Parasitology Practice Quizes

What phenomena does the term "epizootic" describe?

The occurrence of disease in an animal population in excess of the generally accepted number of cases.

As discussed by a parasitologist, what is the primary topical focus of "Epidemiology"?

the distribution of parasitic diseases in human and animal populations

Why is an appreciation of "parasitism" as a natural phenomenon important to your ability to care for pet dogs and cats and production livestock of your clients?

Understanding parasitism as a natural phenomenon is important to knowing the difference between infection and disease for recommending prevention measures and treatment options.

Trichuris vulpis

Identify these eggs found on the fecal examination of an adult dog suspected of having Addison's disease. They measure approximately 80 x 40 um.

What is the preferred treatment regimen for prevention of clinically significant parasite burdens in neonatal puppies and kittens and environmental contamination of their surroundings?

2, 4, 6, and 8 weeks of age with Pyrantel Pamoate

What role does the "paratenic host" play in the transmission of parasitic organisms?

It is an optional host in which the host does not develop. It may be useful for bridging an ecological gap for transmission between intermediate and definitive hosts.

How is the term "prevalence" used to describe the relationship between a disease/infection and a host population?

It is used to describe the "occurrence" of disease or infection based then number of observed cases divided by the number of subjects examined.

Unspecified large strongyles

What parasite group is associated with eggs that look like these (90 x 45um) when they occur in 2 to 3 yr old equines?

To what phenomena does the term "Zoonosis" best describe?

an animal disease transmissible to humans

What is the term for a host that helps to maintain a parasite in the environment for subsequent transmission in a susceptible population?

Reservoir host

Parascaris equorum

The golden brown eggs were found on the fecal flotation of a 12 week old foal with a cough and nasal discharge . They measure approximately 90 um in diameter. What parasite is responsible for the eggs?

Ancylostoma caninum

Identify these eggs found on the fecal examination of a 4-week-old puppy with a profound anemia. They measure approximately 60 x 40 um

How do puppies become infected with canine hookworm, Ancylostoma caninum?

When nursing puppies ingest infective larvae transmitted from their mother by the lactogenic route

How is the canine roundworm Toxocara canis transmitted between hosts?

Susceptible canines ingest infective larvae in eggs present in contaminated environmental sources or ingest larvae encysted in paratenic hosts.

What parasitic organism is associated with pseudo-Addison's disease?

Trichuris vulpis

What role does the "definitive host" play in the transmission of parasitic organisms?

It is the organism in which the parasite is able to successfully engage in sexual reproduction.

Why are "hookworms" important agents of disease in dogs and cats?

because they can literally bleed small puppies and kittens to death

Under what conditions do pet dogs become infected with the canine whipworm Trichuris vulpis?

when dogs living in hyper-contaminated outdoor kennels and runs ingest the eggs containing infective larvae

What role does the "intermediate host" play in the transmission of parasitic organisms?

It is an organism where the juvenile parasite must undergo developmental transformation to become infective for the final host.

What term is used to describe the natural occurrence of disease in an animal population?

The disease is said to be enzootic

Toxocara canis

Identify this egg found on the fecal examination of a 6 week-old puppy with a pot-bellied appearance. The egg measures approximately 85 um in diameter.

Unspecified small strongyles

What parasite group is most likely associated with eggs like these (90x45um) when they occur on the fecal flotation of a 12 to 15 week old foal.

In what way is the transmission biology for the feline roundworm Toxocara cati different from the canine roundworm, Toxocara canis?

T. cati is transmitted exclusively by the lactogenic route and in utero transmission does not occur

What is the most economically important parasite affecting sheep and goat production in the United States?

Haemonchus contortus

The red circle illustrates parasitic infections in "refugia" necessary to maintain genetic susceptibility to available deworming compounds

What does this graph of fecal egg count distribution indicate about the parasite population infecting the herd of goats?

Ostertagia sp.

