Infectious diseases Flashcards
1
Q
Describe the pathogenesis of Brucella canis
A
Infects phagocytes and suppresses TNF-alpha –> disrupts bactericidal activity of NK cells and macs–> replicates within cell –> bacteremia
2
Q
How does Brucella canis infect canine hosts?
A
Penetration through mucous membranes (vaginal discharge and semen have highest concentration of organisms)
3
Q
What are the most common signs of canine Brucellosis?
A
Reproductive failures, abortion
4
Q
Describe the acid-fast staining pattern of Actinomyces
A
Non-acid-fast
5
Q
Where is actinomyces normally found?
A
It is normal flora in the oral cavity, GIT, and genital tract
6
Q
Describe typical lesions of actinomycosis in dogs
A
Cervicofacial or truncal/limb SQ nodules, pneumonia and pyothorax may be seen
7
Q
Describe typical clinical signs of actinomycosis in cats
A
Pyothorax> SQ lesions
8
Q
Describe the culture characteristics of actinomyces
A
Fastidious and can be difficult to grow on culture, should be grown anaerobically
(positive culture does not mean disease since it’s a commensal)
9
Q
Describe cytologic findings for actinomyces
A
Suppurative to pyogranulomatous inflammation, dense mats of filamentous bacteria, sulfur granules
10
Q
What is the treatment of choice for actinomyces?
A
High doses of penicillins for prolonged periods of time (other options: clinda, doxycycline, erythromycin, chloramphenicol are options), +/- surgery
11
Q
What is the prognosis for actinomyces?
A
Low mortality, cure rate as high as 90%
12
Q
Describe the acid-fast staining pattern of Nocardia
A
partially acid-fast
13
Q
Is Nocardia an aerobe or anaerobe?
A
Aerobe
14
Q
Where is Nocardia typically found?
A
Soil saprophyte, fresh and salt water, decaying plant matter
15
Q
What is a predisposing factor to the development of Nocardiosis?
A
immunosuppression or other comorbidity (this is less common in cats)
16
Q
Describe the culture characteristics of Nocardia
A
Usually cultured, aerobic, Sabouraud’s or blood agar
17
Q
What is the treatment of choice for Nocardia?
A
Surgery and antibiotics (sulfas)
18
Q
What is the prognosis for Nocardia?
A
Guarded, moderate to high mortality
19
Q
What are the 4 clinical forms of Actinomyces infection?
A
Cervicofacial, thoracic, abdominal, SQ
20
Q
How is Nocardia acquired?
A
Inhalation or inoculation
21
Q
Where would Nocardia be expected to be more prevalent geographically?
A
SW US, Australia (dry, dusty, windy)
22
Q
What are the clinical forms of Nocardia infection?
A
Pulmonary
Disseminated
Cutaneous/SQ
23
Q
Are sulfur granules more common with Actinomyces or with Nocardia?
A
Actinomyces - sulfur granules on FNA should prompt suspicion of Actinomyces
24
Q
How does Nocardia spread?
A
Direct or hematogenous
25
How does Actinomyces spread?
Direct via adjacent tissue
26
What antibiotic could be considered if you are struggling to differentiate between Nocardia and Actinomyces?
doxycycline
27
What do anaerobic bacteria fail to produce that prevents their growth in oxygen?
They don't produce superoxide dismutase
28
What part of gram-negative anaerobic bacteria results in inflammation?
LPS with endotoxic activity (responsible for endotoxic shock in septicemia)
29
What part of gram-positive anaerobic bacteria results in inflammation?
Thick peptidoglycan layer
30
What are the cell wall components of fungi?
Manno-proteins, beta-glucan, chitin
31
Will Mycoplasma stain with gram stain?
No because it lacks a cell wall (this lack of cell wall also makes it resistant to cephalosporins and penicillins)
32
What organism has a "fried egg" appearance on culture media?
Mycoplasma
33
What is the defining characteristic of L form bacteria?
They lack a cell wall
34
What antibiotics would you consider using to treat L form bacteria?
Macrolides, tetracyclines, chloramphenicol, FQ (resistant to beta lactams due to lack of cell wall)
35
What strain of Streptococcus is likely to be more pathogenic?
beta-hemolytic (Groups A, B, C, E, G, L, M)
36
Where is a dog or cat likely to acquire group A Strep?
Humans (shedding via respiratory droplets; S. pyogenes, S. pneumoniae)
37
What species of Strep has been implicated in canine and feline necrotizing fasciitis?
Strep canis (Group G)
38
What are the virulence factors in Strep canis?
Streptolysin O gene, M-protein (inhibits phagocytosis by neutrophils and macs)
39
What antibiotic has been implicated in triggering Streptococcal toxic shock syndrome?
Enrofloxacin
40
Is Streptococcus gram positive or gram negative?
Gram positive
41
How does the cell wall of gram-negative bacteria differ from that of gram-positive?
Gram negative: thin peptidoglycan layer surrounded by an outer lipopolysaccharide layer (LPS)
Gram positive: thick peptidoglycan layer but no outer layer
42
What is the virulence factor of Rhodococcus equi in horses?
Plasmid that encodes virulence protein VapA, allowing it to persist within macrophages
43
Define the bacterial characteristics of Erysipelothrix rhusiopathiae
Gram-positive, facultative anaerobe, rod-shaped
44
Define the pathogenesis of Dermatophilus congolensis
Motile zoospore attracted to CO2 on skin surface --> germinates on skin to produce a filament which invades epidermis and proliferates
45
What culture media should be used for Dermatophilus?
