2. SYLLABUS
Viral Diseases and fungal diseases:
List of diseases of various organ systems and their causative agents. The following
diseases in detail with Symptoms, mode of transmission, prophylaxis and control Polio,
Herpes, Hepatitis, Rabies, Dengue, AIDS.
Fungal Diseases:
Brief description of each of the following types of mycoses and one representative
disease to be studied with respect to transmission, symptoms and prevention
Cutaneous mycoses: Tinea pedis (Athlete’s foot) Systemic mycoses: Histoplasmosis
Opportunistic mycoses: Candidiasis.
4. TABLE OF CONTENT
• General Properties of Fungi
• Classification of Fungal Infections
• Antifungal Agents
5. GENERAL PROPERTIES OF FUNGI
Fungi are eukaryotic microorganisms (domain eucarya) that occur ubiquitously in
nature.
Only about 200 of the thousands of species have been identified as human
pathogens, and among these known pathogenic species fewer than a dozen are
responsible for more than 90% of all human fungal infections.
The basic morphological element of filamentous fungi is the hypha and a web of
intertwined hyphae is called a mycelium.
The basic form of a unicellular fungus is the yeast cell.
6. STRUCTURAL – FUNCTIONAL RELATIONSHIP
• The fungi are more evolutionarily advanced forms of microorganisms, as
compared to the prokaryotes (prions, viruses, bacteria).
• They are classified as eukaryotes, i.e., they have a diploid number of
chromosomes and a nuclear membrane and have sterols in their plasma
membrane.
• Genetic complexity allows morphologic complexity and thus these organisms
have complex structural features that are used in speciation.
• The cell walls of fungi consist of nearly 90% carbohydrate (chitin, glucans,
mannans) and fungal membranes are rich in sterol types not found in other
biological membranes (e.g., ergosterol).
7. • Fungi can be divided into two basic morphological forms, yeasts and hyphae.
• Yeasts are unicellular fungi which reproduce asexually by blastoconidia formation
(budding) or fission.
• Hyphae are multi-cellular fungi which reproduce asexually and/or sexually.
• Dimorphic fungi usually assume the form of yeasts in the parasitic stage and the
form of mycelia in the saprophytic stage.
• Dimorphism is the condition where by a fungus can exhibit either the yeast form
or the hyphal form, depending on growth conditions.
• Very few fungi exhibit dimorphism.
8. GENERAL PROPERTIES OF FUNGI
• Most fungi occur in the hyphae form
as branching, threadlike tubular
filaments. These filamentous structures
either lack cross walls (coenocytic) or
have cross walls (septate) depending
on the species.
• In some cases septate hyphae
develop clamp connections at the
septa which connect the hyphal
elements.
10. • Fungi are microorganisms in the domain eucarya. They show less differentiation
than plants, but a higher degree of organization than the prokaryotes bacteria
(Table 5.1).
• The kingdom of the fungi (Mycota) comprises over 50 000 different species. Only
about a dozen of these “pathogenic” species cause 90% of all human mycoses.
• Many mycotic infections are relatively harmless, for instance the dermatomycoses.
In recent years, however, the increasing numbers of patients with various kinds of
immune defects have resulted in more life-threatening mycoses.
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12. • The taxonomy of the fungi is essentially based on their morphology.
• In medical mycology, fungi are classified according to practical aspects as
dermatophytes, yeasts, molds, and dimorphic fungi.
• Molds grow in filamentous structures, yeasts as single cells and dermatophytes cause
infections of the keratinized tissues (skin, hair, nails, etc.). Dimorphic fungi can appear
in both of the two forms, as yeast cells or as mycelia (see the following pages).
• Fungi are carbon heterotrophs. The saprobic or saprophytic fungi take carbon
compounds from dead organic material whereas biotrophic fungi (parasites or
symbionts) require living host organisms. Some fungi can exist in both saprophytic
and biotrophic forms.
14. DEFINITIONS - INFECTION
• Process which enables interaction of host and
pathogen.
• The state of process where host is being attacked!
• The invasion and multiplication of microorganisms
such as bacteria, viruses, and parasites that are not
normally present within the body. An infection
may cause no symptoms and be subclinical, or it
may cause symptoms and be clinically apparent.
15. INVASION
• The act of invading:
• A : the penetration of the body of a host by a microorganism.
