P74680 Biosecurity and Pathogen Control for Pig Farms. Updated Edition: Special Emphasis on African

BIOSECURITY AND PATHOGEN CONTROL FOR PIG FARMS UPDATED EDITION: SPECIAL EMPHASIS ON AFRICAN SWINE FEVER

Figure 14. Transmission routes of African swine fever virus to domestic pigs.

Warthogs are naturally resistant to the virus and usually they do not develop the disease.

Facilitated by human activity

Domestic pigs are exposed through contact with infected pigs from other farms and wild boars, and it is also facilitated by human activities.

Wild boars, in which ASFV has become endemic.

The AFSV can be spread through contact with infected animals, body fluids or carcasses

Bites by infectious soft-bodies ticks

Contact with objects contaminated by the virus such as footwear, clothing and transport vehicle

Ingestion of contaminated meat or meat products

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2 Main pathogens of pigs

In farms outside Africa, the domestic pig can be infected in several ways including:

• Contact with infected pigs: Contagious pigs may enter the pig farm looking for food or sex, or they can be purchased from affected areas.

• Ingestion of meat or meat products including kitchen waste and inadequately treated swill. They can also be infected by drinking water contaminated by a pig corpse.

• Contact with contaminated materials, for example, footwear, clothing, vehicles and other equipments.

• Movement of dead animals from adjacent infected farms including dogs, cats, rodent and flies.

• Pigs being fed on food contaminated by body fluids from infected pigs.

• Contact with hands contaminated by the virus from handling infected meat and products. Particularly note people who have hunted pigs.

In farms in Africa, among the potential hazards mentioned above, pigs may also be infected by contact with the native Suidae.

Figure 15. Clinical signs of African swine fever.

Blood clots and necrotic areas under the skin

Weakness and reluctance to stand

Vomiting and diarrhoea often with blood

Red or dark colored skin around the ears or snout

High fever Coughing or breathing difficulties

Abortions High mortalities rates.

Death within 6-13 days

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BIOSECURITY AND PATHOGEN CONTROL FOR PIG FARMS UPDATED EDITION: SPECIAL EMPHASIS ON AFRICAN SWINE FEVER

THREE ZONE FARMING The major function of farm biosecurity is to implement a set of measures to protect the farm from the entry and spread of pathogens. It is therefore vital for all the members of the farm health team to be concerned about how easy it is for a pathogen to enter the unit, and they must adhere to all the biosecurity measures. They must also ensure that visitors, who may not be concerned about this issue, adhere to the rules too.

In order to reduce the risk of spreading pathogens, for example AFSV, by direct or indirect contact, it is necessary to create a ‘gap’ between the farm and the outside world. The three zone concept eliminates the need for specific truck wash facilities.

Figure 1. Major entry points of pathogens on a farm.

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1. On-farm

6. Loading area 1

10. Grey zone truck

2. Grey-zone

7. Inner perimeter fence

11. Grey zone feed bins

8. Outer perimeter fence

12. Loading area 2

9. Low cropped area

14. Office

3. Off-farm 4. On-farm feed bins 5. Isolation area

13. Shower block

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3 How do pathogens get into your farm?

THREE ZONE CONCEPT: • Off-farm: It is impossible to guarantee that trucks are

completely clean materials. Pigs need to be transported over the grey zone. A minimum of 20 metres wide is suggested.

• Grey zone: Vehicles in the grey zone do not leave this area and they do not enter the on-farm zone.

• On-farm: Vehicles from off-farm never enter the on-farm zone.

All the items that need to be introduced onto the farm, they must go through a disinfection zone, e.g. an ozone room. There must be one shower block for each perimeter fence. A tool disinfection area is also required.

Figure 2. Movement of pathogens into and out of the pig. The arrows indicate the direction in which organisms can enter and leave a pig.

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1. Injection 2. Dander 3. Skin 4. Piglet 5. Tail 6. Genital tract

11 7. Faeces 8. Urine 9. Semen (male) 10. Coronary band 11. Umbilicus (piglet)

12. Teeth 13. Mouth 14. Aerosol 15. Nose 16. Eyes 17. Ears

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BIOSECURITY AND PATHOGEN CONTROL FOR PIG FARMS UPDATED EDITION: SPECIAL EMPHASIS ON AFRICAN SWINE FEVER

CLEANING PROTOCOLS • Ensure pressure washing is carried out adequately. Pay particular attention to the removal of all faecal material. Remove dust by vacuuming where possible. Repair all large cracks and holes in concrete. All wooden partitions and removable objects should be soaked in disinfectant for a period of 3 to 5 days using metal baths. Place outside in sunlight to dry. Drain and clean the slurry channels and pits. Ideally, lime wash all surfaces especially up to 2 metres in height and spray with a disinfectant using a knapsack sprayer into the ceiling and loft areas.

