Clinical Signs
Infection with bluetongue can significantly compromise livestock welfare, both in terms of unpleasant symptoms and a potentially high mortality rate (around 30%). Animals can recover from the disease. Such animals become immune to the strain with which they were infected and, after around 60 days, they stop shedding virus into the bloodstream, meaning that they no longer pose a risk in terms of onward infection of the midge population. However, there are long terms impacts on productivity and fertility.
The clinical signs are more apparent in sheep, than other ruminants, and can include:
- fever
- swelling of the head and neck
- inflammation and ulceration of the mucous membrane of the mouth, nose and eyelids
- lameness
- loss of muscle tone and weakness
- haemorrhages in the skin and other tissues
- respiratory signs such as froth in the lungs and an inability to swallow and discolouration; swelling of the tongue.
Although bluetongue usually causes no apparent illness in cattle or goats, cattle may display clinical signs including:
- nasal discharge
- swelling and ulceration of the mouth
- swollen teats.
As with any notifiable disease, if you suspect that your livestock may be infected with bluetongue, you must contact your local Animal Health Office