nematodes of dogs & cats. toxocara sp. significance the most important parasites infection at...
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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
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IS
T
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IC
H
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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