Mycoses in Wildlife Flashcards
what does Pseudogymnoascus destructans cause?
disease in bats known as white nose syndrome
which bats did Pseudogymnoascus destructans coevolve with?
Eurasian bat populations
coexisted for millenia
when does Pseudogymnoascus destructans grow?
in winter: psychrophilic (likes <68 degrees F)
true/false: the bat’s body temperature outside the hibernacula is too high to support Pseudogymnoascus destructans
true
how is Pseudogymnoascus destructans transmitted?
contact between bats
contact with contaminated surfaces in hibernacula
what are the clinical signs of Pseudogymnoascus destructans?
white lesions: worst on wings and tail, also ears, nose, muzzle
wing damage
rouse frequently during hibernation
why is wing damage by Pseudogymnoascus destructans a problem?
problems with physiological processes such as blood circulation, thermoregulation, water balance, and gas exchange
how many species of bat in North America are affected by Pseudogymnoascus destructans and how many have no clinical signs?
12 with clinical signs
8 without clinical signs
how can you diagnose Pseudogymnoascus destructans?
lesions/fungi external: relatively easy
identify lesions
PCR
fungal culture
histopathology
which species of North American bats have had Pseudogymnoascus destructans kill more than 90% of them?
northern long-eared bat
little brown bat
tricolored bat
what makes treatment of an entire population/hibernacula hard with Pseudogymnoascus destructans?
hibernacula can be hard to access
Pseudogymnoascus destructans can persist and grow in wood, soil, guano
lots of bats/high density
what are some things being studied as possible treatments for Pseudogymnoascus destructans?
bacteria with antifungal properties as pro-biotic
oral vaccine
what does Ophidiomyces ophidiicola (Oo) cause?
Ophidiomycosis aka snake fungal disease
is Ophidiomyces ophidiicola (Oo) a specialized pathogen of snakes?
yes
what species is Ophidiomyces ophidiicola (Oo) implicated in the decline of?
timber rattlesnakes (Crotalus horridus)
eastern massaugas (Sistrurus catenatus)
how is Ophidiomyces ophidiicola (Oo) transmitted?
infected snakes shed spores in environment
possible vertical transmission (time when some snake mothers are with their babies)
more research needed
what are the clinical signs of Ophidiomyces ophidiicola (Oo)?
accelerated ecdysis cycles
epidermal flaking and crusting
displaced and/or discolored scales
granulomas
nodules
swelling or disfiguration of infected tissues
why can it be hard to distinguish between novel vs endemic?
lack historical samples/surveillance
delay between actual emergence and recognition of disease
potential for multiple introductions and recombination between strains
what does Batrachochytrium salamandrivorans (Bsal) cause?
disease in amphibians known as chytridiomycosis
how has Batrachochytrium dendrobatidis (Bd) been disseminated globally?
amphibian trade
what has been the impact of Chytridiomycosis?
decline of at least 501 amphibian species: 6.5% of all amphibian species
90 presumed extinctions
>90% loss of 124 species
what environment does Batrachochytrium dendrobatidis (Bd) prefer?
cool regions and seasons
high elevation
aquatic environment
water pH 6-8
Batrachochytrium salamandrivorans (Bsal) and Batrachochytrium dendrobatidis (Bd) infect _________________ in skin of adults and ___________________ of tadpoles
keratinocytes
mouth parts: tadpole skin lacks keratinocytes
what are the clinical signs of chytridiomycosis?
damage to epidermis: brown to red discoloration of skin, excessive shedding, mucous production, muscle incoordination, acute death
fluid and electrolyte losses lead to cardiac failure
how can you diagnose chytridiomycosis?
identify suspicious lesions
wet mount/gram stain
PCR
histopathology
fungal culture not useful
why are we seeing emerging infectious disease caused by fungi?
high virulence
ability to establish environmental reservoirs
broad host range
what parts of the body are most affected by Aspergillus?
bronchi
lungs
air sacs
what is the most common species of Aspergillus that infects wild birds?
Aspergillus fumigatus
how does aspergillosis occur in healthy wild birds?
whopping spore exposure
damp waste grain in agricultural fields
fall/early winter
how does aspergillus occur in not otherwise healthy wild birds?
unhealthy: trauma, gunshot, Pb toxicosis, oiling, emaciation, other infectious disease
stressed: captivity
juvenile
species variability
why are birds more susceptible to aspergillosis?
long/winding trachea
air sacs
what are the clinical signs of aspergillosis in wild birds?
non-specific: lethargy, decreased stamina, poor body condition if chronic
respiratory signs: may or may not see
is aspergillosis easy to diagnose?
no
where can Pseudogymnoascus destructans persist and grow?
wood
soil
bat guano
what happens with Pseudogymnascus destructans when bats are outside of the hibernacula spring through autumn?
their body temperature is too high to support P. destructans
what is Ophidiomyces ophidiicola’s ability to survive in environment like?
limited as saprobe
how many species of snakes have been impacted by Ophidiomycosis?
30
6 families
how can we diagnose Ophidiomycosis?
identify lesions
swab lesions
histopathology
where do Batrachochytrium dendrobatidis live?
aquatic
free swimming
zoospore/zoosporangia
southeast Asia for millenia
when are hosts less likely to be infected with Batrachochytrium dendrobatidis?
tadpole instead of adult
less aquatic lifestyle
defense mechanisms: symbiotic bacteria, skin defense peptides
what is the infective form of Chytridiomycosis?
zoospore
matures to zoosporangia: contain numerous zoospores
what can grow in the environment without their host?
Aspergillus and P. destructans
how do air sacs predispose birds to Aspergillosis?
air flow favors particle deposition
no available macrophages
little to no mucociliary transport mechanism
what respiratory signs might you see with Aspergillosis?
dyspnea
open mouth breathing
gurgles/crackles/wheezing sounds
why is Aspergillosis difficult to treat?
advanced stage of disease when diagnosed
lack of pharmacokinetic data on antifungal drugs in most avian species
failure of drugs to penetrate target tissues
frequent presence of concurrent disease and/or immunosuppression
