African Swine Fever - Advanced Biosecurity Program
The others being Swine Vesicular Disease (SVD), Porcine epidemic diarrhoea virus (PEDv) and Foot and Mouth Disease (FMD).
ASF is extremely dangerous due to its highly contagious characteristics, ability to be easily spread via a variety of vectors, high morbidity and mortality rates, and extreme resilience to withstand high and low temperatures. Add to this the fact that there is currently no effective treatment or vaccine available, and it is easy to understand why pig producers fear this disease.
So how can the spread of this highly contagious and devastating pig disease be prevented and controlled?
Biosecurity is the only real way of stopping its spread. It will reduce the impact on affected farms and will be a key to clinical recovery and virus elimination, especially on larger farms. Producers need to achieve the highest possible levels of biosecurity, leveraged by good buy-in and compliance from management, their staff and their suppliers.
ASF is very good at ‘Hitching a ride’ so it spreads easily. A high proportion of spread will be by pig transportation, and so is the first target of biosecurity. However, there are many other means of spread. All other transport is a risk, from feed to dead-haul, to service vehicles, to manure removal. Perhaps the next biggest risk is from transmission via contact with wild boar. People can also be vectors, via their clothes, on their boots and equipment, or any inanimate objects they may bring onto the unit.
The virus may persist in uncooked meat products and swill for several months, and therefore could be transmitted via contaminated pig feed, or meat products ingested. Aerial spread has been demonstrated, but only over short distances and is unlikely to be a major factor.
ADVANCED BIOSECURITY IS THE ANSWER
For biosecurity to be effective against ASF there must be good planning, good procedures, good training and good tools.
African Swine Fever (ASF) can be considered one of the most feared epidemic diseases of pig production, the others being Swine Vesicular Disease (SVD), Porcine epidemic diarrhoea virus (PEDv) and Foot and Mouth Disease (FMD).
ASF is extremely dangerous due to its highly contagious characteristics, ability to be easily spread via a variety of vectors, high morbidity and mortality rates, and extreme resilience to withstand high and low temperatures. Add to this the fact that there is currently no effective treatment or vaccine available, and it is easy to understand why pig producers fear this disease.
One of the most important aspects of biosecurity is the understanding and use of lines of separation between clean and dirty areas. This has to happen throughout the production system, for example, between the loading chute and pig transporter, between the dirty and clean sides in a Danish entry system, or between the ground and the cab of a feed delivery vehicle. All the relevant lines of separation have to be identified and correct procedures for achieving separation established and used.
There are many other procedures that need complying with. These include such things as correct use of shower facilities, correct procedures for leaving and re-entering the farm, disinfection of equipment arriving at the farm, disinfection after risk vehicles have been near the farm, and contractor and staff behaviour during manure hauling.
In an infected farm, where bio-containment is being practised, examples of procedures are: control of staff movement around the farm, cleaning and disinfection of walkways after pig movement, correct local manure removal and flushing, and high level terminal cleaning and disinfection between batches.
Buy-in and training is an integral part of any biosecurity program. This must include management, farm staff, drivers, service personnel and visitors. They need to understand why biosecurity against ASF is important, that it is still important, and how easily the virus spreads so they can understand what they need to do.
Biosecurity coordinators must make it a prime task to train, review and retrain as needed. One challenge is high staff turnover and the need to keep up to date. Compliance is everything, and failure to comply will lead to a biosecurity breach sooner or later.
With vehicles being the number one vector through which ASF is spread, providing well equipped vehicle cleaning and disinfection areas is essential. Good vehicle washes must allow manure removal, provide good cleaning and subsequent disinfection, and vitally prevent cross contamination. The provision of drying and heating for trucks after cleaning and disinfection is an advantage, but does not replace it.
Other examples of good biosecurity tools are disinfectant arc sprays made available on approach to farms, external washes to disinfect where trucks have been, remote dead pig collection, and good entry facilities such as showers or a Danish entry system.
Some of the most important tools for effective biosecurity are the Biosolve™ heavy-duty detergents and Virkon™ disinfectants for use in the advanced biosecurity cleaning and disinfection program.
Washing with water alone reduces contamination by up-to 60%, but using a heavy-duty detergent decreases the original organic burden by 99%. Therefore, thorough washing of all surfaces and equipment with Biosolve™ PLUS heavy-duty detergent is essential to achieve the best results from any subsequent disinfection procedure.
The choice of disinfectant is vital. It needs to be active against ASF but also have a broad spectrum of activity against other pig pathogens because we still need to control them. Virkon™ S and Virkon™ LSP have an independently tested broad spectrum of activity.
The efficacy testing for Virkon™ S and Virkon™ LSP was undertaken by the Centre for Animal Health Research (CISA) Spain, 2019, in accordance with EN 14675 (modified to enable testing against ASFv).
| Disinfectant | Virus | Test Method | Dilution Rate | Contact Time (minutes) |
| Virkon™ S |
ASFv | EN 14675 (modified) |
1:500 1:400 |
5 10 |
The test method employed included the presence of high organic soiling, hard water and was conducted at low temperature (10ºC), at short contact times, to simulate real world ‘on-farm’ conditions.
Unlike some other disinfectant chemistries, such as Glutaraldehyde and GLUT/QAC mixes, Virkon™ S and Virkon™ LSP maintains efficacy against the ASF virus in cold farm conditions. In addition, adding liquid Propylene Glycol to Virkon™ S solutions may reduce its freezing point to -10˚C, without affecting efficacy, providing farmers with the reassurance that the disinfectant solution they’re using will remain in solution during freezing winter conditions.
The outstanding scientifically formulated properties of Virkon™ S make it the disinfectant of choice in an ASF advanced biosecurity program at all levels from the farrowing house, transport and through to the slaughter plant.
The loading bay and ramp of a pig production unit can pose a major biosecurity risk for the introduction and spread of highly contagious diseases such as ASF and PRRS. Therefore, proper execution of biosecurity best practice procedures must be adhered to each and every time pigs are collected or delivered to farm.
Ensure all swine transportation vehicles delivering or collecting pigs stay outside the perimeter of the farm site and are directed to the pig loading bay area.
The pig loading bay should be located on the perimeter of the production site, positioned as far away as possible from the main entrance and staff car park, with its own dedicated access road.
It should be constructed from concrete, well lit, with a dedicated water supply, pressure washer and a drainage system that takes and stores water and slurry away from the farm.
All transport vehicles collecting pigs must have been thoroughly cleaned and disinfected prior to arrival at site. Any vehicles that have not must be rejected and asked to leave the production site immediately.
The driver of the pig transporter must change into clean coveralls and boots upon arrival at the loading bay and use Virkon™ S disinfectant bootdips immediately when leaving the cab of their vehicle.
The lines of separation between the “dirty” and “clean” areas of the loading bay should be clearly separated using gates to denote the outer perimeter of the farm site.
Display “KEEP OUT” biosecurity signs at this entrance point and keep the gates locked when the loading bay is not in use.
The driver must not be allowed to cross from the “dirty” to the “clean” side through the loading bay gates onto the farm site. Any farm staff members that cross from the “dirty” to the “clean” side, or have to enter the transporter trailer for any reason must not re-enter the farm site until they have showered and changed their clothing and disinfected their boots.
The loading bay and ramp must be dry cleaned, washed and disinfected after each delivery and collection of pigs using a Biosolve™ heavy-duty detergent and then Virkon™ S disinfectant solution.
