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Biodefense
Reference Library
Foreign
Animal and Zoonotic Disease Center
Zoonotic
Disease Online Course
Presented
by
Stephen M.
Apatow, Director
of Research and Development
Humanitarian
Resource Institute
Biodefense Reference Library
Foreign
Animal and Zoonotic Disease Center
[Vitae][Email]
ZOONOTIC
DISEASES
FUNGAL
DERMATOMYCOSES
Centers
for Disease Control and Prevention: Division of Parasitic Diseases
Ringworm...Microsporidiosis
Disease
Overview:
Institutional
Animal Care and Use Committee, University of California, Santa
Barbara.
(Ringworm,
Dermatophytosis, Tinea, Trichophytosis, Microsporosis, Jock Itch,
Athlete's
Foot)
AGENT:
Organisms
are subclassified into: 1. Geophilic - inhabit soil 2. Zoophilic -
parasitic
on animals 3. Anthropophilic - Primarily infects humans All can produce
disease in humans. Grouped in three genera 1. Microsporum 2.
Trichophyton
3. Epidermophyton
RESERVOIR
AND INCIDENCE
Fungal
spores remain viable for long periods on carrier animals and fomites.
Exposure
to reservoir hosts harboring different dermatophytes determines the
type
and incidence of infection in humans. Microsporum canis can be carried
by up to 89% of nonsymptomatic cats. Up to 50% of people exposed to
infected
cats, both symptomatic and asymptomatic, have acquired infection. Pets
may also acquire disease from humans. **T. mentagrophytes is most
commonly
transmitted to man from rodents, M. canis from dogs and cats, and T.
verrucosum
from cattle and horses.
TRANSMISSION:
Direct
or indirect contact with asymptomatic animals or with skin lesions of
infected
animals Contaminated bedding Equipment Fungi in air, dust, or on
surfaces
of room (spores persist on contaminated surfaces).
DISEASE
IN ANIMALS:
In rodents
is often asymptomatic and not recognized until people are affected. In
cats is often asymptomatic. Dogs often show classic skin lesions.
Varying
severity of dermatitis occurs with local loss of hair. Deeper invasion
produces a mild inflammatory reaction which increases in severity with
the development of hypersensitivity.
DISEASE
IN MAN:
Often
mild, self limiting; scaling, redness, and occasionally vesicles or
fissures.
Thickening & discoloring of nails. May show circular lesions which
clear in the center forming a ring. Fungal infections in man are
categorized
as to the location on the body: 1. Tinea capitis - Scalp & hair 2.
Tinea corporis - Body (extremities, arm and hand, are most often
affected
in infections acquired from lab animals.) 3. Tinea pedis - foot 4.
Tinea
unguium - Nails.
DIAGNOSIS:
KOH mount
of skin scrapings, Fungal culture.
TREATMENT:
Macerated
(moist softening and fissuring) stage- aluminum subacetate ("Domeboro")
solution soaks with potassium permanganate for secondary infections.
Athlete's
feet may respond better to 30% aqueous aluminum chloride or the
carbol-fuchsin
paint than to antifungal agents. Broad spectrum antifungal creams and
solutions
containing imidazoles or ciclopirox) instead of tolnaftate and
haloprogin
help to combat diphtheroids and other gram-positive organisms present
at
this stage and alone may be adequate therapy. Dry and scaly stage-
several
topical creams, liquids, or lotions are recommended (miconazole,
clotrimazole,
ketoconazole, econazole, sulconazole, oxiconazole, ciclopirox or
naftifine.
Betamethasone dipropionate with clotrimazole is recommended for acutely
inflamed tinea lesions. For severe cutaneous infections, griseofulvin
or
ketoconazole is recommended.
PREVENTION/CONTROL:
Screen
newly received animals. Routine sanitization of contaminated
environment,
equipment, and caging. Gloves, protective clothing, wash hands after
exposure.
SPOROTRICHOSIS
Centers
for Disease Control and Prevention: Division of Bacterial and Mycotic
Diseases
Sporotrichosis
Disease
Overview:
Institutional
Animal Care and Use Committee, University of California, Santa
Barbara.
AGENT:
Sporothrix
schenckii, dimorphic fungus.
RESERVOIR
AND INCIDENCE
Distributed
worldwide with sporadic outbreaks. Saprophyte that grows on soil or
vegetation.
Has been reported in horses, dogs, cats and many other species. 19
cases
of Sporotrichosis have been reported in man following contact with
feline
abscesses or ulcers (12 of these were veterinarians).
TRANSMISSION:
Penetrating
injury, or contact with plant or soil. Transmission from feline to man
by direct contact with lesions (penetrating injury NOT required).
Inhalation
can lead to pulmonic disease.
DISEASE
IN ANIMALS:
Lesions
can be anywhere but are usually located on distal extremities, head, or
base of tail. Appear as draining puncture wounds, cellulitis. Can
ulcerate
and become nodular with seropurulent exudate. May cavitate and expose
muscle
and bone. May lead to disseminated disease which is usually fatal.
DISEASE
IN MAN:
The most
common clinical form is cutaneolymphatic; it begins with a nodule or
pustule
at the point where broken skin allowed inoculation. The infection may
remain
confined or may eventually spread and produce SC nodules along the
enlarged
lymph ducts. These nodules may ulcerate, and a gray or yellowish pus
appears.
Disseminated forms, which are rare, may give rise to localizations in
different
organs, especially the bones and joints, as well as in the mouth, nose,
kidneys, or the SC tissue. Pulmonary sporotrichosis can be confused
with
TB.
DIAGNOSIS::
Biopsy
and histo fungal culture cytology of impression smear of exudate.
Organisms
are numerous in cats but are difficult to detect in man, horses, and
dogs.
Organism can also be found in feces of infected cat. Antigen tests are
used to diagnose disseminated disease.
TREATMENT:
Potassium
iodide, Amphotericin B, or itraconazole.
PREVENTION/CONTROL:
Gloves
when handling infected animals. Wash with iodine or chlorhexidine.
CRYPTOCOCCOSIS
AND HISTOPLASMOSIS
Centers
for Disease Control and Prevention: Division of Bacterial and Mycotic
Diseases
Cryptococcosis...Histoplasmosis
Disease
Overview:
Institutional
Animal Care and Use Committee, University of California, Santa
Barbara.
Cryptococcosis
and histoplasmosis are systemic fungal infections caused by the
organisms
Cryptococcus neoformans and Histoplasma capsulatum. Cases of infection
are worldwide and sporadic. These organisms are found in soil, pigeons,
and starlings and are spread in bird feces. These systemic fungi have a
predilection for the lung and central nervous system. There is an
increased
susceptibility in humans on steroid therapy and with disorders of the
reticuloendothelial
system.
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