Guidance

Warble fly: how to spot and report the disease

How to spot warble fly, what to do if you suspect it and measures to prevent its spread.

Warble fly mainly affects cattle. It can also affect:

  • horses
  • deer

Warble fly doesn’t affect humans.

The last outbreak in Great Britain was in 1990.

If you suspect the disease in Scotland, you must tell the Animal and Plant Health Agency (APHA) immediately. Failure to do so is an offence.

Warble fly is a notifiable disease in cattle only in Scotland as the England and Wales regulations were revoked from 1 April 2015.

How to spot warble fly

The main sign of warble fly is large, soft and painful swellings on the back of the animal of up to 3 millimetres wide.

How warble fly is spread

The disease is spread by the warble fly, which lays eggs on the hide of animals.

Preventing and controlling warble fly

You can help prevent the disease by practising strict biosecurity on your premises.

If you report suspicion of warble fly in Scotland APHA vets will investigate.

If warble fly is confirmed the outbreak will be controlled in line with the Scotland contingency plan for exotic notifiable diseases.

Further information on prevention and control

Controls to prevent disease

What happens when a notifiable disease is suspected or confirmed

Leglisation on warble fly

The main legislation on warble fly is the Warble Fly (Scotland) Order 1982.