Fungi - opportunistic + systemic mycoses Flashcards
Opportunistic mycoses - normal habitat + predisposing factors + lesion characteristics
Saprophytes or commensals
Invasive w compromised host defences
Localised + granulomatous lesions
Aspergillosis - spp (4) + route of infection
A. fumigatus
A. flavus
A. niger
A. terreus
Inhalation of conidia
Aspergillosis - disease host + characteristics
Respiratory disease in birds
Caseating tubercles w hyphae
Thrush - agent + habitat + susceptible hosts
Candida albidans
Commensal of skin/mucous membranes
Young animals, pregnant, corticosteroid admin, immunocompromise, endocrinopathies etc.
Thrush - tx
Oral nystatin
Fluconazole for UTIs
CuSO4 in water (birds)
Enzootic lymphangitis in horses - agent
Histoplasma capsulatum var farciminosum
Enzootic lymphangitis in horses - route + pathogenesis
Entry via wound (legs)
> spread through lymphatics
> chronic ulcerative lesions
> necrotic/pyogenic/granulomatous rxn
Cryptococcus neoformans - source + route of infection
Environmental fungus
Inhalation/wound infection/teat canal
No transmission b/w animals
Cryptococcus neoformans - VFs (1_
Capsule - inhibits phagocytosis + activates complement + inh leukotaxis + adsorbs opsonins + depresses Ab synthesis
Cryptococcus neoformans - Host facts (1)
CMI deficit important
Chronic ulcerative lymphangitis - agent + habitat
Sporothrix schenckii
Dead plant material
Rhinosporidium seeberi - dz + host
chronic nasal/ocular infections
Horses, cattle, humans
Pythium insidiosum - dz + host + normal habitat
Chronic ulcerative lesions on lower limbs/abdomen w yellow kunkers
Horses (nth Aus)
Saprophytic in water-logged pastures
Pneumocystis carinii
Opportunistic pathogen in lungs of immunocompromised dogs
Mycotic abortion - agents (5)
Mortierella Aspergillus Candida tropicalis Caphalosporium Mucor pusillus
Mycotic abortion - pathogenesis
Inhalation/ingestion of spores > haematogenous spread > localisation in placenta >placental infarction > abortion
Mycotic mastitis - agents (3)
Cryptococcus
Candida
Trichosporon
Mycotic mastitis - pathogenesis
Entry via intramammary infusions/milking
> C. neoformans = permanent agalactia
> other fungi = recovery
Mycotic mastitis - tx
Don’t treat as antifungals damage gland
Mycotic rumenitis/gastritis - Agents (5)
Absidia Aspergillus Candida Mucor Rhizopus
Mycotic rumenitis - apthogenesis
AM therapy/lactic acidosis
> disruption of normal flora
> infarction of mucosa
Mycotic rumenitis - tx
Ineffective
Mycotic keratitis - spp. (5)
Aspergillus Candida Drechslera Fusarium Penicillum
Mycotic keratitis - pathogenesis
Corneal injury/secondary infection
Guttural pouch mycosis -agents (2)
Aspergillus
Mucor
Guttural pouch mycosis - pathogenesis
Unilateral infection
> extension to internal carotid a. + adjacent nerves
Guttural pouch mycosis - tx
ligation of internal carotid a.
