Intro to Parasitology Flashcards
How do you write the genus and species of a parasite?
The 1st letter of the genus is capitalized
When typed, genus and species are italicized
When handwritten, Genus and species are underlined
Endoparasites
Internal parasites
Intestinal tract
Circulatory system
Ectoparasites
Live on the outside of the host’s body
External parasites
Fleas, ticks, lice
Definitive Host
Carries the adult, mature or sexually mature stage of the parasite
Intermediate host
Carries the immature parasite (larval or asexual form)
REQUIRED to complete the life cycle
Example: Mosquitos and heartworm
Paratenic Host
AKA transport host
No development of parasite occurs
Not required for the life cycle to be completed
Dead-end host
AKA incidental host and accidental host
The parasite can not be transmitted to another animal
May or may not cause disease
Direct Life Cycle
No intermediate host required for development to the infective stage
Indirect Life Cycle
An intermediate host is needed for development to the infective stage
Diagnostic stage
The stage will be detected in laboratory test
When the parasite passes from one host to the next
Infective stage
Stage of the parasite when ingested (or other routes of infection) will cause disease
What are the clinical signs and symptoms of a parasite infection?
Vomiting and diarrhea Constipation Anorexia Blood in the stool Lethargy Anemia
Transmission: Ingestion
Fecal oral
Ingestion of an intermediate/paratenic host
Transmission: Vector
Infected via flea, mosquito, or tick bite
Transmission: Transdermal
Infected via skin penetration
Transmission: Transplacental
From mother to fetus
Transmission: Transmammary:
From mother to neonate in the milk
Prepatency Period (PPP)
Time from initial infection until parasite can be detected via lab tests
The shortest time that can occur
What are the types of diagnosis for parasites
Feces Cellophane tape method Blood sample Skin scrape Ear swabs
Fecal tests
Direct Float Centrifugation Sedimentation Baermann
Fecal sample Guidelines
Fresh sample Refrigerate if not examined within 2 hours Clean container Need 1-2 teaspoons Label Treat all samples as zoonotic
Direct Fecal Smears
- Simple, minimal equipment
- Used to quickly estimate parasite load
- Detect motile trophozoite protozoa and motile bacteria
- Used as a screening test, but not sole test
Procedure Direct Fecal Smear
Mix tiny amount feces with saline
Examine on 10x for eggs and 40x for protozoa
Concentrations Techniques
Either forcing ova up or down using solutions with different specific gravity
What are examples of concentration techniques
Standard (passive) Flotation
Centrifugal Flotation
Fecal Sedimentation
What is fecal flotation based on?
The differences in specific gravity of life cycle stages of parasites
What is higher in flotation solutions than in common ova?
Specific gravity
What happens to the ova when they encounter flotation solutions with a higher specific gravity?
They float
What has higher specific gravity than the flotation solutions and sink
Fluke eggs
What happens if the specific gravity of flotation solutions is too high?
It creates a plug of debris that traps parasites, obscuring them from view
What is the specific gravity of most parasites?
1.100-1.200
What is the specific gravity of most float solutions?
1.200-1.250
What are the commonly used solutions?
Sodium nitrate
Sugar solution
Zinc sulfate
What is the better flotation test?
Centrifugal flotation
Why is centrifugal flotation the better test?
Recovers more eggs and cysts in less time
What is the Baermann Technique used for?
To recover larvae (NOT OVA) from fecal samples
What does the Baermann Technique require?
The construction of a Baermann apparatus
What is the Baermann apparatus made up of?
The large funnel, tubing, collection tube
Non-Fecal Parasite Tests
Cellophane tape method (4x)
Blood sample (heartworm, smears)
Skin scrape
Ear Swabs
