Upgrade to remove ads
Only $2.99/month

1

Terms in this set (190)

What topics will we be covering in the "Intro to Parasitology" power point?
- Endoparasites vs. ectoparasites
- Key questions involved in parasitology
- Terminology
- Testing
What is the difference between Endoparasites and Ectoparasites?
Endoparasites live inside host's body; also called internal parasites (Ch.6)
1) found in intestinal tract
2) found in circulatory system (Dirofilaria immitis)
What is the difference between Ectoparasites and Endoparasites?
Ectoparasites live on outside of host's body; also called external parasites (Ch 7)
Examples: fleas, ticks and lice
What are the 8 key things to remember in parasitology?
- What are the definitive & intermediate hosts?
- What is the life cycle?
- Clinical symptoms of infection?
- Method of transmission?
- Prepatency Period (PPP)?
- How is diagnosis made?
- Treatment and prevention?
- Zoonotic?
What ARE the different hosts?
*Definitive host: Carries the adult, mature or sexually mature stage of the parasite
*Intermediate host: Carries the immature parasite (larval or asexual form) REQUIRED to complete lifecycle
*Paratenic host: (also called transport host) no development of parasite occurs, not required for life cycle to be completed
*Dead-End Host: (also called incidental host & accidental host) parasite can not be transmitted to another animal, may or may not cause disease
What is the "Diagnostic stage"?
What is the "Infective stage"?
*Diagnostic stage - Stage of parasite that will be detected in laboratory test; is often stage at which parasite passes from one host to the next
*Infective stage - Stage of parasite when ingested (or other route of infection) will cause disease
What 7 clinical symptoms follow a parasitic infection? Note Maybe different for each parasite and the organ system affected
- Diarrhea
- Constipation
- Anorexia
- Vomiting
- Blood in the stool
- Lethargy
- Anemia
What are 5 ways and their descriptions parasites can be transmitted?
* Ingestion:
- Fecal oral, or ingestion of an intermediate/paratenic host
* Vector:
- infected via flea, mosquito or tick
* Transdermal infection:
- infection via skin
* Transplacental infection:
- from mother to fetus
* Transmammary infection:
- from mother to neonate in the milk
What is the Prepatency period?
Prepatency period or PPP is the time from initial infection until parasite can be detected via lab tests
In what ways can we diagnose a parasitic infection?
Note Depends on the parasite
- Feces (direct, float, centrifugation, sedimentation, Baermann)
- Cellophane tape method
- Blood sample (Heartworm test, smears)
- Skin scrape
- Ear swabs
- Etc.
What are some guidelines to follow when collecting a fecal sample?
(Can be found on pages 212-221 Hendrix)
- Fresh sample (<24 hours old)
- Refrigerate if not examined within 2 hours\
- Clean container (sterile not necessary)
- Need 1 - 2 teaspoons (walnut-sized)
- Label sample with pet, client info, date & time
What are 5 areas we look at when we do a Gross Examination on a fecal sample?
1. Consistency: formed, soft or diarrhea
2. Color: varies with diet, excess fat
3. Presence of blood:
undigested blood = bright red color (Hematochezia)
digested blood = dark red (tarry) color (Melena)
4. Mucus: slimy appearance
5. Gross parasites:
Tapeworms (rice or cucumber seeds)
Roundworms (spaghetti)
What 3 methods can we use when examining a fecal sample?
1. Direct smear
2. Concentration Methods
a) Standard (passive) Flotation
b) Centrifugal Flotation
c) Fecal sedimentation
3. Miscellaneous Procedures (Baermann Technique)
What 3 things do we use direct smears for?
1. To quickly estimate parasite load
2. To detect motile protozoa
3. Used as a screening test; but not sole test
What is the two step procedure to follow when performing direct smears?
1. Mix tiny amount feces with saline
2. Examine @ 10x for eggs & 40x for protozoa
What are two advantages to using the direct smear?