• B : The spread and multiplication of a pathogenic microorganism or
of malignant cells in the body of a host.
16. PATHOGEN
• Cell that can cause infection.
• A pathogen or infectious agent is a biological agent that causes disease or illness
to its host.
• Eg- Bacteria, fungi, algae, protozoa, virus etc.
• Pathogenicity pertains to the ability of a pathogenic agent to cause disease.
17. VIRULENCE
• The ability of an agent of infection to produce disease. The virulence of a
microorganism is a measure of the severity of the disease it causes.
18. TOXIGENICITY
• The ability of a pathogenic organism to produce injurious substances that
damage the host.
19. • Sign: any objective evidence of disease as noted by an observer
• Symptom: the subjective evidence of disease as sensed by the patient
• Syndrome: when a disease can be identified or defined by a certain complex of
signs and symptoms
20. • Epidemiology: the study of the
frequency and distribution of
disease and other health-related
factors in defined human
populations.
• Involves not only microbiology but
also anatomy, physiology,
immunology, medicine, psychology,
psychology, sociology, ecology, and
and statistics.
21. ENDEMIC VS EPIDEMIC VS PANDEMIC
• The WHO defines pandemics, epidemics, and endemic diseases based on a disease's rate of spread.
Thus, the difference between an epidemic and a pandemic isn't in the severity of the disease, but the
degree to which it has spread.
• A disease outbreak is endemic when it is consistently present but limited to a particular region. This
makes the disease spread and rates predictable. Malaria, for example, is considered endemic in certain
countries and regions.
• The Centers for Disease Control and Prevention (CDC) describes an epidemic as an unexpected
increase in the number of disease cases in a specific geographical area. Yellow fever, smallpox,
measles, and polio are prime examples of epidemics.
• The World Health Organization (WHO) declares a pandemic when a disease’s growth is exponential.
This means the growth rate skyrockets, and each day cases grow more than the day prior. In being
declared a pandemic, the virus has nothing to do with virology, population immunity, or disease
severity. It means a virus covers a wide area, affecting several countries and populations.
22. • Etiology: Etiology is the study of causation, or origination.
• Prophylaxis: Action taken to prevent disease. i.e. treatment
23. FUNGAL DISEASE
• Mycoses
• Mycoses are classified clinically as follows:
Primary mycoses or superficial
Subcutaneous mycoses
Cutaneous mycoses
Opportunistic mycoses
Systemic mycoses
Link:
https://www.youtube.com/watch?v=63YdIH2S2ls&t=2s&ab_channel=AlilaMedicalMedi
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25. DISTINCTIVE PROPERTIES
Mycotic infections are classified by the tissue levels that are
colonized.
• Superficial infections or Primary are generally limited to
the outer layers of the skin and hair.
• Cutaneous infections are located deeper in the
epidermis, hair and nails.
• Subcutaneous infections involve the dermis,
subcutaneous tissues and muscle.
In addition, mycotic infections may be systemic, generally
originating in the lungs and other organs.
Finally, some mycoses are termed opportunistic, and these
may involve a variety of body sites.
The following outlines these different types of mycotic
infection, giving examples of representative agents.
26. FUNGAL DISEASE
• Besides fungal allergies (e.g., extrinsic allergic alveolitis) and mycotoxicoses (aflatoxicosis), fungal
infections are by far the most frequent fungal diseases.
• Mycoses are classified clinically as follows:
• — Primary mycoses (coccidioidomycosis, histoplasmosis, blastomycoses)
• — Opportunistic mycoses (surface and deep yeast mycoses, aspergillosis,mucormycoses,
phaeohyphomycoses, hyalohyphomycoses, cryptococcoses;penicilliosis, pneumocystosis)
• — Subcutaneous mycoses (sporotrichosis, chromoblastomycosis, Madura foot (mycetoma)
• — Cutaneous mycoses (pityriasis versicolor, dermatomycoses)
27. CUTANEOUS MYCOSES: TINEA PEDIS
(ATHLETE’S FOOT)
• Tinea pedis or foot ringworm is an infection of the
feet affecting soles, interdigital clefts of toes, and
nails with a dermatophyte fungus.
• It is also called athlete’s foot.
• The infection is caused by the dermatophyte,
Trichophyton rubrum which was once endemic to
many parts of Africa, Asia, and Australia.
• However, today the organism can be found in Europe
and the Americas.
