Virulence and pathogenicity of parasites Flashcards
List three groups of eukaryotic organisms that affect the health and well-being of animals.
Protozoa, helminths, arthropods
What is the difference between ectoparasites and endoparasites?
Ectoparasites- lives on the host, causes infestions
Endoparasites- lives in the host, causes infections
What is a definitive host?
Harbors adult or sexual stage of parasite
What is an intermediate host?
Harbors larval or asexual stage of parasite
What is an incidental host?
An unusual host, unnecessary for the maintenance of the parasite in nature
Often, parasite life cycles can only be completed in a _____ host.
particular
What variables affect the outcome of parasitic infections/ infestations?
type of host (intermediate or definitive), severity, chronic or acute, route of exposure
What are six common routes of parasite entry?
ingestion, skin or mucosal penetration, transplancental, (prenatal), transmammary (milk), arthropod bite (vector), sexual contact
Explain how effective dose and exposure relate to virulence in helminths and protozoa.
Protozoa multiply in host
Helminths DO NOT multiply in host; virulence is proportional to worm load
How do helminths, arthropods, and protozoa attach and penetrate barriers?
helminths and arthropods: mechanical mouthparts
protozoa: molecular interactions
What kind of damage is caused by parasites?
Mechanical: blockage of organs, pressure atrophy, migration
Toxic products
How can parasites result in a loss of nutrients to the host?
Through competition for host nutrients and blockage of nutrient uptake by the host
