Thursday, December 1, 2011

How to investigate wildlife (or cryptozoology) sightings.

In light of the recent Jaguar sighting in southern Arizona, I thought it was interesting to get this email from the Arizona Game and Fish Department on how they investigate reports of rare and/or endangered species. Note that eyewitness sightings need to be corroborated with other forms of evidence for such sightings to be officially confirmed. Good quality photographs or video, or other physical evidence are required to confirm these sightings. It is interesting that animals as small as domestic cats are often mistaken for lager cats, and that reports from the public go up dramatically after a sighting, confirmed or not, is reported in the media.
(Click on the email for a larger view)


Wednesday, November 23, 2011

New Jaguar sighting in southern Arizona.

The Arizona Game and Fish Department and The Arizona Daily Star are reporting a new sighting of a Jaguar in Arizona. This is the first sighting since the tragic case of Macho B back in February of 2009. It is good to see that Jaguars are still making their way into Arizona despite all the border issues which are potentially getting in their way.

Sunday, November 13, 2011

More genetic information on dog breeds, their relationships and possible effects.

     A recent genetic study in PLoS Genetics has some interesting implications relating to claims made by some dog breeders and many practitioners of alternative veterinary medicine.  As our ability to collect and analyze large amounts of genetic data improves, we can learn a lot about how genetics affect the susceptibility of dogs and humans to various diseases. The genetic history of the domestic dog is at least 15,000years, and possibly as much as 100,000 years. Over most of this time, dogs were used for a variety of work including hunting, herding, guarding, and as pets, but breeding practices were haphazard and mixing between types of dogs and even back to wolves as common.
     Basically all modern breeds have been developed in the last 200 years, with many deliberate (small founding populations) and inadvertent (low numbers of dogs during social and political upheavals such as the two world wars) genetic bottlenecks. The history of the Irish Wolfhound is a good example-claims that the breed as it exists today is the same as hounds used in ancient times are not supported by any solid evidence. While it is certain that large sight hounds existed thousands of years ago in the British Isles, the modern breed is the creation of Victorian fanciers who "recreated" the breed in the mid to late 1800's based on their ideas about how the breed should look and on current Victorian ideas of "improving" animals through selective and "pure" breeding.

     While these genetic studies are still preliminary, they are starting to identify gene sequences which have been strongly selected for in the process of creating these breeds. These sequences often contain mutations with major effects on both the phenotype of the dogs and on their health. The diseases which some breeds are very susceptible to are often similar to diseases which also occur in humans, and knowledge of dog genetics is applicable  to human health as well. As the specific portions of the genome which affect disease susceptibility are identified, we will learn more about how to avoid many of these health problems in the future. Unfortunately for many of the alternative medicine crowd, claims that diseases like cancer are product of vague "toxins" and modern industrial society are unsubstantiated by the evidence. While it is true that pets can develop cancer due to exposure to specific, known toxins such as secondhand smoke, these exposures are fairly well known and documented in both animals and humans, and are often related to the owner's lifestyle choices more than any generic effect of modernity. While avoiding known toxins such as tobacco smoke is always a good idea, trying to improve our chances with supplements or "superfoods" generally does not work the way we would wish it did.

     The more we learn about the interaction of our genes with the environment, the more we know that disease is often a result of genetic influences which we can control to some extent in domestic animals.
Claims that cancer and autoimmune diseases are caused by specific diets, vaccines, or undefined toxins remain unsubstantiated, and support for them is getting weaker as we learn more about the genetics of dogs and other species.

