Biomedical Engineering Reference
In-Depth Information
and Northern USA, and histoplasmosis in the central and eastern North
America.
Lacazia loboi, formerly Loboa loboi, is another species in Class
Onygenales that causes disease in otherwise healthy individuals. The disease,
endemic to the Amazon, is known by a number of names: Lobo disease,
lacaziosis, keloidal blastomycosis, Amazonian blastomycosis, miraip, piraip,
and lobomycosis. Clinically, Lobo's disease is a granulomatous infection of
the skin. The disease can be mistaken for Paracoccidioides brasiliensis and
with Blastomyces dermatididis due to the similar morphology of the yeast in
tissues. Lacazia loboi has not been successfully cultured. Like most fungal
infections, transmission comes from the environment, not through human
contagion.
Genus Emmonsia contains two pathogenic organism: Emmonsia parva,
alternately known as Chrysosporium parvum var. parvum, and Emmonsia
crescens, alternately known as Chrysosporium parvum var. crescens. These
organisms are the causative agents of adiaspiromycosis, a disease with a
unique pathogenic mechanism. Adiaspiromycosis causes pulmonary disease
in various animal species, particularly rodents. It is a rare cause of disease in
humans. Although it is referred to as an infection, it is actually a foreign
body reaction, resulting from the inhalation and sequestration of conidial
spores in the small branches of the respiratory tree. The spores are large,
about 300 microns in diameter. Histologic cross-sections of infected lungs
show a walled spore, surrounded by acute and chronic inflammation and for-
eign body reaction granulomas. There is no growth of the organism. In the
literature, the term “disseminated adiaspiromycosis” is sometimes encoun-
tered [109], referring to lesions that involve most of the lung parenchyma.
In this case, dissemination is not an indication the lesion has spread from
one part of the lung to another, but that the load of inhaled spores involves
most of the respiratory tree.
Class Onygenales also contains Class Arthrodermataceae, the dermatophytes:
Genus Epidermophyton, Genus Microsporum, and Genus Trichophyton.
Species within these genera account for most of the tinea, also known as
ringworm, infections of humans. Exceptions are Hortaea werneckii (an asco-
mycote in Class Dothideomycetes), the cause of tinea nigra; and Malassezia
furfur (a basidiomycota), the cause of tinea versicolor. All tinea infections
are colonizations of the superficial layers of the epidermis by keratin-loving
fungi. Like other infections caused by members of Class Onygenales, tinea
infections can occur in immune-competent hosts. Like most fungal
infections, the clinical features of the disease tend to worsen in immune-
compromised patients. In immune-compromised patients, a case of superfi-
cial tinea may progress into a locally invasive process (tinea profunda) or
recurrent infections [110].
As previously described, fungal diseases are not typically spread from
person to person. They are spread by fungi that grow in the environment and
