Exam 1 - Parasites of Canine and Feline hosts

Question 1

Esophageal worm?

Answer 1

Nematode - Spirocerca lupi

Question 2

Hosts of Spirocerca lupi?

Answer 2

DH - dogs, wolves, coyotes, foxes, hyenas, jags, lions, cheetahs
IH - dung beetles
Paratenic - chickens, birds, lizards

Question 3

Adults are pink to red in color. They can reach 8cm in length. Lesions can be up to the size of golf balls and form granulomas in the esophagus. My eggs are small and elongated (paperclip like) 30-35um. WTF am I?

Answer 3

Spirocerca lupi.

Question 4

Life cycle of Spirocerca lupi?

Answer 4

Indirect - Egg with L1 can be passed in feces or vomit. egg hatches after ingestion by the intermediate host. it can develop into L3 (infective form). The PH can ingest the dung beetle. either the dung beetle or PH is ingested by the DH.

• PPP 6 months
• L3 is liberated, penetrates the stomach wall. from there, it will migrate to the thoracic aorta via the celiac artery. 3 months later, they cross to the esophagus where they cause gramulomas, develop into adults 3 months later.

Question 5

esophageal worms will embed in granulomatous nodules in the wall of the esophagus. this site is know as their?

Answer 5

predilection site! it is their preferred site and where they do their best.

Question 6

a dog presents with difficulty swallowing, regurgitation, weakness, emaciation, and a loss of condition. what may you suspect?

Answer 6

esophageal worm

Question 7

you suspect and Spirocerca lupi in a dog that comes into your office. how do you diagnose these bastards?

Answer 7

you may find eggs in the feces or vomitus. you may also find with endoscopy or rads –> because the migrating larvae scar the internal wall of the aorta, which can rupture. the dog may also develop osteaosarcoma (bone tumor), spondylosis of thoracic vert (stiffening veterbral joints), or osteopathy of long bones.

Question 8

what are the hosts of Physaloptera spp (several species of Physaloptera)?

Answer 8

This is a nematode found in the stomach of pets that will be presented

DH - dogs and cats
IH - beetles, cockroaches, crickets
PH - snakes and birds

Question 9

how would you identify Physaloptera spp?

Answer 9

you would find them in the stomach. they adults are 4-6cm in length. they eggs are elongated, more oval than Spirocerca (find in feces or vomit) and about 45um.

Question 10

eggs containing an L1 are passed in the feces or vomitus and does not hatch until ingested by an intermediate host. here the larvae will develop into L3. upon DH’s ingestion of the PH or IH, the L3 will be liberated and form the adult stage within the anterior end of the mucosa in the stomach. T/F?

Answer 10

True!

it has forcep-like teeth that allow them to embed within the mucosa. this will cause small stomach ulcers.

Question 11

what is the ascarid that is found in most puppies upon birth?

Answer 11

Toxocara canis.

they are born with it and it is zoonotic.

Question 12

T/F, ascarids are host specific?

Answer 12

True!

They are zoonotic but can only completely develop into adults within their DH.

Question 13

what is the superfamily of a parasite with the following characteristics?

• host specific
• adults are large (10-30cm), white/cream colored, 3 lips
• eggs are thick walled and resistant and can withstand many environmental changes.
• females produce a large number of eggs.
• the infective stage is an L2!!!

Answer 13

Ascaridoidea

Question 14

if we are presented with a dog and notice that there are nematode/worms that are white and 10-15cm. we also see that the egg is dark brown, round, and 85x75 um with a thick shell. what is this?

Answer 14

Toxocara canis

Question 15

T/F - Toxocara canis can be transmitted in fresh feces?

Answer 15

False - ascarid eggs need 2-4 weeks to develop into the infective form. they are host specific and can fully develop only in dogs. if transmitted to humans, they will die off.

Question 16

describe the life cycle of Toxocara canis.

Answer 16

Toxocara canis has a direct life cycle with 4 modes of infection.

1) Per os - L2 are infective in the environment 2-4 weeks. once ingested, they hatch in the SI, undergo hepatic-tracheal migration. they will return the SI, adults will mature and lay eggs at wk 4-5.
2) Transplacental - most common in pups. at wk 6 of gestation, the nematode will travel across the placenta.
3) Transmammary - L3 is infective through the pup suckling during the first 3 weeks of lactation.
4) Paratenic host - in L2 form

Question 17

what is the PPP of Toxocara canis?

Answer 17

• direct infection following ingestion of eggs or larvae via PH - 4-7 weeks
• prenatal - 3 weeks

Question 18

how do you treat and prevent Toxocara canis?

Answer 18

deworming is effective against the adult stage.

• kill adults with the first dose (at 2 weeks of age) so they cannot reproduce
• 2nd dose (at 4-5 weeks of age) will kill adults that previously larval stages
• begin on monthly preventative at 6-8 weeks

Question 19

Name the common roundworm, ascarid, that is host specific towards cats. and is it zoonotic?

Answer 19

Toxocara cati. Yes, it is zoonotic, but much more uncommon for transfers.

