Midterm Review Flashcards
What is “symbiosis?”
At least two different species living together- may be temporary or permanent.
Host/parasite relationship.
Relationships: predator/prey
Very short term interaction
Relationships: Phoresis
Larger carries smaller
Relationships: Mutualism
Both benefit
Relationships: Commenulism
One benefits
One has no effect
Relationships: Parasitism
Metabolic dependence
Host may be harmed
What is “Parasitology?”
The study of parasites
Define “Host”
An accommodating organism
What is a “parasite?”
-An organism in or on a Host
-Causes harm to host
What is “Parasitism?”
A parasitic relationship
Parasitisasis
A parasite on or within a host
-potentially harmful
-no outward signs
Parasitosis
A parasite on or within a host
-Obvious harm/injury
What is a “Definitive Host?”
Parasite matures inside/on and reproduces
What is a “intermediate host?”
Houses larva
-immature
-does not reproduce
-can have >1 intermediate host
What is a “paratenic host?”
Acts as transport (think Uber)
-no parasite development
-Encysted
What is a “Reservoir Host?”
-Vertebrate
Anything with a spine (also a definitive host)
-source of parasite
-transmits to others
What is an “Aberrant Parasite?”
A parasite in an unusual location
What is an “incidental Parasite?”
A parasite on an UNSUAL host/wrong animal
What is a “facultative Parasite?”
Free-living becomes parasite
-Live in environment then become parasitic in host
What is an “obligatory parasite?”
Cannot be free living
- must live in/on host
What is a “periodic parasite?”
Short visits
-mosquitoes, ticks…
What is a “monoxenous Parasite?”
Only one type of host (host specific)
-can also be referred to as “homoxenous”
What is a “stenoxenous parasite?”
Narrow range of hosts
What is a “Euryxenous host?”
Broad range of hosts
All organisms fall under what classification?
The Linnaean Classification
Linnaean Classification scheme
Kingdom (very general; contains many organisms)
Phylum
Class
Order
Family
Genus
Species (Very specific: contains closely related organisms)
What did king Phillip do?
King Phillip Came Over For Good Spaghetti
Endoparasite
A parasite WITHIN/INSIDE the host
-infection
Types of Endoparasites
-Nematodes (roundworms)
-Cestodes (tapeworms)
-Trematodes (flukes)
-Acanthocephalans (thorny-headed worms)
-Protozoans (single cell organisms)
Ectoparasite
A parasite ON/OUTSIDE the body of a host
-infestation
(Think fleas/ticks..)
Types of Ectoparasites
-Arthropods (jointed feet)
Such as insects; 6 legs/3 body parts & Arachnids; 8 legs/2 body parts
-Hirudineans (leeches)
Direct Life cycle (simple)
No intermediate host
+/- free living stages
Stay on one host
Indirect life cycle (complex)
Two or more hosts
Growth and maturation life cycle
Egg -> larva (multiple) -> +/- nymph -> adult
Live birth -> molt -> adult
Reproduction life cycle
Sexual/asexual
Types of transmission
-ingestion (eggs)
-Penetration
>assisted (ex. HW)
>unassisted
-Direct contact (fleas)
-Transplacental (from mom to offspring)
-Transmammary (through the milk)
Patent period
-Reproducing stages
-Mature parasites
Prepatent period
Infection to adult
-reproducing
Incubation period
Exposure to clinical signs
Parasitic pathology: Endoparasites require what?
Metabolic dependence on host
-compete for nutrients
-deplete vital resources
Protozoology
A branch of biology that studies Protozoa
-unicellular
-free living > parasitic
-most microscopic
-motile (trophozoites)
Helminthology
The study of worms
Arthropodology
The study of arthropods
Types of arthropods
Insecta
-6 legs/3 body parts
-9 orders
Arachnids
-8 legs (adults)/2 body parts
-acarines (mites, ticks)
Crustacea
-Aquatic
>intermediate hosts (helminths)
>causal parasites (fish, reptiles, amphibians)
Myriapoda
-Centipedes, millipedes
>venoms/toxins
What is the general morphology of nematodes?
Unsegmented, elongated, circular cross section, vast size variation
Examples include Strongyloides stercoralis and Dioctophyma renale.
What are proglottids in cestodes?
Segments that are passed in feces, each capable of releasing thousands of eggs
Proglottids are part of the segmented body of tapeworms.
What is the life cycle of eucestodes?
Eggs ingested by intermediate host, develops into metacestode, tapeworm emerges in definitive host
Includes various larval forms like cysticercoid and hydatid cyst.
Describe the general morphology of trematodes.
Unsegmented, flattened, leaf-like, vast size variation
Examples include Fasciola hepatica and Schistosomes.
What are the two types of trematodes?
Monogenetic and digenetic
Monogenetic have a single host, while digenetic require multiple hosts.
What is a characteristic of digenetic trematodes?
Require 2-4 obligate hosts, potential paratenic hosts
Commonly involve animals and humans.
What is unique about the reproductive structures of trematodes?
Hermaphroditic, possessing both male and female organs, except for blood flukes
Schistosomes are an example of dioecious trematodes.
Fill in the blank: Cestodes are _______ with segmented bodies.
hermaphroditic
What are the internal structures of cestodes?
No GI tract, absorb nutrients from the host’s intestine, reproductive tract segmented into proglottids
Each proglottid can be immature, mature, or gravid.
What is the life cycle of nematodes?
Direct or indirect, simple cycle involves egg to larval stages, with L3 being the infective stage
Includes stages L1 to L5 and migration to predilection sites.
What are the egg types found in nematodes?
Ascarid, strongyle, spiruroid, trichuroid (polar plugs; Stewie head)
Each type has distinct shapes and contents.
True or False: Cestodes have a well-defined gastrointestinal tract.
