PRECAUTIONS AGAINST BLUE TONGUE

Press, Volume XCVII, Issue 28618, 21 June 1958, Page 9

PRECAUTIONS AGAINST BLUE TONGUE

At the beginning of this month Australia imposed a ban on the importation of all ruminants to protect its valuable sheep industry from the insect-carried virus disease, blue tongue. Initial New Zealand reaction to this move was one of protest against the cutting off of a valuable export market for New Zealand livestock —last year this country exported to Australia sheep valued at £126.409—but if blue tongue is a menace to Australia’s sheep industry it could conceivably be a menace to our sheep industry also, and it is gratifying to know that the authorities have this matter under close review. Mr J. E. Mcllwaine, Director of the Animal Industry Division of the Department of Agriculture, flew to Australia earlier this year after the announcement .of the proposed ban, and he said this week that he had also called for a report from the agricultural adviser attached to the office of the New Zealand High Commissioner in the United Kingdom pn the outbreak of blue tongue in Spain and Portugal, from which it had been feared that the disease might spread to Fran-be and so to the United Kingdom. This report, now in Mr McTlwaine’s hands, shows that in both countries the disease is being “quite adequately controlled." with eradication the aim. and in the light of this assurance. Mr Mcllwaine said, it would be possible for New Zealand to go on importing cattle from Britain, where there had been no case of the disease, quite safely.

Cattle can be carriers of the disease and the Australians believe that it might be introduced by carrier cattle and eventually spread to sheep flocks. Imports From U.S. Blue tongue was first recognised in the United States a little more than 10 years • ago and in the case of the few animals that had been imported from this quarter this year, Mr Mcllwaine said that the precaution had been taken of bringing them from only clean States and they had been shipped in the winter months in the Northern Hemisphere when the vector, which spread the disease, was dormant.

Even should the disease be brought in by any of these cattle, Mr Mcllwaine doubts very mudh if it would be transmitted > to sheep because he believes, on the best information available, that

no suitable vector is available in this country to transmit it. He said this week that this belief was based on advice'of the Cawthron Institute and the experience with the virus disease myxomatosis. However, the position is still being closely watched, and Mr Mcllwaine said that further precautions were under consideration relating to the importation of any further cattle from the United States ‘ until the disease in that country was under more effective control. According to information which has been received in Christchurch through the Australian Society of Breeders of British Sheep, symptoms of blue tongue include a blue colouration of the tongue and inflammation and eruption of the lining of the mouth and the skin around the nose. There is also a similar type of skin eruption around the top of the hoof. The sheep look dull and listless and show pronounced muscular weakness. They stand stiff and lame with backs arched or they may not be able to stand at all. The state of debility, persisting in some cases for weeks, interferes with feeding, and some sheep, though they resume feeding. continue to lose weight and waste away rapidly. The nutrition of the wool suffers and tufts can be pulled out or parts of the fleece may be cast. ' Deaths In Sheep Death may ensue in one to six days and animals- which have seemed to recover may subsequently collapse and die three weeks or more after the first symptom. In the sub-acute or milder form of the disease the clinical signs are not so obvious and may not be so easy to recognise. Animals may carry the infection for weeks or months after recovery and may therefore be a source of infection to other stock.

Mortality in sheep varies from 5 to 30 q>er cent, with the loss much greater as a rule in young sheep. For many years, blue tongue was regarded as being solely an African disease, but in 1943 there was an outbreak in Cyprus and •he disease in apparently a milder form was seen in Israel. It has since been reported in Turkey, the United States—in country with 10.5 m sheep, or a third of the total sheep population—and more recently in Spain and Portugal.