Helminths Flashcards
What are helminths?
Worms! Invertebrates, Macroparasites
What Phylum do roundworms belong to?
Nematodes
What Phylum do Flatworms belong to?
Platyhelminthes
What phylum do thorny- headed worms come from?
Acanthocephala
Platyhelminthes can be divided into 2 classes. What are they and what is the common name of those within them?
Cestodes (tapeworms) and Trematodes (flukes)
Where can you find Nematodes?
Present in every imaginable habitat. Arctic, Soil, Deep Sea, ect
TRUE or FALSE: Nematodes are Coelomates?
No they are pseudoceolomates
What is the target of antihelmintic drugs?
Nerve function. It is necessary to survival for nematodes
What are key features of nematodes?
- chitinous cuticle, presence of complete digestive system. - Sexual dimorphism, Reproduce sexually
Which nematode does not reproduce sexually?
Strongyloides
Male nematodes have what reproductive structure and what is it for?
BONUS: What is the structure made out of?
Males have copulatory bursa for grasping females, and copulatory spicules for guiding sperm.
Bonus: It is made out of a cuticle modification.
What are the 3 cuticular modifications in nematodes?
- Various size/ shape of buccal cavity
- leaf crown/ alae
- Copulatory bursa
Which nematodes have a large Copulatory bursa?
Strongyles
What is the infective state of nematodes?
L3 and sometimes L1
What is the adult stage of nematodes referred to?
L5
Where are eggs shed from the nematode in regard to the host?
L1 in feces (sometimes in urine), some dont shed at all
What is the most common migration of nematodes?
Hepatic-Tracheal migration
(ascarids)
What kind of lifecycle do nematodes have?
Direct lifecycle, indirect lifecycle, oviparous, viviparous, ovoviviparous, obligatory,
facultative
Nematode development can be completed where?
Entirely at the predilection site.
Larvae/pre-adults can also migrate during development
Nematodes that generally develop ONLY in the gut are ?
Generally asymptomatic with low pathogenicity.
Where do larvae migrate to in the case of tracheal ascarid?
Larvae will migrate to the liver, lungs, and heart.
Can cause hepatic damage, respiratory signs, lung lesions, etc.
What are critical external components for larval/ egg development?
Temperature and Humidity
What is hypobiosis?
-Inhibited larval development to avoid adverse conditions for development and
maturation – adaptation to host and environmental conditions
- Development starts once condition become favorable
Give an example of parasites with thin egg shells?
Hookworm, Strongyloides
Give an example of nematodes with thick egg shells?
Ascarids
What is periparturient?
When the immune system is compromised during parturition → increased number of eggs/larvae
What is spring rise?
Spring rise is the build of larvae of the egg during the spring
What stage of development is L5 in nematodes?
Adult
What are oncospheres?
A hatched hexacanth
Name the two morphological factors that help differentiate between Nematode eggs:
Egg shape
Egg shell thickness
How do you diagnose infections of nematodes?
- Morphological identification
- Identifying eggs/ larvae
- Molecular/ serological testing.
Where can adult Nematodes be found?
In vomit and feces.
How can you ID Nematode eggs/larvae in feces ?
Eggs = fecal smear, flotation, sedimentation
Larvae = Baermann method (larval sedimentation)
In case of Pig ascarid, larval migration from the intestine on to the liver and the lungs can cause what kind of damage to the pig?
hepatic damagerespiratory signs, lung lesions