The number of farms affected by the infectious cattle disease bluetongue has risen to 1,000, product safety board NVWA has said.

It is the first time in 14 years farmers have been faced with an outbreak of the virus, which affects mostly sheep but can also appear in goats and cows and is transmitted by biting midges.

Symptoms of the disease include high fever, lameness, swelling of the lips and red to purplye mucous membranes of the mouth and tongue. In many cases the animals don’t survive. The virus is not dangerous to people.

The rapid spread is worrying, the NVWA said. Last month just four farms in Utrecht and Noord-Holland reported an outbreak. Last week 319 locations were added to the list and since then the number of affected farms has jumped to 1,000 and counting.

Most of the farms are located in the central and northwest provinces but a farm on the Wadden Island of Texel where sheep farming is an important pillar of the local economy has now also reported the virus.

The island has around 15,000 sheep, almost as many as it has people. “We are living in fear,” sheep farmer Koos Tjepkema told local media.

The warmer weather is keeping midges active for longer so farmers are advised to keep sheep inside and to use insect repellent but, caretaker agriculture minister Piet Adema has said in a briefing to MPs, there is little that can be done to stop the spread and that sheep stocks will be reduced.

The virus is of serotype 3, which is primarily known in South Africa. “We have no idea how it came here, perhaps via an infected animals or midges in a plane of car. We’ll probably never know,”Melle Holwerda of the Wageningen lab for vector transmittable and viral animal disease told the NRC.

Researchers are currently testing the safety of a new South African vaccine against the disease but more must be done, Holwerda said. Pharmaceutical companies should put resources into finding a vaccine but, he said, that could take at least a year.