Veterinary Parasitology exam 1

Symbiosis

living together" occurs between two living organism of different sepcies

Parasitosis

Parasite is present on or in the host and there ARE clinical signs of the infection

Parasitasis

Parasite is present on or in the hose and there ARE NO clinical signs of the infection

Commensalism

One symbiont benefits from association, the other is neither helped nor harmed (ex: barnacles on whales)

Mutualism

Both symbionts benefit from association (ex: bacteria in the stomach that aid in digestion and provides the organism a place to live)

Phoresis "to carry

Small organism is mechanically transported by the larger symbiont (ex: flies transport bacteria from one animal to the next)

Predator/Prey

Short term; one symbiont benefits at the expense of the other

Parasitism

One symbiont, the parasite, lives in or on the other, the host

Parasitology

Study of parasites / diseases caused by them

Parasite

Smaller organism that lives in or on a larger organism at the expense of the larger organism

Endoparasite

Lives IN the body of the host (ex: hookworms, roundworms, whipworms)

Ectoparasite

Lives ON the body (ex: fleas, ticks, flies)

Zoonosis

Any disease transmissible from animals to humans

Stenoxenous

Parasites have a narrow range of desirable hosts

Euryxenous

Broad range of desirable hosts

Obligatory parasite

Depend on host for survival (ex:tick, lice)

Facultative parasite

Free living organism that DOES NOT rely on host to complete life cycle (ex: fungi on trees)

Incidental parasite

Parasite found in a HOST that it usually doesnt infect (ex: heartworm in humans)

Aberrant parasite

Found in TISSUES that it does not usually infect (ex: heartworm larva in the brain of a cat)

Permanent

Refers to ectoparasites; stays on the host through entire life cycle

Temporary

Gets on the host to feed then returns to environment

Pseudoparasite

Organisms or objects that appear to be parasites but are NOT

Definitive host

harbors parasite in the adult, reproductive stage (ex: canine heartworms)

Intermediate host

Parasites in its immature stage (ex: female mosquitos are intermediate host for heartworms)

Paratenic host (transport host)

- Harbors immature parasite in tissues
- parasite doesnt develop
- definitive host must eat this host for the adult parasite to develop

Reservoir host

Natural source of a parasite for humans or domestic animals (not affected by host)

Trematodes

Flukes

Cestodes

Tapeworms

Nematodes

Roundworms, lungworms, heartworms

Arthropods

Ticks, fleas, lice, flies, mites

Hookworm (ancylostoma spp.)

Cutaneous (skin) larval migrans
- caninum (canine hookworm)
- tubaeformae (feline hookworm)
- uncinaria stenocephala (nothern canine)

Roundworms (toxocara spp)

Visceral (liver) larval migran & ocular (eye) migran

Whipworms (trichuris spp.)

No zoonotic potentional (polar plugs)

Broadfish tapeworm (diphyllobothrium latum)

Diarrhea and cramping

Beef / Pork tapworm (taenia sollum)

Diarrhea and cramping

Baylisascaris Procyonis

Raccoon round worm

Oviparous

Female lay eggs; round worms

Ovoviviparous

Eggs larvate in uterus; female lay eggs containing L1 larva, threadworms

Viviparious

Eggs larvate and hatch in uterus; heartworms

Ascarid (egg type)

Unembryonated

Strongylid (egg type)

Morulated; embryo at early stage

Trichurid (egg type)

Polar plugs

Spirurid

Larvated

Transplacental infections

- Activated when dog is pregnant
- Major route of infection for puppies

Transmammary infections

- If mother is exposed to infection in late pregnancy or while nursing
- Passes to the pup through the mothers milk

Toxocara cati (roundworm)

- Zoonotic transmission by ingestion of egg
- Paratenic host is important
- Cats: definitive host
- Prepatent period: 8 wks

Toxocara canis (roundworm)

- prepatent period: 3-4 wks
- Definitive host: dog

Hookworm (ancylostoma)

- resembles a fishing hook
- Dog: definitive host
- small intestines
- direct life cycle
- strongylid

Whipworms (trichuris vulpis)

- definitive host: dogs
- direct life cycle
- L1 (infective stage)
- unembryonated
- polar plugs

Strongyloids spp (intestinal threadworms)

- Definitive host: carnivores and primates
- Zoonotic; dogs (s. canis) human (s. stercoralis)
- often asymtomatic
- Facultative - homogenic and free living
- L3 infective stage

Spirocerca lupi (esophageal worm)

- cats and dogs
- can turn into tumor (sarcoma)
- causes difficulty swallowing and vomiting
- indirect life cycle "paperclip shape

Aelurostrongylus abstrusus

- feline lungworm
- cats
- indirect life cycle, snail
- larva coiled up, tail is in the center

Eucoleus aerophilus

- fox lungworm
- fox, dog, cat
- direct life cycle
- more rounded polar plugs and smaller than trichuris

Pearsonema plica

- bladder worms
- indirect life cycle
- flat polar plugs

Dioctophyma renale

- giant kidney worm
- host: dog, mink
- indirect life cycle

Thelazia californiensis

- indirect life cycle
- found in the eyes
- symptoms: conjunctivitis; corneal ulcer