1. Can do with tiny amount of feces
2. Short prep time
What are two disadvantages to using the direct smear?
1. Can miss low numbers of parasites
2. Debris can be misleading
What is the first type of concentration method used to examine a fecal sample?
Standard Fecal flotation
What are two ADVANTAGES to using the Standard Fecal flotation
method?
1. Easy to do & inexpensive
2. Large amount of feces examined quickly
What are two DISADVANTAGES to using the Standard Fecal flotation method?
1. Less efficient than centrifugation method
2. Fewer eggs and more false-negative results
What does fecal float equipment look like?
Fecal floatation kit (Fecalyzer), Fecal float solution, slide, coverslip
What does fecal float equipment look like?
Microscope, Fecal floatation kit (Fecalyzer), Fecal float solution, Slides, Coverslips
What is important to know about solution used for fecal floats?
- Solution to float parasites has HIGHER specific gravity than SG of parasite eggs & other life stages
- Most parasites: SG of 1.100 - 1.200
- Most float solutions: SG of 1.200 - 1.250
- Commonly used solutions:
- Sodium nitrate
- sugar solution
- zinc sulfate
What is the second type of concentration method used to examine a fecal sample? What equipment is needed and why?
Centrifugal Fecal Flotation
- Use of special centrifuge to further concentrate eggs and oocysts
What are two ADVANTAGES to using the Centrifugal Fecal Flotation method?
1. More sensitive & efficient compared to standard float
2. Can batch samples
What is one DISADVANTAGE from using the Centrifugal Fecal Float method?
Requires expensive centrifuge
What does a spun down sample of centrifugal fecal float look like?
What is the third type of concentration method used to examine a fecal sample? How does it work?
Fecal Sedimentation
- It concentrates eggs & larvae by letting them settle to bottom of tube of water
What is one ADVANTAGE to using the Fecal Sedimentation method?
Can detect eggs that will not float or if become distorted in floatation solution
What are three DISADVANTAGES to using the Fecal Sedimentation method?
1. More time-consuming procedure
2. Debris also settles
3. Not used in small animal private practice
Under Miscellaneous Procedures: What technique is used? what is it used for?
The Baermann Technique
- Used to identify nematode LARVAE from fresh feces, soil or tissues using Baermann apparatus
What is one ADVANTAGE to using the Baermann Technique?
Can detect LARVAL STAGE that would be destroyed in fecal float solution
What are two DISADVANTAGES to using the Baermann Technique?
1. Time-consuming & use of special equipment
2. If feces not fresh or contaminated with soil -> can be difficult to identify
What does the Baermann Apparatus look like?
IMPORTANT TO ALWAYS REMEMBER: Are fecal tests 100% accurate?
NO FECAL TEST IS 100% ACCURATE
- Can have NEGATIVE FECAL TEST in animal that is infected...
- How?
- Why?
What are four Non-fecal parasite tests?
- Cellophane tape method
- Blood sample (Heartworm test, smears)
- Skin scrape
- Ear swabs
What does a cellophane tape test look like?
Blood: What are three methods we use to find parasites?
- SNAP tests
- Smears
- PCV
What would a skin scrape look like?
What does an ear swab look like?
Most parasite screenings around the country come out positive or negative? Why?
In many areas of the country most parasite screenings are negative. Many pets are on prevention and that reduces the risk of transmission.
What is parasitic treatment dependent on?
The type of parasite
What are Anthelmintics aka? what are they used for?
"Dewormer"
Anthelmintics are used as a parasitic treatment
What are the seven areas of the Linneaen Classification System?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is a popular mnemonic device used to remember the seven areas of the Linneaen Classification system?
King Philip Came Over For Some Good Spagetti
How do you properly write genus and species?
Capitalize the genus and lowercase the species and underline both words.
What two separate kingdoms do we discuss with parasites?
Protista and Animalia
Protozoan
singular
Protozoans/Protozoa
plural
True or False? Protozoa are Eukaryotes!
