Biosecurity

Biosecurity is a concept for the prevention of disease entry/escape that must be practised by farmers, retailers and food handlers. Lack of biosecurity measures increases the risk of disease entry into production units or markets.

One of the most common breaks in biosecurity for many transboundary animal diseases, including avian influenza, is the entry of people bringing in contaminated materials (clothes, shoes, soil on hands) to where susceptible animals are kept.

Solution

• Do not allow strangers access to where poultry are housed.

• Provide protective clothes, including boots, to those who visit the flock.

• Provide foot baths with disinfectant for boots (use a pre-disinfectant bath to wash off organic matter before entering disinfectant).

• Ideally, all farm workers and visitors should take a full shower and use clothes from the farm before entering areas where poultry are kept; clothes used on the farm should not leave the farm.

• Producers who use outside workers for assistance on their farms should ensure that these workers do not have poultry of their own.

• Animal health officials visiting affected premises should be extremely conscientious because they, through their work in epidemiological investigations or vaccination initiatives, could actually be infection and disease spreaders.

• The producers should know the origin of their feed and water. The quality of these should be periodically checked.

Another method of disease entry into a flock is through the introduction of contaminated equipment or instruments such as lorries, egg trays, cages or feeders.

The reuse of equipment (e.g. egg trays) and the purchase of used equipment (e.g. feeders) represent high-risk activities.

Solution

• Clean and disinfect equipment and instrumentation to be used. If a group brings in specific equipment on a regular basis (e.g. egg trays), insist that these be disinfected prior to introduction.

• Porous materials, such as wood and fibre, are more difficult to disinfect than synthetic materials. Use non-porous materials.

The most common method for disease introduction is bringing poultry that are incubating or are diseased on to the premises and mixing them with susceptible poultry.

Solution

• Ensure the poultry to be introduced to the farm/flock are healthy. If possible, a health certification should be obtained.

• Vaccinate only healthy poultry.

• Establish a quarantine area where new poultry are not housed with poultry already on the farm. These housing areas should be separated from each other as much as possible. Use separate workers to handle the different poultry. If this is not possible, handle or feed new poultry last.

• Establish mechanisms to separate wildlife from poultry production farms (e.g. use of enclosures and nets). Establish mechanisms to exclude access of cats, dogs and rats and other vermin from where poultry are raised or where there are laying hens.

The concept of “all-in-all-out” in biosecurity deserves special attention as it offers an additional safety mechanism. It refers to the exclusion of introduction of new poultry, and equipment and feed, once production has started, thereby diminishing health risks to the growing broilers. Once the age for marketing the chickens is reached, all poultry are removed and sent to the market or abattoir, thereby allowing the workers to clean, aerate, remove old feed and disinfect the premises prior to the entry of new and highly susceptible chicks. This cycle is continuous and supplies the means to provide systematically the necessary points for veterinary care, feed delivery, transportation entry, employee inputs, etc. If and when a disease enters the flock, the process of removal, cleaning and disinfection is already established and can be quickly implemented with little downtime faced by the farmer.

Farmers’ allowing poultry to have free access to their environment and its elements that may carry contagion (roads, stagnant waters, plastic, cats and dogs) is perhaps the most difficult aspect to overcome when attempting to control disease and apply some level of biosecurity. In these cases, biosecurity should commence with making loose chickens truly backyard chickens (not “front yard” or “under-house” chickens) in a place where they can be observed and properly cared for. Being kept in a known and comfortable enclosure is also likely to reduce their stress (caused by competition with vehicular traffic and potential predators) and therefore prompt them to gain weight, lay more eggs and have less risk of contact with diseased animals.

Conceptually, biosecurity is most successful when practised by a group of neighbours, commercial operators or villagers.