BLOOD TYPE AND CHOLERA SUSCEPTIBILITY
For reasons researchers do not understand, peo-
ple who have BLOOD TYPEO have twice the likeli-
hood of contracting cholera than others, and
people who have blood type AB seldom become
infected.Though the profuse, watery diarrhea of cholera
has a characteristic appearance and smell, the doc-
tor may perform a stool culture to confirm the
diagnosis. Treatment is oral rehydration solution
(ORS) to replace the massive loss of fluid that
occurs with the diarrhea, which can exceed a
quart an hour. Doctors may prescribe tetracycline
to shorten the course of illness when symptoms
are especially severe, though most people recover
with appropriate rehydration.
Cholera is rare in the United States, though
people who travel to parts of the world where
cholera is endemic are at risk for infection. Pre-
ventive measures include frequent HAND WASHING;
drinking only bottled beverages or water purified
through boiling, chlorination, or iodinization; and
avoiding raw foods.
See also DRINKING WATER STANDARDS; WATERBORNE
ILLNESSES.
coccidioidomycosis An illness resulting from
INFECTIONwith the spores of the fungus Coccidioides
immitis, which occurs naturally in the soil in desert
environments, inhaled into the LUNGS. Coccid-
ioidomycosis affects the respiratory tract, primarily
the lungs. About half of people infected with C.
immitisdo not become ill. The IMMUNE SYSTEMcan
successfully neutralize small numbers of C. immitis
spores before they cause illness, though the per-
son will test positive for infection. Exposure to
high numbers of spores is more likely to result in
illness. Among those who develop symptoms of
coccidioidomycosis, commonly called valley FEVER,
illness may be acute, chronic, or disseminated.
In people who are IMMUNOCOMPROMISED, coccid-
ioid omycosis may occur as an OPPORTUNISTIC INFEC-
TION.
Symptoms and Diagnostic Path
The most common form of coccidioidomycosis is
acute, in which symptoms develop within four
weeks of exposure. Symptoms include
- nonproductive (dry) COUGHand CHEST PAIN
- FEVER
- fatigue
- chills and night sweats
- diminished APPETITEand weight loss
- HEADACHE
- MUSCLEand JOINT PAIN
- RASH
- LYMPHADENOPATHY(swollen LY M P Hnodes)
The diagnostic path includes chest X-RAYand
coccidioidin SKINtest. The skin test is positive 21
days after exposure. BLOODtests may also show
elevated antibodies.Treatment Options and Outlook
Though the infection is self-limiting and resolves
within three to six months without treatment in
most people, doctors often prescribe ANTIFUNGAL
MEDICATIONSto eradicate the infection more quickly
and reduce the likelihood for complications, which
may include MENINGITIS. Most people recover with-
out residual effects. Some people develop chronic
infection, in which symptoms recur. About 1 per-
cent of people develop disseminated disease (also
called progressive), in which the infection enters
the blood circulation and travels to other structures
and organs. Extended, sometimes lifelong, treat-
ment with antifungal medications is required for
chronic and disseminated coccidioidomycosis.
People who are immunocompromised, take
IMMUNOSUPPRESSIVE THERAPY, or are of Filipino or
African American heritage have especially high risk
for disseminated disease.ANTIFUNGAL MEDICATIONS
TO TREAT COCCIDIOIDOMYCOSIS
amphotericin B fluconazole
itraconazole ketoconazoleRisk Factors and Preventive Measures
The primary risk factor for coccidioidomycosis is
exposure to soil, especially dust, containing C.
immitisspores. Public health officials often note
spikes in reported infections after desert dust
storms. Farm and ranch workers, construction
workers, and archaeologists have increased risk318 Infectious Diseases