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SECTION I - INFECTIOUS AGENT
NAME: Histoplasma capsulatum
SYNONYM OR CROSS REFERENCE: Histoplasmosis
CHARACTERISTICS: Dimorphic fungus, mold form in soil, yeast form in animals and human hosts.
SECTION II - HEALTH HAZARD
PATHOGENICITY: Systematic mycosis of varying severity with primary lesion in lungs; five clinical forms
- asymptomatic, acute benign respiratory, acute disseminated, chronic disseminated, chronic pulmonary; some forms
can be fatal.
EPIDEMIOLOGY: Focal infections are common worldwide; clinical disease and severe progressive disease less
frequent; 80% of population show hypersensitivity to H. capsulatum in eastern and central North America; outbreaks
in families or groups exposed to bird or bat droppings or recently disturbed contaminated soil.
HOST RANGE: Humans, dogs, cats, rats, skunks, foxes and other animals.
INFECTIOUS DOSE: 10 spores lethal inoculum in mice.
MODE OF TRANSMISSION: Inhalation of airborne conidia; small size of infective conidia (<5 mm) is conducive
to airborne dispersal and intrapulmonary retention.
INCUBATION PERIOD: Symptoms appear within 5-18 days after exposure, commonly 10 days.
COMMUNICABILITY: Not transmitted from person to person.
SECTION III - DISSEMINATION
RESERVOIR: Soil (around old chicken houses), caves harboring bats, and around starling roosts- around
older houses sheltering the common brown bat; other soils with high organic content and in decaying trees.
ZOONOSIS: Yes, although not direct zoonosis, however, organism grows particularly well in soil contaminated
with fecal material of birds or bats.
VECTORS: None
SECTION IV - VIABILITY
DRUG SUSCEPTIBILITY: Sensitive to amphotericin B, ketoconazole, itraconazole.
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite (20% commercial bleach), phenolics,
glutaraldehyde, formaldehyde; susceptibility to 70% ethanol questionable.
PHYSICAL INACTIVATION: Inactivated by moist heat (121o C for at least 15 min.).
SURVIVAL OUTSIDE HOST: Spores are resistant to drying and may remain viable for long periods of time.
SECTION V - MEDICAL
SURVEILLANCE: Monitor for symptoms; confirm by culture, microscopic examination of specimens, and serologic
response.
FIRST AID/TREATMENT: Amphotericin B for disseminated or chronic pulmonary cases; conazole drugs may be added
or used in rotation for therapy in immunocompromised patients because relapse is common.
IMMUNIZATION: None
PROPHYLAXIS: None
SECTION VI - LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: Documented hazard in labs conducting diagnostic or investigative work;
71 reported cases with I death - pulmonary infection from handling mold from cultures, local infection from skin
puncture during autopsy, accidental needle inoculation of viable culture.
SOURCES/SPECIMENS: Infective stage (conidia) present in sporulating mold from cultures and in soil from
endemic areas; yeast form in tissues or fluids from infected animals (may produce local infection following parental
inoculation).
PRIMARY HAZARDS: Inhalation of infective conidia, contact with broken skin or mucus membranes, accidental
parenteral inoculation.
SPECIAL HAZARDS: Collecting and processing soil samples from endemic areas has caused pulmonary infections
in lab workers.
SECTION VII - RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 3 practices, containment equipment and facilities for processing
mold cultures, soil, or other material known or likely to contain infectious conidia.
PROTECTIVE CLOTHING: Lab coat; gloves and gown with tight wrists and ties in back when working with agent.
OTHER PRECAUTIONS: Appropriate precautions and practices 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, chemical disinfection.
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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