Biosecurity is a set of management practices which reduce the potential for the introduction and spread of disease-causing organisms onto and between sites.
Biosecurity procedures, particularly cleaning and disinfection, should be combined with vaccination and strategic treatments to either eradicate or reduce these pathogens to non-infectious levels.
The mode of disease transmission between birds, or between sites, differs depending on the type of infection. For example, respiratory disease viruses replicate in the respiratory tract. Subsequent sneezing and coughing release virus particles which are then spread by aerosol transmission. On the other hand, enteric (gut) diseases cause diarrhoea, so infectious agents spread through droppings, whilst air sac and oviduct infections lead to egg contamination and transmission.
Other diseases persist on sites through the contamination of equipment and litter by stubborn virus particles. Many organisms will persist outside the host, and coccidia, salmonella, aspergillus and many viruses can survive in this way for a considerable time, especially in organic material. Pasteurella, mycoplasmas and some bacteria can also live for some time. Respiratory viruses tend to be fairly fragile once outside the host, although may be able to travel at least five miles in the air if conditions are favourable.
Infection may be harboured and spread in a variety of ways. In relation to poultry, these may include by vermin (mainly wild birds, rats and mice), in feed, in droppings, by wind, by inadvertent human intervention and on equipment or litter. These factors all influence the planning of a biosecurity programme.
In an ideal world, sites should be located away from other poultry, and breeders should probably be sited at least five miles from any commercial farms in order to avoid airborne spread of disease. Obviously, this is frequently impracticable, so some air borne respiratory viral challenge will often be a feature of the disease load.
However, disease avoidance measures are still worthwhile and can be undertaken at various stages. For example, avoid building sites near waterways, ponds or lakes utilised by migratory water fowl, and choose well drained areas to avoid standing water. Birds on range will be susceptible to contamination from wild birds and will attract vermin. Wherever possible, poultry houses should also be located away from major roads that handle high volumes of poultry vehicles.
Effective waste disposal and removal of used litter from the site is essential. Areas around houses should be constructed of materials and surfaces that can be cleansed and disinfected, to reduce transmission of organic material on vehicles, tyres, boots etc. Use a multipurpose broad spectrum virucidal and bactericidal disinfectant which will be capable of dealing with gross organic challenge.
People are the most important animate factor - including employees, servicemen, lorry drivers, vaccination crews and vets. Staff movements should be as limited as possible, particularly where the disease situation on a site has deteriorated.
Control site traffic. Keep it to a minimum and exclude all unauthorised persons.
Wherever possible, vehicles should be excluded from the site. Those vehicles which must enter should be subject at the site entrance to spray disinfection of wheels and wheel arches. All visitors should observe standard operating procedures on vehicle cleansing and disinfection, and protective, farm only clothing should be provided to and used by drivers.
All visitors should enter on foot. Use regularly refilled foot dips, charged with a suitable disinfectant (e.g. DuPont’s Hyperox® or Virkon® S).
All site visitors should be provided with adequate protective clothing, and should wash their hands prior to visiting birds. Use an effective hand hygiene system which is equally effective even when there is no available water supply (DuPont Antibacterial Hand Soap™ and Instant Hand Sanitizer™). A shower in, shower out facility should also be put in place wherever possible.
The birds themselves can also be a cause of disease spread. Incoming poultry should therefore be from high health status sources, and there should be a well defined health monitoring and audit procedure for breeder supply flocks. This should extend to hatchery hygiene procedures with regular microbiological monitoring. Avoid the potential spread of infection from diseased carcasses by on-site incineration.
Effective cleaning and disinfection reduces pathogen numbers and the weight of disease challenge, and enhances any biosecurity programme. It can only be achieved with sufficient turnaround/down time to allow removal of all litter, and to satisfy required contact times for the disinfection products used prior to restocking. Cleaning and disinfection should include houses, equipment and surroundings.
Use potable drinking water with a low total viable count. Maintain a closed water system with lids on all header tanks. At turnaround, clean and disinfect the water system with a suitable product (e.g. DuPont Virkon® S) to remove the greasy biofilm that will harbour and protect pathogens.
Treat feed bins and feed delivery systems. Feed delivered to the site must be of high health status and vermin protected. Finished feed and stored raw materials should be sampled regularly for salmonella. "High risk" raw materials or sources should not be used.
Check biosecurity procedures regularly. Use only biosecurity products with independently proven broad spectrum efficacy against viral and bacterial pathogens, and use them according to manufacturers' instructions. Maintain an effective, audited rodent and wild bird control programme, and prevent entry of poultry houses by vermin through good house design and repair.
Properly implemented biosecurity measures will limit the spread of disease-causing organisms.
When these are combined with cleaning and disinfection, vaccination and strategic treatments, many pathogens can be reduced to non-infectious levels.
Remember - different infectious agents spread by different methods, so use appropriate measures against each type.
Site location and design, and density of poultry in a given geographical area, are vital. When planning a new site, there is the opportunity for very effective biosecurity to be implemented at the design stage. However, biosecurity practices must concern themselves with practicalities, rather than a theoretically ideal set-up.
All sites have traffic - personnel, feed, stock, and equipment - but this should be kept to an absolute minimum.
Only essential vehicles should have access to a site, and these should be disinfected on arrival.
Use protective, farm only, clothing to prevent pathogen spread.
Priority should be given to biosecurity measures on breeding sites since errors here are magnified greatly at the commercial level.
Similar priority should be given at the hatchery level.
Site decontamination, turnaround times and a well-audited and structured cleansing and disinfection procedure should be in place for all sites.
Effective vermin control must be maintained.
Only disinfectants with independently proven broad spectrum efficacy against viral and bacterial pathogens should be used and at manufacturers' stated dilutions and directions.
In emergency disease control situations, it is appropriate to consider all restrictions which may be imposed by the country specific governmental agricultural department.
The specified uses and registered claims for Virkon® S, Hyperox®, DuPont Antibacterial Hand Soap™ and Instant Hand Sanitizer™ may vary from country to country. Please contact DuPont Animal Health Solutions directly to verify country specific approved usages.