Chapter 2 - The Nematodes Flashcards
What are the three basic morphologic forms of Nematodes?
Eggs
Larva
Adult worms
What are the 2 Nematode life cycle that tissue is become involved which serve as the primary residence of the organisms?
Trichinella spiralis and Dracunculus medenensis
What are the 6 species that claim under the intestinal species? ( ETANAS)
- Enterobius vermicularis
- Trichuris trichiura
- Ascaris lumbricoides
- Necator americanus
- Ancylostoma duodenale
- Strongloides stercoralis
What are the 2 species that claim under intestinal-tissue species ? ( TD)
Trichuris trichiura & Dracunculus medenensis
The egg is consist of a developing larva surrounded by conspicuous doubled-layered, thick - walled colorless shell.
Enterobius vermicularis
What is the specimen choice for recovery E. vermicularis?
Cellophane tape preparation
What is the infective stage of E. vermicularis ?
Embryonated eggs
What is the diagnostic stage of E. vermicularis?
Eggs in the perianal
What is the mode of transmission of E. vermicularis ?
Embryonated eggs ingested by humans
The average barrel- shaped ( also considered by some to be football-shaped) ,the undeveloped unicellular embryo is surrounded by a smooth shell that retains a yellow-brown color from it’s contact with host bile.
Trichuris trichiura
What is the specimen of choice for the recovery of T. trichiura eggs?
Stool
What is the infective stage of T. trichiura?
Embryonated eggs
What is the diagnostic stage of T. trichiura
Unembryonated egg in feces
What is the mode of transmission of T. trichiura?
Ingestion of embryonated eggs thru soil or contaminated food or hands
A thin shell protects the inner amorphous mass of protoplasm and the egg is usually corticated.
Ascaris lumbricoides
This is the sandwich in between the embryo and mammilated albuminous material.
Corticated
Eggs lacking an outer mammilated, albuminous coating refered to as _________ fertilized egg.
Decorticated
This worm is the largest known intestinal nematodes.
Ascaris adult worm
What is the infective stage of A. lumbricoides?
Embryonated eggs
What is the diagnostic stage of A. lumbricoides?
Unfertilized & Fertilized egg
What is the mode of transmission of A. lumbricoides?
Ingestion of embryonated eggs thru soil contaminated ,food and hands
What is the specimen of choice for the recovery of A. lumbricoides egg?
Stool
This has a thin smooth colorless shell and ranges in length from 60 to 75 um.
Necator americanus
This has also have a thin shell with smooth colorless shell and measures up to 55 to 60 um.
Ancylostoma duodenale
What is the average measurements of immature newly hatched hookworm rhabditiform larva?
15 by 270 micrometer
What is the measurements of 5 days old hookworm rhabditiform larva?
540 to 700 um
This morphologic forms is characterized by the presence of a long oral cavity known as ______________
Buccal cavity or buccal capsule
What is the diagnostic stage of hookworm?
Egg cells and larva
This a precursor structure to a reproductive system consisting of a clump of cells in an ovoid formation.
Small genital primordium
What is the infective stage of hookworm filariform larva ?
Third stage filariform larvae
What is the diagnostic stage of filariform larvae of hookworm?
Eggs in feces
What is the buccal capsule characteristics of N. americanus
Pair of cutting plates
What is the buccal capsule characteristics of A. duodenale?
Contains actual teeth
The eggs of both organisms are similar in that when present,the two-four, or eight-cell stage of embryonic cleavage is surrounded by a thin hyaline shell.
Strongloides stercoralis
These larvae settle by coiling up in muscle fibers and becoming encysted and its fully developed larva may reach up to a length of 1 mm.
Trichinella spiralis
What is the diagnostic stage of T. spiralis?
Encysted larvae
What is the infective stage of T. spiralis ?
Infection is initiated after consuming undercooked contaminated meat , primarily striated muscle.
The tail makes up about one third of the body length and culminates in a point.
Dracunculus medenensis
It has a peanut shaped eggs with striated shells and flattened bipolar plugs and it measures 36 to 45 micrometer by 20 micrometer.
Capillaria philippinensis
What is the infective stage of C. philippinensis?
When embryonated eggs are eaten by small freshwater fish
What is the diagnostic stage of C. philippinensis?
Unembryonated eggs in feces
What is the mode of transmission of C. philippinensis?
When human ingest these raw or undercooked infective fish
It has a thin-shelled , colorless and measure up to 75-95 um in length by 40-50 um in the width.
Trichostrongylus spp.
What is the infective stage of T. spp?
3rd stage larvae
What is the diagnostic stage of T. spp?
Eggs in feces
What is the mode of transmission of T. spp?
Skin penetration
What is the method of choice for the recovery of encysted larvae?
Examination of affected skeletal muscles
