Mysterious Respiratory Disease Reportedly Spreading Among Dogs Across the Country


12/8/23 update — Dr. Crawford to join webcast on “Mystery Respiratory Illness” and Steps to Manage Canine Infectious Respiratory Disease Complex

Date: Monday December 11, 2023
Time: 2 pm ET, 11 am PT
Register:  Canine Respiratory Disease Webcast
Our own Dr. Cynda Crawford will join a panel of experts to discuss practical steps to reduce respiratory disease risk in shelters from all the usual suspects, as well as the latest understanding of the “mysterious respiratory illness” in dogs.
Hear from Dr. Cynda Crawford, Clinical Associate Professor in Shelter Medicine at the University of Florida, Dr. Cynthia Karsten, Director of Outreach at UC Davis Koret Shelter Medicine and Dr. Scott Weese, Director of the Centre for Public Health and Zoonoses at the University of Guelph and author of the “Worms & Germs Blog.” Attendees will have a chance to submit written questions in the chat during the call.
Sign up for the UF Shelter Medicine newsletter so you never miss timely updates on disease trends, educational programs, grants, and advances in animal sheltering:

12/2/23 update — Kansas State Veterinary Diagnostic Laboratory offers testing for “mysterious canine respiratory disease.” 

To help determine the associated pathogen(s) involved in the canine respiratory disease circulating in some areas of the U.S., KSVDL is offering free Next Generation Sequencing testing through December 31, 2023.

Submissions eligible for free testing can originate from veterinary practitioner submissions only and from cases where the practitioner suspects this new respiratory disease is involved.

Suitable samples:

  • (5 gm) Tissue (lung, lymph node, or tonsil)
  • Swabs (Nasal of pharyngeal)
  • Washes (tracheal or BAL)
  • A gel bacterial swab is not acceptable.
  • Cotton-tipped and/or wooden shaft swabs are not acceptable.

The report from KSVDL identifies the organism(s) found in the sample. These may of may not be the causative organism(s) associated with this case.

Find detailed submission guidelines at  Clients must ask for MDL-0202 to participate in this offer.

If you have questions, please contact KSVDL Client Care at 866-512-5650 or

11/29/23 update — webinar on canine respiratory illness

In response to continued reports of an upswing in respiratory illness impacting dogs across various US states, Trupanion invites you to join an exclusive, free live webinar featuring a panel of global veterinary authorities and thought leaders.

  • Real time updates: Stay informed with the latest updates on canine respiratory illness, leveraging Trupanion’s database of over 3 million Trupanion-protected pets.
  • Prevention strategies: Learn effective strategies and practical measures you can take to safeguard your pup’s health.
  • Signs to watch for: Learn how to recognize early signs, empowering you to take proactive steps to address potential concerns.

Your questions during our live, interactive Q&A: Engage directly with our panel of experts to ask specific questions and deepen your understanding of canine respiratory health.

11/27/23 update — This is a rapidly evolving situation – come back for updates as more information develop

Veterinarians are reporting an increased number of dogs presenting with acute respiratory infections ranging from mild and self-limiting to life-threatening pneumonia. The disease is reportedly nonresponsive to commonly prescribed antibiotics, and diagnostic testing is often negative for known canine pathogens.

It is not yet clear if this is caused by a novel emerging pathogen or one of the well-known causes of Canine Infectious Respiratory Disease Complex (CIRDC casually known as “kennel cough”). The lack of a centralized reporting system means it’s not even possible to confirm that there is a spike in CIRDC incidence or severity. The intense media coverage of a “mystery disease” may be raising awareness and discussion about CIRDC cases that would otherwise be managed as usual. It’s also possible that localized clusters are occurring due to one or more known pathogens due to some predisposing factor, such as an asymptomatically infected dog visiting a dog park, day care, dog show, or boarding kennel, etc.

Dog nasal swab

Many of the cases suspected to have “atypical CIRDC” have not had diagnostic testing. Some were tested, but only after weeks of resolving cough. That’s too late to detect some of the most likely culprits, such as influenza virus, pneumovirus, and respiratory coronavirus. And many were tested with a respiratory panel at a large diagnostic lab that does not include pneumovirus, which could be causing the disease in some dogs. Researchers are also looking into the possibility of emerging or increasingly virulent pathogens.

H3N2 CIV is currently circulating along the eastern and western coasts as documented in show dogs and shelters. Although most cases of atypical CIRDC have been reported in privately owned dogs seen at veterinary clinics, the Shelter Medicine Program at the University of Florida is currently working with several shelters with highly contagious pneumovirus and/or Streptococcus equi subsp. zooepidemicus across the country. While these pathogens are familiar to shelters, many private practitioners may not have diagnosed them before. Both cause pneumonia that can progress to a life-threatening situation. Co-infections with multiple pathogens can be especially debilitating.

At this time, we recommend being especially vigilant to identify and segregate dogs with respiratory signs. Respiratory PCR panels should be submitted within 4 days of the first clinical signs, especially in dogs recently exposed to other dogs. Visits with other dog populations should be minimized, and dogs should be kept current on DHPP and CIRC vaccinations (including CIV for owned pets).

While much is unknown about reported atypical CIRDC, basic disease control and treatment protocols as described below will help keep dogs safe and provide a roadmap for diagnosis and treatment.