Question 20

How would you identify the following:

large white nematode (4-10 cm), eggs are thick pitted shell 80x60um. they have a direct lifecycle, 3 modes of infection (per os, transmammary, paratenic). they infect the small intestine.

Answer 20

Toxocara cati - cat.

Question 21

if you suspect a cat to have Toxocara cati, what clinical signs may you see?

Answer 21

depending on the age of the cat, # of worms, site of infection, and age of the nematodes; you can expect to see:

• pneumonia from larval migration through the lungs
• eosinophilia from chronic infection
• hypersensitization
• digestive disturbances such as vomition and diarrhea
• intestinal obstruction from a large # of adults
• pot belly appearance

Question 22

Toxascaris leonina is a type of what?

Answer 22

Ascarid

Question 23

Toxascaris leonina have different strains and will effect who? how will they contract this parasite?

Answer 23

• dogs and cats (domestic and wild)
• direct - per os - egg with L2
• indirect - PH

Question 24

T/F: Toxascaris leonina do not undergo hepatic-tracheal migration

Answer 24

True! they hatch from their eggs, enter the wall of the intestine, re-enter the lumen of the SI where they mature into adults. their PPP is 10-11 wks.

Question 25

Anychylostoma caninum is the model parasite for the tracheal worm. T/F?

Answer 25

False! it is a hookworm that effects dogs, foxes and is zoonotic.

Question 26

If a hillbilly with 3 teeth brings his dog into the clinic and you were to find adult nematodes about 1-2cm, large buccal capsule with 3 pairs of marginal teeth. you perform a fecal and notice thin-shelled, oval eggs that are 60x40um. what do you think we are looking at?

Answer 26

Anychylostoma caninum - hookworm

Question 27

Anychylostoma caninum is infective in the L3 stage. they can rapidly develop from an egg to L3 in less than 1 wk. What are their modes of infection?

Answer 27

There are 5 modes:

1) Percutaneous or penetration of oral mucosa if ingested
2) Per os
3) Paratenic hosts
4) Transplacental - only about 2% of the time
5) Transmammary

Question 28

if the same hillbilly, who somehow knew his dog had hookworms (Anychylostoma caninum), presented, what clinical signs would you expect to see and how could you treat it?

Answer 28

Clinical signs:

• acute –> anemia and lassitude, diarrhea with blood and mucus due to the anemia
• chronic –> weight loss, poor hair coat, loss of appetite

Treatment:
-you want to kill both adult and larval stages with appropriate anthelmintics - mebendazole, fenbendazole and nitroscanate

Question 29

Anychylostoma tubaeforme

Answer 29

hookworm seen in cats that will infect the small intestine. they can enter the body via ingestion (per os), percutaneous (through the skin) or via a paratenic host. the adults are 1-2 cm with a large buccal capsule with 3 pairs of marginal teeth.

Question 30

Which hookworm will cause cutaneous larval migrans (zoonotic disease)?

Answer 30

Anychylostoma braziliense:
CLM - inflammation under the dermis is the route that the larvae take as they wander. this is a dead end for them as they will eventually go away.

Question 31

Anychylostoma braziliense

Answer 31

they will effect both dogs, cats, and are zoonotic (cutaneous larval migrans). in a pet they will cause mild digestive upsets, occasional diarrhea. they can enter per os, percutaneous, or use a rodent as a PH.

Question 32

Uncinaria stenocephala

Answer 32

Hookworm that can parasitize dogs, cats, foxes. it can enter via per os, percutaneous, or PH. PPP is 15-20 days. Site of infection is the SI.

Since they are NOT as voracious a bloodsucker as Anychylostoma caninum, anemia will be rare, diarrhea, interdigital dermatitis. you can diagnose with eggs in feces and if Anych can is endemic, you may want a larval culture.

Question 33

heterogenic VS homogenic

Answer 33

heterogenic: L3 will differentiate into male or female. parasite can be free living, the environment outside of the host may be more suitable for their survival.
homogenic: L3 will differentiate into a female only. this occurs within the host and the eggs actually hatch within the host body. parthinogenesis - ability to reproduce without a male.

Question 34

Strongyloides stercoralis is a threadworm that can effect dogs, foxes, and cats. they can be zoonotic. larvae can be within skin and adults within the SI. they are a slender hair-like nematode

Answer 34

Direct. if free living, L3 can be ingested or percutaneous, the female will lay eggs and will hatch in the environment.

If parasitic, eggs with L1 or hatched L1 will develop into L3, enter via per os or percutaneous. they will travel to the SI, develop as mature females only via pathenogenesis. PPP 10-14 days.

Question 35

Trichuris spp is?

their egg is 80x35um, yellow/brown in color, with a lemon shape. there are plugs at each end of the egg and they can last long in the environment.

patients will show signs of bloody diarrhea. can be diagnosed by eggs in feces.

Answer 35

Whipworm - thin, filamentous anterior end and thick posterior end. the adults are 4-6cm long.

