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28 Cards in this Set

  • Front
  • Back
What are some general characteristics of Nematodes?
1. elongate body.
2. Not segmented
3. Body covering is a cuticle for maintaing shape.
Two modes of reproduction in nematodes.
Ovovivparous; eggs
Larviparous; larva
What are the life cycle stages?
1. Egg
2. 4 larval stages
3. Immature adult (L5)
4. Adult
Name the three ways a nematode is transmitted.
1. Direct life cycle
2. Indirect life cycle
3. Developmental arrest
What is the order of Threadworms?
Which major parasite is included in this order?
Strongyloides spp.
Which sex is parasitic?
What is unique about the life cycle?
they have a free-living phase and a parasitic phase of life cycle.
Definitive hosts?
Most mammals. (cattle, sheep, donkeys, horses, primates, human, cat, dog, fox, pig)
Transmammory infection occurs in which animal species?
pigs, horses, cattle
Strongyloides cont'd

Give the three stages of infection for this nematode.
Invasive; penetration of skin
Pulmonary; bronchial pneumonia
Intestinal; bloody diarrhea
Which larval stage is the infective form?
L3 (always in nematodes)
Diagosis; how is Strongyloides spp. diagnosed?
rarely in eggs. Rhabditiform or filiform larva in feces. ELISA test.
Baermann technique. Sedimentation.
Ivermectin (may need to repeat)
What does ELISA stand for?`
Enzyme Linked Immuno Sorbent Assay
Which animal species acquires a prenatal infection from Strongyloides spp.?
How does this nematode effect humans?
autoinfection, hyperinfection
Order Strongylida

Scientific name for Large Strongyles?
Strongylus vulgaris
Identify the adult worm.
Dk. reddish gray. prominent stoma, w. cuticular fringe, buccal capsule, 2 prominent teeth, Copulatory bursa.
Both male and female have copulatory bursa, but how do they differ?
The female has spicules, and the male has finger-like projections.
where is the infection site for the adult worm?
Cecum and colon
Where is the infection site for the larva? Specifically L3 and L4?
wall of sm. intestine, cecum.
L3; colon
L4; Mesenteric artery
Main importance with infection from this nematode?
Life cycle of Strongyloides vulgaris
Morulated eggs hatch in feces.
L1 hatch in 1-2 days.
Molt to L3 in 1 wk.
L3 ingested, penetrated gut wall, molt to L4.
L4 migrates to Cr. Mesenteric artery (2-3) months
L4 or L5 ->walls of cecum
L5-> gut wall and mature
Pathogenesis of Strongylus vulgaris
Caused by larvae.
Nodules in gut wall.
Ulceration of gut wall.
Thrombi and emboli formation.
Fibrosis of arteries.
Eggs;Fecal flotation
Larvae; Baermann technique
Treatment for Strongylus vulgaris
Benzimidazoles, Ivermectin, Fenbendazole