These eggs were found in a fecal sample from a six month old calf born in the Fall of the year. What parasite species should you be most concerned about as the likely culprit for their appearance?

Migrating Strongylus vulgaris larvae

What parasite is generally associated with the verminous aneurysm seen in the accompanying image?

What type of deworming program is described by administration of treatments at intervals of 2, 4, 6, 8 weeks for dogs and cats, or 2, 4, 6, 8, months for horses and ponies?

A suppressive deworming program at intervals shorter than the egg reappearance period

Dioctophyma renale

What parasite produced this egg found in the urine sediment of a dog living in Northern Minnesota?

Which population of dogs tested with a reputable heart worm serologic test is likely to be associated with the highest positive predictive value?

Dogs exhibiting pathognomonic clinical signs like radiographic anomalies, ascites, dyspnea, and exercise intolerance

Why should cats be placed on monthly heartworm prophylaxis?

Cats have the same risk of infection as dogs, the disease is more severe, and there is no effective treatment.

Acanthocheilonema reconditum

What is the identity of this microfilaria observed on a canine's blood examination that is approximately 265 um in length and 5 um wide?

Thelazia sp.

What is the genus associated with parasites found in the eye of cattle, horses, dogs and cats?

Dirofilaria immitis

These microfilariae seen on a blood examination average > 300um. What parasite is producing them?

Haemonchus contortus

These eggs were found on the fecal flotation of an adult Nubian goat with a FAMACHA score of 3. What parasite is most likely the culprit?

A generic mix of mostly Small and Large Strongyles

Parasites that infect adult horses and produce eggs that look like this are most likely:

What presentation is typically associated with Type 1 Ostertagiosis?

green watery diarrhea and large worm burdens in younger animals during their 1st season on pasture

Ascaris suum

What parasite is associated with the granulomatous lesions "milk spots" seen in this condemned pig liver?

Filaroides

What is this larva measuring ~300 um, was found on the Baermann exam of a coughing dog?

Why is it clinically important to correctly identify an Infection with Acanthocheilonema reconditum in companion animal veterinary practice?

The adults worms are nonpathogenic and do not require treatment with the heartworm adulticide

Syngamus trachae

What are these bright red worms found in the trachea of chicken that asphyxiated from excess mucous while exhibiting open mouth "gaping behavior" breathing?

What presentation is typically associated with Type 2 disease resulting from infection with Ostertagia ostertagia?

brown watery diarrhea associated with the mass emergence of inhibited larvae in older animals their during their 2nd season on pasture

Oesophagostomum dentanum

What parasites are associated with the nodules in the image of the intestine of this necropsied pig?

The llama is an accidental host and does not play a role in further transmission of the parasite.

The black llama seen in this picture was diagnosed presumptively with "meningeal worm disease". How would you describe the host-parasite association illustrated by this case?

What is the primary objective of the "selective de-worming" strategy advocated for livestock producers?

To minimize drug selection pressure and reduce the likelihood of developing resistance in the resident parasite population

Capillaria plica or C. feliscati

What parasite produced this egg found in the urine sediment of a cat with cystitis?

Ingestion of a larvated egg or earthworm serving as paratenic/intermediate host

These eggs were found on the fecal flotation of a sneezing dog. What transmission pathway is the most likely way the dog was infected?

Small Strongyles "aka Cyatostomes"

What parasite group, encysted in the colonic wall of the necropsied pony, is associated with this image?

The reverse D indicating cardiomegaly (enlargment) of the right side of the heart

What distinctive feature seen in the radiograph of this dog is pathognomonic for canine heartworm infection?

Capillaria sp.

What parasite is associated with these eggs found on fecal examinations from selected poultry with a history of decreased productivity and respiratory illness?

Why is the practice of monthly prophylactic treatment of llamas and alpacas with macroccyclic lactone drugs a significant concern for small ruminant producers?

It has the potential to facilitate drug resistance against Haemonchus contortus and increase the risk of production losses from fatal anemia in sheep and goats

Filaroides hirthi

What are the worms seen on this histopath section of lung parenchyma from a coughing dog?

