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Friday, January 2, 2015

NDV To Treat Canine Distemper......Hogwash Or True?

One of my readers passed on this link and question....
Does your office employ the treatment discussed in this link?
I'd like to know if you've heard of this and if so, what is your take on it and why aren't more vet offices using this treatment?
My first thought when reading the website was "well, this is new..."  As I continued to read I was scratching my head in confusion, especially with some of the statements.  Several red flags were raised in my mind and I was at the point of writing it all off as "snake oil".  But I wanted to give a more informed opinion and really break things down, hence this blog post.  I'll warn readers that I may get technical with some of the discussion, so if you're not into virology you may want to skip this one.
Let's start with a quote from the website:
We have received reports from 21 vets who have used NDV to treat distemper dogs. Of those, 12 vets used NDV-induced serum in the early stages of the disease, and in 86 percent of those cases, the distemper dog survived. Dog caregivers — owners, fosters and rescuers — tell us that 63.39 percent of distemper dogs were saved by one of the treatments developed by Dr. Sears using NDV — Newcastle Disease Vaccine.
Okay, that sounds pretty promising!  So what's the issue? Why isn't this being used more?
Let's begin by talking about what these viruses are.  Canine distemper (CDV) is a RNA virus that affects a wide variety of mammalian carnivores, including canids (dogs, foxes, wolves, etc.), raccoons, skunks, and even seals.  It is highly contagious and spreads through aerosol droplets or contact with infected bodily fluids.  Puppies less than six months old are the most common pets affected.  The diseases typically starts out with fever, respiratory signs, and diarrhea.  With prolonged infection it can invade the nervous system, causing inflammation of the brain and spinal cord.  The early symptoms may be subtle and only appear as diarrhea and a runny nose, though the disease progresses quickly over a week or two.  About 50% or more of dogs will die from this disease once symptoms develop, and even if they recover some of them may have long-term neurological problems.  Diagnosis can be difficult, and typically is based on isolating the virus in cells collected from the conjunctiva around the eye.

Newcastle disease is also a RNA virus, but it affects wild and domesticated birds.  The symptoms are similar to what we would see in dogs:  upper respiratory signs, conjunctivitis, diarrhea, neurological signs, and problems with eggs.  The virus can be isolated from swabs of the trachea and cloaca of affected birds.  There really isn't a treatment in birds, and the main concern is the disease spreading among flocks and causing massive bird death.  It can pass to humans, but isn't considered severe in our species, only typically causing short-term conjunctivitis and flu-like symptoms.  Interestingly, Newcastle disease virus (NDV) has been studied as a potential treatment in certain kinds of human cancer.  Apparently a modified version of it can target and kill cancer cells, though there is variability of the result between strains of NDV and types of cancer.

Both viruses are in the family Paramyxoviridae, with NDV in the genus Avulavirus and distemper in the genus Morbillivirus.  As a point of reference, human measels is also in the genus Morbillivirus, while mumps and human parainfluenza are in the genus Rubulavirus.  For those who don't know a lot about taxonomy, "family" can include a fairly broad variety of organisms, though there are considerable similarities.  For example, the family Canidae includes domesticated dogs, wolves, jackals, foxes, and bush dogs.  The family Hominidae includes humans, chimpanzees, bonobos, gorillas, and orangutans.  As you can see by the examples, members of a family have a lot of close similarities, but also some pretty big differences.  Nobody is going to confuse the skull of gorilla with that of a human, or look at a fox and think it's a wolf.

Okay, now let's get into the specifics of this supposed treatment for canine distemper.  Here's quotes from the website again:

The basic principle of the treatment is to use the NDV as an inducer to prompt a reaction in the dog’s immune system that can create a material to kill the distemper virus.....Today, the NDV treatments include the NDV-induced serum, the NDV as an IV injection to the body and the NDV spinal tap, which is for dogs in the neurologic stage of distemper.

Okay, so vets who are doing this are giving NDV vaccine to dogs, something that is not approved and not tested, as well as being a vaccine for a disease that only affects birds.  They they collect serum from that vaccinated dog, inject it into a dog with distemper, and somehow the NDV vaccine will "create a material to kill the distemper virus".  Someone might think that because NDV is a paramyxovirus like CDV that there would be some benefit of giving it.  But if that was the case, why wouldn't giving serum from a dog vaccinated for CDV help even more, since it's the same disease?  Or a measels vaccine, since that's in the same genus as CDV?  Stop and think about that for a minute...would we use serum from someone vaccinated against mumps as a treatment for measels?  Because that's basically what these vets are doing (go back to the taxonomy above).

"Yeah, but Dr. Bern, you already said that NDV has been studied because it kills cancer cells.  See, it's got something in it that helps cure diseases!"  Okay, granted, NDV may attack certain cancer cells.  But cancer cells are quite different from a virus, and these vets are claiming that NDV destroys the virus.  Even if it attacked the cells containing the virus, those cells are still very, very different from cancer cells.  You can't assume that something that destroys cancer would also destroy viruses.

