Prevention

Farm hygiene

NARRATOR: Farm hygiene is important in all aquaculture operations and should be a part of normal farming procedures. Good farm hygiene can prevent the accidental introduction of pathogens onto the farm. Staff and visitors constantly move around the farm and thus have the potential to introduce and spread disease.

Staff should avoid visiting other farms and other places where disease might be picked up. Similarly, equipment should not be shared between farms.

COLIN JOHNSTON, Aquatic Animal Health, Primary Industry and Resources, South Australia: There are five basic areas of farm-level hygiene that you need to consider when you’re trying to prevent disease entry or movement in a farm. They’re very simple. First of all, there’s movement of stock onto or off your farm, or within it. Then you’ve got to consider your water supply; where it’s coming from, how it’s treated. Then there’s movement of people. People can spread disease unknowingly on wet hands or dirty hands or protective clothing. The forth one would be the equipment. How do you disinfect your equipment between areas on your farm or between farms? Finally, potentially there’s an issue of feed. That’s not so important, because generally a lot of feed is now manufactured, but it is worth considering.

GRAHAM MARTIN, Saltas Pty Ltd: There’s a few things we do. We limit vehicles coming onto site. The staff that come onto site change their clothing—street gear is dropped off and they change into work gear. That work gear doesn’t leave the site. We actually have laundry facilities on sight so they can keep it clean. We have foot baths in the critical areas of the farm, so people walking into and out of those areas walk through those footbaths, they don’t carry anything with them.

Footbaths

NARRATOR: The use of footbaths at the entrance to hatcheries and other buildings is not only good practice, but it can help to instil a culture of health management and disease control. It must be borne in mind that organic matter reduces the effectiveness of most disinfectants and the material to be disinfected, including protective clothing, must be clean prior to disinfecting. Established cleaning routines should be in place and monitored, including those following depopulation and deep terminal cleaning. Appropriate storage of equipment and protective clothing must also be provided.

Some thought should also be given to the choice of sanitisers and disinfectants to ensure that they are appropriate for the job. These chemicals should also be stored and accounted for, to prevent any possible contamination.

‘On farm’ outbreaks should be handled by the separation of equipment between production units. For example, don’t use nets or equipment from other ponds, unless they have been thoroughly cleaned and sun dried after previous use.

KEVIN ELLARD, Primary Industries, Water and Environment, Tasmania: We have to show famers that we are doing the right thing—that we are using equipment that can be cleaned down readily, that we are cleaning all our gear before we move between farms. Within regions, we duplicate equipment so that we’re not carting gear. On the farms, for the same reasons, farmers, when they’re moving equipment between farms and between regions especially, need to be vigilante. As I say, we have a number of diseases that are restricted to regions within Tasmania and if we don’t do things appropriately, there is the risk that we will transfer those diseases elsewhere.

NARRATOR: Provision of hand washing facilities and alcohol hand sprays should also be considered to stop contamination of facilities via dirty hands. Each farm needs to have its own specific farm level health plan, including contacts and what to do if there is a disease outbreak.

EVA-MARIA BERNOTH, Aquatic Animal Health, Office of the Chief Veterinary Officer: One of the important things about contingency plans and early intervention in the disease outbreak is that it only works if you know the day to day normal situation. That’s really critical, because you can only detect that something’s wrong if you know perfectly well what is normal. So it’s very important that farmers do their daily checks and walk round the farm and look at the fish and look at what the water looks like, look at the blooms, for instance, in prawn ponds. They have to get a feeling for what is normal, and only then will they be able to tell at first glance that something’s wrong. There is no short cut to that and to a certain extent I guess you’ve got to be a bit pedantic about this and people don’t like that, again it’s human nature, but it pays off in the end. Because only if you know the normal are you going to be able to detect any deviation from the normal very, very quickly and then you can step in early and minimise the damage.

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