In the last few years much has been heard about outbreaks of old and new diseases in animals in may countries around the world. TB in buffalo, Brucellosis in elk, Mad Cow disease, OPP and Scrapie in sheep and so on. One wonders if this is due to increased knowledge of diseases that have been around for a long time or if diseases are actually on the increase. All this got me looking back to my Icelandic origins and made me think about how Icelanders have responded to threats to their sheep farming, and in some cases to their very survival on this remote island, due to diseases that have hit the sheep population.

After the settlement of Iceland, which took place between 800AD and 1100AD, there was no further importation of livestock for a long time. However, in the eighteen century the government became interested in improving the native sheep and in 1756 tem British rams were imported for crossbreeding. That experiment was so successful that four years later a few Merino sheep were imported from Spain. These sheep brought with them Psoroptes Ovis which are mites that live on blood and cause ill thrift and often death. These mites spread around the south and west of the island and caused severe losses. There was no cure and the only way to get rid of this pest was drastic culling of infected sheep flocks. It was made mandatory and caused incredible losses, but a victory was won. To make matters worse, in 1783 one of the biggest volcanic eruptions in recorded world history started in Iceland. The resulting poisonous gases and volcanic ash took a tremendous toll in lives of both people and animals. It is recorded that in 1760 the population of sheep in Iceland was 357,000 head and in 1784, after the eruption, it had dropped to 50,000 head, drop of over 70%. But with it the mites disappeared. This was a rather drastic way to eliminate a problem, but effective.

During the next 90 years or so few importations occurred, in most cases involving only two or three animals . Crossing these seems to have been successful. In 1855 three Merino sheep and four English lambs were imported and with the English lambs the same mites as before. Again, the parasite spread and massive culling was undertaken with considerable loss, both in bloodlines and money. My great-grandfather was one of those ordered to cull his sheep in that episode. Dipping of sheep was also used in this fight with reasonably good results. After this catastrophe laws were passed in 1882 whereby all importation of sheep was forbidden. The ban lasted for fifty years.

Around 1930 interest in experiments with crossbreeding surfaced again. In 1931 the Parliament passed laws allowing importation of 26 yearling from Britain. These sheep were kept for about 15 weeks in quarantine and then sent to a farm where they were bred and the offsprings sold for F-1 crossing. Under the same laws permission was given for importation of 20 Karakul sheep from Germany in 1933 for the purpose of producing crossbred lambskins. Those sheep were kept for only two months in quarantine and then released to farms around the country. The next year a strange disease, that had never before been seen in Iceland, began to appear in and around the farms where the Karakul sheep had been placed. In only one instance had the receiving farmer put his new ram into a further on farm quarantine. He did not like how the ram developed and culled it. he took the carcass a few miles out to sea and sank it there. By doing so he saved the best part of the Northwest peninsula from the worst sheep epidemic Iceland has ever experienced.

By the late thirties it was clear that once again a disaster had struck the Icelandic sheep population. At that time the cause of the diseases was not known, but three different diseases had obviously come with the Karakul and were thereafter called collectively “the Karakul diseases”. The first to be recognized was called Wet Mæði (pulmonary adenomatosis), and by the time this one seemed to be in remission another one appeared which got the name Dry Mæði (Maedi/Visna. OPP). Later, but only in limited area, Visna showed up. The names of these diseases were derived from the symptoms, Mæði meaning shortage of breath and Visna wasting. The third disease was Johne’s.

wpe15714.gif (17411 bytes)Even though these diseases had been found in other countries the causative agent was not known. By the end of the third decade it was obvious that drastic measures were needed and the old method of culling seemed to be the only possible approach. By this time the disease had spread over much of the country. The culling had to be done in an organized manner to stop the spreading of the disease and spread the unavoidable losses over time. The whole country was divided into districts by fencing or by natural barriers where possible. Some 1250 miles of fences were erected by the government and were , and still are kept up by people specifically employed for that purpose. When the barriers had be completed the culling started. All sheep in district after district were culled. After a complete eradication the area was restocked with sheep from a clean district. Most of the northwestern peninsula (areas 11 – 14) had escaped the disease as well as the isolated southeastern region between the Vatnajokull glacier and the Atlantic Ocean (area 26). The new stock came from there. In most cases the restocking was successful. The few unsuccessful cases were traced to carelessness in allowing some old sheep to escape slaughter or to infection of the new sheep en route.

By 1952 the systematic slaughtering was completed. Approximately 650,000 sheep were culled during this period. Occasional outbreaks recurred up to the early sixties. It can happen, for example, that sheep are not found in the annual roundup and these can survive the winter in the mountains. Those could have been the source of infection. The last outbreak occurred in 1965 and since then Maedi/Visna (OPP) has not been found in Iceland. For decades afterwards monitoring was kept up, both on farms and in slaughterhouses but no new cases have ever been found. Iceland is now officially and in fact free of Maedi/Visna (OPP).

The culling was not the only attack made on the disease. Another, and possibly more important one was the work done by Icelandic scientists. A dedicated team, headed by Dr. Björn Sigurðsson, kept looking for the causative agent and based on that work, Dr. Sigurðsson put forth his theory of ASlow Progressing Viral Diseases@ which at that time was a new concept in diseases. He and his team succeeded in isolating the Maedi virus and also proved that the same virus caused Visna. He and his colleagues, among whom were Dr. P. A. Pálsson, Dr. M. Guðnadóttir, and Dr. H. Thormar laid the base upon which AIDS research was later built, since the AIDS virus and the Maedi/Visna (OPP) virus are closely related. Dr. Sigurðsson died in 1959, only 46 years old, but his colleagues kept on the Maedi /Visna research and also studied Scrapie, another disease in some Icelandic sheep. Dr. Sigurðsson and his co-workers also studied Johne´s disease and were successful in producing a vaccine. By using that vaccine Johne´s disease has been put under control in Iceland.

