by only a day.
Antibacterial drugs have no value for the routine treatment of influenza. If fever returns
after several days or a cough productive of purulent sputum indicates a secondary bacterial
pneumonia has developed, it should be treated with an antibiotic having a broad spectrum
of activity, such as a cephalosporin (Keflex® and others).
Influenza vaccines prevent or greatly reduce the severity of influenza infections. Al-
though almost anyone can be immunized, CDC specifically recommends vaccination for
the following groups:
◆ Children ages six months through eighteen years
◆ Pregnant women
◆ People fifty years of age and older
◆ People of any age with certain chronic medical conditions
◆ People who live in nursing homes and other long-term care facilities
◆ People who live with or care for those at high risk for complications from flu