Vet Blog
07/14/09
 A paper published in the July 1, 2009 Journal of the American Veterinary Medical Association caught my eye. Here are some excerpts from the abstract.
Case Description–An 8-month-old sexually intact male rabbit was examined because of a 2-day history of [inappetance], [watering] of the left eye, [tooth grinding], [drooling], and [dizziness].
Despite aggressive diagnostics and treatments, the rabbit could not be saved. His condition deteriorated, and after seven days of treatment he was put to sleep. The cause of death was unknown until an autopsy was performed.
Histologic evaluation of brain tissue revealed [multiple irregularities]. The DNA of human herpesvirus-1 was detected in [nerve cells] . . . The rabbit’s owner, who reported having had a severe labial and facial herbesvirus infection 5 days before the onset of clinical signs in the rabbit, was suspected to be the origin of the infection for the rabbit.
(J Am Vet Med Assoc 2009;235:66-69)
In other words, the rabbit’s owner suffered from a severe cold sore (human herpesvirus-1 is the cold sore virus; herpesvirus-2 causes genital herpes). During the outbreak, it appears that the rabbit contracted the virus and subsequently suffered a fatal neurological infection.
Human herpesvirus-1 is ubiquitous. The vast majority of people in the world are infected. A small portion of infected humans suffer from intermittent cold sores (I am one such unlucky individual). If you own a rabbit and suffer from cold sores, be aware that your pet may be at risk during your outbreaks.
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05/19/09
 Surgery is an important tool for medical professionals. For many syndromes, surgical intervention is the only appropriate therapy. And for many vets, performing surgery is fun.
However, individuals on the other end of the scalpel rarely enjoy the experience. Surgery inevitably leads to pain. Surgical recoveries can be lengthy, uncomfortable, and fraught with the risk of complications.
In general, it is best to choose the least invasive treatment for any given syndrome. Consider a pet dog that swallows a pine cone and suffers from intestinal obstruction. If possible it is best to remove the pine cone with an endoscope (a flexible tube with a camera and various instruments that is passed through the mouth into the intestines) rather than with surgery.
Bladder stones are relatively common in dogs and cats. Historically, veterinarians have resorted to opening the bladder and removing certain types of stones surgically.
However, two articles in the May 15, 2009 issue of the Journal of the American Veterinary Medical Association (JAVMA) report on an alternative technique. A catheter containing a laser is passed into the bladder through the urethra. The laser is used to break down the stone (or stones), and the fragments are removed through the catheter.
The studies found that the new technique is as safe and effective as surgery. The technique is less painful, and recovery is more rapid. The studies only addressed bladder stones in dogs; however, similar techniques hopefully will be available soon for cats.
Unfortunately, the new procedure generally only is available through specialists (almost any vet can surgically remove bladder stones). In time, however, more veterinarians may acquire the necessary instruments to treat bladder stones less invasively.
Photo: not that type of laser. Credit: Fir0002/Flagstaffotos. License: click here.
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05/14/09
 Acupuncture has been used in humans for at least 1000 years. It now is widely used in animals as well.
Some of my acquaintances from veterinary school perform acupuncture on animals. They are convinced it is effective. They also make a tidy profit from performing the procedure.
To this day, nobody can prove, nor disprove, that acupuncture truly works. Some studies have shown significant effects when acupuncture is used in specific circumstances. Others have shown no effect whatsoever. Many studies have been equivocal: they provide some evidence that acupuncture might be effective, but they don’t prove it conclusively.
Acupuncture therefore is perennially controversial.
The theory behind the traditional practice of acupuncture involves the flow of energy through the body. Our current understanding of anatomy and physiology does not back that theory up. Other theories of acupuncture state that the procedure leads to the release of endorphins (morphine-like chemicals that occur naturally in the body).
Plenty of people are willing to offer testimonials in favor of the effects of acupuncture in humans and animals. Many such people may comment on this post. But, as any student of science or medicine knows, personal testimonials are notoriously unreliable sources of information. They are highly subject to bias and confounding factors. Honest-to-goodness scientific studies are needed to verify clinical claims. When it comes to acupuncture, such studies generally have yielded conflicting results.
Some experts believe that acupuncture works mainly through the placebo effect. Acupuncture is not alone in this regard: some recent studies have suggested that Prozac’s effect in many people may be spurious.
Other experts point to some well run clinical studies that show significant effects from acupuncture when it is used to treat specific syndromes. In all, neither side can prove conclusively that it is right.
I personally don’t care why or how a treatment such as acupuncture may work. I care only whether it works. The information I have seen to date is equivocal.
I was therefore excited by a grippingly titled article in the May 1, 2009 Journal of the American Veterinary Medical Association (JAVMA): “Effects of adjunct electroacupuncture on severity of postoperative pain in dogs undergoing hemilaminectomy because of acute thoracolumbar intervertebral disc disease.”
