SQ and Systemic Mycoses Flashcards
1
Q
Which type of fungi (generally) are involved in eumycotic mycetomas, pheohyphomycosis, SQ hyalohyphomycosis, zygomycosis?
A
Saprophytic fungi
-SQ
-Traumatic implantation
-Localized
-Slow spread
2
Q
Geography of Eumycotic mycetomas
A
Worldwide. Most frequent near Tropic of Cancer
3
Q
Geography of phaeohyphomycosis
A
Worldwide
4
Q
Where are Pheohyphomycosis organisms located (zoophilic, anthrophilic, etc)
A
Soil, wood, vegetation
OCCASIONALLY can be found on skin of healthy people and animals
5
Q
Geography of Sporothrix schenckii
A
Tropical, subtropical, temperate zones
Central, South America
Africa
Esp Brazil
6
Q
Geography of Oomycosis in the USA
A
Gulf coast of US
Otherwise, tropical/subtropical
7
Q
Season of oomycosis
A
Late summer, fall
8
Q
Climate of Zygomycosis
A
Tropical/subtropical
9
Q
Most common organisms causing a eumycotic mycetoma
A
Saprophytes
BLACK GRAIN
*Curvularia geniculata
*Madurella
WHITE GRAIN
*Acremonium
*Pseudallescheria
10
Q
Black grain mycetomas organisms
A
*Curvularia geniculata
*Madurella
11
Q
White grain mycetomas organisms
A
*Acremonium
*Pseudallescheria
12
Q
Phaeohyphomycosis’ other name
A
Chromomycosis
From PIGMENTED fungi
13
Q
White animals develop phaeohyphomycosis
A
Cows, horses, cats
RARE in dogs
14
Q
Phaeohyphomycosis organisms
A
Pigmented soil saprophytes. Can be normal animal flora. Dark walled, septate hyphae
*Alternaria
*Drechslera
*Exophiala
*Phialophora
*Bipolaris
(Cladosporium
*Curvularia
*Wangiella
15
Q
Hyalohyphomycosis’ other names
A
Paecilomycosis
Adiaspiromycosis
NONPIGMENTED fungi
16
Q
Hyalohyphomycosis Organisms
A
Nonpigmented fungi w/ septate hyphae
*Pseudallscheria
*Acremonium
*Fusarium
*Paecilomyces
*Geotrichum
*Aspergillus
17
Q
Sporotrix species within Sporothrix schenckii complex
A
*Sporothrix brasiliensis
*Sporothrix schenckii
*Sporothrix globosa
*Sporothrix luriei
18
Q
At what temperature is Sporothrix a yeast? At what temperature is Sporothrix a hyphae
(Dimorphic)
A
Yeast in TISSUE
Hyphae at ENVIRONMENTAL temperatures
19
Q
Name 2 dimorphic water molds
A
*Pythium insidiosum
*Lagenidium
Oomycosis
20
Q
What is “leeches” “bunkers” “Swamp cancer” “bursattee”
A
Pythium insidiosum
21
Q
Why is Pythium not a true fungus
A
1) NO CHITIN in cell walls
-Instead: cellulose, B-glucan
2) NO ERGOSTEROL in cell membrane
3) Sexual process = oogamy
4) Infective biflagellate zoopspores in wet environments
22
Q
2 infections classified as Zygomycosis
A
Entomophthoromycosis
Mucormycosis
23
Q
Entomophthoromycosis (Zoopagomycota) organisms
A
Basidiobolus
Conidiobolus
24
Q
Mucormycosis organisms
A
Order Mucorales
Rhizopus
Mucor
Lichthimia
Sakenaea
VERY uncommon in small animals
25
Species (and 1 breed) most likely to develop pheohyphomycosis
Cats >>>>
GSD dogs are predisposed
26
Which fungus can be spread via inhalation or trauma
Zygomycosis (Entomophthoromycosis, Mucormycosis)
27
Which fungus can be spread by free-standing water exposure or minor skin wounds
Oomycosis
28
How do oomycoses encyst in the skin
Zoospores contact skin, mucosa and encyst via a sticky glycoprotein (adhesion)
Germ tube (hypha) development is stimulated by host body temperature
Invade blood vessels
Proteases weaken host tissue
29
Characteristics of mycetomas (3)
1) Tumefaction (swelling)
2) Draining tracts
3) Grains (aggregates of fungi)
30
Clinical lesion of pheohyphomycosis
Pigmented nodule on face (nose, pinnae) and paws of cats
Can be mistaken for melanoma
31
Clinical lesions of hyalohyphomycosis
Well circumscribed ulcers or nodular masses
-Claws
-Head
-Eyes
-Joints
32
Sporotrichosis: 3 clinical forms
1) Primary cutaneous form (nodules or plaques at point of entry)
2) Cutaneous- lymphatic form (thick, corded)
3) Disseminated form
33
Which clinical form of Sporotrichosis is most common in humans and horses
Cutaneous-lymphatic form
34
Which species develop pythiosis
Horses, Cattle, Dogs, Cats
35
Which species develop lagenidiosis
Dogs
36
Species that develops Basidiobolus
Horse
37
Species that develops Conidobolus
Horses, llamas, sheep, dogs
38
If a cat has Sporotrichosis that spread to its joints (w/fever, anorexia), is the cat immunosuppressed?