28. DERMATOPHYTES
• Dermatophytes are fungi that infect tissues containing plenty of keratin (skin, hair, nails).
• Classification. Dermatophytes are classified in three genera: Trichophyton (with the
important species T. mentagrophytes, T. rubrum, T. schoenleinii, T. tonsurans);
Microsporum (M. audouinii, M. canis, M. gypseum); and Epidermophyton (E.
floccosum).
• The dermatophytes are filamentous fungi. They grow readily on fungal nutrient mediums
at 25–30 C.
29. ETIOLOGY
• Mainly, Trichophyton rubrum causes tinea pedis.
• Trichophyton interdigitale and Epidermophyton floccosum are also involved.
• Other occasional agents include Tricholosporum violaceum. T. rubrum accounts for about 70% of the
cases.
• Risk factors include:
• A hot and humid environment
• Prolonged wear of occlusive footwear
• Excess sweating
• Prolonged exposure to water
30. EPIDEMIOLOGY
• About 10% of the total population may be affected by dermatophyte infections of the toe
clefts.
• It is mostly attributed to wearing of occlusive shoes for long periods.
• Sharing washing facilities is likely to increase the chances of infection as the incidence of
tinea pedis is observed to be higher among those using community baths, showers, and
pools.
• The condition is more common in adult males than in females. The mean age of onset was
15 years in one study.
31. PATHOPHYSIOLOGY
• Occlusion of toe clefts, maceration, and wet conditions with a simultaneous increase in the
bacterial flora probably contribute to tinea pedis infection.
• Skin breakdown, humidity, and temperature play a role in this infection.
• The fungus released enzymes called keratinases to invade the keratin layer of skin. In
addition, the dermatophyte cell wall also contains molecules called mannans which suppress
the body's immune response.
• Dermatomycoses are infections that are transmitted directly by human contact, animal-human
contact or indirectly on inanimate objects (clothes, carpets, moisture, and dust in showers,
swimming pools, wardrobes, gyms). The localization of the primary foci corresponds to the
contact site. Thus feet, uncovered skin (hair, head, facial skin) are affected most frequently.
32. DIAGNOSIS
• The physical exam is usually sufficient to identify tinea pedis.
• The diagnosis of tinea pedis may be confirmed by microscopy and culture of skin
scrapings. Demonstration of the fungus by microscopic examination of the scrapings taken from
the involved site establishes the diagnosis.
• Material suitable for diagnostic analysis include skin and nail scrapings and infected hair.
• A few drops of a 10% to 20% solution of potassium hydroxide (KOH) are added to the material
on the glass slide. A coverslip is placed over the specimen and examined under the microscope.
• The fungi are observed under the microscope in a KOH preparation. Identification is based on the
morphology of the hyphae as well as on the macroconidia and microconidia in the fungal cultures.
33. TREATMENT/MANAGEMENT
• Improvement of hygiene in swimming pools and bathing areas and frequent washing and
cleaning of changing room floors and walkways may help in controlling the infection.
• Topical treatment is usually adequate for the management in most of the patients. Topical
imidazoles such as clotrimazole, econazole, ketoconazole, miconazole, isoconazole,
tioconazole, and sulconazole are effective remedies in tinea pedis with the very low
incidence of adverse reactions.
34. Tinea corporis (ringworm): Microsporum canis and Trichophyton mentagrophytes.
Affects hairless skin.
Tinea pedis (athlete’s foot): T. rubrum, T. mentagrophytes, and Epidermophyton
floccosum. affects mainly the lower legs.
Tinea capitis: T. tonsurans and M. canis. Affects scalp hair.
Tinea barbae: T. rubrum and T. mentagrophytes. Beard ringworm.
Tinea unguium: T. rubrum, T. mentagrophytes, and E. floccosum. Affects nails
Onychomycosis (nailmycosis): Various dermatophytes and Candida spp.
35. SYSTEMIC MYCOSIS (HISTOPLASMOSIS,
BLASTOMYCOSIS)
• mycotic infections may be systemic, generally originating in the lungs and other
organs.
• Histoplasma capsulatum (Histoplasmosis)
• Histoplasma capsulatum is the pathogen responsible for histoplasmosis, an
intracellular mycosis of the reticuloendothelial system
36. MORPHOLOGY
• H. capsulatum is a dimorphic fungus.