Oxyuris equi

What parasite is responsible for these eggs measuring approximately 90x 42 um recovered from the "scotch tape" preparation made from the perianal surface of a 15 year-old mare?

It is illustrating the animals in the herd contributing most of the parasite contamination to the pasture grazing environment

What is the best interpretation of this graphic depiction of fecal eggs counts in llama herd?

Measure the microfilaria and perform antigen test if necessary for confirmation.

These microfilariae were found on the blood examination of an asymptomatic outdoor dog. What steps are necessary to complete your diagnosis:

Which host-parasite relationsip is an incorrect match between the DH and the IH?

Taenia ovis (Human- Sheep)

3 multiple choice options

Which stage of a 3 host tick species is more likely to be associated with transmission of an infectious disease?

Nymph

How is the definitive host for a tapeworm species infected?

By ingestion of the metacestode encysted in an intermediate host

A dog displayed clinical signs of ascites, dysorexia, vomiting, and tachypnea. Following surgical removal of the worms and aggressive chemotherapy with FBZ, a presumptive diagnosis of infection with Mesocestoides was made. How does this parasite cause disease in the host?

Disease results from asexual replication of worms in host & invasion of peritoneum

What is the primary season for highest infection prevalance with Anoplocephala perfoliata?

July to October

How is the intermediate host for a tapeworm species infected?

Ingestion of eggs passed in the feces of an infected host

Ornithonyssus sylviarum (Northern Fowl mite)

A backyard chicken is presented for laying less eggs than normal and listless behavior. Tiny blackish brown specks are seen moving around the hen's vent. What is your best guess?

Cheyletiella sp.

This critter came off of a 10-year-old terrier with flaky dermatitis. What are they?

Ingestion of pork tapeworm eggs by the fecal-oral route

How do humans acquire the zoonotic disease neurocysticercosis associated with the Pork Tapeworm, Taenia solium?

Ingestion of the metacestode in an infected invertebrate intermediate host

Eggs that look like this were found on the fecal flotation of a beagle with persistent flea infestation. How was the beagle infected?

Ingestion of eggs passed in the feces of an infected canine

How do people and other mammalian intermediate hosts acquire the disease hydatidosis produced by the parasite Echinococcus granulosis?

Demodex canis

A dog presents with a dry-flaky erythematous "red" mange showing hair loss around the eyes & boney projections of the body. What parasitic mite should be high on your differential?

What is the tapeworm of horses associated with intussusception and rupture of the bowel?

Anoplocephala perfoliata

Identify the anatomical structure that contains the rproductive organs of Tapeworms.

Proglottids

Why don't macrocyclic lactone drugs kill tapeworm parasites?

Tapeworms don't have glutamate gated chloride channels

What structure is unique to Pseudophyllidian tapeworms?

The scolex with slit-like suckers

Cryptosporidium parvum

You are going on a farm call with the veterinarian to check on a 2 week old dairy calf with diarrhea. Which of the following organisms presents an occupational health risk you want to avoid?

Giardia cysts

These structures were found on the fecal flotation of a dog with diarrhea. They are approximately 12x8 µm. What are they?

The bugs are a potential intermediate host facilitating transmission of the parasite. They should be tested to confirm their infection status.

This is one of several dozen bugs found in the walls and rafters of the house occupied by a dog that recently died from heart disease associated with infection by Trypanosoma cruzi. What role, if any, did these bugs play in the deceased dog's health condition?

Leishmania infantum

Identify the nest of organisms seen in the macrophage from the bone marrow aspirate taken from a dog showing polydipsia, polyuria, and generalized dermatological disease. The owner and his pet recently moved to Lee County after 10 years residence in Greece.

Trypanosoma cruzi

Identify the parasite that produced the little nest of amastigotes seen in this histopath section of heart muscle from a dog that died of cardiac disease in Texas.