Mycotic mycetoma - agents (6) + habitat
Cladosporium Curvularia Fonsecaea Helminthosporium Petriellidium Phialophora
saprophytes - soil + decaying plant matter
Mycotic mycetoma - route + location of lesions
Entry via skin wounds on lower limbs
Phaeohyphomycosis - agnets (3)
Dreschslera
Cladosporium
Curvularia
Phaeohyphomycosis - lesions
Chronic nodular/ulcerating lesions on lower limbs
Prototheca - lesions
Disseminated dz > haemorrhagic diarrhoea > CNS/eye involvement > cutaneous cases > mastitis
Prototheca - tx
Amphotericin B
Dermatophytes - genera (2) + habitat types (3)
Microsporum
Trichophyton
Nannizzia
Geophilic (soil)
Zoophilic (animals)
Anthropophilic (humans)
Ringworm - agents + route of transmission
Dermatophytes (Microsporum/trichopyton/Nannizzia)
Spread by exposure to contam’d soil/other infected animals
Dermatophytes - growth requirements (3)
Dependent on keratin
High humidity/T facilitate growth
Conidia survive in moist environments
Ringworm - pathogenesis
Conidia enter by skin abrasion
> germinate + hyphae grow in stratum corneum
> hyphae invade hair follicles + penetrate hair cortex
> hair breaks + falls out
> hyperkeratosis + centrifugal spread = ring lesions
Ringworm - immunity
CMI important
Delayed hypersensitivity rxn to Ag (keratinase/glycoprotein)
Resistance to reinfection = local or general
Ringworm - dx
Skin scraping to ID hyphae/arthroconidia
Culture on Sabouraud’s agar
Ringworm - tx (5)
UV light
Topical iodine/lime-sulfur
Topical imidazoles
Oral griseofulvin
Environmental disinfection w L-S/formaldehyde
Ringworm - host factors (1)
Young > old
Dermatophyte spp + habitat + natural host (9)
M. canis - zoophilic - cat N. gypseum - geophilic - dog N. nana - geophilic - pigs M distortum - zoophilic - primates M. audouini - anthropophilic M. gallinae - zoophilic - chickens T. verrucosum - zoophilic - cattle T. equinium - zoophilic - horses T. mentagrophytes - zoophilic - variable
Systemic mycoses - pathogenesis
Infection of lungs by environmental exposure
> systemic invasion
> chronic progressive granulomatous lesions
Blastomyces dermatitidis - habitat + route of infection
Soil saprophyte
> inhalation of conidia (cool/wet months)
Blastomyces dermatitidis - affected spp.
Dogs + horses
Cats resistant
Coccidioides immitis - pathogenesis
Inhalation of conidia (low infective dose)
> URT infection involving mediastinal/bronchial LNs
> recovery then immunity
Coccidioides immitis - host factors
Females resistant
Pigmented skin facilitates dissemination
Histoplasma capsulatum - pathogenesis
Inhaled conidia (faecally-enriched soil) > phagocytosed by MP + disseminated intracellularly > lungs, GI, kidney, CNS, bone marrow, skin
Systemic mycoses - tx (3)
Polyene AM (amphotericin B, nystatin)
Imidazoles
NaI
Fusarium graminearum - mycotoxin + habitat + dz
Zearalenone on maize (stored wet/hot then period at low T)
> genital hypertrophy in pigs (vulval/preputial swelling)
Perennial ryegrass staggers - agent + toxin + signs
Neotyphodiuml lolii (fungus)
- Alkaloids (toxin)
- Lolium perenne (pasture)
Muscle spasms, incoordination
Aspergillus flavus - toxin + habitat
Aflatoxins = inhibit RNA/protein synthesis
- on most solid foods (if stored warm/wet)
Ergotism - agents (2) + toxin + habitat + signs
Claviceps purpurea - rye/grain
Claviceps paspali - Paspalum crop
Toxin = ergotamine (LSA derivative)
> CNS stim then depression
> Adrenergic stim = vasoconstrction + thrombosis/ischaemia + gangrene
Phomopsis leptostromiformis
Saprophyte of green plants (winter)/dying plants (summer)
Facial eczema in ruminants - toxin
Sporidesmin
> hepatocellular dmg + cholangitis
> obstructive jaundice
> failure to excrete phylloerythrin = UV active = photosensitisation
Black soil blindness in cattle - what plant + fungus + signs
Mitchell grass (Astrebla)
Carallocytostroma spp.
> high rainfall seasons
> blindness + death
Cyanobacteria - growth conditions + pathogenesis
Stagnant water bodies in drought > eutrophication (↑ P/N/CO2) > algal growth + concentration on surface > ingestion > hepatocellular dmg
