Parasite Final Work in progress

Serology tests (SNAP) can detect heartworms in a dog's blood:

Several months after becoming infected

You have a young cat with diarrhea and you want to rule out Giardia vs. Tritrichomonas foetus. Name one diagnostic or finding in a diagnostic (ie. direct smear) that would help.

The test may miss Giardia infections in cases where the parasite is not shedding antigens at the time of testing (very early infection).

The test was run incorrectly (not enough sample, test wasn't stored correctly, etc.)

Name one deworming medicine that is effective against roundworms, hookworms, and whipworms.

fenbendazole

Occult heartworm infections occur in approximately 90% of:

Cats

A route of infection by hookworms that is not shared by roundworms is:

Skin penetration

Name two differences that can be used to distinguish microfilaria of Dirofilaria immitis from Acanthocheilonema (Dipetalonema) on a blood smear.

- A. reconditum (diameter less than RBC, blunt anterior with cephalic hook, posterior buttonhook tail)

- Dirofilaria (Diameter equal to RBC, Tapered anterior end no hook, straight posterior end)

Which larval stages of Dirofilaria immitis exist in the intermediate host?

L1, L2, & L3

Cattle at necropsy after a heavy infection of this parasite might have abomasal mucosa with the appearance of "Moroccan leather."

Ostertagia ostertagi

What type of fecal solution should be used to find Giardia in a fecal flotation?

zinc solution with one drop of iodine

__________ is an intracellular, gram negative, symbiotic bacteria that is required for all life stages of D. immitis development, reproduction and survival.

Wolbachia

Which of the following nematodes has an operculated egg?

- Syngamus trachea (gapeworm)

- Oxyuris equi (horse pinworm)

- Dioctophyma renale (giant kidney worm)

- Trichuris (whipworm)

- Eucoleus/pearsonema (lungworm)

Define prepatent period.

Prepatent period is the time from an animal being infected with a parasite to when it is detectable.

Which of the following undergoes hypobiosis?

Ostertagia ostertagi

List 2 reasons for false-negative results can occur on a heartworm antigen test.

it could be too early in the infection, or it could be all male heartworms

Which one of the following drugs is not effective against ascarids:

Droncit (praziquantel)

Explain how pasture rotation is used in the control of nematodes.

Since nematodes are shed by feces, rotating pastures can help to keep animal from reinfecting themselves

True or False: AHS recommends annual microfilaria tests because dogs can have a negative heartworm antigen test but still be positive for microfilaria.

True

Which of the following is not a method of detection of Giardia infection?

Serology - can only find them in fecal material

In the dog, adult heartworms are normally found in the:

What mite causes a crusty infection called "canker ear" in rabbits?

Psoroptes cuniculi

Name three features of tick morphology that are unique to soft ticks.

- leatherlike, raisin shaped body

- No dorsal shield

- Mouthparts located ventrally (not visible from dorsal side)

A local dairy farmer has just acquired some livestock from Louisiana and is concerned that they may have Fasciola hepatica. What fecal examination method will give you the best chance of finding the eggs of this parasite?

Sedimentation

Define the term "Intermediate Host".

this is a host that gets infected by the immature parasite (they can't reproduce). Usually the intermediate host gets ingested by the definitive host. Important to note that the IH is a host in which a parasite undergoes some development before infecting the DH.

Fasciola hepatica can be found in all of the following hosts:

Sheep, cattle, other ruminants

Secondary infection: swine, dogs and cats

Flies do not cause damage in which of the following ways:

Transmission of Babesia

Specific name of invasion of living tissue by fly larvae (two words):

deleterious myiasis

Taeniid tapeworm species are found in which type of definitive host:

Carnivores

Taeniid tapeworms are pathogenic to the _____________________ host.

Intermediate

Tapeworm infections are most often diagnosed in small animals by which of the following methods?

Clinical signs - worms in feces.

What nontaeniid horse tapeworm uses the grass mite as its intermediate host?

Anoplocephala spp.

Flies that don't cause myiasis:

Simulium (black flies), Culicoides (no-see-ums), Lutzomyia (sand flies), Anopheles (mosquitos), Tabanus (horse flies), Musca Domestica (house fly), Stomoxys calcitrans (stable fly), Haematobia irritans (horn fly), Musca Autumnalis (face fly), Melophagus ovinus (sheep ked).

You find nontaeniid tapeworm segments in a dog's feces. In addition to giving Droncit (a tapeworm dewormer), what treatment(s) is/are recommended to control the infection?

