6.14 Zoonoses (Last One!) Flashcards
what percentage of pathogens known to affect humans are zoonotic
61%
T/F many zoonotic parasites of companion animals can be controlled effectively
T
in what 3 ways can humans act in a parasitic zoonoses
1) aberrant (dead-end) host
2) unusual intermediate host
3) unusual definitive host
what are the zoonotic protists
- Toxoplasma gondii
- Giardia spp.
- Cryptosporidium spp.
what are the 2 ways humans can become infected with Toxoplasma gondii and what are the consequences
1) ingestion of tissue cysts (bradyzoites) in meat -> usually freezing/cooking kills them
2) ingestion of oocysts in the environment -> tissue cysts and reproductive disease
how long does it take unsporulated Toxoplasma gondii to become sporulated in the environment
24-48h
what disease does acquired toxoplasmosis cause in people (what are the 4 clinical signs)
- lymphadenopathy
- myocarditis
- encephalitis
- pneumonia
what disease does congenital toxoplasmosis cause in people and why does this happen
encephalitis, abortion, stillbirth and neonatal death; when a primary infection occurs during early pregnancy
what are the two instances in which you are going to see pathogenic Toxoplasmosis in people
- naive mother exposed during pregnancy
- immunocompromised
what are the ways to diagnose giardia in people
- fecal antigen test
- IFA
- look for trophozoites in watery diarrhea
- look for cysts in standard fecal floats
are dog or cat species of Giardia more likely to cause zoonoses in humans? which are more prevalent
cat more likely to be zoonotic (in both immunocompetent and immunosuppressed); dog only zoonotic in immunosuppressed; dog more prevalent
T/F companion animal strains of Cryptosporidium are only very weakly zoonotic
T
what is the concern with Cryptosporidium parvum infection (i.e why is it so bad)
thin-walled sporulated oocysts give rise to auto-infection
what are the zoonotic tapeworms
- Taenia
- Echinococcus
- Diphylidium caninum
what are the zoonotic Taenia spp.
Taenia crassiceps
Taenia multiceps
Taenia serialis
Most common large tapeworms (are/are not) zoonotic; some cause _____________ or ________________
are; coenurosis; cysticercosis
what stage of Taenia is zoonotic and what happens in the humans
eggs in gravid segments; get coenurosis or budding cysticerci in various tissues
Taenia crassiceps causes ______________ in humans and Taenia multiceps causes ______________in humans
budding cysticercosis; coenurosis
what caused hydatid disease in humans
Echinococcus
how do we differentiate Taenia and Echinococcus
we cant!
how do we treat hydatid disease
- surgical removal of cysts
- systemic treatment with anthelmintics
how do humans get infected with Diphylidium caninum
ingestion of fleas containing cysticercoids -> we get infection with adult worms
zoonotic roundworm infections cause ______________ whereas zoonotic hookworm infections cause _______________
visceral/ocular larval migrans; cutaneous larval migrans
what two roundworms can cause visceral/cuteaneous larval migrans
Toxocara and Baylisascaris
what is the characteristic of OLM/VLM
eosinophilia
how do we treat OLM and VLM
anti-inflammatory
what is the infective stage of Toxocara
L3 larvae (ingested)
what disease does Baylisascaris cause
it eats through the brain
T/F VLM and OLM is caused by adult roundworms wandering around the body
F; larvae
how do humans get cutaneous larval migrans
hookworm (Ancylostoma) larvae penetrate through the skin
what is Swimmer’s Itch caused by
cercariae of blood flukes of birds
how do we treat Swimmers itch
anti-inflammatory
how do humans get exposed to Swimmer’s Itch
exposure to cercariae in water
what instances are humans dead end hosts of zoonotic parasites
- visceral/ocular larval migrans (Toxocara, Baylisascaris)
- cutaneous larval migrans (Ancylostoma)
- swimmer’s itch (Avian trematode cercariae)
what instances are humans unusual intermediate hosts of zoonotic parasites
- Toxoplasma gondii
- Taenia infections (Coernusus and Cysticercosis)
- Echinococcus infections (Hydatid cysts)
what instances are humans unusual definitive hosts of zoonotic parasites
- Dipylidium caninum
- Strongyloides stercoralis (companion animal or primates)
- Cryptosporidium (non-human isolates)
- Giardia (non-human isolates)
- Heartworm
- Fleas (especially cat fleas)
what are the general principles of good diagnostic parasitolody
1) proper specimen collection and preparation
2) good history
3) appropriate test requests
4) timely results
5) promote better treatment
what are the limitations of all diagnostic samples
- all have limited sensitivity and specificity
- all have limited range of parasites detected
- all require appropriate sampling technique