The paper discusses the study of a special form of acupuncture used to treat pain in dogs recovering from back surgery. From the article:
Conclusions and Clinical Relevance–Results provided equivocal evidence that [acupuncture] might provide some mild benefit in severity of postoperative pain in dogs undergoing [back surgery] because of [slipped discs]. (J Am Vet Med Assoc 2009;234:1141-1146)
In other words, the study determined that acupuncture might have sort of worked to reduce pain after back surgery. But the study authors weren’t sure.
Suffice it to say that I was disappointed by the results of the study. I have been waiting my entire career for some hard science to back up or refute the practice of acupuncture. This study, like so many before it, did neither.
At this point, the only answer I can give to the question posed in this post’s title is I don’t know.
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03/01/09
 In 1991 veterinary medicine suffered a disturbing revelation. Two commonly used feline vaccines were linked to the development of malignant tumors at the site of vaccination. The tumors, called fibrosarcomas, are associated with the vaccines for rabies (in cats only) and feline leukemia. They are aggressive and difficult to remove. They occur in approximately one out of every 3000 – 10,000 cats who receives a rabies or leukemia vaccine.
The discovery of these so-called vaccine associated fibrosarcomas lead to the creation of a special task force (called, unsurprisingly, the Vaccine Associated Fibrosarcoma Task Force). The recommendations of the task force were supposed to cause a dramatic shift in the way cats are vaccinated.
Prior to the discovery of the fibrosarcomas and the formation of the task force, most cats were vaccinated against rabies and leukemia every year. The vaccines were administered between the shoulder blades because that is the easiest place to give injections to cats.
The task force recommended that the leukemia vaccine should be administered only to cats who spend time outdoors. The rabies vaccine should be administered as required by law. If possible, both vaccines should be administered no more frequently than once every three years.
Finally, the task force advised veterinarians to change injection sites. Fibrosarcomas between the shoulders are virtually impossible to remove. Therefore, the leukemia vaccine should be administered in the left rear leg, near the ankle. The rabies vaccine should be administered similarly in the right rear leg. If a fibrosarcoma develops in either of these locations, the cat’s life can be saved by amputating the leg–a less than perfect solution to the problem, but better than the alternative.
Vaccine associated fibrosarcomas are a source of angst for me. I have worked during my career to minimize the number of rabies and leukemia vaccines I give to cats. And I always give the vaccines in the rear legs.
However, a very disturbing paper published in the February 1, 2009 Journal of the American Veterinary Medical Association (JAVMA) indicates that many veterinarians are ignoring the recommendations of the task force and needlessly endangering the lives of their feline patients. According to the paper, significant numbers of cats are developing vaccine associated fibrosarcomas between their shoulder blades. This means that significant numbers of veterinarians are still giving rabies and leukemia vaccines in that spot.
Here are the conclusions of the paper.
Conclusions and Clinical Relevance–Despite publication of the vaccination recommendations, a high proportion of tumors still developed in the [region between the shoulder blades] . . . [v]eterinarians are complying with vaccination recommendations to some extent, but need to focus on administering vaccines as [far down] as possible on a limb to allow for compete surgical margins if amputation of a limb is required. (J Am Vet Med Assoc 2009;234:376-380)
What can you do to ensure that your vet is following the task force’s recommendations? Talk to him or her. Ask whether vaccination for leukemia and rabies is appropriate for your cat. If the vaccines are appropriate, ask where they will be administered. Never accept a one-size-fits-all approach to vaccination.
Photo: A vaccine associated fibrosarcoma between the shoulder blades of a cat, courtesy of Texas A&M’s School of Veterinary Medicine.
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01/09/09
 A few months ago I wrote about a new antibiotic called Convenia. The medicine is available by injection and lasts for a week or longer, eliminating the need to give daily (or, in many cases, twice daily) doses of pills or liquids.
In my original post I mentioned a few reservations I had about prescribing the drug. One of my (not explicitly mentioned) reservations was that there were few independent clinical efficacy and safety studies published in peer-reviewed journals.
That is beginning to change. A study released in the January 1, 2009 Journal of the American Veterinary Medical Association (JAVMA) compared Convenia to a commonly used conventional antibiotic in cats. Here are the results.
Effectiveness of [Convenia] in the treatment of cats with abscesses and infected wounds was similar to that of [the conventional antibiotic]. There were no serious adverse events or deaths related to treatment. (J Am Vet Med Assoc 2009;234:81-87)
This study does not address the long term concerns about injection-site tumors in cats that I mentioned in the original post. But it, combined with my personal experience with the medication (which has been highly favorable), makes me feel better about using Convenia in cats who refuse to take oral medications.
