Canine Infectious Respiratory Disease (CIRD)……

                 A Deeper Dive



Canine infectious respiratory disease has always been somewhat complicated but has suddenly become significantly more complex as we see apparent “outbreaks” of respiratory infection that seem much more severe than our usual pattern. CIRD, as we recognize it, can result from multiple organisms, and occasionally more than one is present during any particular episode of illness. The list at the end of this article shows all of the known organisms that have been associated with CIRD but the ones that we see most commonly when we test with PCR are Mycoplasma cynos, Bordetella bronchiseptica, and Canine Influenza (two strains). To add further confusion, some common infectious organisms can often be detected in perfectly healthy dogs, and this has been verified in multiple studies of well animals in various locations. <Links at end of article>

These infectious agents remain active and many dogs who present with typical upper respiratory symptoms will be suffering from one or more of these pathogens. In a normal, healthy dog, the majority will recover relatively easily and often with no involved treatment. CIRD, previously known as “kennel cough complex,” typically affects dogs of all ages and typically presents with a dry, hacking cough. However, despite this nasty-sounding cough, the pet remains active and alert and often continues to eat fairly normally. The cough may worsen with activities like barking, exercising, or being excited. Some of these dogs may require treatment for the cough or coinfections. It is advisable to isolate them, as they will likely be contagious for a few weeks depending on the specific organism(s). It is important to note that a small percentage of dogs may become seriously ill, especially those who are very young, old or have a weak immune system.

What we are seeing since midsummer in Oregon is a vastly different patient profile. There are 3 common presentations:

1) typical symptoms of upper respiratory infection with a prominent cough, but the cough does not resolve and becomes chronic (weeks to a few months) with little or no response to antibiotics

2) upper respiratory symptoms that progress to bronchitis or bronchopneumonia which, while not life-threatening, remain chronic and poorly responsive to antibiotics and may persist for weeks to a few months

3) an acute syndrome in which the hallmark is rapidly progressive pneumonia that is also poorly responsive to antibiotics. In the acute syndrome, the patients can become desperately ill in just 24 to 36 hours after the initial cough.

Clearly, the dogs that are presenting in these 3 categories are very different from what we are accustomed to in our patients with CIRD.  There are scattered reports of similar respiratory outbreaks prior to Oregon, possibly as long as a year ago, and a few different geographic locations have been reported.

Multiple laboratories are at work trying to isolate the organism or organisms that may be the cause of this new outbreak. Early information from the New Hampshire veterinary diagnostic lab suggests this may be a very tiny bacterium that does not culture readily and is being identified via DNA sequencing . It has not been isolated sufficiently even to permit characterization of the bacterium. As expected with any newly recognized organism, there is no test to determine its presence nor a clear treatment protocol that is consistently successful. Some dogs that have been quite sick over the last 3 to 6 months have tested positive for more traditional agents such as Canine Influenza virus, and Mycoplasma cynos. As noted earlier, dogs can be completely asymptomatic and healthy and still carry some of these respiratory organisms, which will trigger a positive PCR test. Multiple studies have determined that normal healthy dogs are often colonized with one or more of these infectious species that are known to cause respiratory disease in susceptible pets.

Given how early we are in this process, accurate testing will not become available in the near future and immunizations to protect our pets from this organism will take even longer. Since respiratory organisms often work in concert, it is imperative that we prevent infection with our known respiratory agents as much as possible. Influenza vaccines for dogs, like humans, are designed to reduce the severity of the disease but will not necessarily prevent infection 100%. We do know that the presence of canine parainfluenza virus can significantly increase the severity of infection with other agents as it causes damage to the lung tissue directly. We can, and should, vaccinate our susceptible population to try to reduce the risk of Bordetella bronchiseptica, canine parainfluenza virus, and canine influenza viruses. Combined with the new infectious agent, any of these would undoubtedly worsen the outcome. The veterinary labs that are attempting to research this organism are requesting that samples be provided directly from the veterinary hospitals prior to the initiation of any medications as they may reduce the ability to culture this suspected bacterium.

Given that some dogs are becoming severely ill very quickly, it is also recommended to have these animals examined very early in an attempt to intervene before the pneumonia becomes severe. PCR testing is still recommended as many dogs that are presenting with canine cough and respiratory symptoms actually still have one of the better-known organisms that cause respiratory disease. PCR testing is most accurate early in the disease. Delays can cause false negative results. Co-infection will still be a concern if the PCR is positive and the dog is severely ill or presenting with one of the three syndromes associated with this new infection.

Canine respiratory outbreaks tend to wax and wane and pop up in different locations from time to time. There are often isolated but significant outbreaks of respiratory disease in relatively small geographic areas that then move to another area, causing a different outbreak. This has been happening for years but without the severity of the outcomes seen in this current small population, who are affected much more gravely than expected historically.

In summary, if indeed there is a new organism causing these outbreaks, isolation of this new organism may prove difficult, and the ability to test for it specifically is probably long in the future. Dogs presenting with respiratory symptoms should be examined and treated as early as possible during the disease. PCR testing done early can still be informative and should be performed. Since co-infection may worsen the prognosis, it is recommended to ensure all dogs are current on their Canine Parainfluenza, Bordetella bronchiseptica, and canine influenza immunizations.