• Fungus grows as a mold in soil and as yeast in human
host
• As an infectious pathogen in human tissues it always
forms yeast cells
• It is transmitted through the inhalation of spores
(conidia) from soil contaminated with bat or bird
droppings
• The small individual cells are often localized inside
macrophages and have a diameter of 2–3 um.
37. EPIDEMIOLOGY
• Histoplasmosis is endemic to the Midwestern USA, Central and South America,
Indonesia, and Africa. With few exceptions, Western Europe is free of the disease.
• The people who work near to river valleys or travellers visiting the caves are
vulnerable.
• The pathogen is not communicable among humans.
38. PATHOGENESIS AND CLINICAL PICTURE.
• Incubation period: 3-17 days
• Spores (conidia) are inhaled into the respiratory tract, are taken up by alveolar macrophages, and become
yeast cells that reproduce by budding. Small granulomatous inflammatory foci develop.
• 90% infections remain asymptomatic or mild influenza like
• Most patients recover spontaneously in 2-3 weeks.
• The pathogens can disseminate hematogenously from these primary infection foci. The reticuloendothelial
system (RES) is hit particularly hard. Lymphadenopathies develop and the spleen and liver are affected.
• The clinical picture depends heavily on any predisposing host factors and the infective dose. A histoplasmosis
can also run its course as a respiratory infection only. Disseminated histoplasmoses are also observed in AIDS
patients. Dissemination, especially to liver and spleen and central nervous system can occur in
immunocompromised patients.
39. • Culture of H.capsulatum from bone marrow, blood, sputum
• Microscopy of yeast in tissue
• Antibody test
• Therapy: Itriconazole
• Treatment with amphotericin B is only indicated in severe infections, especially
the disseminated form.
Diagnosis & Therapy
40. Blastomycosis
Blastomyces dermatitidis is a dimorphic fungus that causes a chronic granulomatous
infection. The pathogens occur naturally in the soil and are transmitted to humans by
inhalation.
The primary blastomycosis infection is pulmonary. Secondary hematogenous spread
can lead to involvement of other organs including the skin. Laboratory diagnostic
methods include microscopy and culturing to identify the fungus in sputum, skin lesion
pus, or biopsy material. Antibody detection using the complement fixation test or agar
gel precipitation is of limited diagnostic value. Amphotericin B is the therapeutic agent
of choice. Untreated blastomycoses almost always have a lethal outcome.
Blastomycosis occurs mainly in the Mississippi Valley as well as in the eastern and
northern USA. Infections are also relatively frequent in animals, especially dogs.
Susceptible persons cannot, however, be infected by infected animals or humans. There
are no prophylactic measures.
41. Paracoccidioides brasiliensis
• Paracoccidioides brasiliensis (syn. Blastomyces brasiliensis) is a dimorphic fungus that,
in living tissues, produces thick-walled yeast cells of 10–30 lm in diameter, most of
which have several buds. When cultivated (25- 28C), the fungus grows in the mycelial
form.
• The natural habitat of P. brasiliensis is probably the soil. Human infections are caused
by inhalation of spore-laden dust. Primary purulent (pus) and/or granulomatous
infection foci are found in the lung. Starting from these foci, the fungus can
disseminate hematogenously or lymphogenously into the skin, mucosa, or lymphoid
organs. A disseminated paracoccidioidomycosis progresses gradually and ends
lethally unless treated. The therapeutic agents of choice are azole derivatives (e.g.,
itraconazole), amphotericin B, and sulfonamides.
42. • Therapy can prevent the disease from progressing, although no cases are known
in which the disease is eliminated over the longer term. Laboratory diagnostics
are based on detection of the pathogen under the microscope and in cultures as
well as on antibody detection with the complement fixation test or gel
precipitation.
• Paracoccidioido mycosis is observed mainly among farmers in rural parts of
South America.
43. OPPORTUNISTIC CANDIDOSIS (SUPERFICIAL
CANDIDOSIS)
• Opportunistic mycoses (OM) that affect skin and mucosa as well as internal organs
are caused by both yeast and molds. A precondition for development of such
infections is a pronounced weakness in the host’s immune defense.
• Candidiasis is an endogenous infection. Other OMs are exogenous infections caused
by fungi that naturally inhabit the soil or plants. These environmental fungi usually
invade via the respiratory tract. The most important are aspergillosis, cryptococcosis,
and the mucormycoses
44. • Besides Candida and other yeasts, phaeohyphomycetes and hyalohyphomycetes,
which are only very mildly pathogenic, can also cause systemic infections. All OMs
have a primary infection focus, usually in the upper or lower respiratory tract.
