PRRSv – Porcine Reproductive and Respiratory Syndrome Virus

Reducing the spread around the farm

This two page photomontage intends to remind producers of the key routes of spread

Review stopping the virus entering the farm. Essential to avoid new strains of virus entering the farm system

All-in/All-out Pig Flow
Set and maintain breeding targets All-in/all-out can only happen when the farm manages batches of pigs	Cleaning programme Clean each room thoroughly. Note all-in/all-out is animals, floor, water, feed and air. Use hot water and detergents to remove organic materials	Disinfection and drying An essential control measure is the use of suitable disinfectants and then drying. Many disinfectants work against PRRSv. The picture illustrates terminal lime-washing
Reducing virus load
Gilts positive none shedding before introduction Ensure all gilts (boars) are positive to the farm strain and are ideally not shedding before entering breeding area	Feed-back programme To assist pathogen control, practice feed-back programmes using weaner faeces if possible	Tonsil scrape or serum therapy On-farm virus can be obtained from previous gilts and infected weaners. Ensure PRRSv is actually present in materials.
Colostrum intake It is essential that all piglets have access to good colostrum. Particular care is required to care for the weaker piglets	Fostering policies Avoid fostering pigs 48 hours after birth. Euthanasia of weak piglets is preferable. Piglets must not be moved between batches	Streaming programmes Weaker piglets at weaning should be moved to separate facilities – more than 150 metres from other nurseries
Barn specific equipment Reduce movement around the farm by using batch specific boots, scrapers, shovels, overalls, needles	Foot-baths Foot baths and foot washers reduce spread between batches Clean brushes and scrapers daily	Washing hands, Gloves and hand sanitizers Wash hands between batches. Consider gloves between batches
Fly control – weeds Do not have weeds growing within 2 metres of the farm buildings. Note flies can transmit PRRSv 2.5 km. Note White Nose syndrome in bats	Lagoons Do not place lagoons close (within 50 m) to pig buildings	Compost heaps Do not place compost heaps close (within 50 m) to pig buildings
Medicine control – do not share needles between batches Needles are ideal vectors to spread PRRSv between batches. Maintain different needles and syringes between batches and the streamed pigs	Staff visiting slaughterhouses Staff are no to own their own pigs After a visits to slaughterhouses or markets have a thorough shower and change of clothing and 24 away from pigs	Items from other sources Fumigate all items from outside sources. Note electrical and other maintenance contractors who work on other pig units

Measures which would need to be considered even on positive units

to reduce the spread of a new virus strain

Virus direct
One problem is that no matter how good a negative source is at testing, it still can take 2 days before the breakdown can be detected – and may take up to 3 weeks
Gilts Only purchase gilts from a negative unit. All gilts to go through a 60 day isolation period. Gilts can be homebred	Boars Only purchase boars from a negative unit. All boars to go through a 60 day isolation period	Semen – AI Ideally semen should be produced on farm. If semen is purchased ensure good vet to vet communication
Pork and other pig products PRRSv can remain viable in pork products and their juices	“wild” pigs Pigs are able to survive in many environments and “wild” pigs can move between units. Note the security fence must go 0.5 m deep	Live vaccines Use of vaccines must be under veterinary supervision. A live vaccine may bring in a new strain
Virus through the air
Location – nearby farm None of the farm facilities must be within 1.5 km of another pig farm. The photograph illustrates a fictional area with breeding, nursery and finishing farms potential local spread areas (1mile)	Isolation facilities Isolation facilities should be placed no nearer than 150 metres. Note the isolation area must not be 1.5 km from an unknown pig source. The isolation area must be run all-in/all-out	Local road Major roads, especially roads leading to slaughterhouses may be result in PRRSv positive pigs being transported close to the farm. Ideally the farm should not be within 150 metres of a major road

Virus through vectors
Loading area The truck taking animals to slaughter needs to kept away from the animal units	Trucking All trucks moving animals to the slaughterhouse must be cleaned and dried before collecting the pigs. Note trucking bring gilts and boars to the isolation area	Dead animal disposal To avoid the rendering truck having to collect dead animals, practice composting or incineration for all dead animals
Feed trucks All feed deliveries must be made to the perimeter of the farm, through the security fence	Car park Vehicles should be either on- farm or off-farm. Provide a car park	Boot security Foot-wear should be either on-farm or off-farm. Provide a clear on-farm boot area
Showering security All visitors and staff should remove outer clothing before entering the on-farm side. Note the different toweling	Fly control Biting flies can transmit PRRSv. Protect building with fly screens – 2 mm mesh. Do not have plants growing within 2 metres of the unit. Note placement of composting piles and lagoons	Virus filters MERV filters are possible (0.3µm filter), but probably only practical for AI studs. The air requirements of pigs, staff and dust from feed and environment may restrict the use of virus filers. PRRSv is 0.35µm in diameter
Apply common sense – if you are encouraged to buy second hand equipment – check the health status of the original farm and clean thoroughly following your vet’s advice