3 poultry diseases to look out for in 2022

Preventing disease and parasite outbreaks is always a major challenge for broiler and layer producers. But this winter’s avian influenza outbreak – the worst the UK has ever seen – has created additional pressures.

Liam Doherty of MSD Animal Health outlines three diseases to watch out for, and how producers can reduce incidence.

See also: Q&A: Guidance on avian flu with England’s chief vet

What to look out for in layers

Red mite

Avivet red mite control system © MSD

Red mite infestations usually cause more problems during the warmer months. The current housing order, in place to limit the spread of avian flu, means some producers may see increased red mite challenges compared to normal at this time of year.

As well as the impact red mite have on bird performance, the additional stress caused by the parasite can lead to behavioural problems such as feather pecking.

The parasite also acts as a vector for other diseases, including infectious bronchitis (IB), E coli and salmonella, and have the potential to transmit avian flu and erysipelas.

Identifying red mite as early as possible is key. Keep an eye on the typical places red mite are found, including perches and behind the clips on the drinking water line.

One way of assessing levels is to use simple traps. These can be made of corrugated cardboard, placed inside a plastic tube. The red mite will lodge in the ridges and can provide an early warning of a potential infestation.

If high numbers of red mite are identified, it’s important action is taken immediately. Speak to your vet to find the best solution for your system.

Biosecurity tips

  • Provide clean, dedicated overalls for each poultry house
  • Change out of overalls before leaving the site
  • Avoid shared equipment
  • Maintain clutter-free houses and control rooms
  • Limit external site visitors

Infectious bronchitis

Infectious bronchitis (IB) causes respiratory problems in both layers and broilers. It can also affect the reproductive system, hitting production and shell quality in laying hens. Eggs can be downgraded to seconds or completely rejected.

The disease is highly contagious and, therefore, particularly prevalent in areas where there is a high density of poultry. While IB is not as common in broiler flocks, it can quickly spread from nearby layer houses.

Broilers can suffer enteritis, poor growth and carcass rejection. “The virus is able to spread through an entire flock within just 36 hours, via faecal dust and air droplets,” says Mr Doherty.

The virus is untreatable, so good biosecurity and a robust vaccination programme are crucial. Layers are given live vaccinations during rearing to prime the immune system, and then a second dose before transfer to the laying site.

Broilers receive a live vaccination at the hatchery and sometimes again on-farm depending on the field challenge.

Correct application is vital for the vaccine to be effective. “Vets will be able to advise on the most appropriate vaccination and the best means of administration,” says Mr Doherty.

Screening is recommended, whether using serology or PCR tests to diagnose IB. PCR tests can type the virus, which means the vet can design a vaccination programme around the specific problem on the farm.

Biosecurity tips

  • Maintain clutter-free houses and control rooms
  • Limit external site visitors
  • Thoroughly clean and disinfect the poultry house and equipment between crops and flocks
  • Use clean, dedicated, overalls for each poultry house
  • Change out of overalls before leaving the site
  • Control and reduce the presence of rodents on-site
  • Avoid storing litter near neighbouring sites

What to look out for in broilers

Gumboro disease

Infectious bursal disease (IBD), also known as Gumboro disease, impacts the bursa of Fabricius, an organ that is crucial to the development of immunity in the bird.

This means the bird has an impaired ability fight off diseases and is less responsive to vaccines.

The virus is spread when birds ingest infected faeces and the most likely clinical signs are slow growth, poor uniformity and a lack of response to vaccines.

Thorough cleaning and disinfection of the house and equipment between bird cycles will help reduce spread, along with limiting visitor numbers to the site and changing into clean boots and overalls.

But the disease can be very difficult to get rid of.

When chicks arrive, they will have a degree of maternal immunity as breeders are typically vaccinated and chicks hatch with a high level of antibodies.

However, these decline over time so broiler chicks also require a single vaccination via the drinking water.

“In this instance, vaccination timing is crucial. If it’s too early, the chick’s maternal antibodies will recognise and fight the vaccine, making it less effective.

“If it’s too late, maternal antibodies may have declined completely, leaving chicks without protection against field strains of Gumboro,” says Mr Doherty.

A PCR test will identify the exact type of Gumboro on-farm, so vets can advise on the most appropriate vaccine for the strain.