Lungworms Flashcards
What is the bovine lungworm?
Dictyocaulus viviparus (trichostrongyle)
Describe the pathogenesis of bovine lungworm…
PPP = 3.5 weeks
Week 1 - penetration phase, larvae migrate to lungs
Weeks 1-3 - prepatent phase, larvae asced respiratory tree (causing bronchiolitis, eosinophillic exudate, dyspnoea, tachypnoea, coughing)
Weeks 4-8 - patent phase, worms mature + produce eggs
Weeks 8-12 - post-patent phase, most worms expelled BUT 25% cases clinical signs flare up (due to alveolar epithelisation, pulmonary oedema and secondary bacterial infection)
How is it that adult cattle can exhibit disease caused by lungworm without having larvae in there faeces?
Clinical signs can be cause by an inflammatory reaction to larvae in the lungs
Larvae are killed by rxn => no excretion of L1s
At what time of year are calves affected by lungworm?
Middle-late summer
How does the bovine lungworm oral vaccine work?
1000 X-irradiated L3 larvae/dose
Live larvae => migrate to lungs, but do not develop into adults
Prevents disease but no infection
Lifelong immunity following 2 doses
Do not mix vaccinated and unvaccinated calves
Which lungworms affect sheep and goats? Which is most important?
Dictyocaulus filaria - most important
What is the equine lungworm?
Dictyocaulus arnfieldi
Which species carries equine lungworm asymptomatically?
Donkeys
Avoid co-grazing or treat contact donkeys in spring
How is equine lungworm dignosed?
Faecal sample
Embryonated eggs pass in faeces hatch within a few hours
Immediate processing => McMasters method
Processing later => Baermann technique
Tracheobronchial wash => large eosinophils
What is the PPP of canine lungworm?
Angiostrongylus vasorum
PPP = 6-10wk
What are the clinical significance of angiostrongylus vasorum?
CVRS signs - crhonic coughing, exercise intolerance
Coagulopathies - subcut haematomas. internal haemorrhage
Neuro signs - paresis, bevhaviour changes, ataxia, blindness, seizures
How is canine lung worm treated?
Moxidectin
Milbemycin - weekly for 4w
Fenbendazole - daily 1-3wks
Supportive - fluids, blood products, bronchodilators, o2, ABs
What is the asymptomatic canine lungworm associated with breeding kennels?
Filaroides osleri
Atypucal metastrongyle
Direct LC, transmitted from bitch to puppy by grooming
Chronic, dry, debilitating cough
What is the feline lungworm? What are it’s intermediate hosts?
Aelurostrongylus abstrusus
Snails/slugs
Often asymptomatic, but can cause resp disease in immunocompromised cats
Which migrating larvae can cause respiratory disease in horses?
Parascaris equorum
Echinococcus granulosus
