Parasitology--Ch. 17--Spring

The indirect life cycle is when:

a parasite uses an intermediate host. (read e.g. on power point)

What is the common name of a nematode or ascarid?

roundworm

What are anthelmintics?

"Dewormer"--used to kill: Roundworms Tapeworms Flukes Thorny-headed worms *RTFT*

What is the common name of hirudineans? Where are they typically found and what do they feed on?

"Leeches" --annulated (ringed) worms These are BLOOD-feeding ectoparasites typically found in fresh water.

How would you ID a Bovine Trichostrongyle on a medical record?

"Trichostrongyle-type eggs" (don't attempt genus names)

What are Cotyloda (give common term), where are they found?

("pseudotapeworms"--resemble true tapeworms but rare in dogs/cats) *Adults are ribbon-like flatworms that are found in the GI tract of DH (definitive host). *Eggs are operculated

What is a Eucestode (give common term), where are they found and how does it obtain nutrients?

("true tapeworms") --Adults are ribbon-like flatworms that are found in the GI tract of DH (definitive host). --LACK an *alimentary canal* and therefore absorb nutrients through their *tegument*, or skin. *e.g.* Diplidium caninum and Taenia spp.

State the classification scheme order.

(*K*ing *P*hillip *C*ame *O*ver *F*or *G*ood *S*paghetti!) Kingdom Phylum Class Order Family Genus Species

What is an incidental parasite? Give an example.

A parasite that occurs in a host in which it does not usually live. *e.g.* Humans can become infected with Dirofilaria immitus, a heartworm usually found in dogs, cats and ferrets.

What are facultative parasites? Give an example.

Organisms that are free living (nonparasitic) in nature, but can become parasitic in certain hosts. *e.g.* Pelodera strongyloides is a free living soil nematode, but has the capability of penetrating the skin in animals like dogs or "downer cattle" lying in moist dirt.

*Strongi-T* (trade name) What is its active ingredient and the parasites it kills?

PYRANTEL PAMOATE *dewormer--vermifuge* roundworms and hookworms

Name 2 popular vermicides.

Panacur (Fenbendazole) Telmintic (Mebendazole)

What is a Digenetic Trematode (fluke)?

Primarily endoparasites of both large and small animals of the GI tract, but can also infect the lungs and blood vasculature. *e.g.* Liver fluke (gets on a cow)

What is the head of a proglottid called?

Scolex

Name 9 Classes of the Arthropod Phylum.

Spiders Scorpions Ticks Insects Mites Millipedes Pentastomes Crustaceans Centipedes *SSTIMMPcc*

The direct life cycle is when:

there is no intermediate host.

Physaloptera spp. (____) Spirocerca lupi (____) are examples of what egg type?

Spiruroid *aka* spirurid type eggs

Name 4 popular vermifuges.

Strongid-T Anthelban Nemex Piperazine (Pipa tabs)

What is the Baermann technique?

Fecal procedure to Dx lungworm *can use to test most spp.

What are 3 common (1 is not so common anymore) dewormers used to treat Trichostrongyles?

Fenbendazole Ivermectin Levamisole (not so common) --comes as injectable for cattle

What is "pregnant" proglottid?

Gravid

What does "hermaphroditic" mean?

Having both male and female parts

What worms does Heartgard and Interceptor treat? What type of drug is it and what is its active ingredient?

Heartworms, Roundworms, Hookworms and Whipworms *vermicide* --Fenbendazole, Mebendazole *NOT* tapeworms

What adulticide is used to kill the adult HW? How is it administered?

Immiticide --injected into *apaxial* muscle (spine/lumbar muscle)

The alimentary canal is comprised of what 7 organs?

The alimentary canal extends from the mouth to the anus and includes the: Mouth, Pharynx, Esophagus, Stomach, and Small intestine, large intestine, anus. (Also called the digestive tract.) *MPESSiLiA*

Define ovoviviparous.

These are female nematodes produce eggs that contain a *first stage larva* within the eggshell.

Define larviparous.

These are female nematodes that *retain their eggs within the uterus and incubate them*, then give birth to live larvae.

Define oviparous.

These female nematodes produce eggs that *contain a single-cell stage*, or morula stage, within the eggshell.

What are Acanthocephalans (give the common name), and how do they obtain nutrients?

*"thorny-headed worms"* --elongated, cylindric worms that are most often found in the GI tract --LACK an *alimentary canal* and therefore absorb nutrients through their *tegument*, or skin --Adults are very uncommon parasites --eggs seen in fecal

*Panacur* (trade name) What is its active ingredient and the parasites it kills?

*Fenbendazole* roundworms hookworms whipworms (in HIGH doses, tapeworms)

What is the classification scheme of the dog?

*Kingdom:* Animalia *Phylum:* Chordata *(Subphylum):* Vertebrata *Class:* Mammalia *Order:* Carnivora *Family:* Canidae *Genus:* Canis (italics) *Species:* familiaris (italics) *ACVMCCCf* Canis familiaris (italics or underlined!)

