Parasitology - part 2 Flashcards
Nematodes (roundworms), cestodes (tapeworms) and trematodes (flukes) are part of this group.
Helminths
unsegmented flatworms.
Trematodes/flukes
Macroscopically visible intestinal nematode that live in the cecum.
Enterobius vermicularis
Child is woken up by itching caused by eggs that were laid on the perianal skin, or parents will see worms of this causative agent.
Enterobius vermicularis
Most common cause of nematode infection in North America.
30% of children are infected by it worldwide.
Enterobius vermicularis
Although the infection by Enterobius vermicularis is uncomfortable, it is completely _______.
benign (harmless, or other synonym)
Nematode which can be large enough to obstruct a bowel.
Transmitted through ingestion of soil.
Ascaris lumbricoides
Causative agent of the number one untreated tropical disease.
Ascaris lumbricoides - Ascariasis
Where do adult Ascaris lumbricoides worms live?
upper small intestine
Ascaris females produce _______ numbers of eggs, which do not become infective until __-__ weeks in soil.
enormous
2-3
(Eggs excreted in feces)
Ascaris lives primary in the upper SI, however it doesn’t like when the host gets a fever, or receives general anasthetic. In this instance it migrates. What problems can it cause?
Migrate into appendix and cause acute appendicitis
Migrate to biliary duct and cause obstructive jaundice
Migrate out anus
Migrate to stomach (doesn’t like acid) and can run out the mouth or nose.
An important thing to remember, is that if you are practicing in the tropics and a patient has a scheduled elective surgery, a week or two before they must be treated for ________. Why?
Ascaris
worms will migrate when a person receives general anesthetic
If a person is in the tropics and will receive elective surgery, why do they have to be treated for Ascaris infection? Why can’t the stools just be checked for eggs?
Perhaps there are only male worms in the bowel
Other than migration, what is a potential complication of Ascaris infection?
Hypersensitivity to larvae in the lungs
Ancylostoma duodenale and Necator americanus are both this.
intestinal hookworms
Hookworms are acquired this way.
by penetrating intact skin
Walking barefoot, lying on a beach with bare skin exposed is a risk factor for infestation by this group of helminths.
Intestinal hookworms
These worms enter the circulation, are coughed and swallowed and live out in the microvilli of the SI.
Intestinal hookworms
Treatment for these worms is not medically necessary unless their blood meals is causing anemia in the patient (although patients may request treatment).
Intestinal hookworms
_______ _______ is the first manifestation following skin penetration by intestinal hookworms.
Ground itch
Unlucky infection in which the agent cannot complete its life cycle. Ends up crawling under the skin and producing very itchy eruptions on the skin.
Dog hookworm (ancylostoma brasiliense)