Helminths Flashcards
Prolapsed rectum in children
Trichuris trichiura - whip worm
Football shaped eggs in feces
Trichuris trichiura - whip worm
Life cycle - ascaris lumbricoides
Ingestions of fully EMBRYONATED eggs
Larvae hatch and migrate to lungs
Cough up and swallow
Adults live in small intestine for up to one year
Temperate worm
Enterobius vermicularis - pinworm
Don’t attach to intestinal wall , swim against peristalsis
Ascaris lumbricoides - giant round worm
Enterobius vermicularis - life cycle
Pinworm
In humans : eggs to larva to adult
Gravid female worm. Migrates out of anus and deposits eggs around anus and drys out and explodes
Trichuris trichiura life cycle
Whip worm
Ingest FULLY EMBRYONATED eggs (10d)
Larva adhere to sm intestine temporarily
Adults anterior end embed in cecal mucosa
Perianal itchiness at night
Enterobius vermicularis -pinworm
Found in night soil
Ascaris lumbricoides - giant roundworm
Heavy infections can cause ulceration or hemorrhage
May resemble ibd
Trichuris trichiura whip worm
Moist warm climates
Helminths that mature in the lungs
Ascaris lumbricoides - giant roundworm
Necator americansus - new world hookworm
Strongyloides stercoralis- small roundworm
Life cycle of necator americansus and ancyclostoma duodenale
HOOKWORMS
Infection with filariform larva thru skin
Goes to lungs - gets coughed up stalled and adults live in small intestines
- eggs go into poop
Rhabdiform larva hatches in soil becomes filariform larva
Life’s in host for 8-16 yrs
May see occult blood in stool or may become anemic
Hook worms - necator americansus and ancyclostoma duodenale
Life cycle Strongyloides
Filariform larva infects thru skin goes to lungs and is coughed then swallowed
In mucus of sm intestine become adults lay eggs rhabdiform larva in feces. In soil are free living adults lay eggs become rhabdiform larva and then into filariform
Can have autoinfection - rhab to filariform in intestine
Taenia solium
Pork tapeworm ( Cestodes) Infxn with cysticercus ( larvae) via ingestion raw pork Adult in sm intestine, eggs to to poop
Ingested eggs larva hatch in sm Intestine and migrate to muscle - cysticercus
May see cerebral/ neuro and ocular cysticercosis
Taenia saginata
Beef tapeworm - Cestodes
Similar to solium but stays in sm intestine can live more than 30yrs
Contaminated undercooked beef
May see diarrhea , weight loss, nausea
Cestodes
Scolex - head with hooks
Proglottidis - body with eggs
Hermaphrodites
Tapeworms
Tapeworm got by ingesting contaminated undercooked fish
Diphyllobothrium lattum
Can occasionally attach at proximal jejunum - clincial vit b12 deficiency
Causes tropical pulmonary eosinophilia
Wuchereria bancroftii , brugia malayi , brugia timori
Fluid filled cysts containing hydatid sand in liver , lungs
Echincoccus granulosus - dog tapeworm
( sand “etched” ) hydatid sand caused by “etchincoccus”
Definitive host dogs
Incidental - humans
Nematode route of entry
You’ll get sick if you EAT these
These get into your feer from the SANd
Enterobius
Ascaris
Trichinella
Strongyloides
Ancyclostoma
Necator
Ingestion of contaminated undercooked or raw pork
Trichinella spiralis
Schistosomes ( blood flukes)
Trematodes or flat worms
3 infect humans
Mansoni ( colon rectum) japonicum, hematobium ( bladder)
Infect as cercaria thru skin penetration
Mature in the liver - larva in feces and urine
Miracidium - intermediate host (snails)
Become sporocysts- cercaria in the. Water
Can deposit eggs in tissue usually liver
Can cover self with host ag
Life cycle Wuchereria bancroftii , brugia malayi , brugia timori
Mosquito bite with larva Larva go to lymph nodes Adult worms live in lymphatic a Produce embryos - microfilariae Release them nocturnally - matching the feeding habits of vectors
Can cause elephantiasis aka the one that lives in the lymph
Wuchereria bancroftii , brugia malayi , brugia timori
Make ulcers and when contacted with water releases a ton of larva
Dracunculus medicnesis - guinea worm
Intermediate host - crustaceans
Trichinosis is caused by what form of the worm . what does the immune system do
Larval form can have diarrhea and then an acute inflammatory rxn and the paralysis - pmns eos lymphs ige attack and kill the worm
What transmits onchocerca volvulus
Simulium species of black fly
This worm is transmitted by the mango fly species chrysops
Loa loa - African eye worm
Can be seen transverse conjunctival tissue
Causes river blindness
Onchocerca volvulus
Life cycle of Trichinella
Intestine is larva and go to adult
Produce more more larva in intestine and then they form cysts and go to striated muscle there they convert the muscle to nurse cells
