What are the only prokaryotes that cause dz. in humans and animals?
Bacteria
What are the two forms of fungus?
Mold and yeast
What type of fungus is both saprophytic and yeast-like (pathogenic)?
Dimorphic fungi
What is the cell membrane made out of in fungi?
Sterols (ergosterol)
Do bacteria have sterols like fungi?
No
What is the difference between reproduction in fungi and bacteria?
Fungi are either sexual or asexual while bacteria use binary fission
T/F The cell wall of fungi causes disease?
F
Where do pseudohyphae originate from?
The cell
At what temperature does dimorphic fungi reproduce in tissues? What form?
At 35 degrees celsius, yeast form
Do fungi go through sexual or asexual reproduction more frequently?
Asexual
T/F Fungi do not produce endotoxins or exotoxins?
TRUE
What enzyme is secreted my Dermatophytes?
Keratinase
Define superficial mycoses:
limited to superficial layers of the skin and along the hair shafts. NONDESTRUCTIVE! Only of cosmetic importance
Define Cutaneous mycoses:
Restricted to the keratinized layers of the skin and its appendages. May become symptomatic
Define Subcutaneous Mycoses:
Fungal infections involving the dermis, SQ, muscle, fascia and sometimes bone.
Define systemic mycoses:
Deep within the body. Usually caused by dimorphic fungi
Define opportunistic mycoses:
Low virulence and usually affect the immunocompromised
Which media is best for fungal growth and isolation?
Sabouraud's dextrose agar (SDA)
What are the three species related to Dermatophytes? Which two are of most clinical relevance?
Epidermophyton, Microsporum, and Trichophyton (M and T most important)
Are dermatophytes contagious?
Yes
What is the common name referred to dermatophytes?
Ringworm
Define Geophilic:
dermatophytes found in soil and occasional pathogens of humans and animals
Define Zoophilic:
Parasites of the hair and skin of animals but can be transmitted to humans
Define Anthropophilic:
Parasites of human skin that can be transmitted from human to human
T/F Infected skin or hair can be infective for up to 9 months?
FALSE: 12 MONTHS!
Ring lesions appear because of what healing process?
Central healing with peripheral inflammation.
What is the best location to take a skin sample?
Peripheral to the lesion where a fungus may move to during a healing process.
What type of HS response might you see from Dermatophyte proteins?
Type I
What color is a positive DTM for dermatophytes?
Red (Phenol red is the ph indicator, therefore negative would be yellow in color)
Sporothrix schenckii is what level of mycoses?
Subcutaneous and dimorphic
The main host of S. schemckii:
Horses, humans, dogs and cats
Decribe the pathogenesis of S. schemckii:
yellow pus with cordlike and thickened vessels. Ulcers are cutaneous nodules that develop along the superficial lymphatics
Is S. schemckii ascending or descending?
Ascending
Under direct examination, S schemckii take on what shape?
Cigar shaped yeast cell
Where may S. Schmeckii be found (cell type)?
Neutrophils
Common name for cutaneous pythiosis:
Mycotic Swamp Cancer, Florida HOrse Leeches
EA for pythiosis:
Pythium insidiosum
Mycotic swap fever is most common in:
Subtropical and tropical regions. Infiltrates damaged tissue wading through stagnant, swamp water
T/F pythiosis can infiltrate the blood stream and disseminate?
T
What are the skin lesions like in pythiosis?
pyogranulomatous
Canine pythiosis mostly involves:
The stomach and SI with signs of cutaneous lesions
Is pythiosis self-limiting?
No. Surgery is necessary
The pathogenic yeast candida albicans infects mostly by:
endogenous origin
Cadididiasis is also known as:
monilliasis, Thrush, candidosis
What are some predisposing factors to candidiasis?
Immunnosupression
Prolonged use of broad spectrum antibiotics
mucosal damage
intercurrent infections
Pathogenesis of thrush:
ulcerative inflammation of the mucous membranes, esophagus, crop etc.
What pathognomonic lesion would you see in candidiasis of chickens, turkeys and pigeons?
the terry toweling effect of yellowish grey necrotic tissue in the crop and esophagus
What is the only yeast that has a capsule?
Cryptococcosis (Torulosis)
Another name for cryptococcosus:
Torulosis
What is a common finding in cats infected with cryptococcosis?
Blindness
Cryptococcosis can disseminate where?
To the CNS-then to the optic nerve causing blindness
What stain highlights the thick capsule of cryptococcosis?
Indian ink
How long can pigeons carry cryptococcosis without developing signs?
1 year
What is found in pigeon feces that cryptococcosis utilizes?
Creatinine
What specimens can be used to diagnose cryptococcus?
Milk, blood, CSF, exudates, and tissues
Which yeast cells are shaped like a bottle?
Malassezia pachydermatis
M pachydermatis is attracted to what type of tissues?
oily areas of skin because they are lipophylic
Cigar shaped yeast cells?
Sporothrix shenckii
What percentage of aspergillosis is caused by A. fumigates?
90-95%
What is the pathogenesis seen with Aspergillosis?
yellowish-grey nodules on respiratory tissue
EA for Brooder pneumonia:
Aspergillus fumigatus
Which stage of aspergillosis has CNS involvement?
Acute
What species of dimorphic fungi do we have?
Blastomyces dermatidis
Coccidiodes immitis
Histoplasma capsulatum
Blastomyces dermatidis-
affects humans and dogs, not contagious, thick double cell wall, can be fatal
Coccidiodes immitis-
San Jaochim Valley Fever, affects dogs, horses and humans, barrel-shaped, can be fatal, mature endospores are only found in tissue
Histoplasma capsulatum-
found in bat and bird feces and the yeast cells grow in monocytes and macrophages, impaired cell mediated immunity in cats and dogs, more prevalent in eastern US
Mycotic abortion EA's:
Aspergillus spp.
Candida spp.
Mucor spp.
Mycotic mastitis EA's:
*Cryptococcus spp.
*Candida spp.
Aspergillus spp.
T/F mycotic mastitis infections move from quarter to quarter?
F
Guttural Pouch Mycoses EA's
Aspergillus but think Bacterial first (Strep equi)
Mycotic Keratitis EA's:
Blastomyces or Cryptococcus (Systemis dissemination)
What is the most potent natural carcinogen?
B1 aflatoxin
In ergotism, what is ingested to result in the pathogenic lesions?
Sclerotia
Which species is most susceptible to agalactia in ergots?
Swine
What are the three requirements for photosensitization?
Hepato-toxic plant
phylloerythrin (photosensitizing pigment) from plants
UV exposure
What is the pathogenesis of photosensitization?
Chollangitis and pericholangitis leading to biliary obstruction
What is the etiologic agent for estrogenism? What species is most susceptible?