• From this focus, the pathogens can disseminate hematogenously and/or
lymphogenously to infect additional organs. Infection foci should be removed
surgically if feasible. Antimycotic agents are used in chemotherapy. In infected
immunocompromised patients, the prognosis is usually poor
45. CANDIDIASIS
• Candidiasis is an opportunistic infection caused by Candida, a type of fungi.
• At least 70% of all human Candida infections are caused by C. albicans, the rest by C.
parapsilosis, C. tropicalis, C. guillermondii, C. kruzei, and a few other rare Candida species
• Candida is a form of yeast.
• Candidiasis occurs most commonly as a secondary infection in immunocompromised
individuals. Synonyms of candidiasis include candidosis, moniliasis, and thrush.
• These are common inhabitants in the oral cavity, gastrointestinal tract, vagina penis, or other
parts. They become pathogenic only when favorable conditions arise.
• It can affect the oral cavity, vagina, penis, or other parts of the body.
46. ETIOLOGY
• Candida albicans is present in healthy persons colonizing the oropharyngeal, esophageal, and gastrointestinal
mucosa.
• Candida albicans can cause mucosal candidiasis in these areas where they usually are present in
an immunocompromised host. In patients who have leukemia, lymphoma because of the consumption of
corticosteroids or cytotoxic drugs, their immunity is compromised, leading to candidal infection.
• Antibiotic usage is commonly associated with candidiasis.
• Cancer cytotoxic chemotherapy may result in fungemia caused by Candida albicans, which develop from
fungal translocation through compromised mucosal barriers.
• Vaginal colonization increases in diabetes mellitus, pregnancy, and the use of oral contraceptives.
• Oral candidiasis is very closely associated with HIV patients. More than 90% of patients with HIV present
with candidiasis.
47. EPIDEMIOLOGY
• Candidiasis is more prevalent in old age and infancy. In the US, about 37% of newly born babies
may be affected by thrush during the first few months of life. Children using inhaled steroids also
have a higher incidence of oral candidiasis. In women, it is common during pregnancy. Thrush may
be the first indication of HIV infection. Thrush is universal and is more frequent in populations with
poorly nourishment. Thrush occurs equally in males and females.
• Although Candida albicans is the most prevalent etiology of candidiasis, there has been a
significant increase in non-Candida species in recent times. It is important to know about non-
albicans species as the treatment depends on that, and certain medications like commonly used Non-
albicans Candida may be resistant to fluconazole.
48. • Morphology and culture. Gram staining of primary preparations reveals C.
albicans to be a Gram-positive, budding, oval yeast with a diameter of
approximately 5 µm. Gram-positive pseudohyphae are observed frequently and
septate mycelia occasionally
• C. albicans can be grown on the usual culture mediums. After 48 hours of
incubation on agar mediums, round, whitish, somewhat rough-surfaced colonies
form. They are differentiated from other yeasts based on morphological and
biochemical characteristics
49. a Oral soor; surface infection of cheek mucosa and tongue by Candida albicans
b Chronic mucocutaneous candidiasis in a child
50. • Pathomorphologically similar to oral soor is vulvovaginitis. Diabetes, pregnancy,
progesterone therapy, and intensive antibiotic treatment that eliminate the
normal bacterial flora are among the predisposing factors. Skin is mainly infected
on the moist, warm parts of the body. Candida can spread to cause secondary
infections of the lungs, kidneys, and other organs. Candidial endocarditis and
endophthalmitis are observed in drug addicts. Chronic mucocutaneous
candidiasis is observed as a sequel to damage of the cellular immune system
51. • Diagnosis. This involves microscopic examination of preparations of different materials-
Gram-stained.
• Candida grows on many standard nutrient mediums, particularly well on Sabouraud agar.
Typical yeast colonies are identified under the microscope and based on specific
metabolic evidence.
• Detection of Candida-specific antigens in serum (e.g., free mannan) is possible using an
agglutination reaction with latex particles to which monoclonal antibodies are bound.
• Various methods are used to identify antibodies in deep candidiasis (agglutination, gel
precipitation, enzymatic immunoassays, immunoelectrophoresis).