Blood agar (Not MacConkey or Sabouraud's)
46
What category of Staph tends to have higher virulence and is therefore a good indicator of pathogenic potential?
Coagulase positive (Staph aureus, Staph pseud, Staph schleiferi subsp coagulans)
47
What specific type of coagulase negative Staph has a higher potential to be pathogenic compared to other CoNS?
Staph schleiferi subsp scheiferi
48
Name 5 characteristics of the skin that make dogs more susceptible to pyoderma than cats and humans.
1) Thin skin
2) Compact stratum corneum
3) lack of intercellular lipids
4) lack of lipid follicular plug
5) higher pH
49
How does Staph hyicus cause disease in pigs?
Exfoliative toxins (Exh, SHET) digest desmoglein-1 in the epidermis
(Greasy Pig Disease)
50
What species serves as a reservoir for MRSA in the US?
Horses (harbor MRSA strain USA 500)
51
In what cell type would you find Bartonella?
RBC
52
What is the best diagnostic test for Bartonella?
Blood culture, tissue culture
53
What is the primary species of Borrelia isolates in the US?
B. burgdorferi (Lyme disease)
54
What is the vector for Borrelia?
Ixodes scapularis/Deer tick/Black-legged tick
(and other Ixodes ticks)
55
Describe the pathomechanism of transmission of Borrelia from tick to host
Spirochetes multiply in tick while attached to reservoir host --> crosses tick gut into hemolymph --> disseminates to tick salivary glands --> inoculated into host dermis during bite --> spirochetes replicate and migrate through skin
56
What proteins allow for spirochetes to migrate from tick mid-gut to salivary gland before inoculating into the host skin?
Downregulation of OspA (outer surface protein) and increased expression of OspC (blocks clearance of spirochetes so they can disseminate)
57
What species are the reservoir for Borrelia?
Mammals (esp white footed mouse and other small mammals), birds
58
How long does a tick need to be attached in order to spread Lyme disease?
24-48 hours
59
What does a SNAP4Dx detect in Lyme disease?
presence of antibodies to the C6 peptide of Borrelia (encoded by the IR6 gene sequence in the variable surface lipoprotein component)
60
In what cell type would you find Ehrlichia?
leukocytes
61
What is the primary vector for Ehrlichia?
Rhipicephalus sanguineus (Brown dog tick)
62
What are the dermatologic signs of Ehrlichia?
Petechiation, ecchymoses
63
In what cell types would you find Anaplasma?
Leukocytes, RBCs, endothelial cells, platelets
64
What are possible dermatologic signs of RMSF?
Edema and hyperemia of lips, penile sheath, scrotum, pinnae, extremities; vesicles and macules on buccal mucosa, cutaneous necrosis
65
What are the clinical signs of impetigo?
Non-follicular superficial pustules (usually glabrous areas)
66
What organisms would you expect to find in necrotic skin with crepitus?
Bacteroides, Clostridium (gas-producing bacteria)
67
What is the most common bacteria found in bite wounds?
Pasteurella multocida
68
Is Staph gram positive or gram negative?
Positive
69
True or false: M. canis is part of the normal skin microbiome of dogs and cats
False
70
What cat breed is predisposed to dermatophytosis?
Persian
71
What dog breeds are predisposed to dermatophytosis?
Yorkie
Working dogs (GSP, fox terrier, Lab, etc)
72
True or false: FIV and FeLV affected cats are at increased risk for dermatophytosis
False
73
What is the infective form of dermatophytes?
Arthrospores/arthroconidia
74
What is the typical source of Trichophyton infection?
Rodents and rodent burrows
75
What is the typical source of Microsporum gypseum infection?
Contaminated soil
76
What is required in order for dermatophytes to cause infection?
Skin microtrauma
77
What endoproteases are secreted by dermatophytes?
Subtilisins
Fungalysins
78
What is the function of fungal exoproteases?
Digest keratin into peptides and AAs
79
What type of immune response is necessary to cure dermatophytosis?
Cell-mediated
80
What type of dermatophyte lesion is associated with tissue grains?
Pseudomycetomas
Mycetomas
81
What genus of dermatophyte fluoresces?
Microsporum (plus T. schoenleinii)
82
What causes fluorescence of M. canis?
Pteridine within hair cortex/medulla
83
True or false: Hair shafts can fluoresce even when dermatophyte infection is cured.
True
84
What is the recommended mounting medium when examining trichogram for dermatophyte spores?
Mineral oil
85
True or false: The combination of miconazole and chlorhexidine is more effective against dermatophytosis than either ingredient alone.
True
86
What are the currently recommended topical treatments for dermatophytosis and how often should they be applied?
Twice weekly
Lime sulfur
Enilconazole (not available in USA)
Miconazole + chlorhex
87
What is considered the "mycologic cure" in dermatophytosis?
Two negative consecutive cultures taken at least 2 weeks apart
88
What are the most effective and safe oral treatments for dermatophytosis?
Itraconazole (NON-compounded)
Terbinafine
89
How often should bleach solutions be made when treating dermatophytosis in the environment?
At least once weekly
90
What are 3 important steps in disinfecting nonporous surfaces of dermatophytosis?