The assumption is this organism is probably airborne but may also be carried from dog to dog by fomites which includes potentially grooming tools, leashes, collars, and probably direct human contact. When possible, avoid areas where unfamiliar dogs tend to congregate, such as dog shows, canine sporting events, dog parks, doggie daycare, boarding and grooming facilities. These are areas where you are most likely to encounter dogs of unknown health and immunization status. Dogs you know personally, their health, immunization status and recent travel or exposures, are often relatively low risk by comparison. Watch the local news for any indication that the infection has reached your local area. While it may not always be practical to isolate your pet from all other dogs, attempt to reduce direct contact with unfamiliar dogs and sanitize your own hands carefully after touching any other dogs.  If your pet is sick with a cough, please call your veterinary hospital before arriving and they will advise you on protocol to help prevent exposure to the other pets in the facility.  If your dog has been ill with respiratory symptoms, the current recommendation is a minimum of 3-4 weeks isolation from other dogs.

It is likely that we will gain much more information in the coming months, but concrete answers may require patience if this truly is a new organism not previously isolated and described.

The current list of known canine respiratory pathogens:

Viral pathogens include canine distemper (CDV), parainfluenza (CPIV), adenovirus type 2 (CAV-2), influenza (CIV, two strains), herpesvirus (CHV-1), respiratory coronavirus (CRCoV), pantropic coronavirus, reovirus, and pneumovirus (CnPnV). Other emerging viral pathogens associated with CIRD are canine bocavirus, hepacivirus, and picornavirus.

Bacterial pathogens include Bordetella bronchisepticaMycoplasma spp., and Streptococcus equi subsp. zooepidemicus.


For more information on this rapidly changing situation:


From The American Veterinary Medica Association

Updated June 11, 2020


Despite the number of global cases of COVID-19 surpassing the 7 million mark as of June 8, 2020, we are aware of only a handful of pets and captive or farmed wild animals globally that have tested positive for SARS-CoV-2. In all cases, the source of the infection for pets was presumed to be one or more persons with confirmed or suspected COVID-19. At this point in time, there is also no evidence that domestic animals, including pets and livestock, play a significant role in spreading SARS-CoV-2 to people.

Therefore, the AVMA maintains its current recommendations regarding SARS-CoV-2 and animals. These recommendations, which are supported by guidance from the US Centers for Disease Control and Prevention (CDC) and World Organization for Animal Health (OIE), are that:

  • Animal owners without symptoms of COVID-19 should continue to practice good hygiene during interactions with animals. This includes washing hands before and after such interactions and when handling animal food, waste, or supplies.
  • Do not let pets interact with people or other animals outside the household.
  • Keep cats indoors, when possible, to prevent them from interacting with other animals or people.
  • Walk dogs on a leash, maintaining at least 6 feet from other people and animals. Avoid dog parks or public places where a large number of people and dogs gather.
  • Until more is known about the virus, those ill with COVID-19 should restrict contact with pets and other animals, just as you would restrict your contact with other people. Have another member of your household or business take care of feeding and otherwise caring for any animals, including pets.  If you have a service animal or you must care for your animals, including pets, then wear a cloth face covering; don’t share food, kiss, or hug them, and wash your hands before and after any contact with them.
  • At this point in time, there is no evidence to suggest that domestic animals, including pets and livestock, that may be incidentally infected by humans play a substantive role in the spread of COVID-19.
  • Routine testing of animals for SARS-CoV-2 is NOT recommended. Veterinarians are strongly encouraged to rule out other, more common causes of illness in animals before considering testing for SARS-CoV-2.
  • Human outbreaks are driven by person-to-person transmission and, based on the limited information available to date, the risk of animals spreading COVID-19 to people is considered to be low. Accordingly, we see no reason to remove pets from homes even if COVID-19 has been identified in members of the household, unless there is risk that the pet itself is not able to be cared for appropriately.

During this pandemic emergency, animals and people each need the support of the other and veterinarians are there to support the good health of both.

Canine Influenza

June 5, 2017 Update

Canine Influenza update: There have been over 12 cases of canine influenza diagnosed as the H3N2 strain by the University of Florida. All the diagnosed pets attended dog shows in Perry, Georgia on May 19-21 and/or Deland, Florida the following weekend or were in contact with dogs that attended those two dog shows.

To date, this has not spread beyond this population of show dogs. While vaccinations are now available for this strain, it does require a series of two vaccinations 2 to 4 weeks apart and the vaccinated dogs are unlikely to have a protective level of immunity for at least 4-6 weeks. Given the limited population affected thus far and the delay in acquiring protective immunity from vaccination, we are not yet recommending vaccination for our normal non-showing pet population. Show dog owners are being advised to keep their pets at home for at least four weeks to decrease the risk of spreading the virus. Asymptomatic dogs can still be contagious if they have been exposed. We will update this information here and on Facebook should the situation change appreciably. -Dr Baird

Please see this link for information from the University of Florida with more information.