Paragonimus kellicoti

These eggs were found in the sputum of a coughing dog with daily access to a creek in its back yard. They are ~90 x 50 µm. What parasite is producing them?

How does Paragonimus cause disease in the infected host?

significant respiratory distress that may result in pneumothorax

Thorny headed worm

This parasite was found attached to the small intestine of a pig at necropsy. What is it?

Cattle are drawn to exposed vegetation with encysted metacercariae at water sources because of the excessive evaporation

Why are infections with Fasciola hepatica in grazing beef cattle often associated with periods of reduced rainfall and its drought effects on pastures?

Playtynosum fastosum

Eggs that look like these were found on the fecal exam of a cat from South Beach, Miami Fla. What species is most likely producing the eggs?

Heterobilharzia americana

This Golden Retriever from North Carolina presented @ the clinic with weight loss, dysrexia and elevated liver enzymes. What parasite should be included in your differential diagnosis?

penetration by swimming cercarial stages

This Golden Retriever from North Carolina presented @ the clinic with weight loss, dysrexia and elevated liver enzymes. A presumptive diagnosis of Heterobilharzia was made. The owner wants to know how his dog became infected. What will you tell him?

Dicrocoelium dendriticum

Eggs that look like these are often found in cattle when they accidentally ingest "zombie ants" while they are grazing on infested pastures. They measure 36 to 45µm X 20 to 30µm. What parasite species is associated with cattle and zombie ants as definitive host (DH) and intermediate host (IH), respectively?

When they eat poorly cooked crayfish on camping trips

How do people and their pet dogs and cats become infected with Paragonimus?

Tritrichomonas blagburni

The associated pathology report describes this histological section from a necropsied cat as representative of a lymphoplasmacytic/neutrophilic colitis with crypt abscess. What parasite is likely implicated in the poor health condition of the patient?

Toxoplasma gondii

Oocysts similar to these, approximately 10 to 12 um in diameter were seen on the fecal examination from a cat. What are they?

Get tested to know your infection status and risk, avoid eating poorly cooked meat, avoid gardening and soil related activities, most importantly have someone else change the cat's litter box daily

What advice do you give a pregnant woman regarding her pet cat and Toxoplasma gondii?

Eimeria oocysts, probably acquired from eating the feces of a rabbit, squirrel, or some other critter

When "eggs" that look like these are found on the fecal flotation of a dog, what is your best guess of their identity. They measure ~40x30, have a rough or texture-like surface, and a thin operculum-like structure on one end.

An oocyst of Cystoisospora in the sporulated state of development

Structures that look like this (measuring between 25 to 40um in diameter) may be found on the fecal flotation of dogs and cats. What is it?

An oocyst of Eimeria in the sporulated state of development

This structure was found on the fecal flotation of a goat. What is it?

Eimeria sp oocysts

These structures were found on the fecal flotation of a 15 week old calf. What are they?

Isospora felis (Cystoisospora felis)

This structure was found on the fecal flotation of a DSH (cat). It measures approximately 30x 40 um. What is it?

Isospora ohioensis (Cystoisospora ohioensis)

This structure was found on the fecal flotation of a 19 week old puppy with diarrhea. It measures approximately 25 um. What is it?

Hepatozoon americanum

Identify the parasite encysted in the muscle of a dog with myositis and anemia

Cytauxzoon felis

Identify the tiny parasites occluding the blood vessel in the spleen of an icteric cat that died acutely?

Whys is the disease resulting from coccidia associated with hematophagous arthropods generally more severe than intestinal coccidia?

Tick transmitted coccidia undergo unlimited asexual multiplication and tissue destruction in infected RBCs and WBCs

Babesia sp.

Little organisms (3 to 5 um) that look like these were seen on a blood smear of a Burmese fighting dog. What are they:

Toxoplasma gondii

A new client recently took in a stray cat showing flu-like symptoms including lymphadenopathy and sneezing? What infectious agent should be on your differential diagnosis list for its zoonotic importance?