Not necessarily! Disseminated Sporotrix does not require immunosuppression
39
Signalment for Pythiosis
Young, large breed dogs
40
Labwork finding common in pythiosis
Eosinophilia
41
Who is this
Sporothrix schenckii
Ovoid to cigar-shaped
42
Diagnosis of eumycotic mycetoma or pheohyphomycosis
Culture
43
Diagnosis of Sporotrichosis
1) Tissue culture (Sabouraud's agar: white mold that turns brown as pigmented conidia grow.)
2) IHC
3) Antibody immunofluorescense
44
Diagnosis of pythiosis
1) ELISA (monitor response to treatment. Decreased Ab in 2-3 months after treatment)
2) Culture (careful!)
3) PCR
45
Diagnosis Lagenidiosis
1) Culture from fresh tissue
2) RNA gene sequencing
46
Why are dimorphic fungi dangerous to culture?
Mycelial phase is infective to humans
47
T or F: Splendore Hoeppli will be seen on Sporotrix histopath
True
48
Which species will have MORE Sporotrix organisms visible on histopath? Which typically has FEW organisms visible?
MORE: Cats
LESS: Dogs, hrses
49
T or F: Pythium can be visualized on histopath with PAS
FALSE. Cell walls lack chitin
50
Best stain to visualize Pythium
GMS
(thin splendore hoeppli)
51
Best stain to visualize Zygomycosis
GMS
Stain poorly with PAS
Similar to oomycosis, but CAN be treated with antifungals.
(thick splendore hoeppli)
52
T or F: cutaneous eumycotic mycetoma may be fatal
False. Not life-threatening
53
T or F: Surgical excision of phaeohyphomycosis is usually curative
False. Recurrence is common
Make sure you d/c immunosuppressive meds!
54
T or F: Hyalohyphomycosis is typically fatal if generalized
True. Disseminated + CNS signs are grave.
Systemic antfungals only help short turn.
Localized lesions only? Tx with surgery
55
Treatment of Sporotrichosis in cats
Itrafungol >2 months. But difficult
56
Treatment of Sporotrichosis in dogs, horses
Potassium iodide
*Toxic Iodize AE: oculonasal discharge, vomiting, collapse. D/C KI for 1 week then restart at lower dose
-Ketoconazole, terbinafine, amphotericin B, local hypothermia, surgical resection. Continue 1 mo past clinical cure
57
Oomycosis prognosis, best treatment option
Prognosis = poor
Tx = wide surgical excision, amputation. AND itraconazole or terbinafine (but no ergosterol, so not great)
Consider Capsofungin (targets beta-glucan in cell wall)
58
T or F: Sporothrix is zoonotic. Isolate infected cats
TRUE
59
T or F: Oomycosis is zoonotic
FALSE. Infective zoospores only form in water, not in tissue
60
T or F: If an animal has cutaneous Histoplasma capsulatum, you should assume they have systemic infection
True.
True for Blasto, Coccidiodes, Crypto, and Histoplasma
61
Where in the USA is Blastomyces dermatidis most common
*Mississippi, MO, Ohio river valley, mid-Atlantic states, Eastern Canada
*Likes moist soil, like beaver dams. Spread when soil is disrupted
62
Dogs at higher risk for Blastomycosis
Sporting dogs, hounds
Do not have to be immunocompromised
63
Mode of transmission of Blastomycosis
1) Inhale conidia --> airway mucosa --> bind alveolar macrophages (adhesins aka BAD1)
2) Spread of conidia via leukocyte trafficking
3) Acute inflammation, tissue damage. Mediated by macrophages
64
Blastomyces adhesion factor that can cause phagocytosis of conidia
BAD1
65
Immune response needed to clear Blastomycosis
T-cell mediated
Directed to BAD-1 (adhesin)
66
Where is Blastomycosis commonly found, other than the skin
Lungs (85%)
67
Diagnosis of Blastomycosis
Urine ELISA is best!