Tuesday, August 2, 2011

Arizona Black Rattlesnake

This little (approximately 18inches long) rattlesnake was hiding in the raspberry bushes along the top of the Mogollon Rim last weekend. It rattled when we got close to warn us away. This is a subspecies of the Western Rattlesnake (Crotalus viridus subspecies cerberus) They tend to occur at relatively high elevations (this one was at about 7500feet above sea level). Some people think that the black color is an adaptation to high altitude that allows the snake to absorb more heat from the sun, although the leaf/needle litter in their habitat also tends to be quite dark. The dark color may serve as good camouflage as well as helping the snake warm up after cool mountain nights. Most rattlesnakes will assume a defensive position such as this, and usually will not strike unless a person or animal steps on them or persists in approaching within striking distance or tries to handle or contact the snake. This snake rattled a little to warn us and retreated into the raspberry patch. Venomous snakes  in the wild should be left alone to fill their place in the ecosystem and to avoid injury. See my previous post for information on first aid and treatment of rattlesnake bites.

Thursday, June 16, 2011

Buying influence in the early stages of veterinary careers.

 I found a commentary in the latest issue of JAVMA by a second year veterinary student at Colorado State University who is also a lawyer. The commentary addresses the wide variety of free goods, pet foods, medications and industry sponsored seminars provided to veterinary students. When I attended Colorado State 20 years ago, I remember a handful of pharmacy company sponsored seminars and a few coupons for free dog food over the entire 4 years. The seminars were unusual occurrences and there was usually some post-seminar commentary by faculty discussing where the company line may have diverged from the scientific evidence. It would appear things have changed drastically since then.

Here is Michelle Dally's description of the flow of swag that starts the first day of freshman year;
Every first-year veterinary student at Colorado State
University is assigned a small desk in a dingy warren
in the Anatomy building affectionately known as
“the cubes.” These desks are unremarkable in all ways
but one: when students first arrive, they find their desks
piled high with a variety of freebiespens, notepads,
backpacks, notebooks, highlighters, academic calendars,
pet treats, pet food bowls, reference books, and
more—all emblazoned with pet food, pharmaceutical,
and other corporate brand names from across the veterinary
industry. And that is only the beginning.
As the year unfolds, students discover that they are
entitled to free and sharply discounted dog, cat, and
horse food; free heartworm preventative; a free laboratory
coat; and a free clipboard for use in their gross
anatomy laboratory.
 In addition to all of the gifts, students are also invited to "work" as student representatives for many of these companies, often for fairly significant amounts of money;
Soon, first-year veterinary students
are receiving e-mails through the official veterinary college
e-mail distribution list encouraging them to apply
to be corporate student representatives for a variety of
companiespositions that typically involve little more
than distributing additional freebies to their classmates
and organizing one or two free lunchtime lectures. In
return for their efforts, these student representatives are
generally paid between $750 and $2,000 per semester.
Some companies employ as many as two student representatives
in each of the 4 veterinary college classes,
whereas others employ only a single representative for
each class or a single representative for the entire college.
Regardless, the upshot is that there are typically
one or two corporate-sponsored free lunches each week
for veterinary students, and the corporate presence in
the veterinary college is palpable.
In addition to the conscious and unconscious effects these gifts and sponsorships may have on students ideas and practices far beyond veterinary school (which is discussed well in the commentary) it leaves the profession as a whole open to other criticisms. Often one of the first accusations used to defend alternative practices or denigrate any science-based treatment which is produced by a pharmaceutical company is that veterinarians are just shills for "big pharma" or "big pet food". The same companies often sponsor veterinary conferences and seminars for veterinarians as well. The alternative veterinary industry really should not throw this particular stone, as their conferences are sponsored by supplement manufacturers and other companies to a similar extent.

The things that I found particularly disturbing about the commentary were the discussion of how these practices are tacitly and actively supported by the veterinary school with very little time spent educating the students on how they may be influenced by them. This is yet another way that veterinary schools are failing to teach their students critical thinking skills and how to evaluate evidence. This type of corporate influence may be even more insidious than teaching alternative practices which are not evidence based in a credulous manner. Students really should be taught how to critically analyze the claims of all of the players in the veterinary industry, from the pharmaceutical companies to the promoters of supplements and alternative treatments. Increasing the access companies have to students as described in this  commentary really does open the door for legitimate criticism, as well as giving charlatans something to point to to distract from their own lack of evidence.

