Lab Exam 2 Flashcards
What is the common name for Dipylidium caninum?
Double-pored or cucumber seed or flea tapeworm
DH of Dipylidium caninum?
Dogs, cats, and humans sometimes
IH of Dipylidium caninum?
Fleas
What is the site of infection for Dipylidium caninum?
Adults in the small intestine
Where are the germinal pores located on Dipylidium caninum?
The pores are on the lateral margins
What is unique about the rostellum of Dipylidium caninum?
It’s retractable
What is the infective stage to the DH for Dipylidium caninum?
Ingestion of a flea containing cysticercoids
When diagnosing Dipylidium caninum, what can we look for?
Egg packets
What are the signs and pathogenicity of dipylidium caninum in heavy infections?
Chronic enteritis - abdominal discomfort and vomiting
Anal irritation may cause scooting, but most likely it would just be impacted anal glands
What is the size of a Dipylidium caninum egg packet?
120-200 microns
What is the size of an individual Dipylidium caninum?
35-60 microns
What can you see in the eggs of Dipylidium caninum?
Hexacanth embryo
Common name for Taenia spp.?
Armed tapeworm (except T. saginata)
What is the DH for Taenia?
Carnivores
What is the IH for Taenia?
Vertebrate prey species
Site of infection for Taenia spp.?
Adults in small intestine
Metacestodes in a variety of organs and tissues in IH
Identification of Taenia?
Proglottids in the feces or attached to the hair coat
- the proglottids are more or less rectangular
- they have a single genital pore
Can you find Taenia eggs in feces?
Yes, but the proglottid has to rupture first
What does a Taenia egg look like?
25-40 microns in diameter Brown with thick shell wall Radial striations in the shell wall Contains hexacanth embryo Spherical
Anoplocephala perfoliata DH?
Equine
Anoplocephala perfoliata IH?
Oribatid mites
Location of Anoplocephala perfoliata in equine?
Cecum at the ileocecal junction
Does Anoplocephala perfoliata have a rostellum?
No, it has larger suckers in order to compensate
What stage of Anoplocephala perfoliata is infective to a horse?
They ingest a mite with a cysticercoid
What is an easy way to identify an adult Anoplocephala perfoliata?
The lappets under the scolex
What does a mite need to ingest in order to progress the life cycle of Anoplocephala perfoliata?
An egg containing a hexacanth embryo
What are common clinical signs of Anoplocephala perfoliata?
Persistent diarrhea, intussusception (ileum goes into the cecum) and colic
What is the pathogenicity of Anoplocephala perfoliata?
It interferes with the function of ileocecal valve through ulceration and inflammation
What is the preferred diagnostic test for Anoplocephala perfoliata?
ELISA test
Why is a single negative test not diagnostic for Anoplocephala perfoliata?
The eggs are not always found during flotation. They’re irregularly produced and the proglottid has to rupture
Describe an Anoplocephala perfoliata egg.
65-80 microns in diameter
Irregularly shaped with round corners
Contains a pyriform apparatus with a hexacanth embryo
What is an mnemonic for the basic lifecycle of Order Digenea?
Every - Month - She - Really - Can - Menstruate - Abundantly
Egg - Miracidium - Sporocyst - Redia - Cercaria - Metacercaria - Adult
What is the common name for Fasciola hepatica?
Liver fluke - liver rot in sheep
What is the DH for Fasciola hepatica?
Sheep, cattle, goats, and other ruminants
What is the IH for Fasciola hepatica?
Aquatic snails
What is the site of infection for Fasciola hepatica?
Adults in bile ducts
Immatures migrate throughout the liver parenchyma
What is considered the most common liver fluke in domestic animals in the US?
Fasciola hepatica
Are the eggs of Fasciola hepatica immediately infective when passed in the feces?
No
What stage of Fasciola hepatica will an aquatic snail (IH) ingest to further the LC?
Miracidia
What stage of Fasciola hepatica is infective to the DH?
Metacercariae (ingestion of infected vegetation)
Does Fasciola hepatica need to be in the water to survive?
No, it can be on the waters edge
What is the pathogenicity of immature Fasciola hepatica?
Necrosis and anemia due to migration and feeding of the immature flukes through the liver parenchyma
What can migration of Fasciola hepatica cause?
Replication of Clostridium novyi
What is the pathogenicity of adult Fasciola hepatica?
Anemai and thickening of the bile ducts to feeding of adult trematodes
Describe an adult Fasciola hepatica.
Up to 3 cm, leaf-like, brownish
Broader anterior than posterior
Anterior cone-shaped projection with oral sucker
Also has a ventral sucker
Describe a Fasciola hepatica egg.
