Ascaris Flashcards
(50 cards)
what is the type of tissues that ascaris infect
intestines
all nematodes that are parasidic in humans have what
-separate sexes aka males are smaller than females
-egg production varies from species to species
how many eggs per day for stongyloides stercoralis
very few
how many eggs per day for ascaris lumbricoides
200 000
what is the life cycle of intestinal nematodes
- Five successive stages: 4 larval stages and the adult
- In most cases, the third-stage larva is the infective stage
- Eggs and larvae living in the intestinal are passed outside in the feces or may be
deposited on the perianal skin by the female worm. - Eggs are fully embryonated or require an extended period of egg embryonation in the
soil.
-In some cases, eggs are infective when swallowed or will hatch
in the soil and initiate infection by skin larval penetration
what is the host and disease of ascaris lumbricoides
man and ascariasis
what is the host and disease of ascaris suum
pig, man
ascariasis
what is Baylisascaris procyonis
-Found in raccoons (Procyon lotor) causes serious disease in humans – North America
-Larva invade the eyes (Ocular larva migrans), spinal cord and
brain (neural larva migrans) and in the intestine (VLM)
-No effective treatment
what is Gnathostoma spinigerum
-Found in dogs and cats. Endemic in China, Philippines
-Humans infected by the ingestion of raw or poorly cooked or pickled freshwater
fish, chicken, birds, frogs or snakes
-Larva migration including pulmonary, GI, urogenital, ocular, and cerebral tissues
toxocariasis is caused by what
-infections of humans with ascarids of dogs aka toxocara canis or cats toxocara catis
what is the mode of transmission of toxocariasis
transmission by ingestion of embryonated toxocara eggs in food or soil
-eggs are long lived
in toxo eggs, if the larvae do not develop to adult stage, what do they do
- they wander through the body
- migrate to soft tissues (liver, brain) or eye
- can cause blindness
epidemiology of toxocara
-worldwide parasite including usa
-highest incidence in kids
true or false: infected dogs/cats increase the risk of infection
-trie
-20% of all adult dogs are infected
-98% of all puppies are infected
-in halifax: 26% of dogs, 25% of cats, 56% of puppies
seroprevalence in kids of toxocara
-7.3% in usa
-34% in ireland
-50-80% in developing tropical countries
systemic visceral larvae migrans: what is the pathogenesis
-due to invasion of soft tissues by wandering larvae
-pathogenesis include:
-hepatomegaly
-pulmonary and neurological problems
-eosinophilia
ocular toxocariasis
-due to invasion of the eye tissues by the larvae
-jeveniles cause chronic infammation
-granulomas of the retina (may cause blindness)
what is the diagnosis for toxocara
-fecal egg counts
-elisa using es antigens
-high eosinophilia is suggestive
treatment of toxocara
mebendazoles
what is the prevention for toxocara
-regular deworming of dogs and cats
-dispose of feces
-clean up after your dogs
what are the risk factors for toxocariasis
-living in southern us
-dogs defecating near parks
ultrasound findings in kids with toxocariasis on 18 cases
-in 2 of the asymptomatic patients, the diagnosis of toxocariasis was confirmed when eosinophilia was found in presurgical hemograms
the 18 case studies of toxocara showed what?
-that most docs don’t think of the possibility of toxocariasis even when there are hapatic nodules
-at the same time, the identification of hepatic nodules by us can aid in the diagnosis of toxocariasis since many of its symptoms are often non specific or nonexistent
how many people are infected by ascaris
1.3 bilion
