“Its’ not all about housing” says CVO

Published on : 12 Oct 2022

“Biosecurity in free range is not all about housing”, said the UK’s Chief Veterinary Officer at the BFREPA Conference. “Your biggest risk is around your buildings”.

Speaking at the Hilton Metropole hotel near Birmingham on 29 September, Professor Christine Middlemiss said that “housing of free-range hens will give a two fold reduction in the likelihood of infection by reducing the level of direct contact with wild waterfowl.”

 
But she added that housing pales into insignificance compared to good biosecurity around the house which “brings an overall 44-fold reduction in risk”. She said all the evidence suggests that most infections are introduced to poultry by contaminated people or other fomites (vectors) that are taken into or enter the housing. 
 
Middlemiss said that Defra has undertaken a “lessons identified” exercise on the outbreak so far. One of the lessons is that “biosecurity on individual premises is still the major issue” behind the outbreak. APHA had found that, on the whole, perimeter biosecurity had been good on free range eggs farms but the main problem is within the perimeter, particularly around entrances to sheds and generally around the buildings.
 
Defra epidemiologists who have looked at outbreaks on free range egg farms have found that the weaknesses are generally within the inner shell of the farm, particularly around entrances to sheds and the lack of a lobby with separate clean/dirty areas, no dedicated house PPE (not disposable foot coverings), poor disinfectant foot dip with regard to location, dilution or brushes, no washbasin or hand sanitiser, and a lack of secure doors. Issues have been found in the egg room where it serves as a lobby into the poultry accommodation. Staff working in the egg room can then be responsible for the transmission of the virus into the house via the egg belt.
 
Muck belts have been found with parts outside the building with covers missing or broken. Bedding if often inadequately protected from wild birds and then the risk is compounded when producers unwrap infected bedding inside the house (rather than outside).
 
The integrity of the building itself has often been at fault due to poorly maintained walls, doors, windows,  ventilation inlets, and roofs. Leaking roofs and guttering can create a constant stream of viral soup into the house from wild bird faeces on the roof. This is compounded by moss on the roof which encourages wild birds. In some cases broken or absent mesh or slats create ventilation openings for virus vectors, which can include rodents as well as birds.
 
It is important that there is a “senior controlling mind to be accountable for biosecurity”, according to the Chief Veterinary Officer, who makes “biosecurity part of the culture and easy for staff to do”. She said that the occurrence of unusual events such as staff absences and holidays were often ignored, particularly with the introduction of poorly trained or briefed relief staff (see orange squares on previous page).
 
Middlemiss warned producers at the Conference to plan and prepare for another bad winter. According to modelling, the UK, and specifically England, is predicted as being one of the highest risk areas in Europe. 
 
The current rampant spread of the same virus in the United States of America is particularly worrying, indicating that most of the Northern Hemisphere is not immune from the infection.
She offered free range producers the following advice:
 
 
Middlemiss thought that the Government’s full epidemiology reports on all the HPAI H5N1 cases in 2021/22 would be published on the Gov.uk website in the next month or so. But she warned that they would confirm the conclusions presented to delegates at Conference: All the Infected Premises during this outbreak were as a result of direct or indirect contact with wild birds as a result of weak biosecurity around poultry sheds. 
 
She urged producers to do more to improve their biosecurity.