Newsletters -> Free Investigational Treatment for Canine Distemper
Distributed to our Pet Portals members on December 3, 2011.
From Heather Jenkins, DVM, CVA
In This Issue:
Free Investigational Treatment for Canine Distemper
Get suspected cases to Healing Springs as soon as possible. Early distemper shows mild, flu-like symptoms. The goal of this treatment is to stop the spread of the virus, ideally before it spreads to the internal organs. Healing Springs Animal Hospital, Galax, has announced that, as an adjunct to the normal veterinary care for canine distemper, it is offering an investigational treatment at no charge. We will also be offering the PCR test for the presence of canine distemper at cost. Since there is no proven cure for canine distemper, a handful of authorities have recommended high dose retinoid supplementation as an experimental treatment. Retinoids are loosely referred to as vitamin A. We have investigated the science surrounding vitamin A for canine distemper, and we find the science to be sound and very encouraging. Studies have found that vitamin A can stop the canine distemper virus from replicating and can save animals with canine distemper infections. We have also found that retinoid supplementation has been proven highly effective in human medicine for a very similar disease. In addition to the sound scientific rationale for this treatment, we are gratified by the fact that vitamin A is very safe in dogs. Even though this treatment is experimental, it is highly unlikely to do harm.
Canine distemper continues to be a problem in our area. We have been seeing cases from Galax, Grayson County, Wythe County, Carroll County and more. Some cases have been pets with no connection to the regional animal shelter in Galax, which recently closed temporarily due to a distemper outbreak. Canine distemper is easily preventable with timely vaccinations, but for dogs unfortunate enough to contract it without having been vaccinated, distemper often proves deadly.
However, some dogs can survive canine distemper with proper nursing care. Owners who attempt to save infected dogs should also be aware that canine distemper survivors often experience severe neurological complications later in life. Because our investigational retinoid supplementation treatment is supposed to stop the distemper virus from spreading in the body, we are hoping it will both improve survival rates and decrease the severity and incidence of later complications.
Broadly speaking, here's the science influencing our decision to offer this treatment. The canine distemper virus is very similar to the human measles virus (88% amino acid homogeny). Measles still kills hundreds of thousands of children in other countries. As such, medical researchers have studied canine distemper in attempts to better understand measles. In one in vitro study, virologists saw that retinoids (vitamin A) stopped the canine distemper virus from replicating.(1) In a living animal, this would mean that the virus would stop spreading. This finding that retinoids halt the replication of canine distemper is bolstered by the work of Carey Rodeheffer (McGill University Health Centre Research Institute - Montreal) who reports the same finding and Clair Trottier et al. who report that vitamin A similarly inhibits measles virus.(2)
Perhaps more to the point is the animal experiment conducted by Rodeheffer and colleagues.(3) They deliberately infected animals with canine distemper. Some were given retinoid supplement shots, and apparently no other treatment, and some were given no treatment. All (100%) of the animals who received the retinoid treatment lived to the end of the experiment. Why, you might ask, would this treatment still be considered experimental in veterinary medicine after Rodeheffer's work? Here are two reasons. Firstly, Rodeheffer was studying canine distemper to learn more about measles, not about dogs, so they used ferrets as their experimental subjects. Secondly, Rodeheffer gave the animals their retinoid shots at day 1 of infection and another injection on day 2. In real world veterinary practice, it is likely that owners will bring in dogs much later in the course of infection. So how well this treatment would work in dogs in real world situations has yet to be established.
However, we at Healing Springs have turned the tables. Researchers used animals to better understand human disease. We have examined the human measles research to gain insight into canine distemper. Particularly influential for us is the very recent meta-analysis led by Christopher Sudfeld of Johns Hopkins and Ann Marie Navar of Duke University School of Medicine.(4) Combining the results of several studies on measles, they found that retinoid supplementation more than doubles the chance of survival in very real world scenarios.