52. • Therapy
• Nystatin and azoles can be used in topical therapy. In cases of deep candidiasis,
amphotericin B is still the agent of choice, often administered together with 5-
fluorocytosine. Echinocandins (e.g., caspofungin) can be used in severe oropharyngeal
and esophageal candidiasis.
• Epidemiology and prevention
• Candida infections are, with the exception of candidiasis in newborn children,
endogenous infections.
53. DISTINCTIVE PROPERTIES
Mycotic infections are classified by the tissue levels that are
colonized.
• Superficial infections or Primary are generally limited to
the outer layers of the skin and hair.
• Cutaneous infections are located deeper in the
epidermis, hair and nails.
• Subcutaneous infections involve the dermis,
subcutaneous tissues and muscle.
In addition, mycotic infections may be systemic, generally
originating in the lungs and other organs.
Finally, some mycoses are termed opportunistic, and these
may involve a variety of body sites.
The following outlines these different types of mycotic
infection, giving examples of representative agents.
54. MYCOSES
• It can be assumed that cutaneous mycoses are among the most frequent infections worldwide
• Primary and opportunistic mycoses are, on the other hand, relatively rare
• Opportunistic mycoses have been on the increase in recent years and decades, reflecting the fact that
clinical manifestations are only observed in hosts whose immune disposition allows them to develop.
Increasing numbers of patients with immune defects and a high frequency of invasive and aggressive
medical therapies are the factors contributing to the increasing significance of mycoses
• Table 5.2 provides a summary view of the most important human mycoses. The categorization of the
infections used here disregards taxonomic considerations to concentrate on practical clinical aspects
55.
56.
57.
58.
59. HOST-PATHOGEN INTERACTIONS
• The factors that determine the onset, clinical picture, severity, and outcome of a mycosis include
interactions between fungal pathogenicity factors and host immune defense mechanisms
• Compared with the situation in the field of bacteriology, it must be said that we still know little
about the underlying causes and mechanisms of fungal pathogenicity
• Humans show high levels of nonspecific resistance to most fungi based on mechanical, humoral,
and cellular factors
• Among these factors, phagocytosis by neutrophilic granulocytes and macrophages is the most
important. Intensive contact with fungi results in the acquisition of specific immunity, especially
the cellular type. The role of humoral immunity in specific immune defense is secondary
60. • Little is known about fungal pathogenicity factors. The natural resistance of the macro
organism to fungal infection is based mainly on effective phagocytosis whereas
specific resistance is generally through cellular immunity.
• Opportunistic mycoses develop mainly in patients with immune efficiencies (e.g., in
neutropenia). Laboratory diagnostic methods for fungal infections mostly include
microscopy and culturing, in order to detect the pathogens directly, and identification
of specific antibodies.
• Therapeutics for treatment of mycoses include polyenes (above all amphotericin B),
azoles (e.g., itraconazole, fluconazole, voriconazole), allylamines, antimetabolites (e.g.,
5-fluorocytosine), and echinocandins (e.g., caspofungin). Antimycotics are often
administered in combination.
61. SUBCUTANEOUS MYCOSES
• Fungi that cause classic subcutaneous mycoses grow in the soil and on dying plants.
They penetrate through skin injuries into the subcutaneous connective tissue, where
they cause local, chronic, granulomatous infections. These infections are seen mainly in
the tropics and subtropics.
• Sporotrichosis is caused by Sporothrix schenckii, a dimorphic fungus that grows as
yeast cells in host tissues. Sporotrichosis is characterized by an ulcerous primary lesion,
usually on an extremity, and multiple nodules and abscesses along the lymphatic
vessels.
62. • Chromomycosis (also chromoblastomycosis) can be caused by a
number of species of black molds. The nomenclature of these
pathogens is not firmly established. Weeks or months after the
spores penetrate into a host, wartlike, ulcerating, granulomatous
lesions develop, usually on the lower extremities.
• Madura foot or mycetoma can be caused by a wide variety of fungi
as well as by filamentous bacteria (Nocardia sp., Actinomadura
madurae, Streptomyces somaliensis). Potential fungal contributors
include Madurella sp., Pseudoallescheria boydii, and Aspergillus sp.
The clinical picture is characterized by subcutaneous abscesses,
usually on the feet or hands. The abscesses can spread into the
musculature and even into the bones. Fistulae are often formed.