True
Give four descriptions of a protozoa:
-Unicellular (one cell) organisms
-Can infect GI tract or blood (hemoprotozoa) or other tissues...
-Over 30,00 species
-Greek: protos - first zoon - animal
Many protozoa have two stages which are?
-Trophozoites - motile, feeding stage
-Cysts - reproductive version of a ova or egg
Cysts can survive in harsh conditions!
Describe protozoa reproduction?
Reproduction: asexually (binary/multiple fission), sexually
-Individuals are hermaphroditic
What are 9 Protozoan Human diseases?
• Malaria
• Amoebiasis
• Giardiasis
• Toxoplasmosis
• Cryptosporidiosis
• Trichomoniasis
• Sleeping sickness
• Chagas disease
• Leishmaniasis
Complete this sentence: Protozoans cause a lot of problems in humans ____________!
worldwide
What are some protozoans found in the intestines?
Coccidians:
-Isospora spp.
-Toxoplasma gondii
Flagellated Protozoans:
-Giardia spp.
What does coccidia mean? Describe coccidia in two ways:
-This word basically means a unicellular organism of the phylum Apicomplexa.
-Over 2,000 named species from 8-13 different families
-Typically parasitize vertebrates.
What is the term "coccidia" used to describe in the clinic?
In clinic, the term coccidia is often used to describe Isospora spp., Eimeria spp., Crytosporidium spp., and Toxoplasma gondii
What is the common name for Isopora spp.?
Coccidia
What size egg does Isopora spp. have compared to nematodes (roundworms, hookworms)
small
What animals is Isopora spp. a primary disease of?
puppies and kittens
Where in the host does Isopora spp. live?
small intestine
How do you diagnose Isopora spp.?
Fecal float
Coccidia
Roundworm
Isospora spp.
Fecal float - occasionally direct
"Life cycle of Isospora felis"
Feline Small intestine
What is the definitive host for Toxoplasma gondii?
only cat
What two hosts do Toxoplasma gondii need?
(cats & other mammal/bird)
Where doe the sexual stage for Toxoplasma gondii occur?
only in intestine of cats (wild & domestic)
Where does the asexual stage for Toxoplasma gondii occur?
found in various cells of all mammals & birds
With Toxoplasma gondii: what is a very important zoonoses?
highly pathogenic
-Especially to fetus during first 6 months of pregnancy (birth defects, stillbirth)
-Immunocompromised and elderly
What are three different stages for Toxoplasma gondii?
Oocysts: only develop in and shed by felids
Tachyzoites: rapidly dividing tissue stage
Bradyzoites: slowly dividing, encysted tissue stage
What is the prepatent period for Toxoplasma gondii?
-Cats shed eggs 3-10 days after tissue cysts from raw meat ingested
-Cats shed eggs 19-48 days after ingestion of eggs
-Eggs shed by cats become infective 1-5 days later & survive for months to YEARS!
Toxoplasmosis is a disease that affects cats and is usually asymptomatic intestinal infection but if it spreads to the liver it can cause?
-hepatitis
-fever
-enlarged lymph nodes
Why is it uncommon to find oocysts in infected cats with Toxoplasmosis?
because only shed for 1-3 wks
What two routes does Toxoplasmosis use to infect cats?
-Ingestion of infected meat (rodents, birds, mutton, pork) containing bradyzoites
-Ingestion of oocysts from soil and contaminated objects
"Zoonotic potential"
"LIFE CYCLE OF TOXOPLASMOSIS"
Life Cycle
"Transmission to humans"
"Coccidia vs. Toxoplasma eggs"
How do you diagnose Toxo in cats?
-Unsporulated oocysts (eggs) in fecal float, cysts in tissue
-BUT infected cats only shed eggs for 1-3 wks
How do you treat Toxo?
-No approved treatment;
-Sulfa antibiotic for 4 wks > may only reduce oocysts
How can you control or prevent Toxo?