1) Mechanical removal of debris
2) Detergent application
3) Application of disinfectant
91
What water temperature should be used when washing laundry to eliminate dermatophytosis?
Any temp (two washes on longest cycle)
92
How often should environmental decontamination be done to help eliminate Ringworm?
Twice weekly
93
What is the primary dermatophyte pathogen in humans?
Trichophyton rubrum
94
A modified Fite-Faraco stain is applied to a tissue sample and is positive. You are trying to differentiate Nocardia from Actinomyces - which is most likely?
Nocardia
(Fite-Faraco is a modified acid fast stain)
95
Is Actinobacillus gram-negative or gram-positive?
Gram-negative (different from Actinomyces and Nocardia)
96
Is Actinobacillus aerobic or anaerobic?
Aerobic
97
What is another name for bacterial pseudomycetoma?
Botryomycosis
98
What bacteria are usually associated with pseudomycetoma formation??
Coagulase-positive Staph
99
Is Dermatophilus congolensis an aerobe or anaerobe?
Aerobe (or facultative anaerobe)
100
What is the most common aerobic bacteria isolated from cat bite wounds?
Pasteurella multocida
101
What bacterial infection has a "bundle of grapes" appearance clinically?
Botryomycosis
102
Is Mycobacteria an aerobe or anaerobe?
Aerobe
103
What virulence factors are responsible for causing the host granulomatous response in Mycobacterial infections?
Cord factor
Wax D
104
What subspecies of Mycobacteria are tuberculous?
M. tuberculosis
M. bovis
M. microti
105
How is M. bovis typically transmitted?
Through the GI tract
106
What are the most common body sites for localization and shedding of M. bovis?
Ileocecal LN
107
What body system is most likely to be affected by M. tuberculosis?
Lungs
108
What addition to culture media can improve the growth of M. tuberculosis and inhibit the growth of M. bovis?
Glycerol
109
Is Mycobacteria acid-fast?
Yes
110
What is the recommended treatment for animals diagnosed with M. tuberculosis?
Euthanasia (due to zoonotic risk)
111
Where are bacteria of the M. avium complex usually found?
Bird feces
Ubiquitous in soil/water
112
How is Mycobacterium avium complex usually transmitted?
Ingestion of organism
113
What are the typical cytology findings of Mycobacteria?
Organisms within macrophages
114
What are the 4 primary causative agents of feline leprosy?
Mycobacterium lepraemurium
Mycobacterium visible
Mycobacterium lepraefelis
Mycobacterium tarwinense
115
What breed is predisposed to canine leproid granuloma?
Boxers (short-coated breeds overrepresented)
116
You find negative-staining bacilli within macrophages on cytology of nodules from a Boxer's head. What is the most likely diagnosis?
leproid granuloma caused by Mycobacteria
117
What is the treatment recommendation for canine leproid granuloma?
Benign neglect- many will spontaneously regress in 1-3 months
Surgery
Rifampin/doxy/clarithromycin
118
Is there a public health risk in canine leproid granuloma?
No
119
What is the most common clinical presentation of rapidly-growing Mycobacteria?
Panniculitis
120
What is the gold standard culture medium for identification of rapidly growing Mycobacteria?
Broth microdilution
121
Describe the acid-fast staining characteristics of Mycobacteria.
Positive on acid-fast
122
What is the geographical distribution of Mycobacterium tarwinense?
Australia
123
What body region(s) is typically affected by Mycobacterium tarwinense?
Head and ocular tissue
124
What body region(s) is typically affected by Mycobacterium lepraemurium?
Head (without significant ocular involvement)
Forelimbs
125
What is the proposed transmission of Mycobacterium lepraemurium?
Rodent bites
126
What subspecies of Mycobacterium typically affects older cats (>9 years) with feline leprosy?
M. lepraefelis
127
What species of Mycobacterium typically affects younger cats (<3 years) with feline leprosy?
M. lepraemurium
128
What type of feline leprosy is associated with an unfavorable prognosis?
Mycobacterium lepraefelis
129
What species of feline leprosy is suspected to be associated with immunosuppression/comorbidities?
M. lepraefelis
130
What species of Mycobacterium is associated with systemic involvement in cases of feline leprosy?
M. lepraefelis (liver)
131
Where does the disease process occur for rapidly-growing Mycobacteria species?
SQ fat (panniculitis)
132
Where does the disease process occur for slow-growing Mycobacteria species?
Dermis (nodules)
133
What is the most common Staph isolate in horses?
Staph aureus
134
What toxin produced by Staph influences bacterial binding?
Protein A
135
What gene confers beta-lactam resistance to Staph?
mecA
136
What are the 3 members of the Staph intermedius group?
Staph intermedius
Staph pseudintermedius
Staph delphini
137
Which gene is targeted using PCR to help differentiate coagulase-positive Staph species?
thermonuclease (nuc)
138
What sites are swabbed to determine Staph pseud carriage on dogs?
Oral mucosa
Perineum
139
What is the most commonly found Staph species colonizing cats?
Staph felis/Staph simulans
140
What is the most common Staph intermedius group member found on horses?
S. delphini
141
What cytotoxins are produced by Staph pseudintermedius?
Luk-1 (leukotoxic to PMNs)
alpha-hemolysin (hemolysis)
beta-hemolysin (hemolysis)
142
What exfoliative toxins does Staph pseud produce?
