Parasites - Helmiths Flashcards
Ascaris lumbricoides infectious stage
consume fertilized egg
Ascaris lumbricoides diagnostic stage
unfertilized egg will not undergo further development
Ascaris lumbricoides info
most common helminthic infection
internal yolk sac
Enterobius vermicularis infectious stage
embryonated eggs ingested by human
Enterobius vermicularis diagnostic stage
eggs on perianal folds
larvae inside the eggs mature with 4-6 hours
Enterobius vermicularis info
school/pre school children perianal itching (pruritus) collect early morning tape prep thin smooth transparent shell flattened side fin like expansion
Enterobius vermicularis classification
Pinworm
Nematode - roundworm
Ascaris lumbricoides classification
Nematode - roundworm
Trichuris trichiura infectious stage
embryonated eggs are ingested
Trichuris trichiura diagnostic stage
unembryonated eggs passed in feces
Trichuris trichiura info
barrel shaped
thick shelled
polar plugs at each end
whip like anterior
Trichuris trichiura classification
Whipworm
Nematode - roundworm
Trichinella spiralis infectious stage
ingestion of undercooked meat
Trichinella spiralis diagnostic stage
encysted larva in striated muscle
Trichinella spiralis info
treatment - thiabendazole, albendazole, mebendazole
intestinal tissue invasion (1 week post)
striated muscle tissue invasion (2 week post)
Trichinella spiralis classification
Nematode - Roundworm
Dracunculus medinensis infectious stage
larvae undergoes two molts in the copepod and becomes L3 larvae
Dracunculus medinensis diagnostic stage
female worm begins to emerge from the skin one year after infection
Dracunculus medinensis info
worm - whitish filament can be removed from center of ulceration
fluid discharge by worm - rhabditiform larvae
female in human host
remove using a stick to role and remove
Dracunculus medinensis classification
Guinea Worm disease
Nematode - roundworm
Toxocara canis/cati infectious stage
embryonated egg with larva
transplacental or transmammary
Toxocara canis/cati diagnostic stage
larvae in tissues
Toxocara canis/cati info
Cats/dogs
Visceral larva migrans (VLM) - preschool, larvae invade multiple tissues
Ocular larva migrans (OLM) - older/adults, larvae produce ophthalmologic lesions
3 “lips” on anterior end
Toxocara canis/cati classification
Nematode - roundworm
Ancylostoma duodenale infectious stage
Flariform larva penetrates skin
Ancylostoma duodenale diagnostic stage
eggs in feces
Ancylostoma duodenale info
2nd most common helminthic infection Loefflers syndrome "ground itch" oval, thin shelled, smooth, non pigmented and transparent A. duo = 2 pairs teeth A American = pair of cutting plates
Ancylostoma duodenale classification
Nematode - hookworm
Necator americanus infectious stage
Flariform larva penetrate skin
Necator americanus diagnostic stage
eggs in feces
Necator americanus info
2nd most common helminthic infection
Loefflers syndrome
“ground itch”
oval, thin shelled, smooth, non pigmented and transparent
Necator americanus classification
nematode - hookworm
Strongyloides stercoralis infectious stage
Infective flariform larvae penetrate the intact skin initiating infection
Autoinfection: Rhabditiform larvae in large intestine, become flariform larvae, penetrate intestinal mucosa or perianal skin, and migrate randomly to other organs
Flariform migrate to various pathways to the small intestine where they become adults
Strongyloides stercoralis diagnostic stage
Rhabditiform larvae in intestine are excreted in stool
Strongyloides stercoralis info
blood eosinophilia during acute and chronic stages
NO eggs
Strongyloides stercoralis classification
Nematode - hookworm
Wuchereria bancrofti infectious stage
Microfilariae develop to infective larvae in mosquito
Mosquito feeds on human and infective larvae enter skin
Wuchereria bancrofti diagnostic stage
Adult worms in lymphatic channels
Wuchereria bancrofti info
Anopheles or Aedes mosquito
6 months develop then leads to Elephantiasis
Nuclear column do NOT extend to tip of the tail
Wuchereria bancrofti classification
Nematode - Lymphatic filarial worm
Brugia malayi infectious stage
Mosquito takes a blood meal (L3 larvae enter skin)
Brugia malayi diagnostic stage
Adults produce sheathed microfilariae that reach the blood stream
Brugia malayi info
Mansonia and Aedes mosquito
tapered tail, significant gap between terminal and subterminal nuclei
nocturnal periodicity
Brugia malayi classification
Nematode - lymphatic filarial worm
Loa loa infectious stage
Fly (genus Chrysops) takes a blood meal (L3 larvae enter bite wound)
Loa loa diagnostic stage
Adults produce sheathed microfilariae that are found in spinal fluid, urine, sputum, peripheral blood and lungs
Loa loa info
Tabanid fly (horse fly)
Calabar swellings
exhibit diurnal periodicity
uninterrupted column of nuclei extend to the tip
exterior sheath does not stain with giemsa
Loa loa classification
African eye worm
Nematode - Filarial worm