A mysterious respiratory illness with similarities to viral pneumonia is rapidly spreading among dogs across the United States, with cases now reported in over a dozen states. While the exact cause remains unknown, researchers are racing to identify the pathogen and contain the outbreak.
Over 1,000 Cases Reported Nationwide
The first cases emerged in early September 2022 in Otsego County, Michigan. Since then, over 1,000 probable cases have been documented across 14 states, with the highest numbers seen in Michigan, New York, Massachusetts, and California.
The illness produces coughing, difficulty breathing, nasal discharge, lethargy, and loss of appetite. While most dogs recover, some rapidly decline. The overall fatality rate is estimated at around 5-10%, but reaches over 50% in patients with severe pneumonia.
Dr. Rena Carlson, a Minnesota veterinarian who has treated dozens of affected dogs, emphasizes that owners should monitor pets closely but avoid panicking:
"Owners should watch for respiratory signs but not be overly alarmed. This seems very treatable if caught early. But any trouble breathing warrants an urgent vet visit as it can progress quickly."
Flu-Like Symptoms With Severe Pneumonia
The disease initially resembles kennel cough, presenting with fever, sneezing, and coughing. However, some patients – especially those co-infected with other pathogens – rapidly develop pneumonia.
In these severe cases, dogs struggle heavily to breathe and can die without oxygen and fluid support. Symptoms typically arise 2-7 days after exposure but can manifest in as little as 12 hours in vulnerable individuals.
With flu season underway, distinguishing this illness from other canine respiratory diseases has proven challenging. The age range also varies widely, from 6-week old puppies to dogs over 10 years old.
Spread Through Dog-to-Dog Contact
Experts currently believe spread occurs through direct contact with infected dogs, likely via respiratory droplets or fomites. Boarding and daycare facilities have proven high-risk due to the degree of exposure. Kennel cough is already prevalent at many sites and may predispose dogs to this secondary illness.
Several facilities, including Redlands Obedience Dog Club in California, have temporarily halted operations to avoid further spread. However, the long incubation period means we likely have not yet seen the full extent.
Individual cases have been managed by isolating dogs at veterinary hospitals. But wider containment poses difficulties without knowing the exact transmission patterns or risk factors.
Unknown Pathogen – Possibilities Include Canine Pneumovirus
Researchers have ruled out canine influenza as no genomic material has been detected in samples from sick dogs. However, they do see changes resembling viral pneumonia – still without finding a causative virus.
Attention has focused on Canine pneumovirus, which belongs to the same viral family as human RSV. It contributes to kennel cough but only rarely progresses to pneumonia.
University of New Hampshire scientists recently found canine pneumovirus RNA in bronchoalveolar lavages from three affected dogs. However, they remain unsure if it is actually the culprit or just a bystander.
Identifying the underlying pathogen has critical implications for containment and treatment. In the meantime, vets are empirically managing supportively based on symptoms.
Empiric Treatment With Antibiotics, Anti-Inflammatories, Antivirals
With the cause still unknown, treatment consists of addressing secondary infections and controlling inflammation. Broad-spectrum antibiotics like doxycycline tackle bacterial pneumonias that often strike in tandem.
Powerful anti-inflammatory corticosteroids like dexamethasone impede harmful immune responses in the lungs. Some vets are also trying antivirals used for influenza and COVID-19 with mild success so far.
Dr. Laura Struble, a Veterinarian in Iowa, has prescribed the antiviral remdesivir after noticing similarities with human viral pneumonia:
“It’s not a cure-all by any means, but it has taken the edge off the severity in a couple of my patients.”
Those with respiratory distress require oxygen therapy and intravenous fluids to prevent dangerous fluid build-up. Such supportive care proves essential for recovery in advanced cases.
Recommendations For Pet Owners – Vaccines, Avoiding Contact
Veterinary groups advise keeping dogs away from high-risk areas like dog parks and kennels as much as possible in affected regions. Canine influenza boosters may offer partial protection, although effectiveness remains unproven thus far.
Owners concerned about exposure should monitor pets vigilantly for at least 2 weeks for any signs of fever, coughing, sneezing or breathing issues. Early veterinary review provides the best opportunity for intervention before pneumonia sets in.
Investigations Ongoing – Outbreak Expected To Worsen
Even as dogs continue falling ill, researchers across veterinary diagnostic labs, universities, and businesses race to uncover answers. Cornell University College of Veterinary Medicine and IDEXX Reference Laboratories are among those leading the charge.
IDEXX announced detecting a bacterium, streptococcus zooepidemicus, in some sick dogs. However, many infections appear secondary to an unknown initial virus. Nevertheless, pinpointing cofactors brings us steps closer.
With flu season ramping up and a likely viral culprit at play, experts expect substantially more cases in the coming months. Stopping the outbreak presents a formidable but urgent challenge.
Until effective prevention emerges, vigilant monitoring and swift treatment constitute our best options for impacted pet owners. However, the mysterious disease serves as an ominous reminder of viral illnesses ever poised to leap across species and evade our countermeasures.
This developing situation may bring frightening uncertainties. But hopefully shining light on this perplexing pathogen can better prepare us for the inevitable next novel disease.
Timeline of Major Events
| Date | Event |
|---|
| September 2022 | First cases emerge in Michigan dogs
| October 2022 | Outbreak spreads to neighboring Midwestern states
| November 2022 | Cases start appearing along entire Eastern U.S. seaboard
| December 2022 | Western states, including California and Washington, begin reporting illnesses
| December 5th, 2022 | Cornell University and IDEXX Reference Labs announce involvement in investigations
At-A-Glance Facts
- Respiratory disease of unknown cause emerging in dogs
- Possible viral etiology – canine pneumovirus is suspected
- Over 1,000 U.S. cases reported as of December 2022
- Highest case burden in Midwestern and Eastern states
- 5-10% overall fatality rate
- Pneumonia proves deadly in over 50% of affected dogs
- Spread through dog-to-dog contact at kennels, parks, shelters
- No vaccine or targeted treatment currently available
- Supportive care with oxygen, fluids aims to buy time
- Recommend avoiding suspected infection hotspots
- Monitor pets closely for signs of illness
To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.
