INFECTIONS - Medicine for Mountaineering and Other Wilderness Activities - page 319

that should be started one to two days before entering a malaria endemic area and contin-
ued for seven days after return. Consultation with a physician knowledgeable about travel
medicine should be arranged well before the anticipated date of departure.
In cities and towns frequently visited by tourists, malaria is uncommon, and malaria-
carrying mosquitoes are rarely found at elevations above 4500 feet (1500 m). In malarial
areas, contact with mosquitoes shouldbeminimized with screens ormosquito netting, pro-
tective clothing, and insect repellents. The best available repellent is N, N-diethyl- m -tolu-
amide (DEET). In long-acting preparations it remains effective for up to eighteen hours,
a considerable advantage over other repellents, which are effective for only two to four
hours. It may be easier to avoid malarial areas than to take chloroquine for multiple weeks,
as this drug does occasionally cause itching, gastrointestinal complaints, and a variety of
other side effects.
More information is available at www.cdc.gov/malaria .
Babesiosis
Babesiosis is a malarialike parasitic disease occurring primarily along the northeast
coast of the United States and in Mexico, Yugoslavia, and Ireland. The organism is trans-
mitted from mice and voles to humans by Ixodes tick bites. The illness is characterized by
fever,chills, sweats, headache, andmuscle aches. Because redbloodcells are destroyed by
the parasite, anemia may result. The disease is usually self-limited, and most people recov-
er uneventfully. In a few individuals, particularly those whose spleen has been removed,
the disease is severe, even fatal. Treatment with quinine and clindamycin appears to be ef-
fective.
ThetickthattransmitsthisparasiteisthesametickthattransmitsLymediseaseandehr-
lichiosis, and some individuals are infected by two or all three of these organisms. Labor-
atory studies are required to identify ehrlichiosis and babesiosis, and individuals suspected
to have either should be referred to a physician.
More information is available at www.cdc.gov/ncidod/parasites/babesia/default.htm .
Schistosomiasis (Bilharziasis)
Schistosomiasis is a parasitic infestation caused by three different species of the genus
Schistosoma . It affects over 200 million people worldwide, but most infested people have
no symptoms or clinical evidence of disease. Depending upon the particular species, in-
festation can cause complications in the liver, bowel, or urinary tract. The life cycles of all
species are similar. After the eggs leave the human host in stool or urine, they hatch into
tiny miracidia that penetrate any of several species of freshwater snails. The absence of an
appropriate snail host in the waters of the United States probably accounts for the absence
of disease in this country. Within the snail the miracidia mature into free-living cercariae.
When released from the snail into water, the cercariae are able to infest humans by pen-