The website presents data from a study they did.  Let's look at some of the comments about that "study" (yes, the quotation marks are intentional). 
The data for the report comes from two sources:
  1. Veterinarians using NDV
  2. Dog owners, caregivers or rescue groups.
Every case reported to us has been included in our statistics. We are not selective in compiling our information.
 Okay, there's problem #1.  This is in NO WAY a scientific study, based on these statements alone.  In any true medical study it's common for cases to be omitted for a number of reasons:  different diagnosis than expected, incomplete records, improper documentation, and so on.  So this was one of the big red flags to me.

For this survey, the diagnosis of distemper relied on the judgment of each vet. Very often, the dog owners did not want to pay the additional expense of a lab test. So, the vets would make the diagnosis based on their experience, the apparent symptoms and in the context of whether they were in the midst of a distemper outbreak.

And there's problem #2.  Remember that in the early stages there is diarrhea and signs of a sinus infection.  These symptoms may not be severe.  The only way to truly diagnose the disease is by doing swabs of the conjunctiva or the inside of the urinary bladder (rarely performed for obvious reasons).  So there may have been puppies that had diarrhea and runny nose, the vet suspected CDV, treated with the NDV treatment, and the puppy got better.  But it's very possible that many of these cases of unconfirmed distemper actually were not distemper.  A simple case of corona virus can cause diarrhea and be self-limiting.  There are several mild viral and bacterial infections that lead to sinus problems, but again may be self-limiting, with the pet resolving without treatment.  If these cases "responded" to NDV treatment, but were never confirmed to actually be CDV, how do we know that they are not animals who would have gotten better without any treatment because they didn't actually have distemper?  It's very possible that many of the dogs in the study who "responded" never actually had CDV in the first place.

There's also an issue with the variety of treatment protocols.  Some vets are using NDV serum intravenously, some are giving it into the spinal colum via a spinal tap, and some are giving the NDV vaccine directly IV.  Each of those methods is going to affect the body very differently, stimulating different responses.  This lack of consistency makes any conclusion difficult, as a scientific study would be limited to a single method.  In discussing the reports the website says that several vets gave NDV serum but never got follow-ups with the pets.  Are those cases still included in the data?  That's a prime example of the type of information that you delete from a study, yet they state that they didn't delete anything.

Here's a quote from the conclusions section of the website:

As to why these treatments work, our theory is that the NDV causes a reaction within a dog’s immune system that produces a previously unknown material or group of interacting materials, that is able to neutralize the invading virus. However, finding the answer would require extensive scientific research.

If that statement doesn't raise some serious red flags, you may want to go back to science classes.  We certainly don't know everything about the immune system, but postulating a "previously unknown material" that somehow neutralizes the virus is a rather bold statement.  Scientists have a pretty good idea of how viruses affect the body, the defenses the body has against them, and what "materials" are present.  I find it rather suspicious to propose a completely new and previously undiscovered immune system response with a vaccine and diseases that have been studied extensively.  It might be different if it was a completely new drug, but it isn't. 

Essentially vets using this protocol are saying "Well, it does something in the immune system and somehow that counteracts the virus, but we don't know how, where, or why."  Does it affect the cell membrane?  Does it affect antibodies?  Are there special proteins generated?  Does it strengthen the cell nuclear membrane?  I would be very, VERY hesitant to use any form of treatment where the method of action isn't even theoretically outlined.  The people developing this treatment are certainly not acting as responsible scientists, and are certainly not using proper scientific method.  Where is the control or placebo group?  Have they done double-blind studies to prevent bias on the part of the participants?

All of the above is my opinion and analysis.  I'm certainly not a specialist or a virologist, just someone who can look at the data analytically and without bias.  Feel free to ignore my opinion.  But here are some thoughts on this treatment by specialists in the field, as posted on the Veterinary Information Network (VIN).

From Dr. Melissa Kennedy, DVM, PhD, Diplomate American College of Veterinary Internal Medicine.  She is a clinical virologist at the University of Tennessee College of Veterinary Medicine, so with a double-doctorate and a speciality in internal medicine, she spends her career studying and teaching about viral diseases.....

"No cure yet.  There are a number of urban myths out there, like the Newcastle Disease serum."

Dr. Alice Wolf, DVM, Diplomate of the American College of Veterinary Internal Medicine and Diplomate of the Amercan Board of Veterinary practitioners is even more blunt and vocal.

"He doesn't have to 'prove' that it works.  It's not a USDA or FDA product.  He can say anything he wants.  His argument would be for us to prove that it doesn't work."

"If it sounds too good to be true, it probably is."

When asked how he gets away with it she replied "A la P.T. Barnum... There's a sucker born every minute?"

So let's summarize.....We have vets using a treatment for one virus, stimulated by a vaccination for a completely separate virus, and neither virus affects the other species (birds and canines).  There are more closely related viruses that could be used (measels), yet aren't.  The treatment "works", but the people using it don't have an inkling about even how it possibly could, other than some vague and mysterious "unknown material".  The "study" performed has numerous holes in it that significantly calls into question any so-called results, and would be soundly refuted by any scientific publication.  Reputable experts in the field, including at least one virology specialist, have clearly stated that this is a "myth" and should not be considered a valid treatment.

I know that people really want there to be a cure for canine distemper.  So do I.  But based on what I can see from this information, the NDV treatment is not a valid one.