Kennel Cough and other Canine Cooties
From the Desk of Dr. Voorheis
September 4, 2014
The timeliness of this week’s blog is certainly no coincidence. Some of you are already aware of the recent events at Boulevard Grooming and Boarding (the facility behind us that we operate) but for those of you who aren’t, this blog will explain in detail what took place, why it happened and what we did to resolve the situation. It’s important that you all hear this from the horse’s mouth so that details are clear and concise and stories do not evolve with inaccurate facts. Recently, at Boulevard Grooming and Boarding, a number of dogs showed signs of upper respiratory disease. It is not at all uncommon in boarding facilities to have this happen to the occasional dog, but in this circumstance there were more than we (Drs. Voorheis and Throgmorton) were comfortable with. So, PCR testing (DNA) was done on 4 of the dogs and that revealed the reason for the coughing to be a viral disease there was no vaccination against, Pneumovirus. The boarding facility was shut down for a week and all surfaces thoroughly disinfected. Disinfection in both the boarding and hospital facilities is done daily, but what happened during that week was a deep cleaning the likes of which were beyond impressive. I must share with all of you that this has never once happened in the 30+ years that I have been at WBAH. We have never had to shut the boarding facility down. This decision was inconvenient for clients who had made plans to board their dogs but easily understandable from the point of view of safety for their animals and the other animals scheduled to board. This was absolutely the right decision for us to make. Having said that, we do realize it caused a great deal of annoyance and for that we are truly apologetic. Please know that we will always make the right decision for the health and safety of your animals. They are our absolute first priority.
Every dark cloud has a silver lining, right? Our silver lining is that this unexpected situation enabled us to review our vaccination policy for boarding and grooming animals even though this “episode” was caused by an organism that there is no vaccination for. We decided to look at diseases that are generally more common and that we do have vaccinations for. Due to the amnestic response (immune memory), dogs who had previously received a booster against bordetella were “ok’d” to get that booster on entering the facility. This policy has now changed. We are now requiring that the bordetella booster to be given one week prior to boarding/grooming. This gives them their absolute best protection against illness. The goal is to prevent any further preventable situations.
As outlined above, it is clear that this episode was caused by a viral infection that there is no vaccination against. It is worth reiterating that there is risk involved when you take your dog to a grooming/boarding facility. There is risk involved when you take your dog to any place where numbers of dogs have gathered. I guess you can say life is a risk. I would ask any client to consider a number of things before making a decision to groom or board their dog. Are vaccinations current? Is my dog coughing now, or recently had a cough? Upper respiratory organisms can be shed for a month following infection. If your dog is recently recovering from an upper respiratory infection, don’t groom or board it. Does your pet have increased risk factors such as existing cardiovascular disease or lung disease? That pet may not be an ideal candidate for boarding. Is your pet on chemotherapy for cancer? This too may not be an ideal candidate for boarding.
Bear in mind that in spite of significant efforts at cleanliness and disinfection, exposure can still take place. The best analogy is sending a child to school or taking an airline flight and then coming down with a cold or flu. “Cooties” are out there for humans and animals. They are airbourne and they attack. Some of them can be vaccinated against and some cannot. Your best defense is vaccinating against what you can and really think about any risk factors that your pet may have and let that guide your decision. This applies to any grooming or boarding facility you may consider as well as places like dog parks or other places where numerous dogs gather.
So, let’s talk about what is behind all of this, medically speaking. Canine Infectious Respiratory Disease Complex. Wow! That’s a mouth full. Let’s talk about this disease, the body’s defense mechanisms, and our current understanding of the diseases involved. It turns out that “kennel cough” is not just one disease. The signs can be caused by a number of different organisms with different severity of signs and different treatments.