I commend Michelle Dally for her commentary and for drawing attention to this topic.

June 15, 2011, Vol. 238, No. 12, Pages 1551-1554
doi: 10.2460/javma.238.12.1551

Ethical considerations raised by the provision of freebies to veterinary students
Michelle Dally, JD
College of Veterinary Medicine and Biomedical Sciences. Colorado State University, Fort Collins, CO 80523. (Dally)
Ms. Dally was a second-year veterinary student at the time of submission.

Sunday, May 29, 2011

Cancer, Autoimmune disease and MHC diversity-should we blame vague toxins and food or inbreeding and closed registries?

It is common among proponents of certain types of diets and supplements (raw diets, the "evolution" diet, and many types of herbal supplements) to claim that cancer and autoimmune diseases are caused by unidentified "toxins" in commercial foods, vaccines or simply toxins from the environment. Unfortunately, some breeders and even some veterinarians, particularly the "CAVM" crowd, have bought into these ideas, and sometimes try to require new puppy owners to feed specific foods, delay or avoid vaccinations and sometimes avoid certain types of exercise in an attempt to avoid problems that have a strong genetic basis.

Many ideas about breeding dogs date back to the Victorian era when little to nothing was known about genetics and their relationship to the function of the immune system, and ideas of pure blood and avoiding undesirable mixing of different breeds were considered to be the appropriate way to "improve" dogs and other animals. Unfortunately, these ideas were institutionalized and perpetuated through kennel clubs and many breed clubs in the form of policies that allow and even encourage inbreeding (often called "line breeding") and specifically prohibit out-crosses for any reason. The only way to try to eliminate a problem under this system is to eliminate individuals carrying the undesirable genes, which may remove one problem, but is likely to further constrict the gene pool and cause other problems at the same time. While the "holistic" veterinary medicine crowd tries to blame toxins and vaccines, and the large kennel clubs do their best to ignore the underlying problems with their policies, scientists have been working hard to identify the reasons why some breeds are so much more susceptible to certain types of cancer and autoimmune diseases than other dogs or less inbred dogs are.

The underlying genetics associated with susceptibility to several autoimmune diseases and cancers have been discovered in the last few years. While we have known that certain breeds have much higher incidences of certain diseases than others for years (some diseases are named for the breeds which they occur in most frequently), the complexity of the immune system and the genetics associated with it means that only recently have we started to unravel how this affects the health of our pets. There are two main types of Major Histocompatability   Complex (MHC) genes in vertebrates-which are also one of the most polymorphic sets of genes in vertebrates-which are involved with identifying different proteins (antigens) and presenting them to the immune system as "self" or "non-self". This is how the immune system regulates which things to attack and remove (bacteria, cells infected by viruses, cancer cells, etc.) and which things to leave alone (normal cells, harmless proteins from food and the environment).  In general, having a larger number of diverse MHC genes means that the immune system is better equipped to identify and distinguish good and bad antigens in the body.

In the last few years, researchers have identified varying MHC diversity in different dog breeds. Although it is probably still quite early to use MHC haplotype testing to test for suceptiblity to most diseases, such testing is starting to become available. Many studies have been done identifying specific problems and relationships of specific MHC haplotypes with specific diseases. Some examples include; Autoimmune Hemolytic anemia, Hypothyroidism, Canine Masticatory Myositis, Toller arthritis (a disease similar to Lupus), Canine chronic superficial keratitis, and Doberman Hepatitis. These are just a few of the heritable autoimmune diseases which occur in dogs, and active research continues. MHC diversity is also important for detecting and eliminating cancers, and a lot of research has been done into transmissible tumors in an attempt to discover a way to fight
Devil facial tumor disease in Tasmanian Devils. This research is helping to show how many types of tumors in addition to transmissible tumors evade the immune system. Some inheritable diseases have unsurprisingly been discovered to be unrelated to the MHC genes as well.