You should also start the dog on flea prevention. Something like Nexgard combo, would be good because it treats for both fleas and tapeworms

Chewing vs. Sucking Louse

Chewing: Mallophaga (Head as broad as or broader than the thorax) sucking mouthpieces

Sucking: Anoplura (Head narrower than the thorax) Piercing mouthpieces

Puppy comes into clinic gets everything (vaccines, exam , dewormer) - owner calls due to worms in feces; what would you say to them.

We dewormed it - this is normal

Time frame of positive HW test

takes at least 6 months for microfilaria to show up.

Describe procedure for fecal float

- mix a small amount of fecal with zinc solution

- fill container with zinc solution (either centrifuge or let stand)

- if centrifuged top off with zinc solution til meniscus forms. Place a cover slip on top.

- Let sit for 10 minutes

- place the cover slip onto the top of a slide and exam under a microscope.

Facisola hepatica IH & DH

IH: snails

DH: sheep, cattle and other ruminants

Fasciola in sheep

Acute: Seasonal, painful distended abdomen, anemia, sudden death

Subacute: liver damage, death can occur from hemorrhage & anemia

Chronic: subclinical, anemia, submandibular edema, reduced milk production.

modified knotts test:

- Blood in EDTA tube

- put 10mls into centrifuge tube with 1ml of Blood mixed with EDTA

- Spin tube down in centrifuge for 5 minutes (similar to fecal)

- Decant the supernatant

- place one drop of new methylene blue into decanted sample

- gently mix using pipette

- place one drop onto slide and cover with cover slip, view using 10x

Can ticks transmit tapeworms?

no - only flies

Large animal parasites with flies

Hypoderma, gasterophilus, musca autumnalis

Flukes specific grav vs other parasites

Flukes have a higher specific gravity its why they don't float

Flies that don't lay eggs in feces

sand flies, mosquitos, melophagus ovinus

Protozoans: which cause Diarrhea

coccidians & giardia

Commensalism:

One symbiont benefits from the other without causing harm

Mutualism:

Two different species interact with and in some cases, totally rely on one another for survival

Predator-Prey:

One symbiont benefits at the expense of the other

Phoresis:

one organism attaches to the other for transport. Hitchhikers.

Obligate:

a parasite that always requires a host to live and complete it's life cycle

Facultative:

an organism that is free-living and complete its lifecycle without a host — but can become parasitic in certain hosts if the opportunity arises

Host-Specific:

parasites that live on or only in a single, specific host

Incidental: (accidental)

a parasite found in an organism where it doesn't usually live or prefer to live. It's a dead end host for the parasite and it can't complete its lifecycle.

Aberrant: (erratic)

a parasite that wanders from its usual site of infection into an organ or other location

Definitive Host:

the host on/in which the parasite reaches sexual maturity and sexually reproduces

intermediate host

The host on/in which only sexually immature form of the parasite develop; or the parasite reproduces asexually

Paratenic Host: (transport)

the host is infected with a parasite that doesn't undergo any required development. The parasite can remain in a suspended state until the DH consumes the paratenic host.

Reservoir Host:

an organism that harbors a pathogen but suffers no ill effects.

Benign myiasis

feed on diseased and dead tissues

Deleterious myiasis

attack host's healthy tissues

dog that chases and eats wild rabbits is most likely to become infected with which cestode?

Taenia pisiformis

A mature, egg-bearing tapeworm segment is called a _________ __________.

gravid proglottid

An ectoparasite known both for its host specificity and site specificity is the:

Louse

The fly whose larvae form warbles in subcutaneous tissue along the back of cattle is:

Hypoderma spp.

Flies that cause myiasis:

- Cochliomyua hominivorax (screwworm)

- bottle or blow flies

- Oestrus ovis (sheep nasal bot)

- hypoderma spp.

- gastrophilus spp. (stomach bots)

- Cuterebra spp.

Which of the following flies lays live larvae instead of eggs

Oestrus ovis

Which of the following ticks transmits Borreliella burgdorferi (the causative organism of Lyme Disease) on the east coast of the United States:

Ixodes scapularis

Zoonotic protozoans:

nontaeniid:

IH: Arthropod

DH: Carnivore or Herbivore (pathogenic)

Taeniid:

IH: Herbivore (pathogenic)

DH: Carnivore

Mites & cats

- they have there own type of scabies

- Otodectes cynotis

- demodex spp. (only cat version)

- Cheyletiella (walking dandruff)

- Chiggers ( only larvae are parasitic)

Canine hepatozoonosis

Eating a tick is the way they get it but also eating a paratenic host that had eating an infected tick

rhipicephalus sanguineus

Ehrlichia canis