SIET (Staph pseud exfoliative toxin)
EXI (ExpA)
ExpB
143
What Staph toxins cause degradation of Dsg-1?
EXI, ExpB
144
What enterotoxins are produced by Staph pseud?
SEC (Staph enterotoxin C)
se-int
145
What is the function of MSCRAMMs in relation to Staph?
These are Staph proteins which play a role in bacterial attachment to the host ECM
146
What Staph pseud surface proteins (Sps) mediate Staph adherence to canine corneocytes?
SpsD
SpsO
147
What Staph pseud surface proteins (Sps) mediate Staph adherence to the ECM?
SpsD
SpsL
148
What Staph pseud gene encodes tetracycline resistance?
tet(M)
149
What Staph pseud gene encodes macrolide resistance?
erm(B)
150
What genera of fungus are typically found on the skin of dogs and cats?
Alternaria
Cladosporium
Epicoccum
151
Which breed of cat has higher carriage rates of Malassezia?
Devon Rex
Sphynx
152
Which special fungal stain will stain both living and nonviable fungi?
GMS
153
What can be stained by GMS that would not stain with PAS?
Oomycetes
154
What is the typical size of Malassezia?
3-8 um
155
What is the typical morphology of Candida?
3-4 um
ovoid shape
156
What is the typical morphology of dermatophytes?
2-3 um wavy parallel-walled hyphae
2 um arthrospores
157
What is the typical morphology of white-grain eumycotic mycetomas?
2-7 um septate, non-pigmented hyphae
158
What is the morphology of black-grain eumycotic mycetomas?
2-7 um pigmented hyphae
Septate
159
What is the morphology of hyalohyphomycosis?
2-6 um hyphae
Septate
parallel walls
Occasional acute-angle branching
160
What is the morphology of Aspergillus spp?
2-6 um hyphae
Septate
Parallel walls
Frequent acute angle branching
161
What is the morphology of mucorales?
8-20 um hyphae
Sparse septae
Nonparallel walls
Irregular branching
162
What is the morphology of entomophthoromycosis?
6-20 um hyphae (Basidiobolus)
5-12 um hyphae (Conidiobolus, shown in image)
Sparsely septate
Nonparallel walls
Rare irregular branching
Eosinophilic sleeve around hyphae
163
What is the morphology of phaeohyphomycosis?
2-10 um pigmented hyphae with beaded appearance
4-15 um yeast-like form
+/- branching
164
What is the morphology of chromoblastomycosis?
10-20 um pigmented Medlar bodies
Transverse and longitudinal septae
165
What is the morphology of Lagenidium?
8-25 um
Nonparallel walls
Irregular branching
Rare septae
Does not stain with PAS
166
What is the morphology of Pythium?
2-7 um
Nonparallel walls
Irregular branching
Rare septae
Does not stain with PAS
167
What is the causative agent in "thrush"?
Candida
168
What is unique about Candida growth compared to other opportunistic fungi?
It grows as yeast, hyphae, and pseudohyphae simultaneously
169
What is the morphology of Blastomyces?
5-20 um yeast
Double contoured wall
Broad-based budding
170
What is the morphology of Histoplasma?
2-4 um round yeast
Clear halo
Thin cell wall
171
What type of fungal stain is best to highlight Histoplasma?
GMS
172
What is the morphology of Cryptococcus?
2.5-20 um oval yeast
Thick capsule ("soap bubble")
173
What stain is best to highlight Cryptococcus?
Mucicarmine
174
What is the morphology of Coccidiodes?
20-80 um spherules containing endospores
Double contoured wall
175
What is the morphology of Sporothrix?
3-10 um long cigar-shaped yeasts
Yeasts often in macrophages
176
What is the most common dermatophyte in pigs?
M. nanum
177
What is the most common dermatophyte in cattle?
Trichophyton verrucosum
178
Define hyalohyphomycosis.
Fungal infection caused by opportunistic, non-dermatophytic saprophytes that grow as NON-PIGMENTED hyphae in tissue
179
What are the features of eumycotic mycetomas?
1) tumefaction
2) tissue grains within exudate
3) draining tracts
180
What are the typical causative agents of black grain eumycotic mycetomas?
Curvularia lunata
Curvularia geniculata
Cladophialophora bantiana
Phialophora oxyspora
181
What are the typical causative agents of white-grain eumycotic mycetomas?
Pseudallescheria boydii (Scedosporium)
Penicillium dupontii
182
What is usually surrounding eumycotic mycetomas on histopathology?
Splendore-Hoeppli
183
Is Aspergillus pigmented or non-pigmented?
Non-pigmented (looks like hyalohyphomycosis)
184
Are Mucorales pigmented or non-pigmented?
Non-pigmented
185
Are entomophthorales pigmented or non-pigmented?
Non-pigmented
186
What are the primary causes of entomophthoromycosis?
Conidiobolus
Basidiobolus
187
What are the typical clinical signs of Coniodiobolus coronatus in horses?
Rhinitis and sinusitis
188
How could you differentiate an oomycete infection from entomophthoromycosis on histopath?
