BASIC SCIENCES Flashcards
A cat that hunts outdoors develops a rapidly progressive disease with signs including anemia and icterus. Death occurs a few days after the onset of clinical signs. Histopathologic examination of the lungs and liver reveals blood vessels filled with very large cells containing parasitic inclusions. The most likely cause of this cat’s death is infection with:
A. Aelurostrongylus abstrusus B. Cytauxzoon felis C. Leishmania braziliensis D. Paragonimus kellicotti E. Eucoleus (Capillaria) aerophila
Ans. B.
Cats acquire fatal infection with this parasite from tick bites; the sylvatic cycle is tick-bobcat-tick.
An Arabian foal with inherited combined immunodeficiency develops diarhhea. Examination of the feces by sugar flotation reveals large numbers of very small oocysts typical of a parasite known to cause diarrhea in immunocompromised hosts. The name of this parasite is:
A. Eimeria leukarti B. Cryptosporidium parvum C. Klossiella equi D. Trypanosoma brucei E. Parascaris equorum
Ans. B.
Immunocompromised horses, not unlike dogs, cats, and people, can develop severe diarrhea due to cryptosporidiosis.
Necropsy of a lamb from a flock that recently developed severe diarrhea reveals numerous whitish, raised lesions, 3-6 mm in diameter, in the intestinal mucosa. Fecal examinations have not disclosed any parasites present in great numbers; however, saline smears prepared from the lesions reveal hundreds to thousands of small elongate organisms. A likely cause of the diarrhea and the intestinal lesions is:
A. Eimeria ahsata B. Giardia duodenalis (G. lamblia) C. Isospora canis D. Sarcocystis arieticanis E. Trichuris ovis
Ans. A.
Disease is likely to occur before oocysts are being shed in the feces. Diagnosis requires examination of the intestinal mucosa of dead animals.
You and your spouse own a veterinary clinic in a small town, and your 3-year-old daughter accompanies you to the office everyday, where she plays in the reception area. After about 6 months, you note that your daughter is not sleeping well and is complaining that her anal area itches. Your pediatrician diagnoses pinworm infection. Your daughter probably obtained her infection from:
A. your family dog
B. a dog visiting your clinic
C. eggs in feces-contaminated soil in your
backyard
D. another child
E. your family horse
Ans. D.
People often refuse to accept that their pet is not at fault.
Puppies with hookworm eggs in their feces 2 weeks after birth have typically become infected with Ancylostoma caninum by:
A. ingestion of infective larvae from soil
B. transmammary migration od larvae from the
bitch
C. transplacental migration of larvae from the
bitch
D. penetration of the skin by infective larvae
E. ingestion of hookworm eggs containing
infective larvae
Ans. B.
Young puppies with eggs in their feces were likely infected via the dam’s milk.
The prepatent period of Diroflaria immitis poses problems in diagnosis of heartworm infection in dogs. By definition, the prepatent period of heartworms is that period between:
A. the time th e mosquito ingests a microfilariae
and the time the infective-stage larva is fully
developed
B. the time the adult worms have died and the
time the microfilariae are ultimately cleared from
the blood due to old age and natural parasite
death
C. the time a dog has been chemotherapeutically
cleared of its microfilariae and the time the
microfilariaefrom the existing adults return to
detectable levels in the circulation
D. the time infective-stage larvae are inoculated
by a mosquito and the time adult worms first
appear in the pulmonary vessels
E. the time infective-stage larvae are inoculated by
a mosquito and the time microfilarae first
appear in the bloodstream
Ans. D.
The diagnostic dilemma is that there are no detectable microfilariae and antigen tests do not begin to detect infection until several weeks to months after the mosquito bite.
The prepatent period of whipworm (Trichuris vulpis) infection is:
A. 1 week B. 1 month C. 3 months D. 5 months E. 1 year
Ans. C.
It takes about 3 months for whipworms to mature.
In the southeastern United States and the Caribbean, cats are probably the major source of eggs from which the larvae develop that cause the zoonotic syndrome called cutaneous larva migrans. The nematode that most commonly causes this zoonotic disease is:
A. Ancylostoma tubaeforme B. Ancylostoma braziliense C. Uncinaria stenocephala D. Ancylostoma caninum E. Ollulanus tricuspis
Ans. B.
Geographic distributions are important for certain parasitic diseases. The distribution of cutaneous larva migrans mainly parallels that of Ancylostoma braziliense; thus such lesions would typically not be expected in places where this species of hookworm is not found. This worm is found mainly along the eastern coast of the United States and around the Caribbean. In the dog or cat host, the eggs of the different Ancylostoma species are usually indistinguishable.
Necropsy of an equine fetus aborted late in pregnancy reveals pneumonia with fibrinonecrotic casts in bronchi. Which organism is most likely the cause of the abortion?
A. Aspergillus organisms B. equine herpesvirus C. equine viral arteritis virus D. Streptococcus equi E. Taylorella equigenitalis
Ans. B.
Equine herpesvirus causes necrosis of the bronchoiolar epithelium, with sloughing of the mucosa, fibrin deposition, formation of casts.
Over the past 2 weeks, one of your dairy clients has lost four heifers with clinical signs of CNS disease, including circling. You suspect listeriosis. What is th emost appropriate sample to submit to a diagnostic laboratory for culture and histopathologic examination to confirm your tentative diagnosis? A. cerebral cortex B. hippocampus c. cerebellum D. brainstem E. spinal cord
Ans. D.
CNS lesion caused by Listeria organisms are characteristically found in the brainstem.
The most common lesion of Salmonella infection in horses is:
A. hemorrhagic colitis B. fibrinotic colitis C. ulcerative enteritis D.proliferative enteritis E. granulomatous enteritis
Ans. B.
Salmonella infection produces fibrin and necrosis of the colonic mucosa.
Ans. B.
Salmonella infection produces fibrin and necrosis of the colonic mucosa.
A mare exhibits stallionlike behavior and has an enlarged ovary. What is the most likely cause of these findings?
A. dysgerminoma B. cystic follicles C. oopheritis D. granulose cell tumor E. hydrosalpinx
Ans. D.
Answer choices a and c may emlarge the ovary but are rare and do not occur in horses; choice b does not occur in horses; choice e is dilatation of the oviduct.
At necropsy of a dog, one kidney has a dilated pelvis with loss of half the medulla. This lesion is called:
A. cystic kidney B. papillary necrosis C. pyelonephritis D. hydronephrosis E. hydroureter
Ans. D.
Answer choice a is characterized by cysts in the kidney; choice b is necrosis of the renal crest; choice c is inflammation of the medulla; choice e is dilatation of the ureter.
A white plaque on the cornea of a Hereford cow most likely represents:
A. keratits B. a corneal ulcer C. squamous cell carcinoma D. lymphoid hyperplasia E. coloboma
Ans. C.
Answser choices a and b produce ulcers and not plaques; choice d occurs on the third eyelid; choice e is a congenital defect in an ocular structure.
The pregnant, cat-owning client most at risk for passing toxoplasmosis to her fetus during gestation is one who:
A. has repeatedly eaten raw or rare beef B. does a lot of backyard gardening C. already has high circulating Toxoplasma antibody titer at the time of conception D. does not have a high circulating Toxoplasma antibody titer at the time of conception E. owns a cat with a high circulating Toxoplasma antibody titer at the time of conception
Ans. D.
The fetus of an immune woman or sheep is protected unless the mother or dam is immunosuppressed, such as by corticosteroids or, in people, AIDS.