Serology: 41-90% sensitive, 90-100% specific
68
Who is this
Blastomyces dermatitidis
Thick walled yeast, broad-based buds
69
Treatment Blastomyces dermatitidis
Itraconazole is the best
Amphotericin B: nephrotoxic. Can be life saving if needed. Given IV
Fluconazole for urinary tract disease-- excreted in urine
Low dose GCs to help with severe lung inflammation
70
Blastomycosis virulence factors
*BAD1: mediates adherence to CD3, CD14. Decreases TNFa (needed for phagocytosis and disease clearance)
*Cell wall glucans
*Melanin helps resist phagocytosis and killing
*Change polysaccharides on surface to evade immune system; can hide in phagosomes
71
Coccidiodes immitis, "Valley fever" USA geography
SW US, esp AZ
sporulate after rain --> Arthroconidia are then spread via the wind
72
Predisposed dogs to Coccidiodes immitis
*Young, male dogs
*Boxers, Dobermans
+/- immunocompromised (more severely affected)
73
What protects Coccidiodes immitis from phagocytosis
Spherules -- too large to be phagocytosed + virulence factors to cause inflammation (mucosal injury and colonization)
Arthroconidia become spherules rapidly upon entering airway
74
What happens inside Coccidiodes immitis spherules
Endosporulation
When spherules are damaged, endospores are relased and phagocytized by macrophages --> endospores WITHIN macrophages
75
Most common form of Coccidiodes immitis infection in cats
Skin lesions (nodules w/draining tracts)
76
Most common form of Coccidiodes immitis infection in dogs
Low grade lower respiratory infection
77
Who is this
Coccidiodes immitis
Spherules with thick wall +/- endospores
78
Who is larger: Blastomyces dermatitidis or Coccidiodes immitis
Coccidiodes immitis is MUCH larger.
Coccidiodes also may have endospores; Blasto will not
79
Best stain to visualize Coccidiodes immitis spherules
Pap stain
(capsular wall = refractile, purple-black. Cytoplasm= yellow. Endospores = red-brown)
Can also use PAS, Wrights stain
80
T or F: high Coccidiodes immitis IgG titers correlate with more severe disease
False.
There should be IgM within 2-5 weeks; IgG within 8-12 weeks.
81
Treatment Coccidiodes immitis
Fluconazole for >1 year
(CNS penetration)
Lifelong immunity once animal recovers!
82
Virulence factors Coccidiodes immitis
*Spherule outer wall glycoprotein: limits cell mediated immunity
*Host tissue arginase I, Coccidiodal urease (tissue damage)
*Laminin and collagen on surface = receptors for fungal ligands; enhances adhesion
83
Predisposed breeds for Cryptococcus
Dobermans, GSD, Cocker spaniel
Siamese, Abyssinians
More common in immunocompromised, but can happen in healthy animals
84
2 species of Cryptococcus (1 worldwide and from pigeon poop, 1 tropical and ubiquitous in environment)
Cryptococcus neoformans: worldwide, pigeon poop
Cryptococcus gatti: tropical/subtropical, ubiquitous in environment
85
What for is the Cryptococcus neoformans in when it is inhaled by the host
Basidiospores or blastoconidia
Germinate into yeast in tissue
86
What enzyme do Cryptococcus neoformans yeast have to survive in mucosae?
Glucosylceramide synthase
87
What comprises the Cryptococcus neoformans capsule
1)Glucuronoxylomannan
2) Galactoxylomannan
(polysaccarides)
88
Where do Cryptococcus neoformans make their capsule
Within phagosomes of macrophages.
Macrophages become distended wit hthe capsule.
89
Other common clinical signs with Cryptococcus neoformans (other than nodules)
CNS, ocular, osteomyelitis
90
Most common clinical presentation of Cryptococcus neoformans in cats
Intranasal granulomatous disease (80%)
91
Who is this
Cryptococcus neoformans
Yeast w/narrow based budding
Mucinotic capsule (refractile halo)
92
Culture media that can discern Cryptococcus neoformans from Cryptococcus gatti
Canavanine-glycine-bromothymol blue agar (CGB).
