Advanced Search | Help
22 February 2012
The Ministry of Agriculture and Forestry believes biosecurity control measures and lack of a pathway will prevent a new virus diagnosed in European livestock spreading to New Zealand.
Schmallenberg virus, which has just been identified for the first time in four European countries, affects ruminants with symptoms including fever, reduced milk production in dairy cows, birth abnormalities and abortions.
“New diseases like this emerge occasionally and MAF is part of an international system for monitoring such biosecurity events,” says MAF’s Director of Animal and Animal Products Standards Mat Stone.
He says Schmallenberg is very closely related to Akabane virus – which most New Zealand farmers would never have heard of but occurs through Australia and Asia.
MAF already has measures in place to prevent entry of Akabane-type viruses.
Mr Stone says following an initial rapid evaluation of the risks, MAF has determined that the risk of Schmallenberg occurring in New Zealand is at this point negligible or very low, and managed through measures currently in place.
“Specifically, the risks associated with spreading the risk through semen are negligible and the risks associated with embryos are very low. Animal product imports are also considered to present a negligible risk. There have been no imports from Europe of live animals of susceptible species in recent years.”
MAF has identified there have been importations of bovine embryos from the Netherlands in the past two years and has contacted the importer to share information on Schmallenberg virus and its signs, to ensure heightened vigilance. The importer has advised MAF that they have not observed suspect disease in recipient cows or resulting progeny. There have been no imports of sheep or goat embryos in recent years.
It is important to note that Schmallenberg-type viruses, such as Akabane virus, are typically transmitted by insect vectors called Culicoides midges that are not present in New Zealand, says Mat Stone. “So, while importing live animals and embryos presents a theoretical risk of a case arising in New Zealand, the likelihood of any onward transmission is negligible.
“Also, MAF maintains ongoing controls on aircraft and ship arrivals to manage the risk of insects arriving and establishing in New Zealand. MAF also operates surveillance and response mechanisms for early detection of any new pests or diseases.”
Significantly, the Schmallenberg symptoms now being reported in Europe relate to infection that took place some months ago, during the European summer and autumn, which is the time of greatest insect vector activity and when cows and sheep are pregnant.
Mr Stone says MAF will continue to closely monitor information on the virus from scientific agencies in Europe and is receiving and assessing regular reports as they are published.
MAF’s preparedness includes reviewing diagnostic capabilities and communications through a network of MAF specialist staff.
European agencies have assessed that Schmallenberg presents no risk to human health.
What to watch out for – The disease syndrome cause by Schmallenberg virus is very similar to that caused by Akabane virus – including fever in ruminants and an associated drop in milk production in dairy cows, and birth abnormalities and abortions if pregnant animals are infected – depending on the timing of infection relative to stage of pregnancy.
Any farmer who experiences abortion storms or outbreaks of birth defects in their herds of cows or flocks of sheep should work with their veterinarian to investigate the cause, which might be infectious or toxicological. Veterinarians report cases to MAF for further investigation if the syndrome is one not normally seen in New Zealand.
Disease emergence – Europe’s farmers and veterinarians initially investigated fevers and milk production drops in dairy cattle in the late summer and autumn last Northern Hemisphere spring. No diagnosis was able to be made, despite all the important exotic and endemic diseases being tested for. As the lambing and calving seasons begun, abnormalities in lambs and calves were detected and intensively investigated, during which the new virus was found and described.
With heightened vigilance and surveillance across Europe other countries (now including Germany, Netherlands, Belgium and England) have found evidence of the virus and the disease it causes. Information has been shared internationally by scientists using specific networks and the general media.
Formal risk assessments addressing the risk to human health (considered unlikely) and animal production have been completed and shared internationally, and updated as new information emerges from the intensive scientific effort.