Respiratory Parasites I Flashcards
(41 cards)
Lungworms (nematodes)
Dictyocaulus
Cattle lungworm
Dictyocaulus viviparus
Sheep lungworm
Dictyocaulus. filaria
Horse/donkey lungworm
Dictyocaulus. arnifieldi - disease in horses but rare in donkeys (donkeys more commonly infected but don’t display disease symptoms)
Dictyocaulus vivparus (6)
Life cycle of Dictyocaulus viviparus (9)
Penetration phase, pre-patent phase, patent phase, post-patent phase
- L1 larvae shed in faeces -> moult
- L2 in faeces -> moult
- L3 larvae:
- Migrate onto pastures and picked up by other cattle
- Disseminated by rain splash (raindrops)
- Disseminated by pilobolus fungi
- L3 ingested by cattle
- L3 migrate to blood/lymph system then lungs -> moult
- L4 in lungs -> moult
- L5 in lungs
- Adult worms in cattle live in main respiratory passages (trachea + bronchi)
- Female lay eggs in bronchi:
- Hatch almost immediately -> L1
- Get coughed up and then swallowed into the gut -> faeces = sluggish, brown food granules
- L1 -> L3 in 5 days under optimum conditions (wet + mild climate)
What does the penetration phase of Dictyocaulus viviparus involve? (5)
- 0-7 days post-infection (PI)
- L3 ingested
- Migrates to lymph nodes
- Moults to L4
- Bloodstream → Lungs
What does the pre-patent phase of Dictyocaulus viviparus involve? (5)
- 8-25 days PI
- L4 → alveoli
- Moults to L5
- Migrates → bronchi
- Matures to adult
What does the patent phase of Dictyocaulus viviparus involve? (3)
- 26 – 55 days
- PI Adult worms in upper respiratory tract
- L1 in faeces
What does the post-patent phase of Dictyocaulus viviparus involve? (3)
- 55 days PI
- Immune expulsion of worms = strong response
- Larval development can arrest
Pathogenesis and clinical signs of the pre-patent and patent phase (4)
Pathogenesis and clinical signs of the post-patent phase (5)
Cow with husk - severely affected by lungworm, may be reluctant to move, hold their head down, neck extended
Economic consequences of Dictyocaulus viviparus (5)
Epidemiology of Dictyocaulus viviparus - what is larval development and dispersal dependent on? (6)
Seasonality of Dictyocaulus viviparus (8)
Risk factors of Dictyocaulus viviparus (4)
Immunity of Dictyocaulus viviparus (5)
Reinfection syndrome of Dictyocaulus viviparus (3)
Diagnosis of Dictyocaulus viviparus (6)
What is the Baermann method of lungworm detection?
Using gauzed faeces and funnel - leave for 24 hours to drain into a test tube - allow material to sink to bottom and withdraw add Lugol’s iodine on slide and examine under microscope
How is Dictyocaulus viviparus treated? (4)
Vaccine control of Dictyocaulus viviparus (6)
Other control measures of managing Dictyocaulus viviparus (5)
