Parasitology Introduction Flashcards
What is a parasite- wide definition?
Live in or on another living organism (host), obtaining part or all of its nutrients from host
What is a parasite- Narrow definition?
- Cause harm to the host
- Some degree of adaptive structural modification
- Parasites only include those organisms that are eukaryotes
What domain of life does the narrow definition put a parasite in?
Eukaryote
What the four main groups of veterinary pathology?
- Protozoa
- Arthropods
- Platyhelminthes
- Nematoda
Examples of protozoa
- Giardia
- Trypanosomes
- Coccidia
Example of Arthropods
- Ticks
- mites
- fleas
- Mosquitoes
Example of Platyhelminthes
- Tapeworms
- Flukes
Example of Nematoda
- Roundworms
- Heartworm
Two types of lifecycles
- Direct
- Indirect
What classifies parasite life cycle?
Dependent upon number of hosts needed to complete the lifecycle
Direct life cycle?
One host
Indirect life cycle?
Two or more hosts
What are the three classifications of hosts?
- Definitive
- Intermediate
- Paratenic
What is a definitive host?
Host in which sexual reproduction takes place
What is another name for definitive host?
Final host
What is an intermediate host?
Host in which only immature stages grow and develop. May or may not occur asexual reproduction
What a paratenic host?
Host not required to complete the life cycles but helps the parasite get to another host
What is another name for a paratenic host?
Transport host
What is a normal host?
animal recognized as part of the normal parasite life cycle
What is an abnormal host?
- Animal who is not normally used as a host
- dead-end
- Animal could be an abnormal definitive, intermediate or transport host, depending on which stage of the parasite life cycle is present
Does being an abnormal host always lead to disease?
Often does cause dx but not always
What is a reservior?
host that serves as a source of infection for other animals (carrier)
What is a vector
- invertebrate usually arthropod
- Transmits infectious disease
-Biological or mechanical
What is a biological vector?
Parasite that replicates in vector
What is a mechanical vector?
A carrier of parasite
What is an endoparasite?
Internal parasite (In host)
What is an ectoparasite
External parasite (on host)
What is an infection?
Having an endoparasite
What is an infestation?
having an ectoparasite
Words that describe reproductive behavior in the final (definitive) host
Microparasite
Macroparasites
Microparasite reproductive behavior
Multiply inside the host
Macroparasite reproductive behavior
Do Not Multiply- mate and release eggs into the environment
What does it mean to be infectious?
Capable of being communicated by infection
What does it mean to be infective?
Parasite stage capable of infecting the host. Usually only one stage for each parasite and may not occur until after some development of the parasite.
Prepatent period
Term for internal parasites; The time required following infection of the definitive host to reach reproductive maturity.
What is generation time?
time it takes to get from egg to producing egg.
What is patency?
adult reproductive infection
What are the stages in the prepatent period?
- Infection
- Maturity
- Sexual reproduction
what are the stages of patency?
- Sexual reproduction
- Infective stage development
- Infection
What are the determinants of the host-parasite relationship outcome?
- Infection/infestation vs disease
- Parasite usually requires appropriate stimulus and receptors
- Host response: innate and adaptive immunity
- Normal immunity typically limits, but does not eliminate infection
Does infection/infestation always lead to disease?
No
Pathogenesis
The mechanism of the parasite creating a disease
What are the three factor pathogenesis depends on?
- The status of the host immune defenses
- Number of parasites presents (virulence)
- Pathogenicity of those parasites
What are the pathological results from a parasitic infection?
- Parasite induced trauma to cells
- Changes in cellular growth patterns
- Interference with host nutrient acquisition
- toxins released by parasites
- host immune response to infection
Consequences of high numbers of macroparasites
Very uncomfortable –> death
Parasite population in animals are ____
Aggregated
Causes to variation in host susceptibility
- Temporary factors: age, concurrent disease, nutrition
- Genetic difference
70-30 rule
What is the veterinarians role in parasitology?
- Understand infection significance
- Prevention of infection
- Integrated parasite management
- Diagnosis and treatment
Factors contributing of diagnosis of parasites
- Morphologic
- Immunologic
- Molecular tests
Morphologic factors of parasite diagnosis
- Microscopic examination of blood, tissue, feces
- Gross inspection of tissues/feces
- Remains most common way to detect parasites, especially multicellular parasites
Immunologic testing for parasites
Antigen or antibody tests: used mostly with protozoan
Molecular testing for parastie
PCR
Poor baby rule
