Salmonella prevalence in UK laying flocks is low, but maintaining this position means continuing to adapt as production systems and on-farm management practices evolve.
That was a key message from Elanco’s Pride in Protection event, where speakers praised the sector’s achievements.
Former politician Edwina Currie spoke at the event via video, nearly 40 years after her infamous statement claiming that most of the UK’s eggs were contaminated with Salmonella.
She told delegates: “It took some time to put everything right, but it wasn’t governments that put it right, it was the producers and scientists and all the people they work with who did it.
“You are a tremendous bunch of people; you should be very proud of what you have done. The British egg industry is a great success.”
Despite the sector’s success, speakers also warned that while Salmonella prevalence remains low, there is no room for complacency.
As laying cycles become longer and flock management continues to evolve, maintaining the UK’s strong Salmonella status will depend on ensuring control measures and vaccination strategies keep pace.
Leading the way, but not standing still
Doris Mueller-Doblies, global poultry food safety technical lead at Elanco, says the UK’s strong position is clearly reflected in the prevalence data.
“As an industry, you’ve achieved a lot,” she said. “The prevalence of Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) is considerably lower in the UK than in many other major egg-producing countries in Europe[1].
“The 2024 data shows Northern Ireland prevalence at 0.122% and Great Britain at 0.24%, compared with 3.954% in the Netherlands, 2.588% in France and 2.091% in Poland.
However, Mueller-Doblies said these figures should be viewed as a benchmark to maintain, rather than a reason to ease off. EU data shows Salmonella prevalence in adult laying hen flocks has been increasing again since the lowest levels recorded in 20141,.
GB data also highlights the need for continued vigilance. ST increased again in 2024, while SE has fallen back following a peak of 14 positive flocks in 2019.
She adds that older flocks also need careful consideration, as longer laying cycles may increase the risk of exposure later in life.
Protection through to later lay
Recognising the shift towards longer laying cycles, Elanco has spent many years working towards authorisation of AviPro Salmonella Duo for use in-lay.
Joshua Davison, veterinary technical consultant from Elanco, said longer production cycles have created a gap between the duration of immunity provided during rearing and the length of time birds now remain in lay.
“The very low incidence of Salmonella seen today reflects the significant progress the industry has made over many years,” he said.
“However, cases still occur, so it’s important that we continue building on those achievements, as once consumer trust is questioned, it can take decades to regain.”
The in-lay dose of AviPro Salmonella Duo helps bridge that gap, extending protection up to 100 weeks of age against SE and 94 weeks against ST[2] after a fourth dose of the vaccine.
Administered via the drinking water system at around 50 weeks of age, the fourth dose of the vaccine is designed to maintain protection throughout extended laying cycles.
Practical considerations for in-lay vaccination
The event also explored the results of a recent trial by Robert Harrison at RH Consultancy, which gave rise to new recommendations on how to use AviPro Salmonella Duo effectively alongside poultry wormers and red mite treatments.
All four soluble wormers and the red mite treatment which were tested in the trial reduced the viability of AviPro Salmonella Duo, with negative effects often still observed at a 1% dilution of the product’s in-use concentration. The impact varied between active ingredients and was greater at higher temperatures (30°C).
Although adding AviBlue water stabiliser offered a protective effect, it did not completely prevent the loss of viability.
Following the trial, Elanco’s recommendation is that producers should not use soluble wormers or red mite treatments on the day of vaccination. Use should also be avoided in the days before vaccination, as residual traces may reduce vaccine viability.