[E3a] Has there been a shift in the relative numbers of specific ferret diseases, and if so, how have they changed? By many accounts, this question is one that cannot be answered. However, such questions are common enough in historic archaeology, where techniques have been developed to address them. One of those techniques involves the careful scrutiny of historic documents, including older books detailing ferret care, pamphlets, newspapers, and other such material. Believe it or not, there is a surprisingly large amount of such information regarding ferret diseases. Early accounts of ferrets generally ignore their health aspects, concentrating on hunting and physical characteristics. This gradually changed with shifts in human attitudes towards animals, as well as the rise of veterinary medicine. Between the 1600s and 1800s, while reference is made regarding the health of ferrets, with a few exceptions nothing specific is mentioned. Of the mentioned diseases, canine distemper ranks high (usually implied: it is frequently recommended to keep ferrets away from dogs), followed by foot rot and scours commonly caused by spoiled milk. One of the first accounts to dedicate significant space to a discussion of ferret illnesses dates to the late 1870s (there are others, but it was the first to have a separate chapter on the health and care of ferrets, not just a short addendum or mention). In that account, the paramount diseases mentioned are canine distemper (sometimes called the sweats), a vague disease also called the sweats that is probably a form of influenza or other upper-respiratory disease, scours, foot rot, and complications from mange, flea and rat bites. In that account, ferrets lived to 5 or 6 years of age. These health problems, with minor deletions or additions, are mentioned repeatedly in ferret-related documents until the mid-1900s. During this time, ferret lifespan is reported to range from 5 to 9 years, with an average age at death about 5 to 6 years, and a maximum age of 12 years. There were a few farming publications that periodically discussed ferret health issues; one had a weekly "ask-the-vet" column that, over the years, discussed most of the then-current health problems in ferrets. Of all the modern diseases, two have significance for this discussion: adrenal disease and insulinoma. They are important because they have unique symptoms. Historic descriptions of those symptoms would be easily recognizable (new ferret owners easily describe the symptoms of both diseases, and the descriptions are easily recognized by long-time ferret owners), and while they generally impact older ferrets, they occur in younger animals as well. In short, they are diseases that, if present, would have been recognized and described. Arguments that early vets lacked the ability to recognize them are, well, obtuse. Vets a century ago may have had simplistic skills compared to modern vets, BUT, they were careful observers with great skills in describing unknown diseases. If adrenal disease were common, it would have been described. Even in the ferret books of the later half of the 20th Century, when vets were trained with more sophistication, the two diseases are mostly ignored until the mid-to-late 1980s. It is hard to ignore the visual characteristics of an adrenal ferret, yet NONE are mentioned historically. Bob C [E3b] I have scoured more than 1000 historic documents to graph the relative frequency of ferret illnesses, finding some 380+ mentioning ferret disease. In these documents, both insulinoma and adrenal disease are RARE until the mid-1980s. This is a significant era because the first book published solely recommending ferrets as pets was published in 1977. Here is the really cool part. When you graph the individual number of ferret-as-pet publications and compare it to the number of reports of ferret insulinoma and adrenal disease, you find the two highly correlated. We all know that, but the finding is more complex than a simple correlation. If the increase were only due to a simple increase in numbers, then while the numbers would increase, they would remain proportionate to the population as a whole. For example, suppose adrenal disease impacted 0.5% of the older ferret population, numbering 1000. That means even if you increase the population to 2000, the relative number of diseased individuals would remain constant at 0.5%. You would see an increase in ill individuals, but they would remain proportionate to the population as a whole. This is what you see in with a genetic ailment, which is why scientists can cite specific rates of disease for specific populations. But what I have found is for the last twenty years, the RELATIVE rate of both insulinoma and adrenal disease has INCREASED within the population. This is very significant. In population genetics, disease frequencies are very stable in large populations like those existing in American ferrets; shifting those frequencies is extremely difficult. EVEN IF a bottleneck occurred introducing both diseases into the American ferret population, the resulting disease frequencies would stabilize at some specific frequency, and while the numbers would increase or decrease with population changes, the ratio would remain constant. Both insulinoma and adrenal disease frequency rates have increased from the 1980s to the late 1990s. Ferret population has also increased, but the relative frequency of one to the other- -the ratio of sick to healthy- -has dramatically increased as well. THAT suggests that the mechanism spurring the increase is NOT the result of a genetic bottleneck. While adrenal disease and insulinoma are certainly the products of gene expression, it is not simple genetics driving the increase in relative frequencies of either disease. One of the basic principles of population genetics is that genetic disease frequencies are remarkably stable. Change means adrenal disease and insulinoma are not only increasing in USA populations, BUT that the increase is not due to simple genetics, but something else. If the problem was caused by a founder's effect, then relative frequencies of disease would stablize, but they are increasing, and not just in the USA. In the last few years, adrenal disease and insulinoma rates have been reported on the increase in other countries, including Britain, Denmark, the Netherlands, German, Australia, New Zealand, and France. In most of these countries, the difference isn't in housing, lighting conditions, neutering, or even genetic bottlenecks. It is diet. The late onset of adrenal disease and insulinoma mirrors the increase in use of an ad libitum, kibbled diet. Bob C [Posted in FML issue 3967]