-Cats that hunt are more likely to be infected (keep indoors)
-Refrain from feeding cats raw meat
What to tell pregnant owners who maybe exposed to Toxo?
-IT'S COMPLICATED!! No single reliable test to know if you'll get Toxo from your cat!
-Antibody testing (check for antibodies to Toxo)
-Can't accurately predict egg shedding, but if seropositive > less likely to be shedding oocysts
-Have someone else clean out litter box while pregnant! Quarantine cats shedding Toxo eggs for 3 wks
-Remove feces from litter box DAILY! Why?
-More likely exposure from raw/undercooked meat:
*Cook all meat to 160°F to kill cysts
*Freezing isn't reliable method to kill tissue cysts
What can pregnant owners who may be exposed to Toxo do?
>Have someone else clean out litter box while pregnant! Quarantine cats shedding Toxo eggs for 3 wks
>Remove feces from litter box DAILY! Why?
>More likely exposure from raw/undercooked meat:
*Cook all meat to 160°F to kill cysts
*Freezing isn't reliable method to kill tissue cysts
Isosopora spp.
Toxoplasma gondii
SIZE MATTERS!
SIZE MATTERS!
Giardia is a flagellated protozoan and has what two forms?
Trophozoite: motile form; pear-shaped
Cyst stage: resistant in environment
There are many different species of Giardia: what is so special about the dog and cat strains of Giardia?
Dog strain doesn't infect cats & cat strain doesn't infect dogs
What are some clinical signs of Giardia?
Small intestine infection -> malabsorption -> diarrhea or may be asymptomatic in cats and dogs
What route is Giardia usually transmitted by?
Fecal-oral route; ingestion of cysts
"Trophozoite Stage (Giardia)"
"Cyst Stage (Giardia)"
What is the prepatent period for Giardia spp.?
5-7 days
How do you diagnose Giardia spp.?
-fecal float (using standard zinc sulfate) for cyst
-direct smear of fresh feces (trophozoite)
-Fecal antigen SNAP test
-Reinfection is common - bathe during tx
-Cysts survive for months in environment
-Humans usually infected from other humans; NOT usually from dog or cat (but is possible)
"Giardia life cycle"
"Giardia trophozoites"
"Giardia trophozoites"
"Giardia spp. trophozoite"
trophozoite
"Giardia spp. trophozoite"
trophozoite
Babesia spp.
Intermediate host?
Cestodes are?
Tapeworms
Tapeworms class?
Cestoda
-Eucestoda (true tapeworms)
-Cotyloda (pseudotapeworms)
Tapeworms appearence?
Long, ribbon-like adults - segmented into proglottids
A tapeworms segments are called?
proglottids
Tapeworm body parts: Scolex
head
Tapeworm body parts: Acetabula
suckers
Tapeworm body parts: Rostellum
anchor-like organ
- Armed vs. unarmed
Tapeworm body parts: Neck
growth region
Tapeworm body parts: Strobila
body (composed of proglottids)
Tapeworm body parts: proglottids
immature, mature, gravid (anterior to posterior)
"TAPEWORM BODY PARTS"
-scolex = head
-acetabula = 4 suckers (attachment)
-rostellum = armed vs. unarmed (next slide)
-neck = growth area
-strobila = body (composed of proglottids)
-proglottids = immature, mature, gravid (anterior to posterior)
"Armed tapeworms"
Body part? Acetabula & Rostellum
"Unarmed tapeworms"
Body part? Acetabula
Life Cycle: The life cycle of the Cestodes is quite complicated and can take multiple paths. What about them do you need to know for this course?
know the intermediate hosts for each tapeworm presented.
What type of tapeworm is Dipylidium caninum?
Flea tapeworm
What animal or animals is the definitive host for Dipylidium caninum?
dog or cat
Does Dipylidium caninum need an intermediate host? if so, which ones?
Yes,
-Ctenocephalides felis
-Ctenocephalides canis
Describe Dipylidium caninum as an adult:
flat, ribbon-like parasite found in small intestine
When Dipylidium caninum gets long, what are the mature segments that break off called?