Entomophthoromycosis would stain with PAS, oomycetes do not
189
Define phaeohyphomycosis
Cutaneous/SQ infection caused by PIGMENTED opportunistic fungal hyphae that do not result in tissue grain formation
190
What stain could be used to highlight melanin within fungal cell walls when they don't stain routinely on H+E, aiding in the dx of phaeohyphomycosis?
Fontana-Masson
191
What type of infection is associated with sclerotic bodies/Medlar bodies?
Chromoblastomycosis (a subset of pigmented fungi)
192
What type of fungi do oomycetes most closely resemble?
Entomophthorales (Conidiobolus spp, Basidiobolus spp)
193
What oomyctes cause oomycosis?
Lagenidium
Pythium
194
What organism are oomycetes most closely related to?
Algae
195
What is the primary component of an oomycete cell WALL?
Cellulose
196
What is the primary component of the oomycete cell MEMBRANE?
B-glucan
197
What is the primary component of the fungal cell WALL?
Chitin
198
What is the primary component of the fungal cell MEMBRANE?
Ergosterol
199
True are false: most animals with oomycete infections are immunocompromised.
False
200
What clinical feature helps differentiate Lagenidium from Pythium?
Lagenidium infrequently involves GIT and more frequently involves lymphadenopathy
201
What oomycete is associated with slowly progressive disease and a better prognosis?
Paralagenidium (karlingii)
202
What stain is best to highlight infection caused by oomycetes on histopath?
GMS
203
Why is PAS stain a poor choice for highlighting oomycetes?
They have no chitin in the cell wall
204
Define dimorphic fungi
Fungi that exist as hyphae in culture and as yeasts/spherules in tissue
205
Are dimorphic fungi opportunistic or primary pathogens?
Primary pathogens
206
Name 5 dimorphic fungi of pathogenic significance in animals
Histoplasma
Coccidiodes
Cryptococcus
Blastomyces
Sporothrix
207
Where is Histoplasma usually found in the environment?
Organic matter in bat feces
208
What species of Histoplasma typically infects equids?
H. farciminosum
209
Where in the environment is Blastomyces typically found?
Moist, acidic soil near woods or decaying vegetation
210
Where in the environment is Coccidiodes usually found?
Arid soil in SW USA (Valley Fever)
211
Where in the environment is Cryptococcus usually found?
Nitrogen-rich alkaline debris contaminated with pigeon feces
212
Where in the environment is Sporothrix usually found?
Tropical/subtropical soil and decaying plant matter (central/south America)
213
Do dimorphic fungi usually cause cutaneous or systemic disease?
Systemic (cutaneous is uncommon)
214
How are dimorphic fungi usually acquired?
Via inhalation (exception: Sporothrix)
215
What dimorphic fungi preferentially affects bone?
Coccidiodes
216
What fungal organism is associated with endosporulation?
Coccidiodes
217
What is the likely organism demonstrated in this image?
Coccidiodes (endosporulation within spherules)
218
What is the likely organism demonstrated in this image?
Cryptococcus (thick clear capsule)
219
What is the organism highlighted in this image and what is the stain demonstrated?
Cryptococcus, mucicarmine
220
What type of organism is Leishmania?
Protozoa
221
How is Leishmania transmitted?
Bite from Phlebotomus and Lutzomyia sandflies
222
What are the 3 forms of leishmaniasis in humans?
Cutaneous
Mucocutaneous
Visceral
223
Describe the life cycle of Leishmania
1) Lives in host macrophages as amastigotes -->
2) amastigotes multiply and rupture out of macs -->
3) sandfly ingests amastigote after sucking blood from host -->
4) transform into flagellated promastigote form in sandfly gut -->
5) promastigotes multiply and detach from gut epithelia to travel to mouthparts -->
6) promastigotes injected into host skin when sandfly bites and become amastigotes again
224
What cytokines have induced antileishmanial activity of macrophages?
IFN-gamma
IL-2
TNF-a
225
What claw manifestation may be seen with canine Leishmania?
Onychogryphosis (hypertrophy and abnormal curvature of claws)
226
True or false: Dogs with cutaneous signs of Leishmania often have concurrent visceral disease
True
227
What are the most common cutaneous presentations for canine leishmaniasis?
1) Exfoliative dermatitis with silver scaling and alopecia
2) Ulcerative dermatitis over bony prominences, paws, MCJ, pinnae
228
What are the most common signs of visceral involvement in canine leishmaniasis?
Weight loss
Muscle atrophy
229
What is the most common cause of death in canine leishmaniasis?
Renal failure due to immune complex deposition
230
True or false: Leishmania parasites are usually not found on blood smear
True
231
What tissue is most likely to yield positive PCR for Leishmania?
Bone marrow/LN (>skin>conjunctiva>buffy coat>whole blood)
232
What stain allows for best detection of Leishmania amastigotes on cytology?
Giemsa
233
What are the nine inflammatory patterns that have been associated with cutaneous leishmaniosis?
1) Superficial perivascular dermatitis
2) Deep perivascular dermatitis
3) Granulomatous perifolliculitis
4) Interstitial dermatitis
5) Suppurative folliculitis
6) Lichenoid interface dermatitis
7) Lobal panniculitis
8) Nodular dermatitis
9) Intraepidermal pustular dermatitis
234
What prevention measures are recommended for Leishmania?
Permethrin, imidacloprid
Keep dogs inside at dusk and dawn
Vaccination
235
True or false: Most dogs treated for Leishmaniasis are cured.
