Your Healthy Herp: What is Paramyxovirus?
*Disclaimer: I am not a veterinarian and can only share information I have found. PNWHS is not liable for any action taken based on the contents of this article. It is up to the individual to do their own research, and I strongly encourage all keepers to seek out trusted information sources and to rely on the advice of their veterinarian. If you suspect your animal is ill, please take it to a licensed veterinarian.
What is Paramyxovirus, and how does it affect our reptile pets? Aside from the fact that it’s a virus, I didn’t know much at all about it except that I’ve heard vague rumors, spoken in whispers, about the ‘snake virus scarier than IBD’ that is airborne and ‘can wipe out whole collections’. So what is this really all about, and how concerned should I be for my own collection?
As usual, I started digging around on the internet to get a basic idea of what this virus is about. Once I had a general feel for it, I dug around in PubMed to see what had been published in the last few years and get an idea of current research and current veterinary practices regarding diagnosis, treatment, and prevention. I pulled a few papers and found some very interesting information. I also contacted Dr. Maas with a question I couldn’t seem to answer from the sources I had consulted, and he helped to clarify some things for me. Again, I’m no veterinarian – but I can pass along some information that I’ve found that might help others learn more about potential health issues concerning their reptile pets. Please note that links to references and further information can be found at the end of this article.
What is Paramyxovirus? Paramyxoviruses (PMV) were first isolated and characterized in the early 1970’s. These are single-stranded RNA viruses in the large family Paramyxoviridae, which also includes Canine Distemper, some human Parainfluenzae, Measles, and others. There are a number of closely-related strains of PMV that can infect reptiles. A paper by Dr. Sylvia Blahak and her team isolated viral agents from 18 different species of snake that were identifiable as Paramyxoviruses (Virus Research, 2001). Initial reports suggested that OPMV was found in only Vipers (with Crotalidae being particularly susceptible to infection); this has broadened to include Colubrids and Boids (boas and pythons). Recent research by Dr J. W. Frost suggests that strains infecting snakes and lizards can be related, but those infecting tortoises are distinct and possibly host-specific (Virus Research, 2009). PMV seems to be much more prevalent in snakes than in lizards, and even less prevalent in turtles and tortoises. However, published works do not seem to be extensive enough to take this as a given and if PMV were found in one of my pythons, I’d still be very careful to watch the chelonians in the house too until further research can verify this finding.
What are the symptoms of PMV and how is it treated? In some cases there are no symptoms at all in snakes that have died and are found to carry PMV. However, in most cases symptoms overlap those of any other type of respiratory infection, particularly in snakes. Wheezing, respiratory discharge, labored breathing, and gaping are some symptoms that may be seen. Some cases also include suggestion of GI upset, like anorexia and regurgitation; infected snakes will sometimes display neurological symptoms such as head tremors or convulsions. The severity of symptoms can also be determined by which strain (version) of PMV is contracted. (this information came from a variety of sources, including reptilechannel.com, the University of Georgia’s vet school website, and a review written by Dr. N. Pantchev (The Veterinary Journal, 2008). At this time, there is no specific treatment for PMV or available vaccine. Animals are sometimes treated with antibiotics for secondary infections, or given supportive care. Time from exposure to death is anywhere from 6 to 10 weeks (Bronson and Cranfield, Reptile Medicine and Surgery, 2006).
How is PMV diagnosed? Well, in the scientific literature specimens tested were often deceased and so various tissues were selected and tested in a variety of ways for viral particles, using both direct and indirect methods. PMV can be found in the lungs especially but also in the feces, kidneys, and brain. Blood tests can sometimes show, indirectly, the presence of PMV. I wasn’t certain how PMV was to be diagnosed in a living animal, so I consulted with Dr. Maas (Avian and Exotic Animal Hospital) and he suggested that the definitive test on a live animal is a technique called rtPCR (reverse transcription polymerase chain reaction) that can be done on tracheal washes. This technique is also able to indentify which strain is infecting a given animal.
How is PMV transmitted? The consensus I was able to find is that PMV is passed primarily through respiratory secretions and aerosols (basically, breath droplets), or sometimes from fecal matter. There is no evidence yet of vertical transmission (parent-to-offspring) but I did find some implication that snake mites may prove to be a vector once further research is performed.
How can PMV be contained or prevented? Obviously, appropriate husbandry is a must to maintain healthy animals. Bleach is an appropriate disinfect with which to kill PMV viral particles on anything that may have touched an infected animal (10-20% and leave it on for quite some time; be sure to rinse thoroughly and allow to dry completely). A big part of prevention is quarantine of new animals for at least 90 days to watch for symptoms (Bronson and Cranfield, Reptile Medicine and Surgery, 2006), and also to treat rigorously any new animal for snake mites with an appropriate product like Prevent-a-Mite. You can get this from the Beanfarm and other sources; follow the directions carefully. Because of the ability of PMV to spread in respiratory secretions, good hygiene is absolutely essential to keep your collection free of viral infection. Common sense, appropriate husbandry, a few basic precautions, and adequate disinfection practices will go a long way to protecting your collection and keeping your herps healthy.
Branson, E and Cranfield, MR. Reptile Medicine and Surgery, 2nd Ed. 2006.
Pantchev, N et al. The Veterinary Journal 175 (2008) 53-68.
Blahak, S et al. Virus Research 80 (2001) 67-74.
Frost, J et al. Virus Research 144 (2009) 272-279.
Wissman, M. contributed article, “Snake Virus Paramyxovirus”. Reptilechannel.com