Looking into lungworm

Bovine lungworm caused by the nematode Dictyocaulus viviparus has long been recognised as a serious risk to cattle and causes potentially fatal disease.

Understanding of lungworm's clinical and economic significance improved hugely in the 1950s, leading to the development of a live irradiated larval vaccine which soon became a valued control measure.

But with the rising popularity of long-acting anthelmintics treating both roundworms and lungworms, vaccine use fell in the 1980s.

However, despite these innovative anthelmintics and with limited evidence of lungworm anthelmintic resistance in the UK, the number of cases of lungworm reported remains high.

In surveys in Northern European countries, around 40% of farms showed evidence of lungworm infection in first grazing season beef and dairy calves (Forbes, 2021). There has also been a significant rise in cases in recent years in older dairy cattle.

The epidemiology is complex, and out-breaks are often extremely unpredictable. Years differ, with climatic conditions being a major factor. Warm summers with higher-than-average rainfall, or rainfall concentrated in short and intense periods, significantly increase incidence.