Parasites Flashcards
How do anthelmintics work? (2)
- affect the parasites CNS leading to death or paralysis
- some cause digestion of the parasite
Effect of host and environment on parasitism
- Older animals more resistant to parasitic infection
- Parasites reproduce better in warm, moist conditions
Control and prevention of parasitism (3)
- Daily removal of feces from housing areas
- Prevent ingestion of intermediate or paratenic hosts
- Perform routine laboratory tests to screen for parasite infections
Internal Parasites (4)
- Nematodes (Roundworms)
- Cestodes (Tapeworms)
- Trematodes (Fluke worms)
- Protozoa
Which group of parasites are considered the most important?
Nematodes
Where are nematodes found within the body?
there is a nematode for every organ
What is the structure of an adult nematode?
elongated and cylindrical
What size can nematodes get to?
1mm to 100cm
Encyst
when a nematode goes dormant
What can stimulate an encysted nematode?
horomones
Which group of parasites is an Intermediate host necessary in life cycle?
Cestodes
Where do adult cestodes live in the definitive host?
The intestines
What is the structure of an adult cestode?
Long flat worms divided into segments
What are the structures of cestodes? (2)
- scolex
2. proglottids
Scolex
head of a cestode
- What does a scolex contain?
2. What is their purpose?
- has suckers and hooks
2. to help it attach to the wall of the intestine
A proglottid is a…
fully functional unit with digestive, reproductive, and other organs
What is contained within a proglottid?
Eggs
Where are trematodes usually found within the host?
- intestine
- liver
- lung
What is the intermediate host for trematodes?
Snail
What is the structure of trematodes?
Flat worms with leaf-shaped body
Protozoa are…
Unicellular organisms
Where are protozoas found with in the host?
Found in different organs w/in the body
How are protozas seen?
Only visible with a microscope
Definitive host
animal harboring sexually mature parasite
Prepatent period
time elapsed between infection with parasite and when it reaches reproductive maturity
Paratenic host
animal serving as a transport host for immature stages of the parasite, no development occurs
Intermediate host
animal used by the immature stages of the parasite to continue development
Ways parasites can affect their host (3).
- Malnutrition - compete w/ host for ingested food
- Mechanical - destroy tissue, cause obstructions
- Blood loss - anemia
Accurate diagnosis is dependent on…
Performing the right test, at the right time, and doing it correctly
