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
Mansonella streptocerca infectious stage
Midge (genus Culicoides) takes a blood meal (L3 larvae enter bite wound)
Mansonella streptocerca diagnostic stage
Adults produce unsheathed microfilariae which reside in the skin but can reach the peripheral blood
Mansonella streptocerca classification
Nematode - filarial worm
Onchocerca volvus infectious stage
Black fly takes a blood meal (L3 larvae enter bite wound)
Onchocerca volvus diagnostic stage
Adults produce unsheathed microfilariae - in skin and lymphatics of connective tissue
Onchocerca volvus info
Simulium - black fly bite
leading cause of blindness
ocular lesions
Onchocerca volvus classification
River blindness
Nematode - filarial worm
Diphyllobathrium latum infectious stage
Infected crustacean ingested by freshwater fish
Procercoid larva released from crustacean, develops into plerocercoid larva
Diphyllobathrium latum diagnostic stage
Unembryonated eggs passed in feces
Diphyllobathrium latum info
Vit B12 deficiency with pernicious anemia high burden of intestinal obstruction >3000 proglottids largest parasite contains coiled uterus
Diphyllobathrium latum classification
Giant fish tapeworm
Cestode - tapeworm
Taenia saginata infectious stage
Oncospheres develop into cysticerci in muscle
Taenia saginata diagnostic stage
Eggs or gravid proglottids in feces and passed into environment
Taenia saginata info
passage of proglottids in stool 1st indication of illness
Taenia saginata classification
Beef Tapeworm
Taenia solium infectious stage
Oncospheres develop into cysticerci in muscle
Taenia solium diagnostic stage
Eggs or gravid proglottids in feces and passed into environment
Taenia solium info
more prevalent in communities where people live in close contact with pigs and eat undercooked pork
Taenia solium
Cestode - tapeworm
Hymenolepis nana infectious stage
Embryonated eggs in feces
Humans and rodents infected when they ingest cysticercoid infected arthropods
Autoinfection can occur of eggs remain in the intestine
The eggs then release the hexacanth embryo, which penetrates the intestinal villus continuing the cycle
Hymenolepis nana diagnostic stage
Embryonated eggs in feces
Hymenolepis nana info
most common cestode infection
protruding rostellum with a row 20-30 hooklets
pair of polar filaments on either side
outer shell, inner membrane with hexacanth (6 hooklets)
Hymenolepis nana classification
Dwarf tapeworm
Cestode - tapeworm
Hymenolepis diminuta infectious stage
Cysticerci in body cavity of insect ingested by rodent or human
Hymenolepis diminuta diagnostic stage
Eggs passed in feces
Hymenolepis diminuta info
striated outer membrane, space between 2 membranes smooth
oncosphere - hexacanth (6 hooklets)
Hymenolepis diminuta classification
Rat tapeworm
Cestode - tapeworm
Echinococcus granulosus infectious stage
Embryonated eggs in feces
Echinococcus granulosus diagnostic stage
Hydatid cyst in liver, lungs, etc
Echinococcus granulosus info
canine infection
where dogs ingest organs from infected animals
ingestion of eggs from food/water or fomites contaminated with dog feces
migration from intestinal lumen to other body sites and develop into hydatid cysts
Echinococcus granulosus classification
Cestode - tapeworm
Fasciolopsis buski infectious stage
Metacercariae on water plant ingested by human, sheep, or cattle
Fasciolopsis buski diagnostic stage
Unembryonated eggs passed in feces
Fasciolopsis buski info
areas where humans raise pigs and consume freshwater plants
attachment to intestinal mucosa
Fasciolopsis buski classification
Trematode - fluke
Heterophyes heterophyes infectious stage
Host becomes infected by ingesting undercooked fish containing metacercariae
Heterophyes heterophyes diagnostic stage
Embryonated eggs each with a fully developed miracidium are passed in feces
Heterophyes heterophyes info
migration of eggs to heart/brain
surface covered with minute spines
adults reside in small intestine of definitive host
Heterophyes heterophyes classification
Trematode - fluke
Metagonimus yokogawai infectious stage
Host becomes infected by ingesting undercooked fish containing metacercariae
Metagonimus yokogawai diagnostic stage
Embryonated eggs each with a fully developed miracidium are passed in feces
Metagonimus yokogawai info
smallest liver fluke to infect humans
requires snail as intermediate host
Metagonimus yokogawai classification
Trematode - fluke
Clonorchis sienensis infectious stage
Metacercariae in flesh or skin of freshwater fish are ingested by human host
Clonorchis sienensis diagnostic stage
Embryonated eggs passed in feces
Clonorchis sienensis info
following ingestion of imported, undercooked or pickled freshwater fish containing metacercariae
inflammation and intermittent obstruction of biliary ducts
Clonorchis sienensis classification
Trematode - liver fluke
Paragonimus westermani infectious stage
Cercariae invade the crustacean and encyst into metacercariae
Paragonimus westermani diagnostic stage
Unembryonated eggs
Paragonimus westermani info
acute - invasion and migration
chronic - pulmonary and extrapulmonary
oral and ventral suckers
Paragonimus westermani classification
Trematode - liver fluke
Fasciola hepatica infectious stage
Metacercariae on water plant ingested by human, sheep, or cattle
Fasciola hepatica diagnostic stage
Unembryonated eggs passed in feces
Fasciola hepatica info
area where sheep and cattle are raised and where humans ingest raw watercress
acute - migration immature fluke through hepatic parenchyma
chronic - adult fluke within bile duct
Fasciola hepatica classification
Trematode - liver fluke
Schistosoma japonicum infectious stage
Cercariae released by snail into water and free swimming
Schistosoma japonicum diagnostic stage
Eggs circulate to liver and shed in stools
In urine - venous plexus of bladder
Schistosoma japonicum info
more rounded
spine smaller and less conspicuous than other species
Schistosoma japonicum classification
Trematode - fluke
Schistosoma mansonii infectious stage
Cercariae released by snail into water and free swimming
Schistosoma mansonii diagnostic stage
Eggs circulate to liver and shed in stools
In urine - venous plexus of bladder
Schistosoma mansonii info
prominent lateral spine near posterior end
Schistosoma mansonii classification
Swamp fever
Trematode - fluke
Schistosoma haematobium infectious stage
Cercariae released by snail into water and free swimming
Schistosoma haematobium diagnostic stage
Eggs circulate to liver and shed in stools
In urine - venous plexus of bladder
Schistosoma haematobium info
terminal spine
shed in urine
Schistosoma haematobium classification
Trematode - fluke
Schistosoma intercalatum infectious stage
Cercariae released by snail into water and free swimming
Schistosoma intercalatum diagnostic stage
Eggs circulate to liver and shed in stools
In urine - venous plexus of bladder
Schistosoma intercalatum info
terminal spine
equatorial (central) bulge and are shed in stool
Schistosoma intercalatum classification
Trematode - fluke
Schistosoma species symptom
Katayamas fever