False - most remain carriers despite symptoms resolving
236
What breed is a reservoir for visceral leishmaniasis in North America?
Foxhounds
237
Is Actinomyces gram-positive or gram-negative?
Gram-positive
238
What is the length of treatment for Actinomycosis?
Weeks-months past clinical resolution
239
What species of Nocardia usually affects humans, dogs, and cats in the SW US?
Nocardia brasiliensis
240
What species of Nocardia usually affects dogs and cats from the western US and Australia?
Nocardia nova
241
What form of nocardiosis is most common in humans?
Pulmonary
242
What form of nocardiosis is most common in cats?
Cutaneous/SQ
243
What atypical bacterial infection is usually associated with a mixed bacterial population?
Actinomycosis
244
Define rapidly-growing mycobacteria
Mycobacteria that form colonies on solid media within 7 days
245
What are the three syndromes of rapidly-growing Mycobacteria in dogs and cats?
1) Panniculitis (most common)
2) Pyogranulomatous pneumonia
3) Disseminated systemic disease
246
Would a rapidly growing Mycobacterial infection prefer a fat cat or a skinny cat?
Fat cat -- prefers higher adiposity
247
What species of Leishmania is usually associated with cutaneous/MC disease?
L. braziliensis
248
What type of T-cells are protective against Leishmania infection and can lyse infected macrophages?
CD8+ (Cytotoxic)
249
What determines whether a dog infected with Leishmania will develop disease?
Immune response at time of inoculation
250
Describe the structure of canine distemper virus
enveloped ssRNA virus
251
What virus is associated with hard pad disease?
Canine distemper virus
252
What is another name for porcine herpesvirus-1?
Pseudorabies
253
What is the structure of porcine herpesvirus-1?
enveloped dsDNA alpha-herpesvirus
254
What species is the main reservoir for Pseudorabies?
Pigs
255
What are the main clinical signs of Pseudorabies in dogs?
Intense upper body pruritus
Ptyalism
256
What is the prognosis for Pseudorabies in dogs?
Grave - death within 48 hours of CS
257
What is the structure of feline herpesvirus-1?
ds DNA virus with glycoprotein-lipid envelope
258
What is the structure of feline calicivirus?
small non-enveloped ssRNA virus
259
What virus is associated with URI, oral ulcers, and acute lameness in cats?
Calicivirus
260
What is the structure of papillomavirus?
small, non-enveloped, dsDNA virus
261
What type of immunity is necessary for regression of papillomas?
Cellular
262
What genes encode for viral capsid proteins in papillomavirus?
L1, L2
263
What gene regulates viral DNA replication in papillomavirus?
E1
264
What gene activates transcription in papillomavirus?
E2
265
What gene modulates the immune response of infected cells in papillomavirus?
E3
266
What gene disrupts cytokeratins and facilitates viral release in papillomavirus?
E4
267
What genes are oncogenes responsible for cell immortalization in papillomavirus?
E6, E7
268
How does papillomavirus gene E7 cause cell immortalization?
binds and inhibits retinoblastoma (Rb), a tumor suppressor protein
269
Describe the pathogenesis of canine papillomavirus
Virus infects basal KC --> genome replication in S. spinosum and S. granulosum --> release of new infectious virus in keratinized squames
270
What are the cytopathic effects of papillomavirus?
1) Acanthosis and hyperkeratosis due to increased mitosis
2) Formation of koilocytes in upper S. spinosum
3) Giant keratohyalin granules in SG
4) Intranuclear inclusion bodies
5) Expanded blue-gray cytoplasm with enlarged nuclei and marginated chromatin
271
What dog breeds are predisposed to exophytic cutaneous papillomas?
Kerry blue terriers
Cocker spaniels
272
What breeds are predisposed to pigmented viral plaques?
Pugs
Miniature Schnauzers
273
What is the typical age of onset for feline cutaneous papillomas?
Middle-aged and older (unlike dogs)
274
What test would be recommended to confirm a lesion is viral?
IHC
275
What papilloma syndrome in dogs usually regresses on its own?
oral papillomatosis (takes ~3 months)
276
Which cell receptors recognize dsRNA viruses?
TLR3
Rig-like receptors
277
Which TLRs recognize ssRNA viruses?
TLR7
TLR8
278
Which receptors detect DNA viruses?
TLR9
279
Which cytokine is produced within hours of virus invasion, prior to adaptive immunity?
type I interferons (IFN-a, IFN-beta)
280
What is the primary virus-neutralizing antibody?
IgG
281
What protein allows distemper virus to penetrate host cells?
H protein
282
What protein allows distemper virus to fuse infected and noninfected cells?
F protein
283
Where are inclusion bodies typically found in distemper virus?
Intracytoplasmic > intranuclear
284
What papillomavirus is associated with canine oral papillomas?
CPV-1
285
How is FeLV transmitted?
Saliva (food bowls, grooming)
286
Describe the structure of FeLV
enveloped ssRNA
287
What viral family is FeLV a member of?
Retrovirus
288
What IHC stain can be done to diagnose FeLV?
gp70
289
How is FIV transmitted?
Cat bites
290
What virus is associated with cutaneous horns in cats?
FeLV
291
What virus family is distemper a member of?
Paramyxovirus
292
What is the reservoir for feline poxvirus?
Rodents
293
Is feline poxvirus zoonotic?
