Nematodes of D ogs & Cats

Toxocara sp.

Significance• the most important parasites

• infection at birth• death: first two weeks (l

ungmigration)• larval migration

male =- 4 1 0 cm

female =- 5 1 8 cm

Morphology

T. canis cervical alae: - long & narrow - semilanceolate

cervical alae: - broader - arrow head

Life cycle

• modes of transmissio n: T. canis• transplacenta• transcolostrum• direct ingestion• paratenic host

Direct li fe cycle

3age < mths

- 1015 d

tttttttt tttttti on ttttttttt tttt

od- ttttt4 5

Indirect li fe cycle ( > 3 )

- 1015 d

somatic migration

pr epat ent per i od- 35 weeks (neonates)

42> d gestation

transplacentatranscolostrum paratenic hosts

Life cycle•Toxocara cati:

• direct ingestion• paratenic host• no prenatal transmission

Effect onhost• adult: no clinical signs

• puppies: severely affected,pneumonia

signs: vomiting, em aciation, potbelly,

obstruction, dull coats

- death: 2 3 weeks aft er birth

Diagno sis T. canis

T. cati

Infective stage

Ascarid egg

SEM differentiation

large, coarse pitted surface

-92 2000 287294Uga et al., Vetrinary Parasitology ( ):

tttt tttttt ttttttt,

Treatment

ivermectin dichlorvos fenbendazole febantel pyrantel piperazine

• Saprophytic soil fungi• Paecilomyces sp.• Ovicidal activity of T

. canis 2000(Basualdo J.A.,)

• Use of ivermectin during pregnancy

1) dose: 300 mcg/kg on da y 0, 30, and 60 of gestation

- reduce # worms by 90% - reduce # eggs by 99.8%

• Use of ivermectin during pregnancy

2) dose: 300mcg/kg on day 0, 30, 60 of gestation, 10 d post

whelping - reduce # worms by 100% - no eggs were passed in environ.

1999(Payne P.A., )

•Selamectin• topical administration• - dose: 6 mg/kg (6 12 mg/kg)

• -# 9399reduce adults by .8.1%

• -# 909reduce eggsby5%

2000(McTier T.L., )

Control• good sanitation

• regular deworming

• anthelmintics:• 2, 4, 6 weeks

of age

Public Health• visceral larva migrans ( T. canis):

• children: chronic granulomatous– liver, lung, brain, eye

• ocular larva migrans• choroidoretinitis

Toxascaris leonina

( arrowhead worm)

male: up to 7 cm

female: up to10cm

head: lanceolate cervical alae

Life cycle• transmission:

• direct ingestion• paratenic host• no larval migration

• -prepatent period = 8 10 weeks

Effect onhost• puppy: potbelly, intermitten

t diarrhea, poor condition, in testinal obstruction

Diagnosis

T. leonina

T. canis

Treatment

piperazinedichlorvos

pyrantelfenbendazole

febentel + praziquantel

Ancylostoma caninum

(Hookworm)

Ancylostoma caninum

•Geographi c distribution–temperat

e climates–worldwide

•Significance– very import

ant– causes deat

aaaaa( )– causes hea

vy blood losses

Morphology

• worms:redor gray• size:upto1.6cm• mouth: 3 pairs

of promi nent teeth

Life cycle modes of infection:

1. eating (infective eggs)

2. skin penetration (larvae)

tracheal migration

modes of infection:• intrauterine infection

• transcolostrum• parateni c host

prepatent period = 15- 18 days

Life cycle

HOOKWORMS

HOOKWORMS

ANCYLOSTOMA

ANCYLOSTOMA

Larval penetrationคั�น!

moist eczema &

ulceration

effec t on

dog

“ pale mucous membrane”

effec t on

dog

“ severe blood loss”

effec t on

dog blood vessels rupture &

hookworms feed on the released blood (0.25 ml/day)

Ancylostoma caninum

Clinical signs

• factors: dose, age, immunestatus

•dermatitis• puppy pneumonia• diarrhea: dark in color (bloo

d &mucus)

Clinical signs

• severe blood loss:• - iron deficiency anemia• edema, weakness, wei

ght loss• poor coat condition

heavy inf ection: fr

equently fatal with

in 2 week s of birth in puppie

s

Diagnosis

• clinical signs• fecal examination:

• fresh direct smear

• simple floatation -ovoid, thin shelled,

morulate embryo

ttt60 40tttt

Treatment• supportive care: blood tran

sfusions, iron supplement• anthelmintics: fenbendazo

le, ivermectin, tetrahydrop yrimidine (pyrantel)

• Ivermectin + pyrantel• ivermectin = 6mcg/kg

• pyrantel pamoate = 5mg/kg

• 99.6 % reduction of adult hookworms

1992(Nolan T.J. et. al, )

•Doramectin• 1mg/kg on d30 of ge

station reduce somati c larvae in bitches an d adult hookworms in

bitches and puppies 199(Schnieder, T. et al,6)

•Moxi decti n• 1 mg/kg on d5 5 of

- 58gestation ( d before parturition): co

mpletely prevent lact ogenic infections in pu

ppi es. (Epe, C., 1 9 9 9 )