Cleaning protocols when the farm is empty • Midden area: spread all the midden materials, lagoons and slurry store. The soil within the proximity of the midden area has faeces still remaining from the old unit. Skim off this area to a depth of 80 cm. Spray the soil with a suitable disinfectant and then place the 80 cm of excavated soil back.

• Straw and other bedding: old straw remaining from the old unit should be moved and disposed off as this can harbour mice/rats from the old unit. Burn all straw and used bedding.

New stock introduction and biosecurity protocols The new stock requires isolation procedures. Note biosecurity requirements: these obviously vary depending on the health of the incoming stock.

■ Gilts are bred only over a 7-day period (Friday to Thursday for example). It is essential to get the batches together.

The batches of gilts mated in the hatched weeks are mated on the clean farm.

Organise gilts using altrenogest and possibly also use chorionic gonadotropin on the expected day of mating.

■ Week of an event.

The slaughter weight is assumed to be at 22 weeks of age.

Weaners are at max. 28 days of age.

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Last 30 kg born

Last finishers enter grow-finish

Start rodent control programme and prepare for the refurbishment and cleaning of the farm

Sell all 30 kg pigs

Sell 7 kg Sell weaners

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Sell 30 kg weaners

1st gilt breeding

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Farrow last group of sows

Sell sows at weaning from now on

Breed last sows

Sell sows at weaning from now on

Farrow last group of sows

Gilt preparation 9 weeks

Last finishers are born

Farm emptied of all stock

Or if a weaner market:

Breed last sows

Depopulation and repopulation farm

Breeding replacement farm

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Fumigate

Clean farm

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DEPOPULATION AND REPOPULATION CALENDAR OF EVENTS: 7-DAY BATCHES 4

Clean replacement

Gilts arrive

1 Farrow

1 1

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5 Elimination of pathogens from farms

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BIOSECURITY AND PATHOGEN CONTROL FOR PIG FARMS UPDATED EDITION: SPECIAL EMPHASIS ON AFRICAN SWINE FEVER

AFRICAN SWINE FEVER OUTBREAK SLAUGHTERHOUSE CLEANING-UP; DEPOPULATION AND REPOPULATION PROTOCOL The farm must follow local government guidelines.

ASF suspicion on the farm (clinical signs: sick pigs presenting high fever and red skin)

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Check the presence of ASFV using a swab from the mouth or nose.

Blood collection methods, when necessary: • Blood swabs from cut pig ears. After the collection procedure, flame the ears.

• Collecting blood from a spleen sample may be considered as an alternative option.

Prevent virus from massive spreading.

Carcases should not be opened up.

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Place carcases into plastic bags ensuring that the head and the anus are covered.

Disinfect blood spills, urine or faeces.

Wash carcases with soap and water.

Cover carcases with lime.

Store carcases in sealed containers.

Note: This depends on the total number of dead pigs.

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Eliminate all abortion and afterbirth materials from pig breeding farms.

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Report AFS suspicions to the government authorities.

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Do not allow animal movements around the farm.

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Collect saliva samples for PCR confirmation from pigs presenting high fever.

Use infrared technology to identify suspicious animals.

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Abort all veterinary investigations and post-mortem examinations.

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Interrupt all treatments on the unit using needles and syringes.

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Postpone teeth clipping, tail docking, tagging, tattooing and castration on the unit.

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Abort all procedures where blood loss can occur.

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Unauthorized visitors must not enter onto the unit.

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Staff must not leave the farm without taking a complete shower.

Clothing or foot wear must not leave the farm.

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All vehicles and trucks must be cleaned and disinfected before leaving the farm or as soon as possible (immediately).

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5 Elimination of pathogens from farms

ASF suspicion on the farm (clinical signs: sick pigs presenting high fever and red skin) 14

Install video surveillance to ensure that the rules are followed.

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Staff must not visit other pig units, This is imperative

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Staff must not enter the head office without authorisation.

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Dogs and cats must not leave the farm (if present).