130-150 microns by 63-90 microns
yellowish-brown
indistinct operculum
What is the preferred diagnostic method for finding Fasciola hepatica?
Fecal sedimentation or FlukeFinder is preferred
- undifferentiated embryo makes them heavier
What is the common name for Giardia duodenalis?
Giardiasis or beaver fever
What is the host of Giardia?
Wide range of vertebrates depending on Giardia assemblage
- Domestic and wild mammals, birds, amphibians, lizards, rodents, etc.
What is the site of infection for Giardia?
Small intestine
What is a Giardia trophozoite?
The actively motile feeding stage
What is a giardia cyst?
Not moving
Offers environmental resistance
This is the stage that goes into the water
Giardia trophozoites are only found in what type of sample?
Fluid fecal sample
Giardia trophozoites will be found in what kind of sample?
can be found in diarrhea, but are more likely to find trophozoites
you can find these more in dried feces
What is the highly refractile organelle in Giardia? What is its function?
Median bodies
Probably has to do with ventral disk formation
What are the flagella of Giardia supported by?
Axistial
- internal structure that provides central support
What do Giardia trophozoites due in the intestinal tract?
They live on the surface and they blunt the villi - leads to malnutrition
When do Giardia cysts form?
As the intestinal contents are moving out of the host and into the external environment
How many nuclei are in young Giardia cysts?
How many nuclei are in old Giardia cysts?
young - 2
old - 4
What does Giardia use to attach to the intestinal wall?
Ventral disc
How many flagella does a Giardia trophozoite have?
8
What kind of LC does Giardia have?
Direct = fecal-oral
How can someone become infected with Giardia?
Ingestion of cysts from food, water, hands, fomites, etc.
Giardia PPP?
1-2 weeks
How do Giardia trophozoites replicate if there’s only one?
They’re hermaphroditic. They split down the middle (binary fission) and make more trophozoites
What is the pathogenesis of Giardia?
Trophozoites cover the epithelium and can cause acute focal inflammation and increased mucus production.
Villous atrophy can be common - maldigestion and malabsorption
In acute to chronic Giardia infections, what clinical signs do we see?
Pale, pasty semi-formed, foul-smelling stools
Intermittent diarrhea
Vomiting in dog
Migrate into bile duct causing biliary inflammation and or obstruction (heavy infection)
How doe we diagnose Giardia?
Ag detection test - detects cyst wall protein
- only use with clinical signs (diarrhea)
After treatment, retest with centrifugal fecal flotation (not the antigen)
What is the preferred flotation medium for Giardia?
Zinc sulfate with centrifugation (least harsh, doesn’t suck water out of the cyst and distort it like others do)
Describe a Giardia cyst.
9-13 microns by 7-9 microns Elliptical Thin, smooth wall 2-4 nuclei Axostyle (intracytoplasmic flagellum) Comma-shaped median bodies
When can Giardia trophozoites be found within 30 minutes of collection?
When doing direct saline smear of fresh diarrheic feces or when doing a duodenoscopic aspirate
Describe a Giardia trophozoite.
Bilaterally symmetrical with a tear-drop or pyriform shape
2 nuclei
8 flagella
Rod-like median bodies (posterior to the nuclei, stain densely, highly refractile when unstained)
Concave adhesive dish that gives them a clown or monkey face
What kind of motility do Giardia trophozoites have?
Falling leaf motility
What stage do Trichomonads lack that are found in Giardia?
Cyst stages
What is the causative agent of tritrichomoniasis?
Tritrichomonas foetus
What is the host for Tritrichomonas foetus?
Cattle
Site of infection for Tritrichomonas foetus?
Cows - repro tract
Bulls - prepuce (primarily)
What kind of LC does Tritrichomonas foetus have?
Venereal (direct) transmission
Bulls are subclinical carriers; at least 6-8% infected
How many flagella does Tritrichomonas foetus have?
Tri = 3 flagella
What is the pathogenesis of Tritrichomonas foetus?
Presence and multiplication of parasites damage host tissue and cause inflammation
What can Tritrichomonas foetus do, that has an economic impact in regard to reproduction?
It invades the placenta and fetus and results in abortion
How do we diagnose Tritrichomonas foetus?
Visualizing or detecting trophozoites by using smegma from a bull or vaginal secretions from a cow
What are the different diagnostic techniques used for Tritrichomonas foetus?
Direct smear onto slide and visualize organisms (FYI: rare to see organisms without culturing first)
Culture in specific media pouch and then visualize
PCR culture pouch contents following incubation (send it to lab and they will try to detect the DNA through PCR)
What is the typical sign of Tritrichomonas foetus infection?
Lots of open cows
How does trophozoite movement differ between Tritichomonas foetus and Giardia?