This body of research is providing both a broad knowledge of how limited gene pools increase the risk of autoimmune disease and cancer, and which specific genes affect susceptibility to specific diseases. While this line of research will result in specific tests for many of these diseases, eliminating carriers from the population may further restrict genetic variability and is very likely to cause other problems. It would be a much better idea to try to increase diversity in HLA haplotypes first, before eliminating undesirable genes. In some cases, this may mean outcrosses from other breeds to introduce the desirable genetic diversity. In the rare casees that this has been tried, the kennel clubs and breed organizations have not reacted positively. Another problem is that often kennel clubs and breed organizations fund genetic research on purebred dogs, which may deter criticism from organized veterinary medicine.Even worse, the "holistic" or CAVM crowd enthusiastically promote a wide variety of diets, supplements, and even antivaccine nonsense while ignoring the growing body of evidence of genetic problems in purebred dogs. "Holistic" indeed.

For further discussion of these issues in dogs and other animals, see these thoughtful posts;
Pedigree dogs Exposed-How to breed dogs with stronger immune systems.
Border Wars-Inbred Mistakes.
Desert Wind Hounds-MHC, DLA, WTF?
Retrieverman-Misunderstanding the concept of inbreeding tolerance.

Thursday, April 14, 2011

Veterinary Homeopaths don't like criticism.

Please see this post over at The SkeptVet blog; witin 24 hours it is recieving threatening comments from one of the veterinary homeopath's through the North American Veterinary Conference, who should know better. Please repost  if you can.

Sunday, April 10, 2011

Evidence for using caution with herbal medications in cats.

Veterinarians have known for a long time that cats do not handle certain drugs as well a dogs and other animals do. Drugs such as aspirin, acetaminophen, and other NSAIDs can be much more toxic to cats than to other animals. If we give them to cats at all, they are given in very low, infrequent doses (aspirin) or not at all (acetaminophen). We have known for a long time that cats have much lower levels of the liver enzymes which humans and other animals use to metabolize these drugs. Cats are considered "hypercarnivores", meaning they are adapted to a diet that is 70% or more animal matter. Since most drugs are quite recent inventions, it is obvious that these enzymes did not evolve in response to the drugs which they metabolize but to something else.

A recent paper on PLoS One has worked out the genetics behind this enzyme difference in cats (and a few other animals). These enzymes (Glucuronyltransferases) have developed over many millions of years to deal with toxins found in plants used for food. In species such as cats that do not eat many plants, there is no selective pressure to maintain this type of enzyme function, and mutations can cause the genes coding for them to become inactive. This is what has happened in cats with these particular enzymes, with the result that certain drugs that are chemically similar to some types of plant toxins are much more toxic to cats than they are to other species. This type of issue with drug metabolism is known as a "species defect". While the specific difference in metabolism being discussed here is one of the best known and documented of these species defects, other less well documented differences occur as well.

This has important implications for not only the use of pharmaceuticals of known and controlled dosages, but even more importantly for the use of herbal medications in different species. The problems with herbal medicines are best described in David Colquhoun's Patients Guide to Magic Medicine as  "Herbal medicine: giving patients an unknown dose of an ill-defined drug, of unknown effectiveness and unknown safety." The bit about unknown safety is especially applicable in the case of the types of species defects in metabolism that we are discussing here. While some of them are well known, giving an herbal medication that has many different chemical compounds in it may increase the risk of adverse reactions. In addition, the actual dose of active ingredients in herbal products is often very variable, so a product that seems safe when taken once may be toxic the next time. Just because herbs are natural does not mean they are safe, and animals have evolved a lot of natural variability in sensitivity to plant compounds, as this paper documents.

Sunday, March 27, 2011

More evidence that acupuncture does not really work.