**infective stage is L1 within the egg!! the egg will be digested and L1 will be liberated. they will infect the LI/cecum where all 4 stages mature.

PPP - 6-12 weeks

Question 36

Capillaria spp - member of the Trichinelloidea family (whipworms). they infect dogs and cats. describe their life cycle.

they infect 3 areas. what are they?

Answer 36

lifecycle is direct/indirect (depending on species). the infective stage is L1 within egg

infect:
airways (direct): in mucosa of trachea, bronchi, nasal cavity. PPP 6 weeks
intestinal tract of cats (direct): nonpathogenic. found in feces.
bladder of dogs (in/direct): direct or use earthworm as IH. PPP 2 months. eggs in urine.

Question 37

giant kidney worm: infects dogs, foxes, minks.
IH is earthworm.
PH is a frog or fish

infect kidney parenchyma - destroy it so there is a capsule with worm in it

Answer 37

Dioctophyme renale - females can be 60-100 on length. eggs 70um with thick shell
PPP may be 2 years

patients will have pain/difficulty urinating with blood present

Question 38

Oslerus Osleri

Answer 38

• tracheal worm
• dogs and wild carnivores
• small, hair-like, grey nematode, 0.5-1.0cm
• L1 is ingested and all stages develop in lungs, females lay eggs that hatch before expelling with sputum and coughed up, or they can be swallowed passed in feces (yea, girl). PPP is 10-18wks
• nodules in the trachea in the region of the bronchi bifurcation, further into the bronchi, or deep in the lungs
• small, soft grey, millet seed nodules
• asymptomatic unless heavy infection (cough), hypernea (inc resp rate)
• bronchoscope at 2 months, L1 detected in sputum (baermann tech or bronchial washings) or in feces with zinc sulphate flotation test
• benzimiadazoles for days

Question 39

Aelurostongylus abstrusus

Answer 39

• cat lungworm
• FH is cat, IH are snails/slugs, PH are birds/rodents/frogs
• 1cm long, slender and delicate, L1 present in feces (S shaped tail)
• L3 are infective, ingested, enter mucosa of intestin and pass via blood to the to lungs, F will lay eggs with L1 in nests in lung parenchyma. Eggs hatch and liberate the L1, coughed up, swallowed, and passed in feces, enter IH and develop to L3, PPP 6-12wks
• lung parenchyma and bronchioles
• discovered incidentally at postmortem exam
• chronic, mild cough, after exercise, there may be coughing/sneezing
• fecal smear, floatation, or baermann, zinc sulphate flotation
• levamisole and ivermectin

Question 40

Dirofilaria immitis

Answer 40

• heartworm
• dogs, cats, and over 30 other mammals (humans zoonotic). IH - misquitoes.
• adults are long, slender (20-30cm), microfilariae (L1) are 300um long
• mosquito will ingest an L1 from an infected dog and it will mature into L3, it will bite dog and transmit the L3, it will mature into L4 within a day or 2, the L5 will occur 2-3 months after infection in the subQ tissues. it will migrate to the vasculature, where it will mature into an adult within the distal part of pulmonary arteries and caudal lung lobes where it will reproduce
• adults can destroy endothelium of smaller pulmonary arteries esp in caudal lung lobes. predisposes to thrombus and inc vascular permeability, which leads to interstitial and alveolar edema.
• signs are shown more in dogs that exercise due tto their increased blood flow. esp those that are large, outdoor males over 6 months of age.
• diagnosed with lab tests - microfilaria test (6-7 months post infection), radiology - can detect the severity of pulmonary lesions, EKG - RV hypertrophy
• treat ALL life stages. begin on prophylaxis (preventative) immediately and continue monthly. for prevention, start at 6-8 weeks of age

Question 41

T/F. Cats can be treated effectively/safely for Dirofilaria immitis?

Answer 41

False, they can fall victim to it via mosquito bite, but once infected, they will not do well with the parasite. as a DVM, it is necessary to push HW prevention for cats.

Question 42

T/F. it is very difficult to diagnose heartworm in cats.

Answer 42

true, the mff are transient in cats. with a small amount of worms present (under 6), they can cause severe damage. prevention is key!

Question 43

Acanthocheilonema reconditum

Answer 43

mff can be found in blood and site of infection is subQ. transmitted by fleas, ticks, and lice in same endemic region as heartworm.

Question 44

Cestodes (tapeworms) - 2 orders

• Cyclophyllidea
• Pseudophyllidea

what are characteristics of each?

Answer 44

Cyclophyllidea

• at least 1 IH - they all have an indirect lifecycle
• organs of attachment are the scolex and suckers
• eggs contain oncospheres - 1st larval stage developed in the egg, and also, hexaconth embryo - 6 hooks helping it get out of the egg

Pseudophyllidea

• 2 intermediate hosts (first is a crustacean)
• organs of attachment are scolex and bothria
• eggs contain oncosphere (coracidium) and cilia for motility

Question 45

Dipylidium caninum

Answer 45

Common tapeworm - di - 2 genital pores…