preview

Dictyocaulus Viviparous Research Paper

Decent Essays
Bovine lungworm disease arises from infection with Dictyocaulus viviparous. Infection is far more common in younger animals that have never been exposed than older animals that have acquired immunity. In general this condition is endemic in older animals however disease may still occur. These animals were not infected until August even though they had been grazing the pasture presumably since May. A number of theory’s surround this issue. Ingestion of overwintered larvae involves so few, that neither clinical signs nor disease occur. By august the pasture will be sufficiently seeded with L3 larvae to produce disease. Another theory believes overwintered larvae do not migrate out of the soil onto pasture until later on in the season July to November. Depending on the environmental conditions larvae require warm moist environment. The most…show more content…
Larvae from the faecal pat disperse in conjugation with a fungus as opposed to the more traditional migration. The fungus pilobolus aids Dictyocaulus viviparous move from the faecal pat up the stalk of the fungi, inside the sporangium or seed capsule. It is then discharged up to three metres into the air before landing on surrounding herbage. The pathogenesis of bovine lungworm consists of a complex three phase process. The pre-patent phase usually occurs between 8-25 days after infection. It is characterised by the appearance of larvae within the alveoli leading to alveolitis. This continues with bronchiolitis and bronchitis. It occurs as a result of larvae maturing and moving through the bronchi. Bronchitis occurs at the end of the phase. It is caused by immature lungworms present in the airways and cellular infiltration of epithelium. Severely infected animals may die from 15 days onwards due to respiratory failure following the development of severe interstitial emphysema and pulmonary oedema. The patent phase occurs 26-60 days after
    Get Access