What you need to know……

The canine influenza virus first appeared in 2004 & 2005 in several Florida racing greyhound track facilities. Research since this suggests this virus mutated from the equine influenza virus. Influenza antibodies, however, have been found in samples from the 1990’s, suggesting a milder form likely predates this one. There is no evidence to suggest this virus can be transmitted to humans.

In the years since it first appeared, the feared deadly epidemic never occurred. We did have a scare in Chicago and in Atlanta in 2015 with many cases of influenza, which thankfully was far milder and had less impact than the original strain that was so dangerous at the dog tracks in the previous decade. Interestingly, these 2015 outbreaks were of a different strain, H3N2, so likely more mutation has occurred or it is a completely different origin, perhaps Asia. To the best of our knowledge, the Canine Influenza Vaccine originally developed for the H3N8 strain, is not effective in preventing this new strain, H3N2. Crowded housing facilitates the spread of the virus from dog to dog, as is typical of most contagious respiratory diseases, so the best prevention is to reduce exposure to other dogs during an outbreak such as occurred in Chicago.

Of those dogs exposed to the virus, it is estimated 20-50% will show no visible evidence of disease. Evidence suggests that perhaps 50% of infected dogs develop antibodies without ever showing any clinical disease at all. The remainder will have symptoms typical of infectious respiratory disease including cough, fever, decreased appetite and lethargy. Approximately 1% of infected dogs will develop serious complications as a result of canine influenza, most typically secondary bacterial pneumonia. These patients do require intensive treatment, preferably early in the course of the disease.

In 2009, a Canine Influenza vaccine was released. The vaccine carries a conditional license by the FDA, indicating that efficacy has not yet been proven although safety studies have been performed in over 700 dogs. The vaccine is intended as an aid in the control of disease associated with Canine Influenza virus infection. Although the vaccine is not expected to prevent infection altogether, efficacy trials have shown that the vaccination may significantly reduce the severity and duration of clinical illness, including the incidence and severity of damage to the lungs. In addition, the vaccine reduces the amount of virus shed and shortens the shedding interval; therefore, vaccinated dogs that become infected develop less severe illness and are less likely to spread the virus to other dogs.

Locally, there have been no reports from our specialty hospitals of any Canine Influenza cases in Hillsborough, Pinellas or Pasco counties. Given the frequency with which pets travel, this certainly could change in the future. At this time, we heartily recommend vaccination only for dogs traveling to areas with known risk of Canine Influenza, particularly if this travel will include exposure at dog shows, boarding or grooming facilities. Since the influenza virus is only causing problems in certain regions within certain states, it is advisable to check with veterinarians in that specific area prior to travel to determine if there is a known risk locally. The initial dose of vaccine requires a booster 2 to 4 weeks after the first dose is given, and the second dose should be given at least 7 days prior to the dog entering the at-risk situation (boarding kennel, dog show, etc.) , so the vaccine series should be started at least 4 weeks prior to travel.

Links for Canine Influenza ….


Leptospirosis is a bacterial infection resulting from contact with infected wildlife, urine from infected dogs or contaminated water or food. Twenty and thirty years ago, this was primarily a rural disease and often associated with cattle. Unfortunately, the two strains (or serovars) that used to cause most of the Leptospirosis in pet dogs have been surpassed by two additional strains which are now causing the majority of disease in dogs. Furthermore, these two new strains (serovars) seem to be flourishing in suburban and urban environments and are increasing in prevalence nationwide. Pinellas, Pasco & Hillsborough counties have joined the ranks of Florida counties with confirmed cases of Leptospirosis in pet dogs. A vaccine to help protect against these four pathogenic strains is finally available from a reputable vaccine manufacturer (Pfizer). Two additional strains or serovars are currently being studied to determine if they are also contributing to the recent increases in cases of Leptospirosis in pet dogs.

Most dogs in populated areas become infected from drinking contaminated water or coming in contact with contaminated urine. This water (puddles, ponds, outdoor water bowls, creeks) may become contaminated by infected carriers such as raccoons, opossums, citrus rats and other rodents. The Leptospira bacteria can live in the water for months.

Leptospira bacteria infect the kidneys and liver, causing fever, anorexia, depression and generalized pain initially. Diagnosis is complicated by the fact that the early signs of Leptospirosis are vague and nonspecific. Most animals will progress to acute kidney failure and mortality rates in untreated, unvaccinated dogs may vary from 10% to 75%, depending on the serovar involved. Vaccination will not only help prevent the disease, but will also reduce the symptoms and prevent shedding of the bacteria should a breakthrough occur. Two vaccinations are given 3 weeks apart and then followed by an annual booster.

Leptospirosis is also contagious to humans (although uncommon) and this further adds to our concern with this reemerging disease. It is also a potentially life threatening disease in humans, again primarily by causing kidney damage. The mortality rate in humans with the kidney and liver form is about 10%. There currently is no vaccination for humans.

Given the current increase in prevalence of the emerging strains of Leptospira bacteria, we are recommending this vaccine for all our canine patients over the age of 10-11 weeks.

Links for Leptospirosis …….

Disease in Animals
Disease in Animals & Humans
Disease in Humans
More on Disease in Humans (CDC)

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