Conservation Medicine Final Exam

Types of mycosis

superficial cutaneous, subcutaneous, and systemic

Superficial cutaneous mycosis

outer layer of body covering (dead skin and hair shaft) on integument and appendages including nails but doesn’t induce inflammation

Subcutaneous mycosis

found in the fat-containing tissues underneath the skin and in the dermis, entry of fungal spores by traumatic inoculation

Systemic mycosis

result in infection of internal organs (lungs, abdominal viscera, bones, CNS)

Aspergillosis

infection of airways/lungs and often spreads to other organs

Chytridiomycosis (Bd or Batrachochytrium dendrobatidis)

Greatest disease-caused loss of biodiversity in recorded history, aquatic fungus with two life stages

Pathology of Bd

pathogen of skin, amphibian use skin for gas exchange and is very susceptible to pollutants and contaminants

White-nose syndrome (WNS)

affects bats that use hibernation as their winter survival strategy (little brown bats)

WNS history

first recorded in NY in feb 2006 in a cave from a bat doctor

Basic mycology of WNS

Optimum growth temperature ~12.5C a psychropile

Bat immune response to WNS

during torpor there is a decrease in White blood cells, they are sequetered in lung, liver, spleen and not patrolling the body on the lookout for invading pathogens

decreased infalmmatory response, impaired immune response, and decreased elimination of microbes

What causes bats to die?

disruption in engery balance during hibernation ( increased waking periods), dehydration due to wing damage, and inability to regulate body temp

Toxoplasmosis (Toxoplasma gondii)

obligate intracellular parasite, cats are definitive host, natural intermediate host (mice), alt intermediate hosts vary (humans, etc)

T. gondii infectious stages

tachyzoites (trophozoite stage, moving through tissues), bradyzoites (found within tissue cysts static), and sporoziotes (found within oocysts static and reproducing)

T. gondii acquistion

ingestion of sporulated oocyst in cat feces or anything contaminated by cat feces, ingestion of bradyzoites with tissuse cysts, and transplacental transfer of tachyzoites from mother to fetus

T. gondii life cycle

Cats→ infected feces → transport host (flies and mosquitos) → intermediate hosts (mice and meat) → deinitive host (cats)

Fatal attraction Phenomenon

mice seek out cats to be killed by the cats, manipulated by the parasite

T. gondii in humans

~20% of US pop over 6yrs carry the parasite, humans are an alt intermediate host and dead-end host

Acute toxoplasmosis in humans

when symptoms do develop in people: painless swelling of lymph nodes, headache, malaise, fatigue, and low-grade fever

T. gondii in pregnancy

if women develop infection during pregancy or shortly after becoming pregant the tachysoites will cross the placenta and go into the fetus often leading to miscarriage or still births, abnormal developement of brain and eyes, typically apparent normalcy until teen then neurotic symptom disease (anxiety, ADHD, OCD, anxiety, depression, schizophernia

Latent toxoplasmosis

Most common in humans, males can show more signs of dominance or more masculine looking

Neosporosis

dogs are definitive host and cattle are normal intermediate host, very similar to toxo

Direct life cycle of parasites

do not require and intermediate host, only require a definitve host

Indirect life cycle of parasites

may have one or more intermediate hosts

Raccoon roundworm (Baylisascaris procyonis)

intestinal nematode of NA raccoons (definitive host) and has a direct life cycle with raccoons or can be indirect

Raccoon roundworm intermediate hosts

small animals (typically deadly), humans are accidental intermediate hosts, and dogs may be an alt defintive host (shed eggs)

Pathogenicity of RR

larvae grow rapidly and don’t become encapsulated in brain causing mechanical damage and tissue necrosis

Epidemiology of RR

raccoons establish latrines (everywhere) and shed the eggs in feces, the eggs can remain in the soil for a long time and are resistant to disinfectants

RR symptoms in humans

severe disease manifestations: invade spinal cord, brain, and most commonly in the eye