Bluetongue – Complacency Costs!

Watch Defra’s Bluetongue video outlining why farmers can’t afford to be complacent about Bluetongue, featuring farmer Robert Law and Deputy Chief Vet Alick Simmons.

Full transcript of the video (PDF 50KB)

Remain vigilant…

To remain vigilant for Bluetongue you should inspect your stock, particularly focusing on the mucous linings, (lining of the mouth and nose) and the coronary band (where the hoof stops and the skin starts), and; if you suspect one of your animals has Bluetongue, it is vital to report it as early as possible. Telephone your nearest Animal Health Office immediately or call the Defra helpline on: 08459 33 55 77 between 9am – 5pm, 5 days a week.

Definition

Bluetongue is a disease of animals affecting all ruminants, including sheep, cattle, deer, goats and camelids (camels, llamas, alpacas, guanaco and vicuña). Horses and pigs are not susceptible species. The disease is caused by a virus spread by certain types of biting midges.

How to spot the disease (Clinical signs)

Clinical signs can vary between species. Although symptoms are generally more severe in sheep, cattle can occasionally show signs of disease. Cattle are important in epidemiology of Bluetongue as they act as an often silent source of Bluetongue Virus (BTV) – a reservoir for disease and keep the infection circulating. It is important to be vigilant, especially in the case of sheep. If you suspect any signs of the disease you must report this immediately to your local Animal Health Office.

Leaflet: Bluetongue – Guidance for livestock keepers (PDF 150 KB)

Clinical signs in sheep:

• Eye and nasal discharges
• Drooling as a result of ulcerations in the mouth
• High body temperature
• Swelling of the mouth, head and neck
• Lameness
• Haemorrhages into or under the skin
• Inflammation at the junction of the skin and the horn of the foot – the coronary band
• Respiratory problems – difficulty with breathing and nasal discharge
• A bluetongue is rarely a clinical sign of infection
• Deaths of sheep in a flock may reach as high as 70 per cent. Animals that survive the disease can lose condition with a reduction in meat and wool production.

Clinical signs in cattle:

It is possible that cattle will show no signs of illness, however clinical signs have included:

• Nasal discharge
• Swelling of the head and neck
• Conjunctivitis (runny eyes)
• Swelling in, and ulceration, of the mouth
• Swollen teats
• Tiredness
• Saliva drooling out of the mouth

In cattle, the disease cannot be diagnosed on clinical grounds and requires laboratory testing for confirmation.

How to report the disease

If you suspect signs of any notifiable disease, you must immediately notify your local Animal Health and Veterinary Laboratories Agency.

Guidance on the midge mitigation measures

No one measure will prevent midges biting animals.  However, the use of a combination of these measures will help reduce the risk of animals becoming infected with BTV. Culicoides breeding sites can be potentially reduced by:

• Moving dung heaps away from livestock or covering with a plastic, watertight cover
• Scraping the perimeters of heaps/slurry pits to a depth of 6-10cm (this is where the majority of larvae reside)

Housing of animals in an enclosed space (where the means are available close doors and cover entrances with mesh) during periods of peak Culicoide activity may reduce biting rates. Farmers should be aware of the midge conditions on their premises, for example bringing hill sheep into low land where midges are more prevalent would increase the risk of midges biting. No insecticides are authorised specifically to act against Culicoides.

• Deltamethrin-based compounds have performed best in tests, however, they only offer limited coverage of animals and provide 1-2 days protection at best (as do other generic repellants)

Insecticides and repellants do not entirely remove the risk of an animal contracting bluetongue and Defra recognise their use on farms does not provide a practical and cost-effective control measure against bluetongue in most cases.

Application of insecticides for short-term protection of animals transiting BTV zones, or where required for specific livestock movements (i.e. licensed moves) can be required.

• Animals and their vehicle must treated prior to travel.
• The product used should be based on a synthetic pyrethoid (eg Deltamethrin) and hold a GB marketing authorisation
• Insecticide should be used in accordance with manufacturers instructions.

Spraying at rates beyond the manufacturers instructions will not improve efficacy and increases the risk of groundwater and surface water pollution.

Synthetic pyrethoids are highly toxic to insect life in rivers and streams.  Take great care not to allow these products to enter surface of groundwater.  In particular, spraying vehicles on a hard stand presents particular dangers as run-off can be concentrated.

Defra do not recommend the treatment of the general environment with insecticides, as this will have little effect on midge populations and has serious environmental implications.