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12/12/08
 Nobody with a pet will forget the horrible pet food recall that occurred in early 2007. Several brands of cat and dog food were tainted with melamine and cyanuric acid (a byproduct of shoddy melamine production). The contaminants crystallized in pets’ kidneys, sickening and killing pets across the USA.
Veterinarians and scientists have generally believed (hoped may be a better word) that pets sickened but not killed by the tainted food would not experience long-term effects from the contaminants.
Sadly, a well-respected feline practitioner (Dr. Gary D. Norsworthy of San Antonio) wrote to the editor of the Journal of the American Veterinary Medical Association (JAVMA) to describe his experiences with three cats. The letter was published in the October 15, 2008 issue of JAVMA.
The three cats in question had eaten contaminated food in 2007. They had been appropriately treated by veterinarians at the time of the recall. They developed kidney failure in 2008, almost certainly due to the contaminated food. Here is a quote from Dr. Norsworthy’s letter.
[Microscopic] examination of the kidneys [from one of the affected cats] revealed “occasional birefrengent tubular crystals similar to those described with melamine toxicity[.]“
And if that isn’t disturbing enough, here is Dr. Norsworthy’s next paragraph.
The manufacturer of the food refused to pay a claim for damages because it could not be proved conclusively that the cat’s [kidney] failure was related to the contaminated food that it had eaten about one year earlier.
It seems that the misery and heartache from the 2007 pet food recall simply won’t end.
About the photo: Sissy Sue was a victim of the pet food recall.
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12/11/08
 When people think of heartworm disease they generally picture dogs as the victims of infestation. However, heartworms, which live in the heart and are spread by mosquitoes, also can infest cats.
Cats with heartworm infestations may show symptoms of heart failure including coughing, inability to exercise, shortness of breath and sudden death. They may vomit chronically. Heartworm disease is fatal in a stunning proportion of cases.
Historically, treatment options for feline heartworm patients have been extremely limited. Cats generally do not tolerate the drugs that are used to treat canine heartworm patients. Veterinarians generally find it impossible to offer any real help to feline heartworm victims.
However, a paper in the November 1, 2008 issue of the Journal of the American Veterinary Medical Association (JAVMA) discussed a technique that successfully treated two heartworm-infested cats in Texas.
The authors of the paper passed a special type of catheter into the heart through the jugular vein. They used the catheter to snare and remove worms from the heart. Both cats’ symptoms resolved within four weeks.
Sadly, this is not a treatment that will be available at your local vet any time soon. This sort of procedure requires specialists with very sophisticated equipment and skilled intensive care nursing. But I am very happy to know that a viable treatment option for feline heartworm patients may finally be out there.
The study cited in this post is Small, et al J Am Vet Med Assoc 2008;233: 1441-1445.
Click here for photo credit.
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12/04/08
 I am a life long cat lover. I am continuously amazed by the ability of cats to adapt to almost every environment on earth, and to survive and reproduce (although not truly thrive as individuals) without the help of humans.
Feline adaptability and survival skills have led, unfortunately, to a tremendous amount of suffering in cats. Enormous populations of feral cats live in every town and city on the fringes of society. Thomas Hobbes wouldn’t have hesitated to refer to their lives as nasty, brutish and short.
Cat advocates in the United States have largely embraced trap-neuter-return (TNR) as a means of alleviating feral cat suffering. TNR programs attempt to stabilize feral cat colonies by catching cats, surgically sterilizing them, and returning them to the environment.
TNR has not been universally accepted by animal welfare experts. Some people point out that TNR programs have failed to achieve a measurable reduction in feral cat populations. And an exchange of letters to the editor in the October 1, 2008 issue of the Journal of the American Medical Association (JAVMA) drew attention to another possible shortcoming of TNR programs: inadequate postoperative pain control.
Feral cats are completely unaccustomed to handling by humans. To safely perform any form of medical treatment on a feral cat, the cat must be anesthetized. This means that oral pain medications generally are not administered after surgical sterilization. Most cats in TNR programs receive a solitary injection of pain medicine at the time of surgery and are released a few hours after they wake up. The author of a letter to JAVMA pointed out that this is, definitively, inadequate.
Is there a solution? Perhaps. Some pain control medicines are flavorless and can be administered in food to a hospitalized cat–if the cat is willing to eat while hospitalized. Some are, but many aren’t. To provide pain control in this fashion would require that feral cats stay in the hospital for several days after surgery–something that many feral cats would find exceptionally stressful.
Like so many issues surrounding feral cats, the provision of adequate pain control during TNR programs is an ethical minefield. I suspect that this controversy will prove to be as intractable as the problem of feral cats.
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A paper published in the July 1, 2009 Journal of the American Veterinary Medical Association caught my eye. Here are some excerpts from the abstract.
You have questions. 