dermatophytes, cryptococcus, malassezia pachydermatis & Candida albicans Flashcards
describe the dermatophyte microsporum structure
-spindle-shaped macroconidia
- thick walled, rough
describe the dermatophyte trichophyton structure
-cigar-shaped macroconidia
-smooth, thin walled
describe the structure of T. verrucosum in food animals?
chain chlamydospores
what are clinical signs of a dermatophyte infection?
-focal/multifocal alopecia with scaling + inflammatory “ring”
-pseudomycetomas
how are dermatophytes transmitted?
through direct contact or environmental contamination
how does the body react to a dermatophyte infection?
cell-mediated response and transient immunity
-self-limiting infection if immune system is operational
how can you diagnose dermatophyte infection?
-woods lamp
-DTM (not 100% specific for dermatophytes)
what is the treatment for dermatophytes?
topical miconazole/enilconazole
what are clinical presentations for dermatophyte infection?
skin lesions
pruritus
what are some differentials for a possible dermatophyte infection that is experiencing skin lesions and itching?
sarcastic mange, food/drug hypersensitivity, lymphoma, poxviruses
how are dermatophyte infections commonly resolved?
self-limiting (+ antifungals) in healthy animals, antifungals in immunocompromised animals
what is the environmental life cycle of cryptococcus gati?
birds and their habitat contain the yeast and the creatine in the bird droppings get into the foliag, mulch or soil and then the spores of yeast are then inhaled
clinical signs of cryptococcus gattii in cats?
nasal swelling
clinical signs of cryptococcus gattii in dogs?
CNS
clinical signs of cryptococcus gattii in horses?
respiratory
how do you diagnose crytococcus gattii?
cytology/histology
what is the treatment for cryptococcus gattii?
neurological signs= bad
-long term antifungals: azoles
how would you diagnose a case of cryptococcus in a practice?
microscopic examination of exudate with Diff-quick or India ink staining
how is cryptococcus gattii transmitted and what is its life cycle in the environment?
environmental transmission, maintained in creatine-rich soils/foliage under trees where carrier birds have roosted
what are the virulence factors of malassezia pachydermatis?
lipases
zymogens
biofilm
what does the virulence factor lipases trigger?
may trigger seborrhea
what does the virulence factor zymogens activate?
activate complement
what does the virulence factor biofilm formation protect from?
protects from topical antifungals
what is the common organism that is multifactorial, opportunistic and can cause canine otitis externa as well as canine seborrheic dermatitis?
malassezia pachydermatis
what diagnostics can you do when suspect malassezia pachydermatis?
impression smears
cytology
what is the treatment for malassezia pachydermatis?
-focus on underlying causes
-topical: chlorhexadine, diluted vinegar
-systemic: azoles
what does Candida albicans cause?
mucosal/ GI targeted disease
what are the virulence factors of Candida albicans?
adhesion
complement-binding factors
how you do diagnose Candida albicans?
culture- sab. dextrose
what is the treatment for Candida albicans?
focus on underlying causes
what are the predisposing conditions for canine otitis external and what are the common organisms isolated?
-conditions: aural microclimate, diet, metabolic/endocrine, breed, immune disorder
-organisms: malassezia, pseudomonas, otodectes, staph
what are the target organ systems or tissue for Candida?
gastrointestinal, including both upper and lower GI
how do virulence factors help either malassezia or candida infiltrate tissue and cause clinical disease?
variosu enzymes like lipase and zymogens allow the organism to penetrate tissue and subsequently may trigger a severe inflammatory response
how are diseases caused by these tow agents practically treated?
-alleviating predisposing conditions
-antifungals where appropriate
