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Nematodes of Dogs & Cats. Toxocara sp. Significance. the most important parasites infection at birth death: first two weeks (lung migration) larval migration. Morphology. male = 4-10 cm female = 5-18 cm. T. canis. cervical alae: - long & narrow - semilanceolate.
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Significance • the most important parasites • infection at birth • death: first two weeks (lung migration) • larval migration
Morphology male = 4-10 cm female = 5-18 cm
T. canis cervical alae: - long & narrow - semilanceolate
cervical alae: - broader - arrow head
Life cycle • modes of transmission: T. canis • transplacenta • transcolostrum • direct ingestion • paratenic host
Direct life cycle 10-15 d tracheal migration prepatent period 4-5 weeks age < 3 mths
prepatent period 3-5 weeks (neonates) Indirect life cycle (age > 3 mths) 10-15 d somatic migration transplacenta transcolostrum paratenic hosts > 42 d gestation
Life cycle • Toxocaracati: • direct ingestion • paratenic host • no prenatal transmission
Effect on host • adult: no clinical signs • puppies: severely affected, pneumonia
signs: vomiting, emaciation, potbelly, obstruction, dull coats death: 2-3 weeks after birth
Diagnosis T. canis T. cati
Infective stage Ascarid egg
SEM differentiation large, coarse pitted surface small, fine pitted surface Uga et al., Vetrinary Parasitology 92(2000): 287-294
Treatment ivermectin dichlorvos fenbendazole febantel pyrantel piperazine
Saprophytic soil fungi • Paecilomyces sp. • Ovicidal activity of T. canis (Basualdo J.A., 2000)
Use of ivermectin during pregnancy 1)dose: 300 mcg/kg on day 0, 30, and 60 of gestation - reduce # worms by 90% - reduce # eggs by 99.8%
Use of ivermectin during pregnancy 2)dose: 300 mcg/kg on day 0, 30, 60 of gestation, 10 d post whelping - reduce # worms by 100% - no eggs were passed in environ. (Payne P.A., 1999)
Selamectin • topical administration • dose: 6 mg/kg (6-12 mg/kg) • reduce # adults by 93.9-98.1% • reduce # eggs by 90-95% (McTier T.L., 2000)
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
head: lanceolate cervical alae male: up to 7 cm female: up to 10 cm
Life cycle • transmission: • direct ingestion • paratenic host • no larval migration • prepatent period = 8-10 weeks
Effect on host • puppy: potbelly, intermittent diarrhea, poor condition, intestinal obstruction
Diagnosis T. canis T. leonina
Treatment piperazine dichlorvos pyrantel fenbendazole febentel + praziquantel
Ancylostoma caninum • Geographic distribution • temperate climates • worldwide • Significance • very important • causes deaths (all ages) • causes heavy blood losses
Morphology • worms: red or gray • size: up to 1.6 cm • mouth: 3 pairs of prominent teeth
Life cycle modes of infection: 1. eating (infective eggs) 2. skin penetration (larvae) tracheal migration
Life cycle modes of infection: • intrauterine infection • transcolostrum • paratenic host prepatent period = 15-18 days
H O O K W O R M S A N C Y L O S T O M A
Larval penetration คัน! moist eczema & ulceration
effect on dog “pale mucous membrane”
effect on dog “severe blood loss”
effect on dog blood vessels rupture & hookworms feed on the released blood (0.25 ml/day)
Clinical signs • factors: dose, age, immune status • dermatitis • puppy pneumonia • diarrhea: dark in color (blood & mucus)
Clinical signs • severe blood loss: • iron-deficiency anemia • edema, weakness, weight loss • poor coat condition
heavy infection: frequently fatal within 2 weeks of birth in puppies
Diagnosis • clinical signs • fecal examination: • fresh direct smear • simple floatation 60 x 40 microns ovoid, thin-shelled, morulate embryo
Treatment • supportive care: blood transfusions, iron supplement • anthelmintics: fenbendazole, ivermectin, tetrahydropyrimidine (pyrantel)
Ivermectin + pyrantel • ivermectin = 6 mcg/kg • pyrantel pamoate = 5 mg/kg • 99.6 % reduction of adult hookworms (Nolan T.J. et. al, 1992)
Doramectin • 1 mg/kg on d30 of gestation reduce somatic larvae in bitches and adult hookworms in bitches and puppies (Schnieder, T. et al, 1996)
Moxidectin • 1 mg/kg on d55 of gestation (5-8 d before parturition): completely prevent lactogenic infections in puppies. (Epe, C., 1999)
Deworming program • CDC recommendation: • bitch: fenbendazole in the 3rd trimester (kill migrating larvae) • pups: 2, 4, 6, and 8 weeks of age
Control • feces elimination • keep kennel-floor dry • regular deworming • treat bitch with ivermectin