Give an example of phoresis.

*Moraxella bovis* (the bacterial etiologic agent of bovine pinkeye) is carried from the eyes of one cow to those of another on the sticky foot pads of the face fly, *Musca autumnalis*.

What is a periodic parasite? Give an example.

A parasite that makes short visits to its host for nourishment or other benefits. *e.g.* FEMALE mosquito (only females) Without blood, she will not have sufficient protein to lay her eggs.

What is an obligatory parasite?

A parasite that must lead a parasitic existence to survive. *e.g.* Most of the parasites that affect domestic and wild animals

What are the final 2 tests done in Tx?

--ELISA test --Microfilariae test (direct blood evaluation)

1. What is an ectoparasite? 2. What is an endoparasite?

1. A parasite that lives on the body of the host. 2. A parasite that lives within the body of the host.

Arthropods are important in veterinary medicine because:

1. Arthropods can serve as *casual agents* themselves. 2. They may serve as *intermediate hosts* for certain helminths and protozoans. 3. They may serve as *vectors* for bacteria, viruses, spirochetes, and chlamydial agents. 4. They may *produce toxins or venomous* substances. *Ca-Ih-V-TV*

What are the 5 Kingdoms?

1. Planta (plants) 2. Animalia (animals) 3. Protista (unicellular organisms) 4. Monera (algae) 5. Fungi (fungi)

5 types of symbiotic relationships

1. Predator-prey 2. Phoresis 3. Commensalism 4. Mutualism 5. Parasitism *PPPMC*

What is the shape of an ascaroid egg? A strongyle or hookworm egg? A trichinelloid egg?

1. round 2. oval; paperclip-like 3. oval with *operculum, or polar plugs*, @ each end (whipworm)

What is the typical treatment plan for a vermicide?

1x/day for 3 days repeat in 3 weeks repeat in 3 months (not sure if vermifuge has to be repeated in 3 mths...)

Define dioecious.

2 separate sexes (males and females) *e.g.* Nematodes are dioecious.

What's the difference between a vermicide and a vermifuge?

A *vermicide* is an anthelmintic that kills the parasite and allows it to be broken down. A *vermifuge* is an anthelmintic that paralyzes the parasite so it passes in feces.

Who was Carl Linnaeus and what country was he from?

A Swedish scientist that formed the Linnaeus Classification Scheme (the Latin taxonomic system)

What is a definitive host?

A host that harbors the adult, sexual or mature stages of the parasite *e.g.* HW can't replicate till inside their definitive host (the dog/cat)--not adults in a mosquito

What is the copulatory bursa?

A lateral, flattened expansion of the cuticle posterior region of some male nematodes that holds or grasps the female during mating. --Composed of fingerlike projections called *Bursal rays*

What is a reservoir host?

A parasite or disease that occurs in nature and is a source of infection for humans and domesticated animals. *e.g.* wolf to mosquito to dog

Under the Phylum "Platyhelminths" what is the Class name for a thorny-headed worm?

Acanthocephalans

Name 4 Phyla of protozoa.

Amoebae Flagellates Apicomplexans Ciliates *"AF(L)AC"*

Define mutualism and give example.

An association in which both organisms in the symbiotic relationship benefit. *e.g.* protozoans in the cow's rumen break down cellulose and aid in digestion

Define commensalism and give an example.

An association in which one symbiont benefits and the other neither benefits nor is harmed. *e.g.* The remora on the shark's underside eats the food scraps after the shark's meal

Define parasitism.

An association that exists between 2 organisms of different species, in which one member lives on or within the other member and may cause harm.

Which 2 kingdoms are veterinary medicine most concerned with?

Animalia & Protista

Under the Phylum "Platyhelminths" what is the Class name for a leech?

Annelids (indicates "ringed")

Define zoonosis.

Any disease or parasite that is transmissable from parasites to humans *e.g.* Toxoplasma gondii (cats), hookworms, roundworms

What is the largest Phylum in the animal kingdom? What does the word mean?

Arthropods --*"arthro"* means joint --*"pod"* means leg or feet "Jointed leg"

Why must dogs be kept quiet and still during HW Tx?

As the adult HW's die, they move with the flow of blood toward the lungs.

Why are "roundworms" entitled as such?

Because they are round when observed in cross section --eggs seen in fecal

Explain the canine hookworm's life cycle.

Canine hookworms develop to infective third stage larva in the external environment, then they penetrate the dog's skin and migrate to the small intestine where they mature to adults. The canine hookworm has a *direct* life cycle.

Under the Phylum "Platyhelminths" what is the Class name for a tapeworm?

Cestode

What is a parasiticide? Name the 4.

Chemical compound used to treat specific internal and external parasites. 1. Anthelmintics 2. Acaracides 3. Antiprotozoal 4. Insecticides *AAAI*

Name 9 key morphologic features of Nematodes.

