Background Debris
Background debris is an indication of the amount of non-biological particulate matter present on the slide (dust in the air) and is graded from 1+ to 4+ with 4+ indicating the largest amounts. To evaluate dust levels it is important to account for differences in sample volume. This background material is also an indication of visibility for the analyst and resultant difficulty reading the slide. For example, high background debris may obscure the small spores such as the Penicillium/Aspergillus group. Counts from the areas with 4+ background debris should be regarded as minimal counts and may actually be higher than reported.
Bactrodesmium
Characteristics: No information is available regarding health effects, or toxicity. Allergenicity has not been studied.
Description: Bactrodesmium species comprise a very small proportion of the fungal biota. No information is available regarding health effects, or toxicity. Allergenicity has not been studied. Rarely found but may be identified on surfaces by tape lifts, tease mounts from bulk samples, and in air by spore trap samples. (Spores have distinctive morphology.) Natural habitat includes wood and bark of various deciduous trees such as ash, oak and sycamore.
Basidiospores
Characteristics: Allergen Type I and Type III also considered to be rarely pathogenic and toxigenic.
Description: Basidiospores are basically mushrooms. Some people are allergic to mushrooms. That’s why this is included in this section. It is often found in saprophytes (an organism that grows on and derives nourishment from dead or decaying matter) and other plant pathogens. It is found everywhere in nature. It is commonly the cause of wood rot indoors. It is disseminated by the wind during period of high humidity or rain. For indoor growth this fungus requires wet conditions. Occasionally, a benign, non-wood rotting mushroom will fruit inside a building, growing in some unique ecological niche if enough moisture is present. As an allergen, it has been known to cause Type I allergies (hay fever, asthma) and Type III hypersensitivity pneumonitis (Lycoperdonosis, and Mushroom culture hypersensitivity symptoms. As a pathogen, it has been known to cause rare opportunistic infections. As a toxigenic agent, it produces mushroom toxins that are usually ingested including amanitins, monomethyl-hydrazine, muscarine, ibotenic acid, and psilocybin.
Beauveria
Characteristics: Allergen Type I, also considered a rare pathogen, and it is unknown whether it is a potential toxin.
Description:
It is often found in soil, plant debris, and dung. It can ald=so be found as a parasite on insects. It is disseminated as a dry spore by the wind. As an allergen, it has been known to cause Type I allergies including hay fever and asthma. As a pathogen, it has rarely been known to cause isolations from corneal lesions and lungs from an immunocompromised patient. It is not known to be toxigenic agent. It is a pathogen of silk worms and other insects.
Beltrania
Characteristics: No information is available regarding health effects, or toxicity. Allergenicity has not been studied.
Description: Beltrania species comprise a very small proportion of the fungal biota. No information is available regarding health effects, or toxicity. May be identified in air by spore trap samples. (Spores have distinctive morphology.) Beltrania needs specialized media for sporulation in the laboratory. Natural habitat includes dead leaves and plant litter of semi-tropical and tropical plants.
Bipolaris/Drechslera Group
Characteristics: Allergen Type I, occasional pathogen, not known to be toxigenic.
Description: It is often found in soil, plant debris, and as a plant pathogen on grass with a dark grey to brown coloration. It is disseminated as a dry spore by the wind. For indoor growth this fungus can grow on various surfaces. As an allergen, it has been known to cause Type I symptoms of hay fever and asthma. As a pathogen, it has been rarely known to cause phaeohyphomycosis (keratitis, sinusitis, and osteomyelitis) most often occurring in immunocompromised persons, although infections also occur in normal hosts. One case of brain abscess reported in an immunocompromised patient. It is not considered a toxigenic agent.
Blastobotrys
Characteristics: No information is available regarding health effects, or toxicity. Allergenicity has not been studied.
Description: Blastobotrys species comprise a very small proportion of the fungal biota. No information is available regarding health effects, or toxicity. Allergenicity has not been studied. Rarely found but may be identified on surfaces by tape lifts, tease mounts from bulk samples, and in air by culturable (Andersen) samples. (Spores do not have distinctive morphology and would be categorized as “other colorless” on spore trap samples.) Recorded isolations include seeds and compost.
Botryomyces
Characteristics: No information is available regarding health effects, or toxicity. Allergenicity has not been studied.
Description: Botryomyces species comprise a very small proportion of the fungal biota. This genus is not treated by many reference books on fungi. Described by the mycologist de Hoog, the multicelled irregularly septate, thick-walled “spores” may be regarded by some to be vegetative structures. Botryomyces caespitosus is a very rare agent of chromoblastomycosis-like subcutaneous infections after trauma. No information is available regarding other health effects, or toxicity. Allergenicity has not been studied. May be identified on surfaces by tape lifts or tease mounts from bulk samples. This organism is most commonly found on wood.