Proglottids
How many embryos will you find in a Dipylidium caninum egg packet?
20-30 hexacanth embryos
"Dipylidium caninum egg packet"
"Dipylidium caninum egg packet"
"Proglottids filled with egg packets contain male & female reproductive organs"
Proglottids
"TAPEWORM ADULTS"
"TAPEWORM ADULTS"
Proglottids can be seen on?
feces or perianal area
This is what proglottids look like when owner notices rather than diagnosing egg packet on fecal:
What is stage 1 of Dipylidium caninum life cycle?
Has INDIRECT LIFE CYCLE & REQUIRES INTERMEDIATE HOST
What is stage 2 of Dipylidium caninum life cycle?
transmission by ingestion of flea containing LARVAL STAGE (called CYSTICERCOID)
What is stage 3 of Dipylidium caninum life cycle?
Larval stage into intestine -> develops into adult stage
What is stage 4 of Dipylidium caninum life cycle?
Adults stage consist of PROGLOTTIDS (segments)->break off & pass in feces
What is stage 5 of Dipylidium caninum life cycle?
When proglottids break open -> release thousands of egg packets which contain many embryos
"LIFE CYCLE OF A TAPEWORM"
Tapeworms: Dried proglottids look like?
white rice
Tapeworms: Fresh proglottids look like?
cucumber seeds
Tapeworm proglottids can be found in feces and?
bedding, and around anus
Tapeworms can cause anal?
pruritis, scooting but RARELY CAUSE SIGNIFICANT DISEASE
What can you use to treat Dipylidium caninum?
Praziquantel or Epsiprantel
What can you use to prevent Dipylidium caninum?
Flea control!
How is Dipylidium caninum zoonotic?
if ingestion of flea intermediate host (not proglottids)
"One Dipylidium caninum egg packet"
"Two Dipylidium caninum egg packets"
"One Dipylidium caninum egg packet with many hexacanth embryos and two outside"
"Dipylidium caninum egg packet"
There are times in parasitology that you will be unable to determine the Genus and species of the parasite due to similar appearance in the ova. "TAENIA TYPE" OVA. This is true with many types of tapeworms.
"Taenia type" ova
"Taenia Type Ova" Each genus and species to the right has a very similar ova, called "Taenia type"- you can narrow it down by host, but an exact diagnosis cannot be made.

Intermediate host for nearly all Taenia spp. are?
-Taenia pisiformis
-T. hydatigena
-T. ovis
-T. taeniaformis
-T. saginata
-T. solium
-Echinococcus granulosus
-E. multilocularis
-Multiceps spp.

rodents and rabbits.
"TAENIA TYPE OVA"
Taenia egg
What is a Taenia-type ova that's zoonotic and fatal?
Echinococcus spp.
What is the intermediate host for Echinococcus granulosus?
sheep
What is the intermediate host for Echinococcus multilocularis?
mouse
Monezia spp.
Float (will not test us on)
Monezia spp.
Float (will not test us on)
Trematodes & Nematodes What Intestinal endoparasites of dogs and cats will we be covering?
-Trematodes (flukes)
-Nematodes (roundworms, hookworms and whipworms)
What are the characteristics of trematodes?
-Trematodes are the flukes
-their bodies are flattened, unsegmented, and leaflike.
-In mammals, they most often inhabit the liver.
-Hermaphroditic - they have a very complicated life cycle that almost always includes a snail.
-Fluke eggs are heavy and are typically found via sedimentation.
The life cycle of a fluke picture?
Life Cycle of a fluke
The life cycle of a fluke picture 1?
Life cycle of a fluke 1
Flukes (size, body) Flukes found in humans picture?
Flukes found in humans
Flukes (size, body) Fasciola hepatica, the sheep liver fluke picture?
Fasciola hepatica, the sheep liver fluke
Fasciola hepatica the sheep liver fluke picture 1?