One might think that after all these sacrifices and losses that Icelanders were through with drastic measures; but, no. In 1878, before the van on importation in the last century, an Oxford Down ram was imported to a farm in the North of Iceland. From that farm a new disease spread through the district by selling of sons of the Oxford ram. The disease was named “riða” (tremble), we know this as Scrapie. It was confined to this area up till the early fifties when it started to spread slowly but with increasing speed as the years went by. It was not considered a serious threat at that time and it was hoped that in the Maedi/Visna culling it would disappear. It did not. The causative agent for this disease was much more resilient that the Maedi/Visna virus. After Maedi/Visna had been eradicated Scrapie was still around. In the next four years the disease appeared on 30 farms all of which and been Scrapie farms before the complete Maedi/Visna culling. Some of these farms had been out of sheep for three years. The Scrapie agent had somehow survived without sheep being on these farms. By 1978 it seemed obvious that Scrapie would overflow the whole country unless drastic measures were taken. It was decided to start a new battle against the disease, firstly by stopping the spread of it by culling all flocks where new cases appeared, on the borders of epidemic areas. Secondly, by culling all sheep in the epidemic areas. This was done with full co-operation between farmers, and the government. In addition to mandatory culling of all sheep on farms where Scrapie was confirmed or suspected, conditions for permission to restock were made stricter and minimum of two years of sheeplessness was demanded. However before full consensus was reached there was some dissent among farmers. some even suggested the losses from Scrapie were so low that they could live with it. However, culling according to the new rules was begun in 1978 and restocking from areas where Scrapie had never been found or suspected was allowed after the minimum time lapse. In most cases that was two years, ion some cases three years and in one experimental case, one year. In order to be permitted to restock, the following conditions have to be met: One year before restocking, all buildings, machinery and manure storage have to be washed and disinfected. This involves complete emptying of all buildings, scraping all floors and walls, opening all walls and ducts and all places where insects or mites could be hidden. Then the areas have to be sprayed with a jet sprayer using hypochlorite solution or some thing similar. After this has dried, the area has to be sprayed with iodine with a regular garden sprayer. After inspection by a government approved inspector the buildings are sealed until the new animals arrive. All woodwork that cannot be properly disinfected has to be burned or buried. worn tools and tools that are used to treat the animals, such as hoof clippers, marking tongs, reusable needles, etc. are to be disposed of. All areas where sheep commonly gathered have to be scraped and the soil buried. Then a minimum of four inches of gravel has to be put on these places. Manure can be spread on fields that are well fenced but not on any place where water runoff is likely. The hay taken from fields of farms where culling has taken place cannot be used for sheep feed. Hay, sod, manure etc., is not permitted to move from farm to farm. All surfaces that cannot be perfectly disinfected have to be sealed with durable paint on metal and concrete and creosote on wood. All this work has to be inspected and approved by government inspector. Restocking is not permitted without previous disinfection. Farmers do get financial assistance with cleaning and compensation while out of business due to Scrapie culling.

Between 1978 and 1987 all sheep on several farms were culled and the new rules applied. Restocking was done from Scrapie-free areas. The results were promising. These were in districts where the incidence of Scrapie was just a few cases and culling was undertaken before any sign of serious spreading of the disease occurred. The disease was most widespread and serious in the eastern and northern part of the island. In the fall of 1987 the biggest onslaught was undertaken when 26,000 sheep from 130 farms were culled. In 1988 a further 20,000 sheep were culled from 100 farms. That culling left the eastern part of the country with any sheep. Last fall, in 1990 restocking in these areas began. since 1988 all confirmed and suspected cases have been culled. In some instances flocks from farms where no cases have been found have been culled on the grounds that Scrapie has been found on neighbouring farms. At present (March 1991), no cases of Scrapie are known to exist in Iceland but it is expected that some will surface in the next few years. In that case, culling of the flock, where Scrapie has been found, will be immediately undertaken. Some 280 farms have been restocked since the new regulations took effect, that is in the last 11 years, and in only two cases has Scrapie reappeared. In one case the cause could be traced o carelessness, in the other case the new stack was bought farm a farm nearby where Scrapie was later found.

The veterinarians are not the only ones to report suspected cases. Farmer themselves do so also. Search is furthermore conducted in the slaughterhouses during the slaughtering season, in sheep brain samples. It seems to be that again Icelanders have gotten together to fight a disease in their sheep. Compensation to farmers is reasonable and peer pressure is very strong. Any one flock that harbors Scrapie is a threat to the whole district. Recently, the Chief Veterinarian for sheep disease control in Iceland, Dr. Sigurður Sigurðarson told me that they were pleasantly surprised over how well the fight was going. He stated that even though no known cases exist at present the battler is far from over. No country has undertaken eradication on such a large and thorough scale before. Countries such as Australia, New Zealand, Kenya and south Africa have found Scrapie and eradicated it, but in all these countries the disease has been found in recently imported animals and has been stopped before spreading into the native sheep populations. Scrapie has been known in Iceland for over 100 years and if eradication is successful, as appears to be happening, many countries may benefit from the lesson that is being learned in Iceland today.