Giardia:
- concave ventral disc
- sluggish
- falling-leaf; herky-jerky
Tritrichomonas foetus:
- undulating membrane
- forwardly progressive (have to chase it to keep up with it)
What disease is associated with Trypanosoma cruzi?
Chagas disease
What is considered to be the reservoir to the arthropod host throughout Latin America?
Dogs
What are the hosts of Trypanosoma cruzi?
Wildlife reservoirs (opossum, armadillos, rats, raccoons, wild canids)
Dogs
Humans
Site of infection for Trypanosoma cruzi?
Blood in early course of infection
Later in variety of tissues, especially cardiomyocytes (heart tissue)
What is the IH for Trypanosoma cruzi?
Triatomines (kissing bugs)
How can a DH be infected with Trypanosoma cruzi from a kissing bug?
Stercorarian from the bug or ingestion of the bug
What are modes of transmission for Trypanosoma cruzi?
Transplacental, blood transfusion/organ transplant and food-borne (in Latin America)
What stage of Trypanosoma cruzi is infective to the kissing bug?
Metacyclic trypomastigotes
What is the pathogenesis of Trypanosoma cruzi?
Cell damage as trypomastigotes rupture from host cells, especially cardiac muscle cells, causing inflammation/damage
What are symptoms of Chagas disease that are only found in dogs?
Chagoma and Romanas sign
What are the clinical signs with acute phase Trypanosoma cruzi?
Lethargy, generalized lymphadenopathy, slow capillary refill/pale mucous membranes, syncope, tachyarrhythmia, L&R sided heart failure, enlarged spleen and liver, death
What are the clinical signs with indeterminate chronic phase Trypanosoma cruzi?
No clinical signs, parasitemia undetectable
ECG usually normal, exercise may induce arrhythmias
What are the clinical signs with determinate chronic phase Trypanosoma cruzi?
ECG abnormalities become prevalent
Anemia, myocarditis, intermittent fever, enlargement of heart, weakness, exercise intolerance, syncope, right sided chamber failure, death
How do you diagnose Trypanosoma cruzi?
It’s difficult, you use suspicion and then try to confirm
Know if you’re in an endemic area and know if the animal has travelled to an endemic area
Can you diagnose Trypanosoma cruzi with blood/buffy coat smear in acute phase?
Rare trypomastigotes
What is the gold-standard diagnostic technique for Trypanosoma cruzi?
Clinical signs and positive serology
- PCR assay (specific, reduced sensitivity in chronic infections)
Hosts of Leishmania?
Mammals and sand flies
Site of infection for Leishmania?
Macrophages of host tissues, skin, spleen, liver, bone marrow, mesenteric lymph nodes
Pathogenesis of Leishmania?
Cell damage as amastigotes rupture from host cells –> inflammation
IH for Hepatozoon americanum?
Canids
DH for Hepatozoon americanum?
Gulf coast tick
Site of infection for Hepatozoon americanum?
Leukocytes and skeletal and cardiac muscle
Distribution of Hepatozoon americanum?
Endemic in states along Gulf coast, is expanding northward
What is unique about the primary route of transmission for Hepatozoon caninum?
The dog ingests the tick, not just the tick feeding on the dog
What does the Gulf Coast tick contain that is infective to dogs for Hepatozoon americanum?
they contain sporozoites in the hemacele (not the mouth parts)
What does the tick need to ingest to become infected with Hepatozoon americanum?
Gamonts (gametocyte in leukocytes)
What is the pathogenicity of Hepatozoon americanum?
Schizogony in muscle tissue –> inflammation
Periosteal bone proliferation - unknown mechanism
What are the clinical signs of Hepatozoon americanum?
Fever, lethargy, ocular discharge, gait abnormalities, lameness, muscle atrophy, wasting, often fatal (sometimes), and chronic
Increase in the bone opacity is the periosteal bone proliferation
IH for Hepatozoon canis?
Canids
DH for Hepatozoon canis?
Brown dog tick/kennel tick
Why does Hepatozoon canis cause anemia?
Schizogony in bone marrow, liver, spleen, gut lymphatics
Where can you see gamonts of Hepatozoon canis?
Readily found on blood smears (< or = 100% WBC)
Does hepatozoon canis have transplacental or transmammarial transmission?
Transplacental transmission
What are diagnostic techniques for Hepatozoon canis?
blood smear (gamonts), CBC (anemia), and PCR
What are the diagnostic techniques for Hepatozoon americanum?
clinical signs, patient history, enzootic areas blood smear (not sensitive) gamonts very rare (0.1% in WBC) Radiographs CBC (neutrophilia, anemia) PCR Muscle biopsy (preferred diagnostic!!!)
What is the primary route of transmission for Hepatozoon canis?
Ingestion
