The language of veterinary parasitology and parasites that infest and infect domestic animals

Predator prey

one benefits at the
expense of the other (cat-mouse)

Phoresis

(phore means “to carry”) the
smaller member is mechanically carried by the
larger (mosquito-dirofilaria)

Mutualism

both organisms benefit in the
relationship (protozoan in cows gut aids in digestion, warm
place for protozoan to live)

Commensalism

one organism benefits and the other neither
benefits or is harmed (shark-remora/hitchhiker)

Parasitism

an association exists between two organisms of
different species, in which one member (parasite) lives on or within the
other member (host) and may cause harm (roundworms-dogs)

5 types of symbiotic relationships

1. predator prey

2. phoresis

3. mutualism

4. commensalism

5. parasitism

Parasitology

The study of parasitic relationships

Parasitism

type of symbiotic relationship
between two organisms of different species in
which one member (the parasite) lives on or within
the other member (the host) and may cause harm;
parasite is metabolically dependent on host for its
survival.

Parasitiasis

parasites present on or with the host
and are potentially pathogenic (harmful). The
animal does not exhibit clinical signs of disease

Parasitosis

parasite is present on or within the host and does
produce obvious injury or harm to the host animal.

Ectoparasite

parasite lives on the body of the host.
causes infestation (fleas)

Endoparasite

parasite lives within the body of the host.
causes infection (heartworms)

Parasiticides

Chemicals used to treat parasites on or in the animal

Anthelmintics

compounds used to treat/kill roundworms,
tapeworms, flukes

Acaricides

compounds used to treat/kill mites and ticks

Insecticides

compounds used to kill insects

Antiprotozoal

compounds used to kill protozoans

Aberrant parasite

parasite that wanders from it’s usual site of
infection

Incidental parasite

when a parasite occurs in a host in which it
does not usually live

Facultative parasite

“free living” (non-parasitic) that can become
parasitic in certain hosts

Obligatory parasite

a parasite that must lead a parasitic existence

Periodic parasite

one that does not have to live on or within a
host but simply makes “short visits” (mosquitos)

Pseudoparasites

organisms that are mistaken for parasites on
microscopic examination. They may look like an ova but really
aren’t (pollen)

Definitive host

the host that harbors the adult, sexual, or mature stage
of the parasite

Intermediate host

the host that harbors the larval, juvenile, immature
or asexual stage of the parasite

Paratenic host or transport host

a special type of intermediate host in
which the parasite does not undergo any development but instead
remains in an arrested or encysted state of suspended animation within
the host’s tissue

Reservoir host

a vertebrate host in which a parasite or disease occurs in
nature and is a source of infection for humans and domesticated animals

Homoxenous or monoxenous

parasite that will infect only one type of
host

Zoonosis

any disease or parasite that is transmissible from animals to
humans

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Carnivora

Family

Canidae

Genus

Canis

(italicized and capitalized)

Species

familiaris

(italicized but not capitalized)

Trematodes

flukes

Monogenetic Trematodes

Ectoparasites primarily affecting fish

Digenetic Trematodes

Endoparasites affecting large and small animals

Flat, leaf shaped

Primarily affects the GI tract, can also infect lungs and blood vasculature

Operculated eggs on fecal flotation

Cestodes

tapeworms

Eucestodes are aka

true tapeworms

Eucestodes

Ribbon like flatworms in GI tract of definitive hosts

Lack a gut or alimentary canal

Cause more harm to intermediate host then definitive host

Cotyloda (pseuodotapeworms)

Resemble true tapeworms and are also found in the GI tract of the definitive host

Larval stages found in microscopic aquatic crustaceans and muscle of fish and reptiles

Operculated eggs on fecal flotation

Rarely produce pathology in domestic animals

Nematodes aka

roundworms

Nematodes

Long unsegmented, cylindric worms

Most numerous, complex and variable helminth parasite of domestic animals

2nd only to Arthropods in number and complexity of life cycles

Comes in all shapes and sizes, can infect a variety of organs and organ systems

Eggs and larva can be found on fecal flotation

Must become proficient in their identification

Acanthocephalans aka

thorny-headed worms

Acanthocephalans

Elongated, unsegmented, cylindric worms

Possess spiny proboscis(feeding apparatus that aids in attachment) on anterior ends

No gut or alimentary tract

Adults are uncommon and found primarily in the GI tract

Eggs seen on fecal flotation

Hirudineans aka

leeches

Hirudineans

Blood feeding ectoparasite

Annulated(ringed) worms

Found in fresh water

Can also be beneficial when used in reconstructive surgical procedures

Arthropods

Largest phylum in the animal kingdom

Contains pentastomes, crustaceans, centipedes, millipedes, insects, mites, tick, scorpions, and spiders

Can parasitize host in adult or juvenile stage

4 reasons that arthropods are important

1. They serve as casual agents themselves

2. They serve as intermediate hosts for some helminths and protozoans

3. They serve as vectors for bacteria, viruses, spirochetes, and chlamydial agents

4. And they produce toxins or venomous substances

Protista aka

protozoa

Phyla:

flagellates, amoebae, ciliates,
apicomplexans

Protista

Phyla: flagellates, amoebae, ciliates, apicomplexans

Unicellular organisms

Complex life cycles

Causes changes in tissues and organs