New containment lab will enhance diagnosis of exotic animal diseases

5 May 2000

The containment lab being commissioned for the Ministry of Agriculture and Forestry's National Centre for Disease in Wallaceville will operate at a level in excess of requirements for a physical containment level 3 laboratory.

The laboratory is expected to start operation later this year once commissioning trials demonstrate that the building's biosecurity features are fully operational.

The Lab's physical biosecurity barriers, laboratory techniques and detailed operating procedures will ensure safety and microbiological security to protect both the staff and the environment.

The PC3 Lab will provide safe and reliable screening tests for animal diseases. This will reduce New Zealand's reliance on overseas laboratories for exotic disease testing and will speed up finding out whether an exotic animal disease is in the country or not.

"Sometimes New Zealand has to wait several weeks before an exotic disease is ruled in or ruled out. This time delay could have huge economic consequences in the event of a real disease outbreak," says Hugh Davies, General Manager of the National Centre for Disease Investigation.

"When porcine reproductive respiratory syndrome virus was suspected in a group of pigs in quarantine last year, it took five weeks to get confirmation of our test results from Australia, and another five weeks to get proof of their seronegative status from a lab in Holland. If the live organism were held in the new PC3 Lab this could be reduced to two weeks," he said.

"Quick diagnosis results in a smaller number of infected animals and a smaller number of infected properties to deal with, which in turn means smaller quarantine zones, increased opportunities for maintaining disease-free zones, quicker disease eradication, and decreased outbreak costs overall."

Currently, some exotic disease testing is done at MAF's low-security PC2 laboratory at Wallaceville. The new laboratory will improve the security of this type of work.

The Lab is built on accordance with Australia /New Zealand Laboratory Standards for a Physical Containment level 3 facility but it also has the additional PC level 4 biosecurity features of shower out, a double ended autoclave to heat sterilise solid waste and systems to decontaminate liquid waste. These biosecurity features are consistent with international standards for laboratories dealing with exotic animal diseases.

Hugh Davies says nothing is allowed out of the lab.

"Security is paramount. Access to the lab will be restricted and entry and exit will be through airlocks. The airlocks, corridors and laboratories are held at negative pressure with the most secure areas at the lowest pressure. Staff must strip off all their street clothing before entering the lab through an airlock. On the other side they put on specially provide clothing right down to their underwear,"

"Before leaving they must again strip and shower, leaving any possible contamination inside. No equipment, clothing or waste water can leave the building without being sterilised," he said.

The primary biosecurity and safety barriers in the new laboratory are class II biohazard cabinets, which minimises the chances of organisms escaping into the laboratory area. Secondary barriers surround these cabinets. The Lab operates at negative pressures of up to 85 pascals below atmospheric pressure. Air pumped out of the building to maintain negative pressure is carefully filtered to remove any possible infectious agents, preventing contamination of the environment.

The air handling, sterilisation and security systems will be monitored and recorded electronically. Alarms will sound and an automatic paging system will be activated if systems deviate from specifications. A full-time microbiological security officer ensures that all systems are operating to specifications and staff comply with standards operating procedures.

The Ministry plans to have internal and external audits of the facility and its operating systems by New Zealand and overseas experts.

There will also be inter-laboratory comparison programmes to ensure test accuracy and international acceptance of test results. The accredited test method regime requires the use of positive control materials (sometimes live organisms) to validate tests and ensure the tests are immediately functional when required.

These tests are expected to cover most of the agents that are of potential risk to New Zealand and those where trading partners are likely to ask MAF to prove New Zealand is free from infection.

Where possible, the tests will use killed antigens and non-infectious nucleic acid sequences. However, in some cases, the live infectious agent is required to establish and validate the test. If possible the live organisms will be vaccine strains but these are not always available.

NCDI staff are working on a detailed application to the Environmental Risk management Authority (ERMA New Zealand) for approval to import into containment a number of live unwanted organisms for this purpose.

For further information contact:

Hugh Davies, General Manager, Centre for Disease Investigation, MAF Operations. Telephone: 04 526 5600
Gita Parsot, Communications Adviser. Telephone: 04 4989 806

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