ASF Control

ASF Control

  • Biosecurity
  • Diagnostic Technology
  • Prevention
  • Restocking
  • Vaccine

General precautions from OIE for commercial farmers:

  • Declare any suspicious case (dead or alive) to the Veterinary Services
  • Ensure that all your workers and visitors are aware of biosecurity rules
  • Clean and disinfect material and equipment coming in or out
  • Prevent direct or indirect contact with wild boar. Implement quarantine measures for new pigs on farm
  • Do not feed untreated swill or kitchen scraps containing meat to your pigs

Clean and disinfect material and equipment coming in or out:
Cleaning and Disinfection
Goal: Prevent the Introduction of ASFV on Hard Surfaces

  1. Identify Line of Separation
  2. Mechanically remove all solid waste
  3. Apply appropriate detergent
  4. Wait appropriate amount of time for detergent to work
  5. Pressure wash the area with water. Use hot water where available.
  6. Audit area for cleanliness
  7. Apply appropriate disinfectant
  8. Allow disinfectant to dry
  9. If available, heat surface

SBC Biotech: The solution of ASFV detection on hard surface.

Water Disinfection
Goal: Prevent the Introduction of ASFV via Drinking Water

  1. Identify Source of Drinking Water
    • If surface water, consider converting to deep well
    • Take water sample from source and at end of drinker line
  2. Install filters to collect large particles and minerals if needed
  3. Clean water lines regularly to minimize biology growth with an EPA-registered disinfectant
    • After every turn
  4. Install Water Disinfection System
  5. Determine appropriate disinfection levels
    • 3-5 ppm ClO2 is recommended at the end of the waterlines. Adjustments will be necessary based on ClO2 levels.
  6. Determine appropriate acidification levels based on water treatment program
    • A 2:1 ClO2 to acid ratio is recommended; however, adjustments may be required to reach optimal levels.
  7. Continuously evaluate chemistry levels
    • ClO2 test strips will provide an easy and economic solution to evaluate water treatment chemical concentrations. Weekly to Monthly evaluations will be important to ensure adequate water palatability, volume and quality.

SBC Biotech: The solution of ASFV detection in drinking water.

Pest Control
Goal: Minimize pest populations to prevent the introduction of ASFV via vector introduction

  1. Identify level of infestation with an infrared surveillance system and/or performing a manual audit
  2. Maintain a minimum of 3 foot gravel barrier around all buildings
    Mow and maintain weeds, grass and brush to help control rats, mice, and ticks from having easy access to facilities
  3. Continuously apply rodenticides and insecticides inside and outside of barns
  4. Maintain continuous rotation programs to prevent resistance to active ingredients
  5. Evaluate effectiveness by performing monthly manual audits and conducting an infrared surveillance annually

SBC Biotech: The solution of ASFV detection in feed.

The Human Element

Goal: Prevent the Introduction of ASFV via human movement
Develop a visitor control plan

  1. Ensure only invited visitors and employees have access to the premise
  2. Ensure all visitors utilize disposable boots, gloves, and coveralls prior to entering the facility
  3. Provide farm-specific attire to all visitors and employees who may have access to pigs
  4. Require all visitors and employees to follow the following programs where applicable:
    • Shower-in/Shower-out
    • Vehicle disinfection
    • Boot bath disinfection
    • Supply and equipment disinfection
    • Any other farm-specific biosecurity protocols
  5. Require that no personal items are brought into the facility
  6. Perform regular evaluations and trainings to ensure all employees are aware of the biosecurity protocols on site

SBC Biotech: The solution of ASFV detection on trucks, boots and tools.

Laboratory diagnosis of ASF

Detection of ASF Virus
ASFV genome detection by polymerase chain reaction (PCR)
PCR is used to detect the ASFV genome in porcine samples and ticks. Small fragments of viral DNA are amplified by PCR to detectable quantities. All validated PCR tests allow viral DNA detection even before the appearance of clinical signs. PCR enables the diagnosis of ASF to be made within hours of sample arrival to the laboratory. PCR provides a sensitive, specific, and rapid alternative to virus isolation for the detection of ASFV. PCR provides higher sensitivity and specificity than alternative methods for antigen detection, such as the antigen enzyme-linked immunosorbent assay (ELISA) and the direct fluorescent antibody test (FAT). However, the extreme sensitivity of the PCR makes it susceptible to cross-contamination, and proper precautionary measures should be taken to minimize and control this risk.

Conventional and real-time PCRs recommended by the OIE in the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (2016) have been fully validated over time and are useful tools for routine diagnosis of the disease. Primer sets and probes used in these molecular techniques are repeatedly designed within the VP72 coding region, a well-characterized and highly conserved region of the ASFV genome. A wide range of isolates belonging to all the 22 known p72 virus genotypes can be detected with these PCR assays, even in inactivated or degraded samples.

Types of biological sample
a.Whole blood
b.Sera
c.Organs and tissue samples
d.Soft tick sample
e.Oral fluid
f.Swab

Prevention
The risk of introducing ASFV (or any other pathogen) is reduced by adopting good biosecurity practices, not just on the farm, but at every step of the supply chain, e.g. at live-animal markets, slaughter sites, while transporting the animals, etc. Special attention should be paid to small commercial and backyard operations, which are characterized by low biosecurity standards, and to live-animal markets, which bring together animals from many sources. Both are key in the spread of ASF, and although the same biosecurity concepts apply, specific measures and manuals have been specifically developed for them.

  • Swill feeding
  • Containment of pigs
  • Cleaning and disinfection
  • Other biosecurity measures

African swine fever is different from most other transboundary animal diseases (TADs) in that no vaccines or drugs are available to prevent or treat it. Therefore it is particularly important that ASF-free areas are maintained as such. Preventing the entry of ASFV into both domestic and wild suid populations, and controlling and eradicating the disease as soon as it is detected, are the best ways of minimizing its impact. There are, however, also successful examples of ASF eradication, e.g. Brazil, Portugal, Spain or Côte d’Ivoire.

Once the disease is deemed to have been contained, the rehabilitation of the farm or
region to its pre-outbreak production is the final step in ASF control. Following a massive outbreak, some owners may not wish to restock or continue animal breeding. But the majority will wish to return to their traditional way of life and will have to restock.

Before any restocking, farms must be free of the pathogen. This can be achieved through cleansing and disinfection, often carried out twice. In addition, it is advisable to improve farm biosecurity before restocking. Following cleaning and disinfection, empty premises should not be restocked for 40 days at least, but the period will depend on the prevailing situation and should be risk-based rather than arbitrary. If sentinel pigs are introduced, which is highly recommended, animals should be monitored to detect possible reinfections. If there is no evidence of infection after 40 days, the sentinels may be used as part of the restocking programme.

Pigs for restocking should, if possible, be bought locally or in neighbouring areas. Such animals are adapted to local conditions and they are usually those animals that farmers know best. Buying from several sources means purchasing animals that have different health and immune status. Mixing them together under stress can lead to cross-infection.

SBC Biotech: The solution of ASFV detection for sentinel pigs.

Cleaning and disinfection
Tick control
Wildlife control
Zoning and compartmentalization

  • ASFV is currently spreading across Russia, Europe and Asia.
  • No effective and safe vaccine against ASFV is currently available.
  • Advances in subunit and live attenuated vaccines are reviewed.