Micro Block 5 Flashcards
Define Tegument
Protective covering or cuticle found in helminths
What are the attachment structures of helminths?
Hooks
Suckers
Teeth
Plates
Helminths include what sub-phylums?
Platyhelminths- flat worms
Cestodes- tapeworms
Trematodes
What are the segments of a tapeworms body called?
Proglottids
Strobila- chain of proglottids
Define Scolex
Head of Cestodes
Define Rostellum
Pointed end of scolex w/ points of attachment
How do tapeworms eat and reproduce?
Absorption
Hermaphroditic
Most Cestode eggs are ____ and contain ____?
What is the exception?
Nonperculated, hexacanth embryo
Exception- Diphyllobothrium Latum, unemyoneated operculated eggs
Define Oncosphere
Six-hooked larval form released when Cestode eggs hatch
What is the life cycle of Taenia?
1- eggs/gravid proglottids in feces passed to environment
2- cattle/pigs infected from eating
3- oncospheres penetrate intestine wall->muscles
4- cysticerci develops in muscle
5- humans infected by eating raw/under cooked meat
6- scolex attaches to intesetine and matures to adult
Which Taenia species gets bigger?
Saginata- 5m or less
Solium- 2-7m
Where are Taenia found?
Worldwide distribution
How does Taenia Saginata persist within the US?
Where is Taenia solium more prevalent?
Larva ingested with eating raw/rare steak
Communities w/ close relations w/ pigs/under cooked pork
Where is Taenia Asiatic predominantly found?
Asia Korea China Indonesia Thailand
How does Taenia Saginata present clinically?
Mild abdominal symptoms
Passing ACTIVE proglottids
Appendicitis/cholangitis
How does Taenia Solium present clincally?
Passage of proglottid
What is the most important feature of Taenia Solium?
Risk of developing cysticercosis
How are Taenia Saginata diagnosed in the lab?
Eggs and proglottids in feces
Not possible within first 3mon of infection before adult is formed
Count # of primary uterine branches (Solium= 7-13, Saginata= 15-30)
Gravid proglottid longer than wide
How long for Taenia Saginata to mature and lifespan?
2-3mon to mature
Lifespan- 5 years
What do the scolices of Taenia Saginata look like?
4 muscular cup suckers
No crown of hooklets on restellum
Can Ab detection methods detect Taenia infections?
Yes, especially in early stages when adult form is growing
How long after Taenia treatment are samples collected?
3 days after treatment
Repeat @ 1 and 3 mon
What is different/unique about the Taenia Solium life cycle and infection ability?
Larva infect humans and pigs
Infection by ingestion of contaminant or autoinfection
What is the intermediate host for Taenia Solium?
Pigs
How is human cysticercosis acquired?
Ingesting T. Solium eggs from feces of a human carrying T. Solium adult tapeworm
Acquired in populations w/out interaction/consumption of pork
What is the greatest concern about Cysticercosis?
Cerebral or Neural
Causes seizures, mental disturbances, space-occupying lesions
Extracerebral cysticercosis can cause lesions in what 3 areas?
Ocular
Cardiac
Spine
How would asymptomatic cysticercosis be seen?
Subcutaneous nodules
Calcified intramuscular nodules
Taenia Solium eggs and proglottids in feces diagnosis ____ but not _____
Taeniasis
Cysticercosis
Why do people with Taenia Solium eggs/proglottids found in feces need to be evaluated seriologically?
Autoinfection resulting in cysticercosis can occur
What kind of scolex branches would be seen with Cysticercosis infection?
4 muscle-cup suckers and crown of hooklets
What is the immunodiagnostic test of choice for confirming clinical/radiographic presumptions of Neurocysticercosis?
Immunoblot assay with purified T. Solium Ags
Can PCR tests detect T. Solium infections?
Yes, detects DNA in CSF
What is the Fish or Broad Tapeworm?
Diphyllobothrium Latum
What is the largest human tapeworm?
Diphyllobothrum latum
What are the two intermediate hosts of Diphyllobothrium?