Yes - fatal to immunocompromised humans
294
Is feline poxvirus reportable?
Yes
295
What is the causative agent of feline poxvirus?
Cowpox
296
Where are inclusion bodies of poxvirus found?
Intracytoplasmic in KC (eosinophilic inclusions)
297
Describe the structure of feline poxvirus
enveloped dsDNA
298
What is another name for "orf?"
Contagious ecthyma
Contagious viral pustular dermatitis
299
Is Orf zoonotic?
Yes - painful umbilicated papules/nodules
300
Is Orf reportable?
No
301
What is the seasonal distribution for feline poxvirus?
summer and fall
302
What is the primary causative agent of feline herpesviral dermatitis?
FHV-1
303
True or false: Oral lysine has been demonstrated to be of major benefit in treatment of feline herpesvirus
False
304
What papillomaviruses are associated with cutaneous papillomatosis in dogs?
CPV-1
CPV-2
CPV-6
CPV-7
305
Are dogs who have recovered from oral papillomatosis usually reinfected?
No- they are immune to reinfection
306
What breeds are predisposed to cutaneous inverted papillomas?
Beagles
Bernese Mt Dogs
Cocker Spaniels
Kerry Blue Terriers
Great Danes
Irish Setters
Whippets
307
What CPV are associated with pigmented viral plaques?
CPV 3-5, 8-12, 15, 16, 18
308
What is the causative agent of feline sarcoids?
Bovine papillomavirus-14
309
What virus has been associated with feline bowenoid in situ carcinoma?
Feline papillomavirus-2
310
Describe the structure of FIV
enveloped ssRNA
311
What is the structure of Orf virus?
enveloped dsDNA
312
Where are inclusions found in feline herpesvirus?
Intranuclear (basophilic)
313
What virus has been associated with exfoliative erythema multiforme following URI?
FHV-1
314
Where does calicivirus remain latent in cats?
Oropharynx
Tonsils
315
Which virus has a hemorrhagic virulent form in cats?
Calicivirus
316
Which T-cell subset is essential in the cell-mediated immunity to fight papillomavirus?
CD4+ (T-helper)
317
What is a typical history in a cat with cutaneous fibropapillomas/feline sarcoids?
Exposure to cattle
318
Are Rickettsia gram-positive or gram-negative?
Gram-negative
319
What organism typically transmits Rickettsia ricketsii?
Dermacentor andersoni (Rocky Mt wood tick)
Dermacentor variabilis (American Dog tick)
320
What organism typically transmits Ehrlichia canis?
Rhipicephalus sanguineous (Brown dog tick)
321
What species is the definitive host of Toxoplasma?
Cats
322
In what cells would you find toxoplasma organisms?
Macrophages
323
What species is the definitive host of Neospora?
Dogs and coyotes
324
A dog is presented with multisystemic disease and pyogranulomatous dermatitis. What 2 organisms should be evaluated via serology?
Neospora
Toxoplasma
325
What breed has the highest incidence of Babesia canis?
Greyhounds
326
What breed has the highest incidence of Babesia gibsoni?
Pitbulls
327
What is the typical distribution of skin lesions in Leishmania?
Head
Pinnae
Extremities
328
What is typically the earliest cutaneous sign of RMSF in dogs?
Edema and hyperemia of extremities
329
In what cells does Rickettsia replicate?
Endothelial cells
330
What serves as the greatest human health risk in a dog with RMSF?
Exposure to tick feces and hemolymph (use forceps when removing!)
331
In what cell type would you find Ehrlichia organisms?
Macrophages
332
What antibiotic class would you want to avoid when treating Mycoplasma or L-form infections?
Beta-lactams (they generally lack a cell wall)
333
What is the primary clinical sign of borreliosis?
Polyarthropathy
334
What is the most common species of Staph in food animals?
S. aureus
335
What Staph organisms are part of the normal skin flora in food animals?
S. aureus
S. hyicus
336
What is the major MRSA strain associated with swine?
ST398
337
What exfoliative toxins from S. hyicus are associated with the pathogenesis of greasy pig disease?
Exh A, B, C, D
SHETA
SHETB
338
Describe the pathogenesis of greasy pig disease
Staph hyicus toxins digest desmoglein-1 --> scale/crust
339
Is Erysipelothrix rhusiopathiae zoonotic?
Yes
340
Is Erysipelothrix fast-growing or slow-growing on culture?
Slow-growing
341
What is the infectious stage of Dermatophilosis congolensis?
Zoospore
342
Is Dermatophilosis congolensis zoonotic?
Yes (Pruritic/painful pustules or nodules)
343
What is the causative agent of lumpy jaw in cattle?
Actinomyces bovis
344
What is the causative agent of "wooden tongue" in cattle?
Actinobacillus lignieresii
345
At what part of the hair follicle does a dermatophyte stop growing?
Adamson's fringe
346
What are the growth requirements for T. verrucosum?
Thiamine
Inositol
347
What is the cause of "swamp cancer"?
Pythium insidiosum
348
How are cats infected with cowpox?
Hunting rodents
349
What papillomaviruses have been associated with equine sarcoids?
BPV-1>BPV-2
350
What is the causative agent of teat fibropapillomas?
BPV-1
351
What is the causative agent of head/neck/shoulder fibropapillomas in cattle?
BPV-2
352
What does Staph protein A bind to?
