Topic 9 -Parasites Flashcards
What is the difference between ecto and endoparasite?
Ecto - on the host
Endo - in the host
What are the classifications of parasites?
- Protozoa
- Nematoda
- Platyhelminthes
- Arthropoda
What are examples of protozoa?
Amebae, flagellates, coccidia, sporozoans and microsporidia.
What are examples of nematodes?
Roundworms
What are examples of platyhelminthes?
flatworms, cestodes and trematodes
What are protozoan characteristics?
Trophoziote (vegetative state), sexual reproduction by conjugation, produce cysts and asexual is through fission/budding or schizogony.
What protozoans cause disease?
Giardia lamblia (cyst) and Trichomonas vaginalis (not cyst stage)
What are helminths?
Parasitic worm in the animalia kingdom. There are two phylums:
- platyhelminths = flat worms and the classes include = traematodes (flukes) and cestodes (tapeworms).
- Nematodes = roundworms
What are helminth characteristics?
- Reduced digestive system
- Reduced nervous system
- Reduced locomotion
- Complex reproduction
What is the life cycle of helminths?
Egg —-> Larvae —-> Adult
What is the difference between monoecious and dioecious?
Monoecious is a hermaphrodite which means it has both male and female reproductive systems in one animal while dioecious have separate male and female parts.
What is a definitive host?
A host where adult stage of parasite emerges and produces eggs that are passed onto intermediate host
What is an intermediate host?
A host where parasite can’t produce eggs in
What are virus characteristics?
- Intracellular parasites
- Contain DNA and RNA
- Protein coat
- Some have spikes
What is the virion structure?
- Nucleic acid, either DNA or RNA never both
- Capsid, made up of capsomeres
- Envelope, spikes may protrude from envelope and envelope is host-cell derived
What are bacteriophages?
Viruses that are pathogenic to bacteria
What is the structure of the virion structure?
- Head
- Sheath
- Baseplate
- Tail
What is T-even mean?
Bacteriophage will have an even number
What is a T4 bacteriophage?
A complex virus which is non-enveloped
What is the taxonomy of viruses?
Family = -viridae Genus = -virus Species = common names Subspecies = number
What is a plaque?
A clearing in bacterial lawn caused by bacterial colony lysis.
What does embryonted egg mean?
A fertilised egg
Animal viruses can grow in living animals but not embryonated eggs. True or False?
False, they can grow in both
What are the step with growing viruses in cell cultures?
- Treat tissue with enzyme to separate cells
- cells suspended in culture medium
- Transformed or continous cell cultures dont grow in a monolayer
How is the viral one step curve different then bacterial growth?
Bacterial growth has a lag, log, stationary and death phase
What are virus identifications?
- Cytopathic effects
- Serological tests
- Nucleic acid
What is the lytic cycle?
- Attachment - phage attaches by tail fiber to host cell
- Penetration - lysosome opens cell wall and sheath contracts and forces DNA into cell
- Biosynthesis - production of DNA and proteins
- Maturation - assembly of phage proteins
- Release - lysosome breaks cell wall
What is the result of bacteriophage multiplication?
lytic cycle - causes death of host cell
lysogenic cycle - incorporates DNA into host DNA, phage conversion and specialized transduction
What are the life cycles of animal viruses?
Attachment Penetration Uncoating Biosynthesis Maturation Release
What are plant viruses and viroids?
PV - enter through wounds or insects
Viroids - Infectious RNA
What is parasitism?
A symbiont that lives/harms at the expense of another organism. This relationship involves the host and the parasite.
It may result in disease.
What are prion diseases caused by?
An aberrant form of a naturally occuring protein PrP
Why are prion diseases different to other diseases?
It’s the first transmissible disease without a nucleic acid being involved which is different to viruses and bacteria
What is a normal cellular prion? What causes plaques?
PrPc
PrPsc
What is the post mortem appearance of a prion?
Large vacuoles in cortex and cerebellum, known as spongiform encephalopathies
What are transmissible forms of prion diseases?
TME CWD BSE vCJD Scarpie
What are inherited forms of prion diseases?
CJD
GSS
FFI
Kuru