Since no one has published a study on retinoid injections for the real world treatment of dogs with canine distemper, the optimal dosage, route, and number of treatments has yet to be established. We have decided to deliver the retinoids in the form of retinyl palmitate delivered by intramuscular injection, as Rodeheffer did in his in vivo study.(3) In an online article suggesting the use of vitamin A for treatment of canine distemper, Richard Meadows (University of Missouri Department of Veterinary Medicine) suggests a dose of 10,000 international units (IU) or greater - apparently based on the established vitamin A dose for dermatological problems. We are opting for one 200,000 IU injection per day for two days. Our decision in this regard was influenced by human medicine and the work of Sudfeld et al.(4) In the treatment of human measles, doses of less than 200,000 IU were found to have no statistically significant effect or survival. Only doses of 100,000 IU in infants less than one year of age and doses of 200,000 IU in children age 1+ were found to be effective. These very high doses of retinoids should be safe in dogs. Retinoids are fat soluble vitamins, and dogs prove particularly tolerant of vitamin A. As Richard Meadows points out, one study found that puppies could ingest 300,000 IU / kg of vitamin A, 6 days per week, for 30 days before showing the first signs of vitamin toxicosis and could go another 30 days at that rate before mortality.(5)
Based on our review of the current science, we have opted for a protocol of two intramuscular injections of 200,000 IU of retinyl palmitate delivered 24 hours apart. Upon presumptive diagnosis of canine distemper, a lab sample will be drawn for PCR test and the first retinyl palmitate injection will be delivered right away. Retinoid supplementation will be delivered as an adjunct to normal veterinary care for dogs with active canine distemper infections. Clients will have the option to elect or reject the retinoid supplementation as part of their care. Clients who want the experimental retinoid supplementation will be required to sign an informed consent form.
- Yao, H. The Anti-Viral Effects of Retinoids in Canine Distemper Virus Infection: The Missing Link Between Measles and Vitamin A. Montreal General Hospital - Research Institute: Division of Experimental Medicine. Published by Heritage Branch, Otowa Canada. 2010; ISBN 978-0-494-66351-6.
- Trottier C, Chabot S, Mann K, et al. Retinoids inhibit measles virus in vitro via nuclear retinoid receptor signaling pathways. Antiviral Research. 2008; 80(1): 45-53.
- Rodeheffer C, Messling V, Milot S, et al. Disease manifestations of canine distemper virus infection in ferrets are modulated by vitamin A status. The Journal of Nutrition. 2007; 137: pages 1916 - 1922.
- Sudfeld C, Navar A, Halsey N. Effectiveness of measles vaccination and vitamin A treatment. International Journal of Epidemiology. 2010; 39: 148-155.
- Maddock C, Wolbach B, Maddock S. Hypervitaminosis A in the dog. The Journal of Nutrition. 1949; 39: 117-137.
Concerns over the So-Called Newcastle Vaccine Treatment for Canine Distemper
Injecting Newcastle Disease Vaccine, a modified live bird virus, into the veins of sick dogs runs the risk of making dogs more vulnerable to their real infections.
Injecting a modified live bird virus into the veins of sick dogs also presents the low but potentially dangerous risk of creating new diseases. Newcastle vaccine in particular has been cited by virologists for its potential to create new diseases. The current outbreak of canine distemper in southwest Virginia and perhaps northwest North Carolina has created heightened attention to the plight of dogs infected with this deadly virus. Because there is no established treatment protocol with a high level of success, people in our area have been researching and requesting experimental protocols. Unfortunately, the treatment idea that shows up most readily on Google and that is easily readable by people without medical training is the WordPress blog of New York journalism teacher Ed Bond. Of the three protocols promoted by Ed Bond, the particular "protocol" that has gained the most attention in our area is the IV NDV, referred to by others as the "simple body cure." Our review of this idea leaves us more concerned than hopeful. Online anecdotes notwithstanding, the IV NDV idea appears to present more potential for harm than for cure.
