Flashcards in Lecture 19 Deck (66):
Types of Metazoa parasites
cestodes, trematodes, nematodes
What are cestodes?
How many parts do tape worms have?
2- rounded head and flat body of multiple segments
What is the rounded head of the tape worm known as?
What is the flat body of multiple segments of the tape worm called?
What is the host of tape worms?
4 types of tape worms?
pork, beef, fish, and dog tape worms
What do pork tape worms cause?
disease known as cysticircosis in humans
name of larvae in pork
What happens when humans swallow eggs?
larval form cysticerci develop in various organs like brain and eye where they encyst
What will happen when the cysticerci is in brain
mimic brain tumors and causes headache, vomiting, seizures
What will happen when cysticerci is in the eye?
may cause uveitis and retinitis
Where is the pork tape worm most common?
Asia, S. America and eastern Europe
Treatment for adult pork tape worms
Treatment for cysticercosis from pork tape worms
Transmission of beef tape worm
humans infected by eating under cooked beef containing larvae
Who is the host of beef tape worm?
Who is the intermediate host of beef tape worm?
Where is beef tape worm commonly found?
Africa, S. America and Eastern Europe
Clinical features of beef tape worm?
adult worms do not cause symptoms- proflatids protrude through anus
Treatment for beef tape worm?
Transmission of fish tape worm?
eating raw/uncooked fish containing larvae
Symptoms for adult worm fish tape worm
asymptomatic- may produce anemia due to B12 deficiency
What does dog tape worm cause?
hydatid cyst in humans
Who is the definitive host in dog tape worm?
What is the intermediate host for dog tape worm?
What is the dead and intermediate host of dog tape worm?
Transmission of dog tape worm
worms in the dog liberate thousands of eggs- ingested by sheep or human and embryo emerges into intestine and migrates to liver, lung, bone and brain
Where do the large fluid filled hydatid cyst develop in the body?
brain, lung, liver
What does hydatid cyst cause?
causing pressure effects on tissue
Treatment of dog tape worm
surgical removal to prevent accidental dissemination- hypertonic saline injection used
Life cycle of trematodes?
a sexual cycle (in humans) and an asexual reproduction in freshwater snails (intermediate host_
Transmission of trematodes to human
occurs either through penetration of skin by free-swimming larval form (cercaria) or via ingestion of cysts
What is the name for free-swimming larval?
What are the two things that schistosoma effects?
GIT and urinary tract- the forms exist as separate sexes
Where do S. mansoni and S. Japanicum live?
in mesentric veins draining the intestines
Where do S. Hematobium live?
in pelvic veins draining the bladder
What is the size of an adult Schistosoma worm
How does human infection of Schistosoma occur?
in water- when you swim in ponds or lakes- penetrate legs and enter blood circulation to reach liver
Clinical manifestations of Schistosoma?
most are asymptomatic- granulomas in liver, portal hypertension, enlarged liver and spleen, GI bleeding, granulomas in bladder causing hematuria
How do you diagnose Schistosoma in the lab?
finding characteristic eggs in stools
Treatment for Schistosoma
What are Nematodes?
2 types of Nematodes
intestinal and tissue nematodes
Describe what Nematodes look like?
have cylindrical body with complete digestive systems from mouth to anus- body has acellular resistant coating- female larger than male, 2 larval forms!
What is the host for nematodes?
Intermediate host for Nematodes?
What do Nematodes cause?
eosinophilia and allergy
What are enterobius vermicularis?
Transmission of enterobius vermicularis
eggs are ingested- hatch in small intestines and migrate to colon
Who is enterobius vermicularis common in?
Clinical manifestations of Enterobius vermicularis?
perianal pruritus, scratching
What country is Enterbius vermicularis most common in?
Lab diagnosis for Enterobius vermicularis
eggs not found in stool- may be in perianal scrapings
adult worms can be seen in stool or diapers
Treatment for Enterobius vermicualris
Mebendazol or pyrental palmoate
What type of worm is Ascaris lumbricoides?
How does human infection of Ascaris lumbricoides occur?
ingestion of egg in soil contaminated with human feces hatch in small intestines and larvae spreads through blood stream
Where can Ascaris lumbricoides be found?
in intestinal lumen- not attached to walls- live on ingested food
Clinical manifestations of Ascaris lumbricoides
larval migration through lungs causes eosinophilia, chronic bronchitis and cough
What can adult round worm cause?
Where are Ascaris lumbricoides common?
in tropical countries
Lab diagnosis of Ascaris?
detection of eggs ins tools- sometimes adult worms are passed in stools
Treatment for ascaris?
Mebendazol and pyrantel palmoate
Prevention for Ascaris?
proper disposal of night soils
What are the two types of Hook worms?
Ankylostoma duodenale, necator americanus