Deworming program

• CDC recommendation:• bitch: fenbendazole in th

e 3rd trimester (kill migrati ng larvae)

• pups: 2, 4, 6, and 8 weeks of age

Control

• feces elimination• - keep kennel floor dry

• regular deworming• treat bitch with ivermectin

Effect on man• Adul t Ancyl ostomacani num

• excretory/secretory antigens

• causes hypersensitivity i nman

• human eosinophilic enteritis

Cutaneous larval migration

Cutaneous larval migration

Trichuris vulpis(whipworms)

size: 4.5- 7 .5 cm

a anterior part: 3/4 of body, long & slender

Morphology

Life cycle• location: caecum• infection: direct in

gestion of infective egg

T

R

IC

H

U

R

IS

T

R

IC

H

U

R

IS

LIFE

CYCLE

- prepatent period = 11 12 weeks

Effect on host• intestine: irritation of c

aecum& large intestine• profuse diarrhea, loss o

f weight, unthriftiness• anemia in heavy infection

Diagnosis

- Lemon shapedwi thbi pol ar pl ugs

- - 7090 3040x microns

Treatment

mebendazole fenbendazoledichlorvos febantel

avermectins are not as effective.

Spirocerca lupi (esophageal wor

m)

• Definitive host• dogs

• Intermediate host• coprophagous beetles

• lizards, chickens , mice (paratenichost)

morphology:red,coi l ednematode - 38cm long

beetle s

encystlarvae

tttttt tt tttttt

gastroepiploic artery coeliac artery thoracic aorta

esophagus

(1)

tt3

)

prepatent period- 56mths

Effect on host• larval migration: aorta

•haemorrhage• granuloma, stenosis• aneurysm, rupture

Effect o n host

• adult: embe dded in the walls of aort

a, esophagu s and stomach

Effect on host• adult: nodules,tumor

• nodules: interf ere with swallo

wing, respirati on and circulat

ion

• signs: persis tent vomitin

g, wt. loss, hemoptysis

• aneurysm burst

causes sudd en death

“esophage al sarcoma”

10% of infected dttt

Diagnosis

• floatation method

• radiography• endoscopy• necropsy

Diagnosis• - egg:small,oblonginshape,thi ck shel l ed,

larva inside

- - 30381115x mi cr ons

Treatment• fenbendazole

• avermectins

Control• isolate infected animals• dispose of the vomit and feces

• keep dogs from eating be etles, paratenic hosts

Strongyloides stercoralis

(threadworms)

Morphology• parasitic stage: pathen

ogenetic female• - size: 2 9 mm. long• filariform esophagus

Life cycle• host: dogs, cats, men• -direct life cycle: free livin

g, parasitic• prepatent period = 7 days

Life cycle• modes of infection:

• skin penetration• ingestion (rare)• hyperinfection (mucosa

l migration)• autoinfection (perianalarea)

Significance• reinfection: kennel situation

• causes severe disease only in young animals

• heavy infection: death in puppies

Effect on host• skin:dermati ti s

intestine: irritation , catarrhal inflamm

ation, mucosal ero sion, necrosis

signs: diarrhea (bl ood), low appetite,

weight loss, dehyd ration, weakness,

death

lung migration: alve oli destruction, ecc

hymotic hemorrhag e, pneumonia

Diagnosis• fecal exami nati on

• larvae,eggs contai ni ngl arvae

- 40 50 mi cr ons

TreatmentDichlorvosFenbendazole Control

clean & d ry floor

Gnathostoma spinigerum

G. spinigerum

• - size: 1 3 cm. long• headbulb: “ballonets”• head&anteriorpart: spines

Life cycle• 7prepatent period: months• 1st a aaaaaa. :• 2nd int. host: fresh water fis

aaaaaaaa,• aaaa aaa:

Gnathostomaspinigerum

cats, dogs nodule in the gastric wall

eggs (L1)

Cyclops (L2)

fish, frog, snake (L3)

man

Effect on host

• aaaaa aaaaaaaa:– cause intermittent,migraaaaaa aaaaaaaa ,swelling

Effect on host• visceral larva migrans:• cough, hematuria,• ocular involment• eosinophilic meningtitsis

• myeloencephalitis

Pathogenesis• larvalmigration: liverdamage,

mesentery, diaphragm, thoraciccavity

• adult: migrate in stomach wall

• cavity, pus, cyst

Diagnosis

• egg:rare i nfeces

Treatment• no specific drug (albendazole)

Physaloptera praeputialis

Morphology

• - size: 1.5 4.8 cm long• body: large,thick,stout nematodes• egg: contain a larva when laid

Life cycle

• host: dogs, cats, other carnivores

• intermediate hosts:• crickets, cockroaches, beetles

• - 4183prepatent period =days

• location: stom ach, duodenum

• worldwide distribution

Effect on host•adult

• irritation: firmly attac h to the lining of the g

astric mucosa• bleeding,mucosaerosi on• digestion interference

Clinical signs• loss of condition• vomiting (possibly bl

oody, mucoid)•anorexia

Diagnosis• fecal examination (floatation)

• small, oblong eggs con taining larvae

- - 4058 3034x microns

Treatment•anthelmintics

• dichlorvos, benzimid azoles, avermectins

• control pets’ eating habits