NAME: Histoplasma capsulatum
SYNONYM OR CROSS REFERENCE: Histoplasmosis; Ajecllomyces capsulatus
CHARACTERISTICS: Dimorphic fungus, mold form in soil, yeast form in animals and human hosts
PATHOGENICITY: Systemic mycosis of varying severity with primary lesion in lungs; disease appears as a mild, flu-like respiratory illness with symptoms including malaise, fever, chest pain, dry or non-productive cough, headache, loss of appetite, shortness of breath, joint and muscle pain, chills; five clinical forms - asymptomatic, acute benign respiratory, acute disseminated, chronic disseminated, chronic pulmonary; some forms can be fatal; asymptomatic infection provides partial resistance to re-infection
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; prevalence increases from childhood to 15 years of age
HOST RANGE: Humans, dogs, cats, cattle, horses, rats, skunks, opossums, 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 µm) is conducive to airborne dispersal and intrapulmonary retention
INCUBATION PERIOD: Symptoms appear within 3-18 days after exposure, commonly 10 days
COMMUNICABILITY: Not transmitted from person-to-person
RESERVOIR: Soil (particularly in high-nitrogen content soil), caves harbouring 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; organism grows particularly well in soil contaminated with fecal material of birds or bats
VECTORS: None
DRUG SUSCEPTIBILITY: Sensitive to amphotericin B, ketoconazole, itraconazole
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, phenolics, glutaraldehyde, formaldehyde; susceptibility to 70% ethanol questionable
PHYSICAL INACTIVATION: Inactivated by moist heat (121° C for at least 15 min)
SURVIVAL OUTSIDE HOST: Spores are resistant to drying and may remain viable for long periods of time
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
LABORATORY-ACQUIRED INFECTIONS: Documented hazard in laboratories conducting diagnostic or investigative work; 71 reported cases with 1 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 or humans (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 laboratory workers
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: Laboratory 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
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towels and apply sodium hypochlorite, starting at perimeter and working towards the centre; 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 labelled
Date prepared: March, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001