Crustaceans/copepod
Freshwater fish
What is the life cycle of Diphyllobothrium?
1- unembryonated eggs pass in feces
2- eggs embryonate in water
3- coracidia hatch from eggs and ingested by crustaceans
4- procercoid larva in crustacean
5- infected crustacean eaten by fish, precercoid larva->plerocercoid larva
6- predator fish eats smaller fish
7- human eats infected fish
8- adult lives in small intestine, proglottids release immature eggs
Where is diphyllobothrisasis located geographically?
Northern Hemisphere and South America
What kind of food is diphyllobothriasis infections associated with?
Ceviche
How long do diphyllobothriasis infections last?
Decades
Most are asymptomatic
What are the S/Sx of diphyllobothriasis infections?
Abdominal discomfort Diarrhea, vomiting Weight Loss B12 deficiency w/ pernicious anemia Massive infections cause obstructions
How are Diphyllobothriasis infections confirmed diagnostically?
Eggs or proglottids in stool
Eggs are operculated
What does the scolex of Diphyllobothriasis look like?
Lance shaped, two leaf shaped with bothria (lateral groobes for attachment)
What do Diphyllobothriasis proglottids look like microscopically?
Wider than long
Central uterine structure resembling a rosette
How are Diphyllobothriasis infections acquired?
Eating under cooked/raw fresh water fish with pleurocercoi larvae
Diphyllobothriasis infections are often asymptomatic unless?
Proglottids migrate to gall bladder/bile ducts
What causes Human Echinococcosis?
Hydatid Disease
Ingestion of larval Echinococcus cestodes
What is the most frequently encountered Echinococcosis?
Where is it found?
Echinococcus granulosus causing Cystic Echinococcosis
Worldwide, but predominantly where dogs eat infected animal parts
What does E. Multiocularis cause?
Where is it found?
Alveolar Echinococcosis
Northern Hemisphere
What does E. Vogeli cause?
Where is it found?
Polycystic echinococcosis
Central and South America
What does E. Oligarthrus cause?
Where is it found?
Rarest form of human echinococcosis
3 cases
Central and South America
What are the definitive and intermediate hosts in the Echococcus life cycle?
Definitive- Dogs/canidae,
Intermediate- sheep, goats, swine
What form of Echinococcus do the definitive and intermediate hosts ingest?
Dogs/canidae: Cysts
Goat/sheep/swine: Eggs
Humans infected with Echinococcus ingested the microbe in what form?
Embryonated egg in feces
What is the diagnostic stage of Echinococcus life cycle?
Hydatid cyst in liver/lungs
What is the infective and diagnostic stage of the Diaphyllobothrium life cycle?
I: infected crustacean eaten by fish
D: Unembryonated egg in feces
What does the scolex of Echinococcus look like?
Scolex has 4 sucking discs and double row of hooklets
Strobila has 3 proglottids: one mature, one immature, one gravid
Define Hydatid cyst
Larval form of Echinococcus that slowly grows tumor-like in humans with a unilocular membrane
Define Brood Capsule
Structures on wall of membrane in hydatid cyst
Define Protoscolices
Tapeworm head that develops in brood capsules
Define Hydatid sand
Formed when daughter cysts and brood capsules disintegrate and liberate protoscolices
How do Echinococcus granulosus infections present S/Sx?
Silent for years or decades before enlarged cysts cause symptoms
What happens if a Echinoccus cyst ruptures within a patient?
Fever
Urticaria
Eosinophilia
Anaphylactic shock
Which form of Echinocccus infects the liver as a slow growing/invasively destructive tumor?
Multiocularis- destructive tumor
Vogeli- slow growing tumor
How is Echinococcus diagnosed clinically?
Radiological examination
What is key when dealing with Echinococcosis?
Prevention
Washing hands/utensils
Keeping dogs clear of infected organs
Hymenolepsis nana is AKA ?
Dwarf tapeworm
What is the egg appearance of Hymenolepsis?
6 hooked embryo
Polar filaments
What is the scolex appearance of Hymenolepsis?
