Small Group Parasites 2 Flashcards
What are the infectious forms of hydatid disease and beef, pork and fish tape worm? What are the resulting diseases?
hydatid- egg
beef, pork and fish tapeworm: encysted larvae for intestinal illness
pork neurocytocerocis: eggs
Describe the life cycle of the tape worms. How can you prevent infection?
ingestion of encysted larvae hatch in the intestine leads to only taniasis, ingestion of adult worms or auto infection by eggs the oncospheres are released into the intestine and penetrate the intestinal wall, migrating to striated muscles, brain, and liver (and many other tissues)
fully cook or freeze meat, appropriate hand hygiene so foods are not fecally contaminated with eggs
Describe the life cycle of hydatid disease. How can you prevent infection?
Echinococcus granulosis infection only occurs after canids (definitive host) have eaten raw intestines of ungulates (intermediate host) and pass on the eggs to humans
only eggs prouduce hydatid disease not undercooked meat
prevent dogs from undercooked offal and deworm dogs, wash hands before eating and avoid dog tongue in your mouth
Outline the lifecycle of the pinworm. (Enterobius vermicularis)
eggs are swallowed and hatch in the intestine where the adults mate and migrate to the colon
gravid female emerges from anus to lay eggs put to 20,000 and perianal scratching facilities transmission to mouth
adult worms do not directly invade tissue, immune response is responsible for most of the symptoms
Recommend a set of procedures to eliminate a family outbreak of pinworm infection and prevent it from spreading to non-family members.
treat household contacts, bedding and clothes should be washed in hot water
strict sanitation at daycare centers
Outline the life cycle of the human schistosomes.
eggs shed into water and invade appropriate snail species
larvae contact skin of human and penetrate, reaching circulation; reaching the portal system they mature and and produce a ton of eggs (responsible for symptoms) as they are trapped in body tissues causing immune reaction and pathology due to obstruction
S. mansion and S. japonicum (colon) S. haematobium (bladder)
Describe the counsel you would give to a patient infected with human schistosomiasis, including expectaitations of the course of the disease after treatment.
S. haematobium can cause granulomatous fibrotic response to the eggs and scarring in the urinary vasculature, psuedopolyps may progress into bladder carcinoma; eggs will resolve quickly with treatment, granulomas take time to regress
Describe the only form of schistosome associated disease seen commonly in the US and an approach to avoiding it.
swimmers itch- the larvae penetrate skin but only go on to create an IgE response and sometimes delayed type hypersensitivity reaction
Name the helminth causing ascariasis infection, the infectious form and the stage responsible for the pathology seen in the host..
ascaris lumbricoides, humans ingest the mature eggs that hatch in the stomach and sm, intestine
Discuss how this round worm is diagnosed.
identify eggs in the feces
Describe the epidemiology of round worm including the life cycle.
larvae penetrate the intestinal wall and disseminate to various sites including the lungs (where they can be coughed up and swallowed again) and mature into adult worms
Explain what determines the severity of disease with round worm.
worm burden is directly related to severity of illnesses (intestinal obstruction possible)
as burden increases, nausea, cramping will increase and in young children malnutrition can result
Can O&P results alone confirm Tania sodium infection?
no, the eggs of pork and beef tapeworm are indistinguishable microscopically
(seropositivity along with radiology results would confirm the dx. of neurocyticercosis)