C. gatti turns the agar blue
93
What antigen does the latex agglutination test use for Cryptococcus neoformans
Polysaccharide capsule antigen
(latex particles coated with anticryptococcal ab)
94
Stain to visualize capsule of Cryptococcus neoformans
Mucicarmine, Alcian blue
(PAS, methenamine silver, Fontana masson will stain organism, but not capsule)
95
Best treatment for Cryptococcus neoformans
Amphotericin B.
Can work for CNS, despite poor penetration. Stimulates host immunity
BUT Fluconazole is great (CNS and urinary excretion)
96
Virulence factors for Cryptococcus neoformans
*Phospholipase: injury alveolar type II epithelial cells, limit surfactant production, enhance adhesion, affects phagocytosis
*Polysaccharide capsule: antiphagocytic, immunosuppressive, complement depletion, inhibits leukocyte chemotaxis
*Melanin: yeast survival during CNS infection. Antioxidant.
97
Histoplasmosis geography
Worldwide. Center of USA
98
Breeds Histoplasmosis
Pointer, weimeraner, Brittany Spaniel, Working dogs
99
Mode of transmission Histoplasmosis
Inhalation of microconidia
100
Histoplasmosis immune response
*Turn from microconidia to yeast in tissue to avoid death by phagocytosis
*Yeast produce proteins to inhibit acidification of Phagolysosomes. Spread via macrophages.
101
Common signs (other than cutaneous) for Histoplasmosis
GI (large bowel diarrhea)
102
Who is this
Histoplasma capsulatum
VERY SMALL
Round, basophilic center with a halo (shrinkage from stianing)
103
Treatment Histoplasmosis
Itraconazole +/- GCs for >4-6 months
Consider Amphotericin B
Voriconazole, Posaconazole
104
Histoplasmosis virulence factors
*Heat shock proteins 70, 83
*M phase cell cycle enzymes
*Tubular proteins
*Cell wall chitin when in yeast form
*When phagocytosed, yeast RAISE the pH by releasing urease, ammonia, bicarbonate --> Absorb Fe).
*Yeast produce IL-4, interferes with immune resopnse
*Melanin
105
What stain is this
Gomori's methenamine silver -- GMS (Pythium organisms)
106
Signalment of cats that are predisposed to Sporothrix
Young adult, male, intact
Outdoor access
Fighting --> affects nose and limbs (also respiratory tract)
107
Where are nodules from Conidiobolus typically formed on the body
Nares, nasal passages
Horses, dogs >>> cats
Ulcerative
108
How can you differentiate Entomophthoromycosis from oomyctes on histopath
BOTH have eosinophilic sleeve around the organisms
BUT
Basidiobolus/Conidiobolus will stain with PAS (and GMS), and Oomyctes only stain with GMS
109
Which is more likely to cause pulmonary nodules and vascular invasion: Lagenidium or Pythium
Lagenidium
110
"Kunkers"
Massive of necrotic debris 2' Pythium in horses
111
What has a better prognosis: Lagenidium or Paralagenidium
Paralagenidium. Usually slowly progressive; limited to cutaneous or SQ lesions (not lungs, vessels)
112
Structures of dimorphic fungi in tissue vs in culture
Tissue: Yeast/spherules
Culture: Hyphae
113
Name 5 dimorphic fungi important in vet med
1) Blastomycosis
2) Histoplasmosis
3) Coccidiomycosis
4) Sporotrichosis
5) Cryptococcus
114
Which dimorphic fungus is most commonly associated with puncture or wound contamination, rather than inhalation
Sporothrix
115
Which cell do most dimorphic fungi live in
Macrophages
116
Which dimorphic fungus has a tropism for bone, with most cutaneous lesions over a site of osteomyelitis
Coccidiodes
117
Which histopath stain can stain LIVING fungi ONLY? Which stain can stain BOTH living AND dead fungi
Living only: PAS
Living AND dead: GMS
118
What characterizes chromoblastomycosis
Sclerotic bodies or Medlar bodies
= large, rounded, thick-walled fungal cells
Pigmented
119
T or F: the SAME fungal organisms that cause pheohyphomycosis and hyalohyphomycosis can cause eumycotic mycetomas
TRUE
To be a mycetoma, they need to make tissue grains!