Circular in cross section Unsegmented Rounded on both ends Bilaterally symmetrical Variety of Shapes Variety of Sizes Covered by a thin cuticle Multicellular Elongate *"CURB-VSVS-C-ME"*

What are antiprotozoals?

Compounds used to kill: Protozoan organisms

What are acaricides?

Compounds used to kill: Ticks & Mites

Give an example of an ectoparasite.

Ctenocephalides felis (cat fleas) on a dog. (Fleas are NOT host specific.) *This is the most common spp. of flea on dog and cat.

What is symbiosis?

Describes any association, temporary or permanent, between at least 2 living organisms of different species.

What is a life cycle?

Development of a parasite through its life stages. Each has a least one definitive host and each MAY have at least one intermediate host.

What are the 4 tests used to Dx HW?

Direct blood test Knott's test (uses formaldehyde) Di-fil test (traps microfilariae) ELISA test (Idexx snap test)

Give an example of an endoparasite.

Dirofilaria Immitus (heartworm) --in dogs, cats, ferrets.

Who says this about continual improvement of professional knowledge and competence? "Any student of veterinary parasitology must use the terms presented in this chapter and their definitions as the "framework" on which to build a greater proficiency in this discipline. As with the veterinarians with whom they work, vet techs must be encouraged to embrace the continual improvement of professional knowledge and competence."

Dr. Charles M. Hendrix, DVM (author of our book, Auburn University College of Vet. Med.)

What is a Monogenetic Trematode (fluke)?

Ectoparasites of fish, amphibians, and reptiles (water based). Rarely parasites of mammals. *e.g.* Farm raised catfish

What is the difference between infestation and infection?

Ectoparasites produce an infestation (outside) on the host. An endoparasite will produce an infection (inside) within the host.

What organs/chemistries would be used in Pretreatment testing for HW? What would need to be done to determine the status of heart & stage of disease?

Liver & Kidneys ALT & BUN/Creatinine *Radiographs* need to be taken.

What is a Pseudoparasite? Give an example.

Living things that are not parasitic but are mistaken for parasites. *e.g.* Pollen grains in a fecal float

Why is the somatic muscle layer important to a nematode?

It is the layer of muscles that enables the nematode to move about

An immiticide is given to kill adult HW. What is usually given to treat the dog for microfilariae?

Ivermectin (microfilaricide)

Under the Phylum "Platyhelminths" what is the Class name for a roundworm?

Nematode

What is parasitology?

The host-parasite relationships between domesticated and wild animals and their parasites.

Define parasitosis.

The parasite is present and the host exhibits obvious signs of clinical parasitism.

Define parasitiasis.

The parasite is present but the host does not exhibit clinical signs of disease.

Define phoresis.

The smaller member of the symbiotic relationship is carried about by the larger member.

How does the L.C.Scheme work?

There are several million spp. of the 5 Kingdoms living on earth. Due to different languages in different regions, he gave each organism a scientific name composed of 2 Latin words (commonly written in italics). The first word is the capitalized genus name, and second word isn't capitalized and is the species name.

What is an intermediate host? Give example.

This is a host that harbors the larval, juvenile, immature or asexual stages of the parasite. *e.g.* The female mosquito is the intermediate host for the developing stages of HW. *e.g.* The flea is the intermediate host for tapeworms.

What is a Homoxenous (aka-monoxenous) Parasite?

This is a parasite that will affect only one type of host. (homo=same) (Stenoxenous is a parasite with a NARROW host range)

What is a Euryxenous Parasite?

This is a parasite with a very BROAD host range. *e.g.* Toxoplasma gondii--infects more than 300 SPECIES

What is a prepatent period? *important*

This is the time from the point of infection until a specific diagnostic stage can be recovered. (eggs in fecal) *KNOW*

Which of the Toxocara spp. cannot cross the placenta to infect?

Toxocara cati

Under the Phylum "Platyhelminths" what is the Class name for a fluke?

Trematode

Trichuris vulpis (____) Capillaria spp. (____) are examples of what egg type?

Trichinelloid *aka* Trichoroid (whipworm) type eggs

Haemonchus contortus (____) Strongylus vulgaris (____) Ancylostoma caninum (____) are examples of what egg type?

Trichostrongyles *aka* strongyle or hookworm type eggs

What are protozoans? Give 2 examples.

Unicellular organisms that replicate by BINARY FISSION. *e.g.* Giardia & Coccidia

What does the "Knott's test" test for and what is used as its reagent?

Used to Dx heartworms *Formaldehyde* is used as reagent

What type of anthelmintic ("dewormer") is Anthelban and Nemex (trade names) and their active ingredients?

Vermifuges PYRANTEL

What is an erratic parasite? Give an example.

When a parasite wanders from its usual site of infection into a location that it does not ordinarily live. *e.g.* Cuterebra (wolf worm) is usually found in the skin of dogs and cats but may accidentally wander into the cranial vault.

Define proboscis.

elongated tubular process *e.g.* the spiny *proboscis* on the anterior ends of a thorny-headed worm that is an organ of attachment