The IV NDV idea is to inject a chicken vaccine from the feed store directly into the veins of sick dogs with suspected canine distemper. IV stands for intravenous - injection in the vein. NDV stands for Newcastle Disease Vaccine. The Newcastle Disease Vaccine is a modified live bird virus intended for use in vaccinating chickens and other birds.
Firstly, we have found no medical reason that injecting a modified live bird virus into the veins of distemper infected dogs would help dogs fight off the distemper infection. While there is at least an attempted rationale for the other two ideas promoted by Bond's blog, we can find no attempt to rationalize the IV NDV idea. Furthermore, it is generally discouraged to give vaccinations to animals actively fighting a real infection. Vaccinations tax the immune system. During an active infection, one should avoid treatments that tax the immune system. Since there is no sound rationale for a bird virus injection helping a distemper infected dog, and since it could hamper the dog's immune response to the active infection, it is our conclusion that the bird virus injection idea is more likely to do harm than good.
Secondly, routinely injecting a modified live bird virus into the veins of sick dogs presents the low but potentially dangerous risk of recombination. Recombination refers to a virus's tendency to mix with other viruses and form new diseases. Interspecies recombination can be particularly problematic - as we have seen with recent outbreaks of the bird flu. The Newcastle vaccine in particular has been cited by virologists for its capacity to cause recombination with "wild" viruses in animals.(1,2)
The WordPress blog promoting bird virus injections into dogs reports that some vets have done this and that 71 of 130 dogs have survived (55%). While it would be natural for the public to find this claim encouraging, this claim proves frustrating for responsible veterinarians. Before risking such a problematic treatment in clinical practice, people with medical training will want to know answers to very basic questions:
- What tests, if any, were used to confirm these dogs had distemper and not a more common infection?
- If treatment was based on a presumptive diagnosis, what were the symptoms?
- Were these 130 consecutive cases or 130 selected cases.
- What other treatments did these dogs receive?
It is unknown if these cases were even tested for distemper, but the test promoted on Mr. Bond's blog is frankly inaccurate and out of date. The test promoted on the blog tests for anti-bodies and does not confirm a distemper infection. Instead, it merely confirms that the dog has been exposed to the distemper virus at some point in the past and now has antibodies to fight distemper. Dogs that have been vaccinated for distemper show as positive for distemper on this outdated test. The modern test for distemper is the PCR. The PCR test actually verifies the presence of active distemper virus. We find it disconcerting that this blog has been promoting bird virus based cures for 12 years and claims to have 130 cases reported by less than 19 veterinarians, but has yet to present even a case series that answers the most basic questions doctors would ask when evaluating claims of efficacy.
In conclusion, Healing Springs will be offering an investigational treatment that is safer, has a sound rationale, and has scientific backing. We will not be offering to inject modified live bird viruses into the veins of sick dogs. We feel the bird virus idea is likely to compromise the immune system's ability to fight the real infection. We are also aware of the potentially dangerous risk of creating new diseases by using live vaccines in very unintended ways.
- Hang G, He C, Ding N, Ma L. Identification of a natural multi-recombinant of Newcastle disease virus. Virology. 2008 Feb 5; 371 (1): 54-60.
- Qin Z, Sun B, Ma Z, et al. F gene recombination between genotype II and VII Newcastle disease virus. Virus Res. 131: 299-303.
Click here to see the photo album and individual stories. Twelve new orphan profiles are on our Facebook page. If you Facebook, please "Share" this photo album to help these pets find homes. Healing Springs constantly works with various organizations and individuals to save pets destined for euthanasia at our local shelter or otherwise facing a certain end. We provide complimentary services and boarding to orphan pets so they can have increased opportunity to get adopted. Here are some of the pets you can meet at Healing Springs and adopt from their organizations.
Click here to see the photo album and individual stories.