  There have been several new developments in the evidence base for the effectiveness of acupuncture recently. The first, and more important is a recent systematic review of the evidence for the effectiveness of acupuncture for pain. The Skept Vet has addressed this review in detail here. In short, the review found that the evidence for pain relief in general was contradictory and weak, with the possibility of rare but serious side effects to consider as well. As The Skept Vet points out this type of mild, patient expectation-related effect (placebo effect) may not exist in our animal patients, and any perceived effect may be due more to owner and clinician expectation and observation bias than to any real effect felt by the patient.

     Another human study was published recently on the effects of acupuncture on nausea in humans being treated for cancer. This study is interesting because it is one of the few studies which included not only a standard care control group, but also had a sham acupuncture group in addition to the acupuncture group. The sham group involved both a telescopic sham needle and a sham acupuncture point to help control for both patient perception and any effect possibly related to the specific acupuncture point used. The sample sizes in this study were not huge, but were better than many other acupuncture studies, with 62 (standard treatment), 88 (acupuncture) and 95 (sham acupuncture) patients completing the study. The participants in the study were also interviewed top measure their expectations related to the treatment.

    The results of the study showed that both the acupuncture and sham acupuncture groups  had lower levels of nausea and vomiting than the standard care group, and that this effect was strongly correlated to patient expectations. While the therapists applying the acupuncture were not blinded, the results between the two groups were not significantly different. This study is better controlled than most acupuncture studies in the past have been despite the lack of double blinding.  This reinforces the view that many skeptics have that the apparent effects of acupuncture on subjective symptoms such as the perception of pain and nausea may be due to patient expectation rather than any specific physiological effect of the acupuncture itself. Veterinarians claiming that acupuncture is effective should be very careful-their patients may be experiencing some discomfort or pain related to the acupuncture, without any benefit of expectation of improvement, while the veterinarian and owner may believe they see improvement because of their own expectations and desire to help. While an argument may be made that inducing positive expectations in human patients may be useful for managing problems such as pain and nausea, this should be done without misleading the patient or exposing them to risks of serious side effects. In the case of animal patients, it is probably unrealistic to assume that they have the same type of expectation of benefit, and we should be doubly careful to be sure the treatments we use have good evidence of effectiveness.

Monday, February 14, 2011

Pedigree dogs-many health problems are genetic, despite what some say.

 A short video well worth watching if you are not familiar with the problems associated with breed standards and the inbreeding allowed and even encouraged by the large kennel clubs. Unfortunately, many breeders do not understand these problems well enough either and often blame (often with the encouragement of holistic vets) vaccines, ill defined "toxins", commercial dog food, and sometimes the owners for problems that quite clearly have strong genetic components, even when not entirely genetic diseases. These problems have not really received enough attention from organized and science and evidence-based veterinarians, but the alternative and integrative veterinarians seem to be exploiting them without any mention of the responsibility the kennel clubs and breeders hold for creating so many health problems in the first place.

Sunday, February 13, 2011

Nonsense On Stilts by Massimo Pigliucci

Nonsense on Stilts, Massimos Pigliucci's most recent book is and interesting read for anyone interested in distinguishing science from pseudoscience, or from "bunk". The author also discusses the book on the Rationally Speaking podcast, produced by the New York City Skeptics.

While the book does not directly address CAM, it is an interesting and detailed look at the development of science from an historical and philosophical viewpoint that provides a lot of insight into what makes a subject or field scientific, proto-scientific, or just plain nonsense. It includes interesting discussions of what the differences and similarities are between different fields of science (physics and biology, for example) and how something like SETI may not be currently considered science due to it's lack of evidence, but could become scientific if such evidence is found. Some types of alternative medicine clearly fit into the bunk category (homeopathy, reflexology, Reiki, traditional chinese acupuncture) due to the lack of evidence for effectiveness and the complete lack of plausible mechanisms for action. Other things such as herbal medicine can be scientific or not depending on how they are approached by the people pursuing them.

 The book is well worth reading for anyone interested in a deeper understanding of how science can be understood as a process practiced by humans, and how it has developed over time. It will give you a better understanding of what science is and how to evaluate claims about different topics.