Emerging Infectious Diseases
Coccidioidomycosis Following the Northridge Earthquake --
California, 1994
From January 24 through March 15, 1994, 170 persons with
laboratory evidence of acute coccidioidomycosis * were identified
in
Ventura County, California. This number -- which comprises cases
identified through active surveillance -- substantially exceeds the
total number of coccidioidomycosis cases (52) reported through
routine passive surveillance during all of 1993 in Ventura County,
which has been considered an area of low incidence for this
disease. The increase in cases follows the January 17 earthquake
centered in Northridge (in adjacent Los Angeles County), which may
have exposed Ventura County residents to increased levels of
airborne dust. The California Department of Health Services, local
public health agencies, and CDC are conducting an investigation to
determine the magnitude of the outbreak, risk factors for
infection, and its possible association with the Northridge
earthquake.
Reported by: D Pappagianis, MD, Univ of California, Davis; G
Feldman, MD, M Billimek, MSH, Ventura County Public Health Dept,
Ventura; L Mascola, MD, Los Angeles County Health Dept, Los
Angeles; SB Werner, MD, RJ Jackson, MD, GW Rutherford, III, MD,
State Epidemiologist, California Dept of Health Svcs. Emergency
Response Coordination Group, National Center for Environmental
Health; Office of the Director, National Institute for Occupational
Safety and Health; Div of Bacterial and Mycotic Diseases, National
Center for Infectious Diseases; Div of Field Epidemiology,
Epidemiology Program Office, CDC.
Editorial Note
Editorial Note: Coccidioides immitis is a dimorphic fungus that
grows in soil in much of the southwestern United States; infection
results from inhalation of airborne C. immitis arthroconidia.
Coccidioidomycosis is not transmitted from person to person.
Approximately 60% of infected persons are asymptomatic; the
remainder can develop a spectrum of manifestations that range from
mild to moderate influenza-like illness to pneumonia to
disseminated disease, including meningitis (1). Extrapulmonary
coccidioidomycosis in a person infected with human immunodeficiency
virus is considered an acquired immunodeficiency syndrome-defining
illness (2).
Previous outbreaks of C. immitis infection have occurred in
association with windborne exposures; such outbreaks illustrate the
relation between environmental conditions and emergence of
infectious diseases (3). Since 1990, the number of reported cases
of coccidioidomycosis in California has increased substantially;
most illnesses have occurred in Kern and Tulare counties in the San
Joaquin Valley (1). Most cases have occurred in residents of areas
where coccidioidomycosis is endemic; however, visitors to these
areas also are at risk for infection.
Because the incubation period for this infection usually
ranges from 1 to 4 weeks, persons who may have become infected
while visiting areas where coccidioidomycosis is endemic may not
become ill until after they return home, and the diagnosis may not
be considered by clinicians in areas where coccidioidomycosis is
not endemic. Recent environmental exposure to C. immitis may have
occurred among residents of and travelers to Ventura County, Los
Angeles County, or other counties in or near the San Joaquin Valley
following the earthquake and its aftershocks and during clean-up
activities.
Acute coccidioidomycosis can be diagnosed by serologic tests
for immunoglobulin M (IgM) detection (such as tube precipitin,
enzyme immunoassay, latex agglutination, or immunodiffusion), and
immunoglobulin G (IgG) detection (such as immunodiffusion or
complement fixation) in the presence of pneumonia or erythema
nodosum and occasionally by positive sputum culture (4).
Cases of coccidioidomycosis suspected to be temporally
associated with the earthquake should be reported through state and
local health departments to CDC. Information about
coccidioidomycosis is available from CDC's Voice Information
System, telephone (404) 332-4554, and from CDC's Emerging Bacterial
and Mycotic Diseases Branch, Division of Bacterial and Mycotic
Diseases, National Center for Infectious Diseases, at the same
telephone number.
References
CDC. Coccidioidomycosis -- United States, 1991-1992. MMWR
1993;42:21-4.
CDC. 1993 Revised classification system for HIV infection and
expanded surveillance case definition for AIDS among adolescents
and adults. MMWR 1992;41(no. RR-17).
Pappagianis D, Einstein H. Tempest from Tehachapi takes toll or
Coccidioides conveyed aloft and afar. West J Med
1978;129:527-30.
Einstein HE, Johnson RH. Coccidioidomycosis: new aspects of
epidemiology and therapy. Clin Infect Dis 1993;16:349-56.
The presence of Coccidioides immitis-specific immunoglobulin M
(IgM) antibody (using enzyme immunoassay or immunodiffusion) OR
serologic evidence of acute C. immitis infection, by positive IgM
using latex agglutination test in the presence of pneumonia or
erythema nodosum OR if IgM was not available, serologic evidence of
recent infection, by positive immunoglobulin G (IgG) using
immunodiffusion or complement fixation tests in the presence of
pneumonia or erythema nodosum OR a positive sputum culture (with no
history of previous coccidioidal infection).
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