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SECTION I - INFECTIOUS AGENT
NAME: Coccidioides immitis
SYNONYM OR CROSS REFERENCE: Coccidioidomycosis, Valley fever, Desert fever.
CHARACTERISTICS: Dimorphic fungus, arthroconidia, swelling of arthrospores in vivo into spherules (burst
and release endospores).
SECTION II - HEALTH HAZARD
PATHOGENICITY: Systematic mycosis beginning as a respiratory infection; primary infection asymptomatic
or influenza-like; 115 clinical cases develop erythema nodosum; rare progression to disseminated disease (more
common in pregnant women, African-Americans, Filipinos & HIV positive individuals); progressive, frequently
fatal granulomatous disease with lung lesions and abscesses throughout body. Meningitis common, 90% fatality rate
if not treated.
EPIDEMIOLOGY: Primary infections common in highly endemic arid and semiarid areas of Western Hemisphere
(California to South Texas, northern Argentina, Paraguay, Colombia, Venezuela, Mexico and Central America); dusty
fomites from endemic areas can transmit infection elsewhere; affects all ages, both sexes and all races; most frequent
in summer after wind and dust storms.
HOST RANGE: Humans, domestic animals, wild desert rodents and other animals.
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: Inhalation of infective arthroconidia from soil (arthrospore is 2-5 micrometers and
is conductive to ready dispersal in air and retention in deep pulmonary spaces); laboratory accidents common; parasitic
spherules not usually infective (larger size 30-60 micrometers of spherule reduces effectiveness of this form as
an airborne pathogen) but accidental inoculation of infected pus or other materials can result in granuloma formation.
INCUBATION PERIOD: One to 4 weeks in primary infection; disseminated infection may develop insidiously,
sometimes without recognized initial symptoms.
COMMUNICABILITY: Not directly transmitted from person to person; parasitic form on dressings or casts and
in clinical specimen may however change to the infective form after 7 days.
SECTION III - DISSEMINATION
RESERVOIR: Soil; especially in and around rodent middens and burrows, in regions with appropriate temperature,
moisture and soil requirements.
ZOONOSIS: Not directly transmitted from animal to humans.
VECTORS: None
SECTION IV - VIABILITY
DRUG SUSCEPTIBILITY: Sensitive to Amphotericin B, ketoconazole.
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite (20% commercial bleach), phenolics,
glutaraldehyde, formaldehyde; susceptibility to 70% ethanol questionable.
PHYSICAL INACTIVATION: Spores can withstand dry heat; inactivation by moist heat 121o C for at
least 15 min.
SURVIVAL OUTSIDE HOST: Arthrospores survive for months to years in soil, dust.
SECTION V - MEDICAL
SURVEILLANCE: Monitor for symptoms; microscopic demonstration of fungus in specimens; skin test for coccidioidin
or spherulin; serological analysis for confirmation (serology may be negative with disseminating disease).
FIRST AID/TREATMENT: Amphotericin B or Fluconazole for severe or disseminated forms.
ACTION: None
PROPHYLAXIS: None
SECTION VI - LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: Well documented laboratory hazard; 108 reported cases with 2 deaths;
10th most commonly reported lab-acquired infection; 90% of cases in one institution resulted in clinical disease
(more than half of infections acquired in nature were asymptomatic).
SOURCES/SPECIMENS: Spherules may be present in clinical specimens and animal tissues; infectious arthrospores
in mold cultures and soil samples.
PRIMARY HAZARDS: Inhalation of arthrospores from soil samples, mold cultures, or following transformation
from spherule form in clinical materials; arthrospores are easily dispersed when cultures are opened.
SPECIAL HAZARDS: Accidental percutaneous inoculation of the spherulle form may result in local granuloma
formation.
SECTION VII - RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 3 practices, containment equipment and facilities are recommended
for all activities with cultures of C. immitis and for processing soil or other materials known or likely to contain
infectious anthrospores.
PROTECTIVE CLOTHING: Laboratory coat; gloves and wrap-around gown with tight wrists and when manipulating
cultures.
OTHER PRECAUTIONS: Appropriate practices and precautions to minimize the production of infectious aerosols.
SECTION VIII - HANDLING INFORMATION
SPILLS: Allow aerosols to settle- wearing protective clothing, gently cover spill with paper towels and
apply 1% sodium hypochlorite( 20% commercial bleach), starting at perimeter and working towards the center; allow
sufficient contact time (30 min.) before clean up.
DISPOSAL: Decontaminate before disposal, steam sterilization, incineration.
STORAGE: In sealed containers that are appropriately labeled.
Date prepared: October 11, 1997 Prepared by: Canadian Office of Biosafety Information edited by the Colorado State
University Office of Biosafety, June 16, 1998.
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