MAF Biosecurity New Zealand announced on Friday that samples taken from horses imported directly from the United States to the Karaka quarantine facility would be retested for equine influenza due to conflicting results. The horses had tested negative prior to export in the US but positive in New Zealand.
"We have completed a second round of tests and retested the original samples, and are now certain that the initial positive result was due to contamination in the laboratory. While we are very pleased that all samples have now tested negative, it is disappointing that cross-contamination occurred," said MAF Biosecurity New Zealand's Animals Imports Team Manager, Dr Rachelle Linwood.
The horses arrived in New Zealand on March 23, and testing positive to EI five days later.
An investigation is under way to ascertain how the tests became contaminated and initial findings are expected by the end of the week. Findings from the investigation will be used to identify ways to reduce the likelihood of cross-contamination occurring in the future.
All restrictions placed on the Karaka facility have now been lifted and the horses will be cleared for release later today.
"The horses have been in a secure quarantine facility since their arrival from the United States and at no time was the New Zealand horse population at risk. Having now completed the required 14-day post-arrival quarantine, the horses can be cleared for release," Dr Linwood said.
Under import health standards horses are required to undergo 21 days quarantine before departure for New Zealand, including testing and vaccination, and a further 14 days in post-arrival quarantine in New Zealand, where they undergo further testing. Such stringent requirements are in place to ensure that horses entering New Zealand do not carry diseases like equine influenza.