Dogs at Risk

  • Dogs that visit with other dogs, such as boarding, day care, dog shows, dog parks, groomers
  • Suspect cases have been reported in at least 12 states, including Florida
  • So far, animal shelters seem to be less frequently affected by unknown pathogens, although historic levels of crowding present risks for outbreaks
  • People and other species have not been reported to be at risk


  • Implement standard isolation and quarantine procedures for dogs with respiratory signs
  • Promptly isolate dogs with respiratory signs and use PPE
  • Have clients call ahead before bringing a dog with respiratory signs to a veterinarian or shelter and assess them outside before bringing them into the facility
  • Use disinfectants effective against nonenveloped viruses and hardy pathogens such as accelerated hydrogen peroxide or calcium hypochlorite
  • Sanitize animal areas, fomites, and potentially contaminated items such as doorknobs, phones, and desk spaces
  • Avoid venues where groups gather with unfamiliar dogs, such as dog parks, day care, boarding, dog shows, groomers unless limited to a stable group of healthy dogs
  • Keep DHPP and Bordetella bronchiseptica vaccinations up to date
  • Vaccination against canine influenza virus is appropriate for pet dogs or dogs expected to be in custody for prolonged periods (months); however two doses are required and protection requires at least 4 weeks to develop

Clinical Signs

  • Highly contagious, rapidly spreading among dogs in contact with other dogs
  • Acute cough, sneezing, nasal discharge, eye discharge, fever, anorexia, lethargy
  • Severe form can progress to life-threatening pneumonia requiring oxygen and ventilator support
  • Cough may persist for weeks to months


  • Swabs for PCR testing should be collected within 4 days of the first clinical signs to avoid missing pathogens with short shedding periods such as CIV, Pneumovirus, and respiratory coronavirus
  • Respiratory PCR panels should include Bordetella bronchiseptica, Canine adenovirus type 2, Canine distemper virus, Canine herpesvirus (CHV-1), Canine parainfluenza virus, Canine pneumovirus, Canine respiratory coronavirus (CRCoV), Influenza A virus, Mycoplasma cynos, and Streptococcus equi subsp. zooepidemicus
  • Respiratory cultures may be indicated for suspected bacterial infection not responsive to first-line treatment
  • The three major commercial diagnostic laboratories offer respiratory PCR panels for the following pathogens:
Table of respiratory PCR panels


  • Mild disease may be self-limiting without treatment. Cough suppressants may be used as indicated to increase comfort. Hospitalization for rehydration, nebulization, intravenous antibiotics, oxygen therapy, or ventilatory support may be required for more severely affected dogs.
  • Download the Firstline app for Antimicrobial Use Guidelines designed for common veterinary conditions and antimicrobial stewardship
  • Note: Streptococcus equi subsp. zooepidemicus may be resistant to doxycycline and fluoroquinolone antibiotics. If Strep zoo is suspected, treatment should be started with a cephalosporin or potentiated penicillin, such as cefpodoxime proxetil (Simplicef) or amoxicillin clavulante (Clavamox) for 5-7 days (or other antibiotic shown to be effective based on culture and sensitivity). Outbreaks of Strep zoo infection in dog populations are often characterized by hemorrhagic pneumonia,  rapid deterioration, and high mortality.
  • Firstline guidelines for CIRD

    • Usually viral or self-limiting bacterial infection, often antimicrobials not required; other treatment options (i.e. macrolides (e.g. azithromycin)) rarely needed
    • If <10d duration with no evidence of pneumonia: No treatment
    • If >10d duration and fever, lethargy or inappetence, plus mucopurulent discharge: consider doxycycline or amoxicillin-clavulanic acid as below
    • Treat for 7-10 days. Note: recent human guidelines for community-associated pneumonia recommend 3-5 days, a duration that might equally apply to CIRDC
  • Firstline guidelines for pneumonia without systemic disease

    • Affected dogs typically have radiographic evidence of pneumonia but no signs of systemic disease (e.g. fever, lethargy, inappetence)
    • Lower airway sampling for culture recommended
    • Doxycycline 5 mg/kg PO q12h or 10 mg/kg PO q24h preferred over amoxicillin-clavulanic acid as broader spectrum (Mycoplasma spp.) and recent evidence most B. bronchiseptica not susceptible to amoxicillin-clavulanic acid
    • Amoxicillin-clavulanic acid 12.5-25 mg/kg PO q12h If doxycycline is contraindicated in the dog
    • Re-evaluate in 7-14 days. Seven days is likely adequate in most cases. However, recent human guidelines for community-associated pneumonia (a close analogy to this condition in dogs) recommend 3-5 days. This shorter course is reasonable to consider in dogs. Radiographic resolution is a lagging indicator and should not be the target for stopping treatment.
  • Firstline guidelines for pneumonia with systemic disease/sepsis

    • Affected dogs typically have combinations of fever, lethargy, inappetence and tachycardia + radiographic evidence of pneumonia
    • Lower airway sampling for culture recommended
    • Enrofloxacin 10-20 mg/kg IM/IV q24h alone or in combination with ampicillin or clindamycin
    • Ampicillin 22-30 mg/kg IV/SQ q8h or clindamycin 10-15 mg/kg IV q12h
    • Re-evaluate in 7-14 days; total therapy is often 4-6 weeks but shorter durations (e.g. 7-14 days) may be appropriate. Optimal duration is not established and might be shorter. Transition to oral therapy is appropriate based on clinical response; amoxicillin can be used in place of parenteral ampicillin.

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