Let’s talk about the dog’s defenses against disease first. In the respiratory system, there are three levels of defense. The first level is the mechanical barrier level. Mechanical barriers are things like mucus, enzymes and the mucosa itself. These guys work to inhibit attachment and facilitate clearance of organisms in inspired air. Then there is the second level of defense, an immune response called the innate response. There are circulating white blood cells that move out of the blood into tissues. They recognize certain molecular patterns associated with pathogens. These cells types are phagocytic (engulfing) cells, neutrophils, basophils, mast cells, eosinophils, and natural killer cells (T-lymphocytes). They are what is called non-specific, so they do not have an “immunologic memory”. The third level of defense is an “Acquired Immune Response”. This has to do with lymphocyte development and memory. It is this level of immune response that we are stimulating when we vaccinate. We talked about some of this in my vaccination blog. That blog, at this point, would be an excellent one to go back and refer to.
Allow me to give you a little more detail on the mechanical barrier. The majority of micro-organisms that we inhale every day are handled by anatomical or mechanical barriers. Bacteria, dust, viruses are suspended in inspired air. The conducting airways use turbulence and decreased velocity to accomplish filtering inspired air. This causes these particles to be directed onto mucus-covered walls where they can be easily cleared. These mechanical barriers include the complex turbinate structure of the nose, the changes in angle and direction of the pharynx and larynx, and the multiple branching pathways of the bronchi. In addition, the bronchi and trachea have things called mucociliary escalators. These are the cells that line these airways and are constantly moving to “escalate” the mucus out the bronchi and up the trachea where it can be cleared.
Now for a bit more detail on the innate immune system. That mucus I mentioned? Filled with host defense molecules, defensins, lysozyme, surfactant proteins; these have anti-microbial activity. These substances are secreted by the epithelial cells lining the airways into the mucus. Yes, it turns out someone other than Dr. Egon Spengler studies mucus! Anyone know who that is? Extra credit from me if you do! Anyway, the epithelial cells lining the airways have pattern recognition receptors. These both trigger and amplify the immune response to infection. Then there are patrolling white blood cells that are directed to where the immune response is occurring. These guys engulf the pathogens allowing them to be cleared by expectoration (coughing) or swallowing.
Last, but certainly not least, a little more information on adaptive/acquired immunity. At the same time the above is happening, mucociliary clearance is presenting the organisms to mucosa associated lymphoid tissue (MALT) or bronchial associated lymphoid tissue (BALT). This is lymphoid tissue either in nose, pharynx or nasopharynx (MALT) or trachea and bronchi (BALT). The MALT guys get to work producing an immunoglobulin (IgA). Mucosal antibodies work by immune exclusion or immune elimination. IgA works by immune exclusion. This prevents adherence of bacteria and viruses to epithelial surfaces. IgA is not bactericidal and is fairly short lived. BALT tissues produce IgG, these immunoglobulins are potent activators of destruction of the micro-oganisms by opsonization (the process by which a pathogen is marked by destruction by a phagocyte), and virus neutralization. These guys mediate the immune elimination of the infection by controlling an arm of the immune system called humoral immunity (IgG, IgM and IgE). They get activated if organisms evade IgA and gain access to tissues. They are bactericidal and they have long immunologic memory. These are the cells that we activate when we give an injectable vaccination.
Now that you have some relevant information on the defense system, let’s talk about canine infectious respiratory disease (CIRD). Canine infectious respiratory disease (CIRD) is also known as “Kennel Cough” or “Shipping Fever”. These are a highly contagious group of infections that are spread through respiratory secretions. These secretions are aerosolized when an animal coughs or sneezes, thereby facilitating exposure especially where there are dogs gathered in moderate to large numbers such as dog parks, grooming and boarding facilities, pounds and shelters, rescues and veterinary hospitals. “Fomites” (inanimate objects such as tennis balls, rope toys etc) can be the source of infection as the organisms can survive on inanimate objects for over 48 hours. These pathogens colonize airway epithelium, the nasal cavity, larynx, trachea, the bronchi and bronchioles. They act to disrupt mucociliary clearance. This disruption or dysfunction allows further colonization by other viral and bacterial pathogens. There is a wide range of clinical presentations, from mild self-limiting disease to severe life-threatening disease, although that is fortunately rare.
