The recent identification of a sheep carrying H5N1 influenza virus of avian origin (more commonly known as bird flu) marks a world-first in sheep. But what does this actually mean for the general public and for the rest of the UK livestock population? 

How was this diagnosed? 

Following the diagnosis of avian influenza in farmed birds on a premises in Yorkshire, routine surveillance testing was carried out on other livestock resident on the farm. This led to one sheep testing positive for the disease following repeated milk sample testing. The animal showed no signs of illness but was humanely euthanased to allow further investigations to be carried out. The remaining livestock on this holding were found to be clear of the disease.  

Why is this important? 

The identification of avian influenza in this sheep is significant because it adds to the list of non-avian (non-bird) species that can be infected with the virus. Worldwide the list of species confirmed to have been infected with bird flu also includes various wildlife species such as rodents and foxes, marine mammals including seals, zoo animals including tigers, domestic cats, pigs, cattle and of course humans.  

Spread between species 

Thanks to extensive worldwide disease surveillance and information sharing, it is not only known that many species may be infected with bird flu, but also how transmission (spread) of disease occurs. In the UK sheep case, it is understood that transmission was from poultry on the same holding to a sheep with which they were in close contact, but no sheep-to-sheep transmission was detected.  

There has also been one confirmed human case of bird flu in England this year, which was associated with “close and prolonged contact with a large number of infected birds” indicating bird to human, but not human to human spread. 

Since 2024 there have been around 70 cases of bird flu confirmed in humans in the USA, with 41 thought to have been exposed via cattle herds and 24 exposed via contact with infected poultry. Cases of bird flu in domestic (pet) cats in the US have also been recorded with several traced to the consumption of raw milk or raw pet food.  

Risk to human health 

Whilst there have been recorded human cases of bird flu, it is important to recognise that the risk to the general public remains very low and in fact, significantly lower than that of other zoonotic diseases (those transmissible from animals to humans) such as leptospirosis (145 cases documented annually in England) or Lyme disease (estimated 2000-3000 cases annually in England). No human-to-human transmission of bird flu has been identified despite extensive ongoing surveillance for this both in the UK and around the world.  

Human cases that have been detected in the UK and US are connected with significant exposure to affected animals, so the risk to livestock workers is higher than that of the general public. As such all those connected with livestock should remain vigilant as always for signs of disease (of any kind) in our animals and report any concerns promptly. 

Preventative action 

As with any health concern, be that human or animal, prevention is better than cure. So, what action can we take as members of the public, pet owners or livestock keepers, to minimise the risk of bird flu to our animals, ourselves, and to those around us? 

The public remain at very low risk of bird flu but are advised to: 

  • Avoid touching sick or dead birds 
  • Keep dogs on leads particularly around coastal areas or ground where birds are more likely to be found, as this will minimise contact with dead or sick birds 
  • Ensure basic handwashing and hygiene, particularly if you are in contact with any wildlife, feathers or droppings 

Our pets are also at low risk, but this can be further minimised by; 

  • Avoiding contact with wild birds for example by keeping dogs on a lead in areas likely to have wild bird populations, and by avoiding contact with wild bird feeding and watering areas such as garden feeders 
  • Keeping cats indoors if there is an outbreak of bird flu in the local area and avoiding walking dogs off lead in affected areas 
  • Avoid contact between pet birds and wild birds, both directly and indirectly via outdoor shoes and clothing. Wash hands thoroughly before handling pet birds. 
  • Avoid feeding non-commercial raw pet feed with meat ingredients. 

Keepers of poultry such as chickens, ducks, geese and pigeons should; 

  • Remain vigilant for signs of bird flu in your animals and report any concerns promptly 
  • Discourage wild birds from contact with your poultry. Keep food and water sources protected and store feed and bedding under cover and away from rodents 
  • Keep up to date with the latest guidance for your area regarding bird flu 

Livestock keepers must remain as vigilant as ever for any signs of disease in their animals 

The recent identification of this potentially zoonotic disease in sheep should serve as a reminder to all those working with livestock to review their biosecurity efforts and awareness. Particular recommendations would be to: 

  • Ensure thorough hand washing 
  • Enforce disinfection of clothing, footwear and equipment particularly of visitors but also of yourself when leaving and returning to your premises 
  • Report any animal health concerns promptly to your vet or appropriate animal health office 
  • Seek medical attention for yourself if you become unwell 

Conclusions 

In the UK we can be reassured that extensive surveillance and monitoring is in place regarding avian influenza in all species and that the risk to both human and livestock health remains low. The Food Standards Agency (FSA) advises that properly cooked meat and animal products are safe to eat and that bird flu poses a very low risk to UK consumers. But we are all part of the surveillance effort, whether as members of the public, pet owners, poultry enthusiasts or livestock keepers, and we can all play our part in the control of this global disease. 

Further Reading 

RSPB information on avian influenza 

A small flock keeper’s guide to biosecurity 

Bird flu: rules if you keep racing pigeons, birds of prey and other captive birds