Trichinella & Anisakis (Lecture 9)

what type of host are humans for Trichinella & Co.?

dead end host

what are the TWO lifecycles for Trichinella spiralis?

domestic and sylvatic

how do you prevent Trichinella infection?

cook meat

The sylvatic cycle is perpetuated by _____ animals through _____ or _____

wild; predation; scavenging

the domestic cycle is perpetuated by _____ animals through _____ or _____

livestock; meat scraps; cannibalism

how are humans infected with Trichinella?

ingesting meat with encysted larvae

once eating the parasite, the larvae is released in the _____, where it undergoes _____

small intestine; maturation

adult trichinella produce _____ that are deposited into the _____

larva; mucosa

the larvae in the mucosa will _____ in the _____ tissue

encyst; striated muscle

True or False: Trichnella is diganosed a stool O&P

FALSE: it encysts in tissue → not shed in stool!

trichenella diagnosis is mainly _____ but the parasite can be visualized in a _____ or detected through _____

clinical; muscle biopsy; serology

Trichenella causes the peripheral blood to have _____ up to _____%

eosinophilia; 90

Trichenella can live in the small intestine for _____, so treatment is provided to prevent _____ formation

>1 month; cyst

how can you prevent Trichenella infection?

cooking or freezing food, don’t microwave, no raw meat scraps to hogs

freezing does NOT destroy a Trichenella species called _____ which is found in _____

T. nativa; Alaska

what nematode is this?

anisakis

why type of host are humans for Anisakis?

dead end

Anisakis ia normally found in _____

marine mammals

how are humans infected with anisakis?

eating raw infected seafood

what stage of anisakis is the infective to humans (and marine mammals)?

L3 larvae

when fish or squid containing Anisakis L3 larvae are ingested by marine mammals, the larvae develop into _____ that produce _____ which are shed by the animal

adult worms; eggs

anisakis eggs become _____ in water and form _____ WITHIN the egg

embryonated; L2 larvae

L2 larvae eventually hatch from the anisakis eggs and are ingested by _____ where they mature into _____

crutaceans; L3 larvae

Anisakis infected crustaceans are ingested by _____ and _____ which transfer the parasite to mammals via _____

fish; squid; predation

why are humans a dead end host for Anisakis?

larvae never mature into adults (no eggs produces and thus lifecycle stops)