No link to NZ cattle in BSE scare, expert says Sunday, Aug 10, 2003
One of New Zealand's recognised authorities on mad cow disease believes New Zealand will keep its international reputation intact for having BSE-free cattle.
That is despite the concern generated over what might be this country's first human case of a disorder linked to mad cow disease.
Doctors say it is possible a young Waikato farm worker may have the type of Creutzfeldt Jakob Disease - variant CJD, or vCJD - that has been linked to BSE in the UK where the disease first appeared.
Although Creutzfeldt Jakob Disease kills several people a year in New Zealand, it would be the first case of the BSE-related variant seen here.
That has raised fears that New Zealand's BSE-free status would be thrown into doubt, harming its meat export trade.
But Stuart MacDiarmid, a Food Safety Authority vet who is recognised as one of the international authorities on BSE, says there is no logical way the disease could be linked to New Zealand's cattle herd.
"If it is confirmed to be a Variant Creutzfeldt Jakob Disease, it reflects a situation of exposure that happened at least 12 years ago, possibly even longer than that.
"It's in no way a reflection on the current BSE status of New Zealand cattle. Any case of vCJD in New Zealand that is not in somebody who lived in the UK, it will be in somebody who was exposed to food made in the UK, food containing certain tissues that come from infected cattle.
"Not beef - beef, you and I think of that as being meat as recognisable as such. The villain by which people were exposed in the UK to BSE is a product called 'mechanically recovered meat', which is recovered by a machine from the vertebral column of the carcass and it contains quite a high proportion of central nervous tissue - spinal cord - and it is the spinal cord where the BSE infectivity is found.
"Really the only rational explanation for this person's exposure is in certain meat products imported from the United Kingdom," Dr MacDiarmid says.
Those products have been banned since 1996, when the possible link between Creutzfeldt Jakob Disease and BSE was established.
New Zealand has been testing cattle showing any signs of neurological disease since 1990 and currently tests more than 2000 cattle and 3000 sheep a year, well above international requirements, he says.
And Dr MacDiarmid says there would be no point in testing all cattle processed at meat plants, as the European Union and Japan are now doing.
"Even in Europe they recognise that it is actually illogical and a waste of money to test all slaughter animals.
"BSE occurs in animals that are four-and-a-half to five years of age and unfortunately the test will only work in animals that are within a few months of showing clinical disease.
"While an animal with BSE is infected and infective from about weaning, the test will only work just towards the end of the course of the disease. Now in this country we slaughter our cattle for eating at 18 months to two years of age. So even animals that had BSE would not be positive to the test. So the test in clinically normal animals is a waste of money."
Dr MacDiarmid says cattle become infected with BSE through meat and bone meal, which is commonly used as stock feed in Europe.
Contaminated imported bone meal is thought to be the source of BSE cases in Japan and Canada.
But New Zealand has not imported bone meal for many decades and feeding meat and bone meat containing ruminant protein to ruminant animals is also banned here.
Nevertheless, Dr MacDiarmid is urging all farmers to be vigilant in reporting any suspected neurological illnesses in stock to vets.
Meanwhile, Meat New Zealand says the possibility that New Zealand has a case of vCJD could be damaging to exports and it will be working to limit the fall-out in international markets.
Chairman Jeff Grant says a food safety scare related to sheepmeat a few years ago is a good example of what can happen.
"About four years ago when there was a claim made in Germany that New Zealand sheepmeat had scrapie that gave quite a scare to the market for a short period of time, and that's the reason why Meat New Zealand, on behalf of sheep and beef farmers, always gets on the front foot on the international market about making statements."
Mr Grant says this is the sort of event that could trigger the use of the board's $52 million contingency fund to deal with the impact of food safety scares.
Meat New Zealand ring-fenced the fund from its reserves about four years ago after observing the effects of BSE in the UK and the E.Coli scare in Japan.
The policy is to use the fund to help New Zealand's export meat sales recover from the damage such scares can have on international markets, he says.
Mr Grant says the fund is untouched so far, but it could be used if tests show New Zealand does have its first case of vCJD.
"If there was a situation where New Zealand product was seen as being detrimental to consume by the consumer, yes we would have to look at it immediately in terms of what would we do, and we would do that in conjunction with the exporters and processors."
The retention of the fund for those purposes by a merged meat and wool industry organisation is subject to farmer approval in a levy vote this month, Mr Grant says.