Biosecurity in Poultry Production: What Makes it Work - and What Doesn't12 February 2016
US - Over the past several years, the US poultry industry has been challenged by emerging and re-emerging infectious diseases. In fact, every year since the 1970s, we have on average identified one new disease or a more virulent strain of a known disease.
Since the beginning of 2014, for example, there have been 41 outbreaks of H5 and H7 avian influenza (AI) reported, involving seven different viruses in 20 countries worldwide, including the US. Several are new viruses that have recently emerged in wild and domestic birds.
We know that several basic biosecurity measures are effective for controlling infectious diseases because when these measures are not in place, or are less likely to be in place, we see associated outbreaks.
In a 1994 field study, I was able to demonstrate that growers who required outside teams to remove used litter were eight times more at risk of having a flock infected with infectious laryngotracheitis (ILT) than those who did not use outside teams. Likewise, those who hired outside vaccination crews were 13 times more at risk of having a flock infected with ILT.
In North Carolina in 2000, I found that 65% of growers with a Mycoplasma gallisepticum (MG)-infected flock allowed visitors to enter poultry houses without clean or farm-owned coveralls. Conversely, only 12% of growers with MG-free flocks reported allowing this same breach in biosecurity.
Not surprisingly, in the same survey, MG-infected flocks were more likely to be identified on farms where growers did not require a change of boots before entering the barn. Failing to change boots has also been associated with the spread of infectious bronchitis (IB) in chickens. The absence of an effective darkling beetle-control program is another key risk factor for IB.
In essence, biosecurity is all about preventing contact and the spread of microbes between susceptible birds. Barns that house commercial birds should be considered a restricted access zone, or RAZ. The farms where these barns are located should be considered a controlled access zone, or CAZ, and are potentially contaminated. Everything else around these two zones must be considered an environmental source of contamination.
Susceptible birds, microbes, reservoirs for microbes — which include other animals and organic material — and the modes of direct and indirect transmission are all links in the chain of infection. Any action having a substantial impact on one or more of these links will affect the risk of disease transmission.
Avoiding visitors is the first key to protecting the RAZ. If you must have visitors, make sure they’ve showered and changed clothing and footwear before entering barns. Even if they haven’t been on another farm before, they might become contaminated on their way to visit — particularly if they visited a diagnostic laboratory! It’s best for farm employees to wear either farm-specific clothing they launder daily or clean clothing supplied by the farm.
Within the poultry house, the separation between the door to the outside and the RAZ must be clearly delineated. When a shower is present, the shower itself is the demarcation. In the absence of a shower, it’s best to separate the entrance to the barn into three areas. The area closest to the outside door is the first area and has the same status as the outside. The next area is where hands are washed and is a transitional zone between the outside, contaminated area, and the third area, which is the area closest to the inside door giving access to the birds; it is known as the clean area.
Proper footbath use
Putting on barn-specific boots or disposable boots for short visits and donning coveralls after washing hands is a basic necessity that must be employed on every commercial poultry farm. Footbaths, when used properly, can reduce the risk of disease spread. The problem is that to achieve this, you must first use a brush to remove visible organic material from boots. You must then soak boots for well over 30 seconds in a clean disinfectant solution. This virtually never occurs under normal field conditions. Quickly dipping boots into a footbath has actually been associated with increases in boot contamination. The bottom line? Anyone entering a poultry house should change his or her boots!
Using an alcohol-based gel helps ensure effective hand sanitation and it’s important, but I can’t overstress the importance of washing hands before using a gel. This can be done by using a degreasing cream or soap and water before applying an alcohol-based gel. However, based on a survey of catching-crew personnel, warm water and soap were much preferred to a degreasing cream.
Disinfecting barns effectively is also critical to a successful biosecurity program. Use of a commercial disinfectant is essential, of course, but good barn sanitation needs to begin with removal of all organic material, starting with manure. It is followed by washing with a detergant prior to disinfection. Scheduling about 2 weeks of downtime between flocks provides enough time to accomplish this and should include letting everything thoroughly dry. Proper down time and disinfection help reduce infection pressure, which is the number of microbes in contact with birds.
Heating a building to about 100° F (38° C) for a few days has also been used effectively against avian influenza and Mycoplasma.