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Implement effective rodent control strategies.

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Investigate potential sources of outbreaks.

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Keep all farm clothing at 70 ºC overnight.

African swine fever confirmed 1

Euthanise all pigs present on the farm. Bloodless lethal injection.

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Do not transport any post-mortems.

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Staff must not leave the farm without taking a complete shower.

Clothing and foot wear must stay on the farm.

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Staff must remain in the farm during the stamping out and the cleaning up procedures.

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Entrance should be prohibited to visitors.

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Staff staying in the area should wear disposable clothing and new footwear.

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Follow government guidelines for animal disposal.

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Place all food into a bag and burnt it on a specific site.

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Burn all bedding material on a specific site.

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Burn all clothing and office material on site.

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Dispose all the medicines, needles and syringes by burning them in a concrete burial liner.

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Burn all the wooden materials on site.

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Burn all dead rodents.

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Bury all unburned materials at a depth of at least two metres.

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Place all the indispensable equipment into a sealable room.

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Staffs who are not involved in the cleaning-up procedure must take a complete shower and leave the farm.

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Remove all dogs, cats and other pet animals from the security perimeter.

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Burn all dead animals (open stomach first).

Implement protocols for dealing with disposal pits. Pit must be near the farm. 2 kg/m2 of lime on the top is needed.

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Fence all areas used to burn or bury dead animals.

Avoid blood spills.

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BIOSECURITY AND PATHOGEN CONTROL FOR PIG FARMS UPDATED EDITION: SPECIAL EMPHASIS ON AFRICAN SWINE FEVER

Clean-up procedures Staff Staff must remain in the farm until the cleaning-up procedure is completed.

Staff must follow the regular rules, i.e. no pigs at home, etc.

Perimeter Ensure farm has a perimeter security system.

No pig and pork products allowed onto the farm.

Use lime on all walkways, driveways and around farm.

Rodents Implement efficient rodent control strategies.

Cleaning Ensure that the regular cleaning-up procedures are effective, starting from top to bottom. Note: this includes all rooms and passageways.

Remove all the animals and all feed from the farm.

Brush the surface to remove major faeces.

Seal all electrical equipment.

Use detergent, soap and water.

Soak for at least two hours.

Ensure there is enough washing pressure, from top to bottom.

Rinse.

Disinfect with an adequate concentration and contact time.

Clean all the cleaning equipment.

Clean all clothing.

Leave the room overnight at minimum temperature of 60 °C (use a temperature logger).

Clothing Boil all clothing with soap.

Store clothing overnight at minimum temperature of 70 ºC. Wash the clothing.

Repeat the procedure.

Fumigation Use 200 ml of formaldehyde (40 %) and 90 g of potassium permanganate per each 100 m3 of building.

Application of lime wash Mix builders’ lime with water to produce limewater and cover all surfaces.

This desiccates and indicates.

Lagoon and slurry pits After ASF confirmation:

• Add lime or acid to faeces inside the building.

• pH values more than 11 or less than 4.

• Use approximately 2 kg of lime per tonne of slurry.

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5 Elimination of pathogens from farms

Clean-up procedures Remove all faeces (as much as possible) from the buildings to the lagoon.

Mix slurry in lagoon twice per week.

Spread manure on land after 30 days.

Separate staff and clean all equipment afterwards.

Store equipment overnight at 70 ºC. Clean and disinfect the manure storage facilities, including the lagoon.

Land and road around farm Add 2 metres of soil over the pit or burn the pit.

Add lime regularly over a year.

Keep dogs away from the area.

Spray lime around the farm and the road used to transport dead animals:

• Add 2 kg/m2 of lime.

• Add 10 l/m2 of water.

Veterinary examinations Repeat at least three times during the next two months (or see government programme).

Sentinel animals Obtain sentinel animals from a negative source. Check PCR and ELISA. Place six pigs weighing from 30 to 60 kg from a negative source in each room.

Allow the pigs to wander around the room (during farrowing more pigs will be needed).

Provide feed and water enough for three weeks.

Feed the pigs in different places to let them experience and investigate the entire room including passageways.

No clinical signs Collect mouth swabs from 20 pigs.

Check for ASFV by PCR.

Negative sentinel animals confirmed Nursery or finishing farm Start farming as normal.

Breeding farm Introduce gilts at the farrowing stage to reduce downtime.

See depopulation/repopulation.

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