Fasciola hepatica, the sheep liver fluke 1
Fasciola hepatica the sheep liver fluke picture 2?
Fasciola hepatica, the sheep liver fluke 2
Fluke ova are operculated - little door?
operculated - little door
Fluke ova are operculated - little door, Miracidium emerging?
operculated - little door, Miracidium emerging
Flukes found in fish picture?
Flukes found in fish
Nematodes are also called? picture?
roundworms
Just so you are aware - I use the term "nematode" for this class of parasites and the term "roundworm" for the?
ascarids
Nematodes Roundworms scientific names, 3 of them?
-Toxocara canis
-Toxocara cati
-Toxascaris leonina
Nematodes Hookworms scientific names, 2 of them?
-Ancylostoma caninum
-A. tubaeforme
Nematodes Whipworms
scientific name?
Trichuris vulpis
General nematode life cycle picture?
General nematode life cycle
Nematodes What is in the lab notebook?
-There is a very extensive list in your lab notebook, but that entire list is really out of the scope of this course.
-In your lab notebook is a chart of information I want you to know about the commonly found intestinal nematodes found in dogs and cats.
Ascarids Adults live in, can be seen in, looks like, diagnosed by, picture?
-small intestine of dogs and cats
-may be seen in feces or vomit
-Look like spaghetti
-Diagnose: fecal float
Ascarids Adults live in, can be seen in, looks like, diagnosed by, picture 1?
-small intestine of dogs and cats
-may be seen in feces or vomit
-Look like spaghetti
-Diagnose: fecal float
-picture 1
Ascarids
Definitive hosts:
Clinical signs:
Prepatent period:
Toxocara canis?
Toxocara cati?
Toxascaris leonina?
-dogs and cats
-Diarrhea, Pot-bellied appearance
-depends on genus & species and route of infection
Toxocara canis: 3-4 wks
Toxocara cati: 5 wks
Toxascaris leonina: 8 wks
Transmission of Toxocara canis four ways and picture?
-Ingestion of eggs
-Ingestion of paratenic host (small rodent)
-Transplacental
--Larvae from cysts go uterus & placenta
-Transmammary
--Larval stage migrate through mammary glands; pups get infected while nursing. Larvae mature in pup's intestine
Life Cycles Toxocara cati transmission 3 ways and picture?
-Ingestion of eggs
-Transmammary
-Ingestion of paratenic host
Life Cycles Toxascaris leonina transmission 2 ways and picture?
-Ingestions of eggs
-Ingestion of paratenic host
Puppies can be infected 3 different ways Toxacara spp.?
-Ingestion of larvae in infected milk
-Transplacental
-Ingest egg from contaminated environment
ZOONOTIC cycle picture!
zoonotic cycle
Zoonotic Potential Which Toxocara species is and is not zoonotic?
What are they called in humans?
-Toxocara canis and T. cati
Not Toxascaris leonina
-Visceral larva migrans: damage to lungs and liver
-Ocular larva migrans: damage to retina, causes blindness
Ocular Larva Migrans picture
Ocular Larva Migrans
Ascarids Life cycle, Swallowed larval in intestines mature into adult worms, whats next?
-Adults produce eggs which are passed in feces
-1 female worm produces 80,000 eggs per day!
-Eggs in feces or environment remain infective for 2 weeks
Egg containing larva picture
Egg containing larva
Larval stage emerging from egg picture
Larval stage emerging from egg
Toxocara larva picture
Toxocara larva
Toxocara spp.
T. canis
Definitive host:
Larger eggs and size:
Shape:
Center:
Outer shell:
ZOONOTIC?
-dogs
-75-90 microns
-spherical
-pigmented
-pitted
-yes
Toxocara spp.
T. cati
Definitive host:
Smaller eggs and size:
Shape:
Center:
Outer shell:
ZOONOTIC?
-cats
-65-75 microns
-spherical
-pigmented
-pitted
-yes
THIS SET IS OFTEN IN FOLDERS WITH...