Fc portion of IgG
353
Which Lancefield groups of Strep are beta-hemolytic?
A, B, C, G, E, L, M
354
What is the only Lancefield Group A Strep?
Strep pyogenes
355
What organism is primarily responsible for fading puppy syndrome?
Strep canis
356
What Lancefield group is Strep canis part of?
Group G
357
What are the most commonly zoonotic poxviruses of large animals?
Pseudocowpox (parapoxvirus)
Contagious Viral Pustular Dermatitis (orf)
Bovine papular stomatitis (parapoxvirus)
358
What organism can mechanically transmit poxvirus?
Stomoxys calcitrans (stable fly)
359
What is a vector in the spread of swinepox?
Haematopinus suis (swine louse)
360
What condition is a "horseshoe scab" pathognomonic for in cattle?
Pseudocowpox
361
What poxvirus has a vaccine that should be given annually?
Orf
362
What are the typical lesions of Orf?
Proliferative lesions with thick crusts (lips, muzzle, nostrils, eyelids, teats, udders)
363
Does poxvirus in ruminants require treatment?
No - low mortality and is self-limiting (careful for zoonosis)
364
What is the causative agent of Valley Fever?
Coccidiodes
365
What antigen is detected on enzyme immunoassay for Blasto, Coccidioides, and Histoplasma?
galactomannan
366
What are the virulence factors of Malassezia?
1) Thick cell wall
2) Biofilm
3) Phospholipase A2
4) Production of enzymes (sphingomyelinase, chitin deacetylase)
367
What receptor expressed by phagocytes selectively recognizes Malassezia but not other fungi?
Mincle -- binds glucosyl and mannosyl glycolipids
368
What receptor expressed by Langerhans cells is a PRR for commensal and pathogenic fungi?
Langerin -- recognizes mannose and B-glucan
369
What cat breeds are predisposed to Malassezia?
Sphynx
Devon Rex
370
What are fungal cell walls made of?
Chitin
Chitosan
Mannan
Glucan
371
What should be added to a culture plate for growth of Trichophyton equinum?
Niacin
372
What antigens are virulence factors for Blastomyces, causing adherence of yeast to host cells?
BAD1
WI-1
372
What organism causes ringworm in hedgehogs?
Trichophyton erinacei
373
Which dog breeds have an increased risk of disseminated Coccidiomycosis infection?
Boxers
Dobermans
374
What occurs in inflamed skin that stimulates Malassezia to produce more phospholipase?
Endogenous opioids (i.e. beta-endorphin)
375
What antibiotic is recommended for treatment of toxic shock syndrome?
Clindamycin
376
What causes Mycobacteria to be positive on acid-fast?
High mycolic acid lipid content in their walls
377
What organisms are most likely to cause black grain mycetomas?
Curvularia geniculata
Madurella
378
What organism is likely to cause white grain mycetoma?
Pseudallescheria
Acremonium
379
What is the major strain type for MRSP in the US?
ST68
380
What is the major strain type for MRSP in Japan and Europe?
ST71
381
What is essential for antibiotic treatment of Brucella canis?
combine multiple antibiotics (tetracycline + FQ or aminoglycoside + sulfonamide)
382
How long should dogs in an infected Brucella kennel be tested for after seronegative status is reached?
3 months
383
Which Brucella species cause disease in people?
B. canis
B. abortus
B. suis
B. melitensis
384
Why is B. canis less virulent than other Brucella species?
It lacks LPS in cell wall
385
What cutaneous lesions can be seen with Burkholderia?
Ulcers
Chronic abscesses and SQ granulomas
386
What is the definition of extensively drug resistant (XDR)?
Susceptibility to <=2 antimicrobial classes
387
What is the definition of multidrug resistant?
Resistance to >= 2 antimicrobial classes
388
Where is the most consistent site of Staph carriage in dogs and cats?
Oral cavity
389
What is the best predictor of pathogenic potential of a Staph strain?
Ability to coagulate plasma
390
What Staph species are carried most frequently by cats?
S. aureus
S. pseudintermedius
391
What is the most frequently isolated MRSA strain from pets in the US?
CC22
392
What genes expressed by Staph pseud confer resistance to tetracyclines?
tet(M)
tet(K)
393
What tetracycline will Staph be susceptible to if it possesses tet(K) but not tet(M)?
Minocycline
394
In equine sarcoid, what early genes of the virus possess transforming capability?
E5, 6, 7
395
In equine sarcoids, what early genes of the virus regulate replication and transcription?
E 1, 2, 4
396
Which viral genes encode structural proteins in BPV?
late genes (L1, 2)
397
Which BPV viral genes have been positively correlated with disease severity in equine sarcoids?
E 2, 5, 6, 7
L 1, 2
398
Which BPV viral genes function as the major oncoproteins that stimulate sarcoid development in horses?
E 2, 5, 6, 7
399
True or false: BPV DNA has been found in non-sarcoid lesions in horses and in normal equine skin
True
400
What controls the invasiveness of equine sarcoids?
MMP 1, 2, 3
401
What horse breeds are predisposed to develop sarcoids?
QH + Franches-Montagnes > TB> SB
402
What stain could be applied to a slide to highlight Leishmania kinetoplasts?
Giemsa
403
What is the gold standard for diagnosis of Leishmania?
PCR on bone marrow or LN
