Lungworm Flashcards
Resp parasites I
Name the two types of lungworm
Dictyoculus and Metastrongylus
D. viviparus condition in cattle
- what is it called
- seasonality ?
- risk factors
- immunity ?
- CS ?
- diagnosis ?
- treatment ?
- control ?
Parasitic Bronchitis (“husk”)
seasonality : L3 survive on pasture over winter. low levels of L3 in spring so no disease. ideal conditions lead to a rise in L3s and hence an outbreak in later season (summer)
risk factors : wet summers, heavy stocking densities, host age, immunity status
immunity : rapidly acquired under field conditions due to decreased larvae reaching the lungs and the immune destruction of adult worms. to note, cattle can be re-infected if enough larvae reach the lungs
CS : parasitic bronchitis, frothy white mucus in bronchi, parasitic pneumonia, coughing, increased BR, laboured breathing, anorexia
diagnosis : CS, season, ELISA, L1 in faeces, eggs/larvae in sputum
treatment : rapid anthelmintic use with a broad spectrum being effective.
control : live attenuated vaccine available to eradicate all L3 worms in body - needs boosting by natural exposure
Dictyoculus lifecycle
penetration phase –> 0-7d. L3 ingested and migrate to LNs. moult to L4. moves through blood to lungs
pre-patent phase –> 8-25d. L4 in alveoli moult to L5 and migrate to bronchi, moult to adult.
patent phase –> 26-55d. adult worms in URT and L1 released in faeces
post-patent phase –> immune expulsion of worms, some larvae can arrest development
Metastrongyles main features
worms found in the lungs and the associated BVs. they show lymphotracheal migration
larvae can be found in faeces, with recognisably “kinky” tails
Metastrongyles lifecycle
indirect, with a mollusc as an intermediate host
L1 larvae passed in faeces –> ingested by slugs and snails –> slug/snail ingested by dog –> larvae mature into adults in pulmonary arteries and right heart
Angiostrongylus
- fact file
- risk factors
- pathogenesis
- CS
- diagnosis
- treatment
- control
lung worm infecting dogs for >2 years
wild canids act as reservoir hosts
risk factors : younger, certain breeds, location
pathogenesis : poorly understood, inflammatory response forming granulomas, haemorrhages and fibrosis. worms also physically block BVs
CS : pulmonary (most common - coughing, dyspnoea, lethargy). coagulopathy (haematoma, anaemia, haemorrhage). CV (myocarditis, murmurs). neuro signs and death
diagnosis: direct faecal smear or blood antigen test
treatment : anthelmintics and supportive care
control : regular prophylaxis with anthelmintics
Name some other metastrongyles and the species they infect
Aelurostrongylus abstrusus in cats (asymptomatic, L3s penetrate gut wall and adults live in alveolar ducts and terminal bronchioles)
Metastrongylus apri in pigs (earthworm intermediate host!, adults live in bronchi/bronchioles. asymptomatic)
Synagmus trachea (“gape worm”) fact file
adults live in trachea of chickens, turkeys and gamebirds.
infection via ingestion of eggs coughed up/passed out in faeces
CS : pneumonia, resp distress, suffocation, gurgling, head shaking, coughing, choking.
Oestrus ovis fact file
sheep nasal bot, larvae found in nasal passages and frontal sinuses
light = nasal discharge and sneezing
heavy = thriftiness and lack of coordination
