Key Concepts Flashcards
(37 cards)
What is a definitive host?
The host in which a parasite reaches sexual maturity or completes its final stage.
What is an intermediate host?
The host that harbors the larval or immature stage of a parasite, where development occurs, but not sexual maturity
What is visceral larval migrans
Human infection by larvae (e.g. Toxocara canis) that migrate through internal organs—especially the liver and lungs.
Characteristics of a Good Dewormer
Broad-spectrum
Short withdrawal period
Easy to administer
Low toxicity
Effective on all life stages
Economical
What is a paratenic host?
Host that harbors immature parasite stages without development—acts as a transport host.
Examples of Nematodes and Predilection Sites
Haemonchus: abomasum
Oesophagostomum: large intestine
Ascaris suum: small intestine (pig)
Syngamus trachea: trachea (bird)
Stephanurus dentatus: kidney/perirenal (pig)
What is the significance of knowing a parasite’s lifecycle?
It helps in targeting the right stage of the parasite for control and prevention.
What are some general signs of parasitism in animals
Weight loss, diarrhea, poor growth, anemia, and rough coat.
What type of worms are affected by praziquantel?
Tapeworms (cestodes) and some flukes (trematodes).
What is the difference between a direct and indirect lifecycle?
A:
Direct: No intermediate host; infection from environment or directly from host.Ascaris suum (pig roundworm) – no intermediate host required.
Indirect: Involves one or more intermediate hosts.Fasciola hepatica (liver fluke) – uses snails as intermediate hosts.
How are trematode (fluke) eggs typically detected?
Through sedimentation technique due to their heavy eggs that sink in flotation solutions.
Which parasite causes “bottle jaw” in ruminants?
Haemonchus contortus – a blood-sucking nematode in the abomasum.
What is the infective stage of most nematodes?
The third larval stage (L3).
What is a common drug used against coccidia
Sulfadimidine or amprolium.
Name one common protozoan parasite in poultry
Eimeria spp. – causes coccidiosis.
How is Eimeria transmitted?
Ingestion of sporulated oocysts from contaminated feed, water, or litter.
What is the scientific name for the dog roundworm
Toxocara canis
What are the intermediate hosts of Fasciola hepatica
Freshwater snails, e.g., Lymnaea spp.
What are clinical signs of Haemonchus infection
Anemia, submandibular edema (bottle jaw), weakness, and sudden death in severe cases.
prepatent period’ mean?
The time between infection and when the parasite begins to produce detectable eggs or larvae.
Name one parasite whose eggs are very resistant in the environment.
Toxocara canis – eggs can survive in the soil for years.
What is the predilection site of Oesophagostomum spp
large intestine, where it forms nodules.
Name two non-bursate nematode
Ascaris suum
Toxocara canis