Four muscular suckers
Crown of hooklets
What is the infective stage of Hymenolepis nana?
Embryonated egg eaten by human from contaminated food/water/hands
What is the diagnostic stage of Hymenolepis nana?
Embryonated egg in feces
What larvae can develop in human intestines as a cysticercus?
Hymenolepis nana
Where is Hymenolepis nana predominantly found?
20mill infections worldwide, mostly children or institutionalized peoples
What are the infectious and diagnostic stages of Hymenolepis diminuta?
I= Cysticerci in body of insect ingested by human/rodent D= Eggs in feces
What is the most common cause of all cestode infections worldwide?
Hymenolepis nana
Hymenolepis Nana and Diminuta usually present ? clinically?
Asymptomatic
Heavy infections of Hymenolepis Nana can present clinically with ? S/Sx?
Headache
Anorexia
Abdominal pain
Diarrhea
What does Hymenoleps Diminuta require in order to reach infective cysticercoid stage?
Larval insect mealworms
What is the pumpkin seed tapeworm?
Dipylidium caninum
How many eggs are in each Pumpkin Seed packet of the Dipylidium Caninum?
25 eggs/packet
What are the infective and diagnostic stages of Dipylidium caninum?
I- adult flea carries infectious cysticercoid
D= Proglottids w/ eggs in feces
Where are Dipylidium Caninum infections reported?
Worldwide
Europe, PI, China, Japan, Argentina, US
How do infections of Dipylidium caninum present in humans and in animals?
Humans- asymptomatic
Animals- Anal pruritis
What is the most striking feature/sign of Dipylidium infections in humans/animals?
Passing proglottids
Motile when passed, resemble maggots
How do humans acquire Dipylidium infections?
Accidental ingestion of flea from dog/cat
What are the diagnostic and infectious stages of Spirometra species?
I= infected crustacean ingested by second intermediate host D= unembronated eggs in feces
Where are Spirometra infections reported?
Worldwide but predominantly in Southeast Asia
Endemic to animals in North America
What type of infection causes painful inflammatory tissues reactions, nodules and periorbital edema?
Sparganosis from spirometra
How does Spirometra ocular diseases get introduced?
Frog/snake flex as covering for wound near eye
How are Sparganum infections diagnosed?
Recovery of sparganum from infected tissue
How is Sparganum infections acquired?
Eating/drinking infected copepod, undercooked meat, tissue exposure
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Trematoda digestive systems
What do the digestive systems of Trematodas include?
Mouth
Pharynx
Esophagus
Ceca- blind sac intestines
What are the 3 types of reproductive systems Trematods have?
Monoecious- male and female in one organism
Dioecious- separate male/femal organisms
Fertilization- cross or self
Most trematodes require two intermediate hosts, what are the ones called that only use one?
Schistosome
What are the 4 shapes of intestinal ceca in trematodes?
Straight
Undulating
Branches
Rejoined
What are the 3 testicular positions of trematodes?
Para
Oblique
Tandem
What is the name of the Lung Fluke?
Paragonimus Westermani
What are the two intermediate hosts of Paragonimus Westermani?
What is it’s reservoir host?
Snail then Crab/crayfish
Piscivores (fish eating animals)
What is the infective form of Paragonimus Westermani?
Metacercaria
What is the mode of ingestion of Paragonimus Westermani?
Ingestion of undercooked crustaceans carrying metcercaria
What is the specimen of choice for laboratory diagnosis of Paragonimus Westermani?
Sputum or Feces with eggs in it
What is the name of the Sheep Liver Fluke?
Fasciola Hepatica
How does Fasciola Hepatica cause infections in the body?
Eating metacercaria on leafy greens plants
Watercress
Where are adult forms of Fasciola Hepatica found in the body?
Bile ducts
Liver tissue
How is Fasciola Haptica diagnosed?
Eggs in feces
CT scan
ELISA
What is the name of the Giant Intestinal Fluke
Fasciolopsis Buski
Where is Fasciolopsis Buski found geographically?
SE Asia
India
China
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Slide 41 F Buski
