I have made this statement several times, and I remain convinced it will happen sooner or later IF established public health procedures which prevent the spread of disease are not followed. It almost cannot not happen if current practices by shelters and ferret shows are not changed to contain this very real problem. The REAL danger is that ADV could potentially skip the Atlantic and do it's nasty deeds in Europe. And over there, not just domesticated ferrets are at risk, but so are European and steppe polecats and the European mink. While none of these species are currently endangered with extinction, there are local populations at risk. My expertise comes from a intensive zooarchaeological study of infectious disease to explain Post-Columbian wildlife declines and to refute the Pleistocene Overkill hypothesis.

That does not make me an expert on ADV, and I encourage those with a better understanding to improve on or correct these efforts.

I am not going to waste people's time by trying to do a review of ADV; there have already been several webpages mentioned which do a good job and the disease has been discussed in great detail here. What I will discuss is HISTORY, so my remarks can be understood in the context in which they were meant.

In 1492, Columbus sailed the ocean blue. You might remember that little rhyme from grade school. What the rhyme never revealed was introduced European diseases, including smallpox (poxvirus complex), measles (canine distemper/measles/rinderpest complex), cholera, bubonic plague and other diseases, sailed the ocean blue with him. There is no agreed upon population numbers for Pre-Columbian Native Americans, but it is generally accepted that whatever those numbers were (somewhere between 5 and 9 million), between 70-90% of them died from introduced diseases within a century of Columbus's first visit. Some areas of the Caribbean and southern Florida were virtually denuded of humans. The loss of human life was so great that it destroyed the oral history of most tribes, and the survivors couldn't explain who built the vast monuments and mounds in the Midwest and East. The death toll reached millions in what one scholar called "Native American bacteriocide". I have read journal accounts of people finding villages long abandoned by everything except the skeletons. Not just one wave of disease ravaged the Native Americans, but wave after wave every generation or so helped European expansion during the days of the Monroe Doctrine. When Lewis and Clark visited Mandan villages in the early 1800s, the people had just recovered from a smallpox epidemic which reduced the number of villages from about a dozen to just a few (the Northern Plains Native Americans suffered an epidemic every 5.7 years on average from 1682-1920). The southern Washington archaeological site I am involved with was abandoned prior to 1830s when local populations dropped from the thousands Lewis and Clark saw to hundreds because of a combination of introduced diseases.

There is a term for this type of spread of disease; it is called a "virgin ground epidemic." In other words, it is a disease which has never been seen before by a population, and it spreads like wildfire, usually with devastating results. Bubonic plague was a virgin ground epidemic in western Europe, and killed millions of people in a single generation. It did a similar thing on a smaller scale in Central and South America during the time of Spanish conquest. Currently, AIDS is a virgin ground disease in humans. The same thing happens in animal species; in the 1920s foot and mouth disease spread into the California mule deer population, killing more than 20,000 deer. It is very probable the initial decline of the black-footed ferret was due to the introduction of canine distemper (I just returned a reviewed paper on this subject for second review). When plague was introduced into the USA in 1907, it spread through the rodent populations like wildfire, and can now be found throughout the west in ground squirrels, prairie dogs, marmots, and wood rats. Canine distemper is currently spreading through Africa, killing jackals and African wild dogs, and has been reported (but I am not sure if confirmed) in African lions and hyenas. Rinderpest is likewise infecting antelope and wild bovines. Wildlife epidemics (epizootics) are quite common in recorded history, and were probably responsible for the decline of the Pleistocene megafauna, helped perhaps by Paleoindian over hunting and climate change. In fact, according Swabe, the rise of veterinary medicine was a response to increasing epizootics resulting from trade, conflict and population growth during the 1700s.

Virgin ground diseases seem to fester, sporadically infecting what appears to be isolated populations, then snowball exponentially into major epidemics. Because they have never seen the disease before, the victims have little resistance to infection. In many cases, if the disease is a virus, it is recent species crossover; that is, a variant of an existing disease infecting another species (the canine distemper variant in humans is measles; in cattle it is rinderpest). Recent species crossovers TEND to be moderately virulent (not always), and initially have high morbidity (ratio of infected to healthy individuals, sometimes called the infection rate) and mortality (death rate). This usually changes as those individuals with the more virulent forms die and fall to pass on the nastier variants of the disease, as well as individuals developing immune responses and passing them to offspring. If the incubation period of the disease is short and the disease has a limited period of expression, it can burn itself out by killing the local population and leaving no hosts alive. However, if the disease has a long or hidden incubation, and rarely kills individuals prior to sexual maturity and reproduction (like AIDS and ADV), it has a very good chance of establishing itself so solidly within a population that it will never be totally eradicated.

ADV is acting like a classic virgin ground disease in domesticated ferrets. It is a recent species crossover (about 50 years old). It is not all that virulent (compared to influenza, ECE, or canine distemper). However, even with a relatively low virulence, in areas where it has gained a foothold (mostly shelters), it seems to have a moderately high morbidity, and we are all aware of the mortality rate hovering at the 100% mark. I think we have been watching the slow growth for some time now; as more and more ferrets are tested, I fear we will begin to see the beginnings of exponential growth that is already seen in AIDS. The problem with a disease which has a long incubation period and a long period of infection is that you could already be in the period of exponential growth and not know it.

Just because ADV is acting like a virgin ground epizootic, it doesn't necessarily follow that it has to BECOME one. We can look at history, recognize the signs, and use established public health procedures (and a good deal of common sense) to prevent ADV from entering the exponential portion of the growth curve. We could try:

1. Testing all ferrets for ADV prior to breeding, sale, adoption, introduction to other ferrets, or geographic relocation.

2. Isolating all infected ferrets. As drastic as it sounds, in some instances, culling may be the best public health solution. I do not advocate euthanasia lightly, but the dead truth is, it is better to lose a few than to lose a lot, and while the option may be rightly discouraged (especially with private ownership), it should never be eliminated.

3. Requiring certificates of testing for entering shows or ferret events, as well as requiring judges take precautions.

4. Creating a central data bank to monitor outbreaks of ADV, recording type of ownership (private, shelter, etc.), date of diagnosis, breed, geographic location, age, sex, etc., and which follows up to record death information. This could perhaps be the project of a ferret club or an individual with a web page and little else to do.

5. Establishing an accepted method of disinfection which is effective, uses commonly available products, and is easily carried out by people of limited means and abilities. This has got to be simple and effective; just remember how many cases of AIDS that might have been prevented if someone had used a condom. Hard to find something simpler than that.

6. Convincing breeders and pet shops to make information regarding ADV part of the package given to new ferret owners.

7. Contributing to ADV research.

Will these ideas work? Probably not totally; there will always be the odd ferret owner who doesn't care and takes no precautions. However, since there is currently no cure for ADV and no hope for recovery, the best solution is prevention. History gives us a good idea of the potential for ADV to become a modern ferret plague, but we don't have to repeat past mistakes. We can learn from history, take the appropriate public health steps, and enjoy our ferrets for a very long time.

Bob C and 15 Mo' Virgin Ground Ferrets
rrc961@mizzou.edu