Introduction to endoparasites Flashcards
What are commensal parasites?
Less damaging parasites to completely benign relationship between two species
What are symbiotic parasites?
They both rely on each other for survival, Lichens for example
What are micropredator parasites?
Species that prey on tissues rather than whole organisms
What are the two major classes of endoparasites?
- Protozoa
- Helminths (worms)
What are some types of Protozoan parasites?
- Euglenozoa
- Metamonda
- Parabasalia
- Apicomplexa
- Amoebozoa
What are the two classes of helminths?
- Phylum Platyhelminthes (trematoda/ fluke, Cestoda/ tapeworms)
- Phylum Nematoda
What are some general features of helminths?
- Complex multicellular organisms
- Generally do not multiply in mammalian hosts
- Disease severity depends on worm load
- Usually causes chronic infections and disease
What is a highly aggrevated distribution in infected populations called?
- wormy people/ wormy animals
What does digenic mean?
There are more than 2 generations of different hosts to complete the life cycle
What is the adult morphology of fluke?
- Two suckers
- Blind-ended gut
- All hermaphrodite apart from the schsitones
What are some features of Cestodes (tapeworms)
- Segmented adults
- No gut
- Always parasitic
- Hermaphrodite
What is the pathogenesis of cestodes?
- The adult worms are rarely pathogenic but adults in intestines cause ‘fullness’ and mild/ vague abdominal pain
- Juveniles are usually pathogenic
- cause cysts in muscles, organs, tissues, eyes, brain asymptomatic to severe (can cause death)
What is the lifecycle called if there is only one host?
Direct
What is the lifecycle called if there is two or more hosts?
Indirect
What is the host called in which the parasite reaches maturity?
Definitive host
What is the host called that harbours the parasite in developing stages
Intermediate host
What are two examples of indirect lifecycles?
- Transmission via a vector
- Transmission by ingesting another vector
What is the definition of pathogenesis?
- The biological mechanisms that lead to a diseased state
What is the definition of parasite pathogenesis
How a parasitic infection causes disease
What are some features of parasitic diseases
- Usually long-term and chronic rather than acute
- Mortality generally only occurs after a long period of sickness
- Disease severity often depends on parasite burden
- Pathology may simply be a side effect of infection…
OR - An adaptive strategy to enhance parasite transmission
Likelihood of disease and clinical presentation depend on
- Parasite density
- Parasite species or strain
- Host factors
What are some other host factors?
- Immunosuppression
- Co-infections
- Nutritional status
What is a difference between male and female nematodes?
Male nematodes have curled tails