False
What is the general morphology of apicomplexans?
Intracellular parasites with complex life cycles, often pathogenic
Includes genera such as Eimeria and Toxoplasma.
Fill in the blank: Pathogenic ciliates include _______.
Balantidium coli
What is the characteristic morphology of flagellates?
Motile trophozoites, found in liquid environments
Examples include Leishmania and Giardia.
What is the life cycle of Acanthocephalans?
Eggs passed, ingested by intermediate host, larva develops, definitive host ingests intermediate
Acanthocephalans have a unique proboscis for attachment.
What is the pathogenic amoeba associated with severe disease?
Entamoeba histolytica
Causes amoebic dysentery.
What are the types of eggs produced by nematodes?
Single cell stage, morula stage, first stage larva
Each type corresponds to different nematode families.
What is the size variation of Acanthocephalans?
14 mm to 70 cm, depending on the species
They are characterized by their retractable proboscis.
What is “dioceious”
Separate sexes
What is the genus of hookworms that affect canines?
Ancylostoma
Includes species such as Ancylostoma caninum.
Which hookworm species is associated with felines?
Ancylostoma tubaeforme
This species specifically affects cats.
What is the common name for Ancylostoma braziliense?
Canine & feline hookworm
It can infect both dogs and cats.
What is the primary location of hookworms in the host?
Small intestine
They attach to the mucosa and feed on blood.
What condition can result from hookworm feeding behavior?
Anemia
Continuous hemorrhage can lead to this condition.
What type of life cycle does Diphylobothrium latum have?
Indirect life cycle
What diagnostic method is used for detecting lungworm larvae?
Fecal flotation
Other methods include Baermann and tracheal wash.
What is the definitive host for Dirofilaria immitis?
Canine
This is the primary host for heartworms.
What is the intermediate host for Dirofilaria immitis?
Mosquito
Over 30 species can serve as hosts.
What is the primary location of Dirofilaria immitis in the host?
Right ventricle and pulmonary arteries
This is where adult heartworms are found.
What is the prepatent period for Dirofilaria immitis?
6 months
This is the time before larvae can be detected.
What type of eggs do whipworms (Trichuris vulpis) produce?
Eggs passed every 3 days
They are resistant and can survive for years.
What is the zoonotic potential of Toxocara canis?
Visceral larval migrans
Humans can become aberrant hosts.
What is the characteristic feature of the larvae of Toxocara cati?
Can migrate to various tissues including lungs
This occurs after larvae hatch and migrate.
What is the life cycle of Strongyloides stercoralis?
Larvated eggs produced, hatch, and larva pass
It includes free-living stages.
What is the definitive host for Echinococcus spp.?
Canine
They can also infect felines and other carnivores.
What is the prepatent period for Pearsonema plica?
~8 weeks
This is the time from infection to egg detection.
Fill in the blank: The adult kidney worm in Dioctophyma renale is found in the _______.
Right kidney
This species is the largest parasitic nematode.
What is the common name for Thelazia californiensis?
Eyeworms
They can infect various animals, including humans.
What is the method of transmission for Eucoleus spp.?
Ingestion of ova
These nematodes affect the respiratory system.
What is the diagnostic method used for identifying microfilariae in Dirofilaria immitis?
Modified Knott’s test
This method helps differentiate it from Acanthocheilonema reconditum.
What type of nematodes are Aelurostrongylus spp. and Eucoleus spp.?
Respiratory Nematodes
They are associated with lung infections in animals.
What is a significant characteristic of Ancylostoma spp. related to their feeding behavior?
Anticoagulant secretion
This allows them to feed on blood continuously.
True or False: Dirofilaria immitis produces eggs.
False
They produce microfilariae instead of eggs.
What is the definitive host for Diphylobothrium latum?
Canine, feline, human
Diphylobothrium latum is a type of pseudotapeworm.
How many intermediate hosts does Diphylobothrium latum have?
2 intermediate hosts
These are aquatic crustaceans and fish.
What is the larval stage of Diphylobothrium latum called after ingestion by fish?
Plerocercoid
What diagnostic method is used for Diphylobothrium latum?
Fecal flotation
What is the definitive host for Echinococcus multilocularis?
Feline, fox
What type of egg does Diphylobothrium latum produce?
Operculated egg
Similar to fluke eggs.
What is a notable characteristic of the hydatid cyst formed by Echinococcus multilocularis?
Multilocular
What is the intermediate host for Echinococcus multilocularis?
Small rodents
Humans can also serve as incidental hosts.
What is the zoonotic potential of Echinococcus multilocularis?
Extreme
What type of tapeworms are considered true tapeworms?
Eucestodes
What is the definitive host for Taenia ovis?
Canine
What is the intermediate host for Taenia ovis?
Ruminants
What is the larval stage that develops from the hexacanth in Taenia ovis?
Cysticercus ovis
What is the diagnosis method for Taenia ovis?
Fecal flotation, Segment squash
What is the definitive host for Hymenolepis diminuta?
Rodents
What is the incidental parasite for Hymenolepis diminuta?
Canine, Human
What is the larval stage that develops in the villus for Hymenolepis diminuta?
Cysticercoid
What is the unique feature of Dipylidium caninum?
Double-pored
What is the intermediate host for Dipylidium caninum?
Flea / louse
What is the zoonotic potential of Dipylidium caninum?
Yes
What is the definitive host for Echinococcus granulosus?
Canine
What type of hydatid cyst does Echinococcus granulosus form?
Unilocular
What is the intermediate host for Taenia hydatigena?
Ruminants
What is the larval stage that develops in the viscera for Taenia hydatigena?
Cysticercus tenuicollis
What is the definitive host for Taenia pisiformis?
Canine
What is the intermediate host for Taenia pisiformis?
Rabbit