For years, we have known that the primary agents of CIRD were either Bordetella Bronchiseptica + canine parainfluenza virus (CPV2) or Bordetella Bronchiseptica + canine adenovirus2. These agents can act by themselves or in combination with one another. This knowledge or paradigm is what most veterinarians practiced with for years and years. We know now there are many other causes for CIRD (canine infectious respiratory disease). A more complete list is below. Vaccination is not available for every organism on this list.
- Canine Adenovirus type 2
- Canine Parainfluenza virus type 2
- Canine influenza virus
- Canine respiratory corona virus
- H1N1 influenza virus
- Mycoplasma cynos
- S.Equi zooepidemicus
- canine pneumovirus
- canine herpes virus
- canine reovirus
So what does it look like when you dog is infected with one of these organisms? Signs relate to the degree of respiratory tract damage and range from non-existent to severe. In uncomplicated cases the cough is a dry hacking cough, followed by gagging or expectoration of mucus. Exercise, excitement and pressure of a collar all seem to stimulate cough. Severely affected animals may be inappetant (not interested in food), be lethargic and have trouble breathing. Fortunately, this group is uncommon. The vast majority of dogs with this presentation are treated as outpatients. Antibiotics are used for this group because many of these cases are infected with bacteria, or an organism that is responsive to antibiotic therapy. Cough suppressants may be used to treat these outpatient animals as well. Lastly we will also use bronchodilators to relieve bronchospasm.
There is a subset of dogs that present very ill, with pneumonia. These dogs are treated with IV antibiotics, supportive care including IV fluids, oxygen therapy, nebulization (a process in which antibiotics are put into a small amount of saline and aerosolized into the air the animal breaths. The highest risk dogs for this group are the very young, the very old or dogs with existing heart and lung disease. Animals who are undergoing chemotherapy for cancer would also be an at risk group as mentioned above.
Prevention can be broken into a couple of categories; risk reduction and vaccination.
Studies done at the Western College of Veterinary Medicine, University of Saskatchewan, and published in the Journal of the American Veterinary Medical Association have given us the best information on how to protect dogs against Bordetella.
1. Puppies – who have never been vaccinated.
a. First vaccination – intranasal/oral vaccination
b. 4 weeks later – subcutaneous vaccination
Studies also showed that two subcutaneous vaccinations in puppies spaced 4 weeks apart were nearly as effective as “a” above.
2. Adult dogs – subcutaneous vaccination annually.
Reducing risk is reducing exposure. This would mean don’t take your dog to dog parks, to dog shows, don’t board your dog at a boarding facility. Don’t take your dog to a grooming parlor. Don’t walk your dog through a pet supply store. The lobby of a veterinary hospital is also a place where exposure could take place. Of the list above, boarding is probably the highest risk. Why? Large populations of dogs, stressed because they are not at home, shedding organisms as outlined above and sharing a common air supply. Is the list above realistic? Absolutely not. We cannot have our animals live in a bubble anymore than we ourselves can live in a bubble. We can only educate ourselves and do things that attempt to reduce risk. As I have outlined above, even vaccinated and “protected” dogs can come down with signs of “kennel cough”. There is NOT a vaccination to protect against all organisms that can cause upper respiratory disease in the dog. Sad, but true.
I hope this blog has given you all some solid information and some things to think about. In closing, I want to thank a couple of people for this blog. First, John Barrier from Zoetis. Zoetis is the pharmaceutical company that was formerly Pfizer Animal Health. John offered me the opportunity to have a two hour long sit down with Dr. Stephan Carey, a respiratory specialist who teaches at Michigan State University. The second person I’d like to thank is Dr. Carey himself. Dr. Carey was visiting the southland in late spring, and was gracious enough to give myself and 4 other veterinarians a couple of hours of his time (and his lecture notes). Most of this blog is a direct carryover of the information he shared. I believe he also shared that his young son was an avid Los Angeles Kings hockey fan. I’d say that young man had a good June.
Until next time,