Preserving CAZ integrity
To ensure CAZ integrity, start by making sure that all farm personnel avoid live-bird markets and contact with any other poultry. The CAZ should be clearly marked and its meaning understood by all those who access the farm. A fence is best when economically feasible.
An integrated pest-management program is paramount for removing potential disease carriers. It should include cleaning out vegetation for at least 15 feet around barns. Standing water should be eliminated because it’s a breeding environment for insects and attracts pests, including wild birds that may be AI carriers. Feed spills should be avoided for the same reason.
If rendering is used to dispose of dead birds, the disposal area should not be located in the CAZ.
Finally, equipment and vehicles must be washed and disinfected, particularly when they’re used on more than one farm. In this case, it’s best to clean and disinfect when leaving the farm as well as prior to use on the next farm.
The vast majority of infectious diseases are horizontally transmitted. Cross-traffic between farms and the joint use of equipment are certainly significant modes of disease transmission. With potential vectors such as flies and darkling beetles, which are known vectors of AI, disease-control efforts in regions of high farm concentration cannot rely solely on farm-level measures.
In a competitive environment, it’s tempting to limit data sharing. Although liability will always be a concern, pointing fingers has never been an effective disease-control strategy; poultry organizations sharing a region must also share the information needed to prevent and contain significant contagious diseases.
A regional approach to biosecurity includes establishing separate geographical working zones for service personnel. When an important disease is suspected on a farm, a self-imposed quarantine matched with communication to key personnel will go a long way toward preventing a major epidemic.
Poor compliance: The elephant in the room
Compliance, which is the application of consistently employed biosecurity measures, is often low on commercial poultry farms. Wherever I consult in the US, Canada, Mexico and Europe, biosecurity measures are only applied between 25% and 60% of the time. Most errors are related to zone delimitation (clean versus contaminated). The nature and frequency of errors suggest a lack of understanding about biosecurity measures by some people, an unwillingness to comply by others and poor barn-entrance design.
Never assume a high level of knowledge among farm personnel and visitors. In a study on hand washing habits by bird catchers, only 62.2% answered “yes” when asked if they always washed their hands after catching birds if they had the opportunity to do so. When asked what the most important reason was for washing their hands in their work environment, only 13.0% mentioned the importance of preventing the spread of microbes between farms.
Training programs explaining why each task is important must reach all poultry personnel. To achieve buy-in from them, they must also be able to contribute to the development and/or the regular review of the biosecurity program.
The application of biosecurity measures varies greatly in the poultry industry. Some of the people intimately involved in implementing biosecurity measures may not appreciate the chain of events that encourages the spread of disease. The challenge is to convince all poultry personnel about the impact of their actions on the risk of disease transmission.
Education of all poultry personnel working or visiting farms is key if we want to substantially change people’s perception of disease risks and, consequently, increase their level of awareness and compliance regarding biosecurity measures.
Proper biosecurity requires securing individual farms and implementing biosecurity measures in partnership with regional competitors. Toward this end, here’s a list of considerations and suggestions:
- Remember that as regional farm density increases, so does the risk of infectious-disease transmission.
- Once biosecurity measures are put into place, don’t assume everyone involved applies them on a regular basis.
- Focus on basic measures that are known to work, such as changing boots and putting on coveralls as well as washing hands and using an alcohol-based gel before touching anything that may come into contact with birds.
- Make compliance easy. Provide ample space for changing boots, putting on coveralls and washing hands. Make sure the necessary supplies and equipment are available and readily accessible.
- Emphasize proper communication. It’s an essential biosecurity measure and it’s futile to try and biosecure a farm without regional consideration. Have a plan in place that enables rapid communication among key poultry people, in particular those who may come onto the farm, especially when there is suspicion of an important contagious disease.
- Although technological advancements that benefit biosecurity will evolve in the years ahead, people-related issues will still have the most impact on the poultry industry’s ability to biosecure its farms.
By Jean-Pierre Vaillancourt, DMV, MSc, PhD
Research Group on the Epidemiology of Zoonoses and Public Health
Faculté de Médecine Vétérinaire
Université de Montréal Public Health Research Institute, Québec, Canada
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