Microbiology - Helminths Flashcards
Platyhelminths =
flatworms
Nematodes =
Roundworms
Name three roundworms who’s life cycle involve a larval form that migrates through the tissue and into the lung
1 Ascaris lumbricoides
2 Necator americanus
3 Strongyloides stercoralis
Necator americanus mode of transmission?
This long, slender fiariform larva can penetrate skin.
When larva of Strongyloides stercoralis hatch in the small intestine, they can do three different things. What?
1 Autoinfection - penetrate the intestines directly -> then go to lung
2 Direct cycle - passed in feces. Penetrate the skin of new host
3 Indirect cycle - Larvae are passed in stool. Then lay eggs in soil which must hatch to infect new person.
Ascaris lumbricoides and Necator americanus have very similar life cycles. How do they differ?
Ascaris - moves from intestines to lung.
Necator - moves from foot(penetrate skin) to lung.
How do Trichinella infection occur?
Ingestion of raw/undercooked pork.
Trichuris trichiura =
whipworm
Enterobius vermicularis =
Pinworm
Enterobius vermicularis and Trichuris trichiura life cyles?
Both have very simple life cycles. Transmission occurs by infestion of eggs. These eggs hatch in the small intestine.
What ass-related manifestation occurs with Enterobius vermicularis infection?
Female pinworm migrates to the perianal area(usually at night) to lay her eggs. This causes severe perianal itching!
Enterobius vermicularis = itchy asshole!
Blood and tissue nematodes route of spread?
Bite of an arthropod.
How is Ochocera volvulus spread?
By infected black flies.
Manifestations of Onchocerca volvulus infection?
1 Skin lesions that are intraepithelial granulomas = lizzard skin
2 Microfilariae migrate to the eye causing blindness.
Onchocerca volvulus = a blind lizzard
Wuchereria bancrofti & Brugia malayi, type of infection and clinical manifestation?
Both cause lymphatic infection and can result in chronic leg swelling.
