A new and unknown respiratory disease that affects dogs has been reported in 16 states across the U.S., according to the Louisiana State University School of Veterinary Medicine. The illness, which has been named Atypical Canine Infectious Respiratory Disease Complex (ACIRDC), causes symptoms such as fever, cough, and lethargy in dogs, and can sometimes lead to pneumonia and death. Experts are still investigating the cause and the treatment of the disease, as well as the risk of transmission to humans.

Mysterious Dog

What is ACIRDC and how does it affect dogs?

ACIRDC is a term that veterinarians use to describe a complex of respiratory signs that are not typical of the common canine infectious respiratory disease (CIRD), also known as kennel cough. CIRD is usually caused by a combination of viruses and bacteria that infect the upper respiratory tract of dogs, and can be prevented by vaccination. ACIRDC, on the other hand, seems to affect the lower respiratory tract of dogs, causing inflammation of the trachea and bronchi, and sometimes pneumonia that does not respond to antibiotics. ACIRDC can last for six to eight weeks or longer, and can be fatal in rare cases.

The symptoms of ACIRDC include:

Coughing
Sneezing
Nasal discharge
Fever
Lethargy
Loss of appetite
Difficulty breathing

Some dogs may show mild or no signs of the disease, while others may develop severe and rapid respiratory distress that can lead to death within 24 to 36 hours. Dogs with preexisting chronic respiratory illness may be more likely to develop pneumonia. The disease seems to affect dogs of all ages, breeds, and sexes, but may pose a higher risk for brachycephalic breeds, such as pugs and French bulldogs, that have flat faces and short snouts.

Where and when did ACIRDC emerge and spread?

The first cases of ACIRDC were recognized in Oregon earlier this year, where more than 200 cases have been reported, mostly in the Portland area. Since then, the disease has spread to 15 other states, including California, Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Maryland, Massachusetts, Nevada, New Hampshire, Pennsylvania, Rhode Island, Vermont, and Washington. The most recent cases were confirmed in Pennsylvania and Nevada in December 2023.

The exact number of cases nationwide is unknown, as there is no official reporting system for ACIRDC. However, the Louisiana State University School of Veterinary Medicine has been collecting data from veterinarians and diagnostic laboratories across the country, and has created a map that shows the states where ACIRDC has been confirmed or suspected.

The map shows the states where ACIRDC cases have been confirmed (red) or suspected (cream) as of November 22, 2023.

What is the cause and the treatment of ACIRDC?

The cause of ACIRDC is still unknown, and experts are working to identify the agent or agents that are responsible for the disease. Several diagnostic tests have been performed on samples from affected dogs, but none of them have revealed a definitive answer. Some of the tests have detected the presence of common respiratory pathogens, such as canine influenza virus, canine parainfluenza virus, canine adenovirus, canine distemper virus, Bordetella bronchiseptica, and Mycoplasma spp., but none of them have been consistently found in all cases. Other tests have ruled out the possibility of novel or emerging pathogens, such as SARS-CoV-2, the virus that causes COVID-19 in humans.

One of the leading hypotheses is that ACIRDC may be caused by a new strain of Streptococcus zooepidemicus, a bacterium that is commonly found in horses and can cause respiratory infections in dogs. The University of New Hampshire’s Veterinary Diagnostic Laboratory has reported that it has identified this bacterium in 30 dogs from New Hampshire in 2022 and 40 dogs from Rhode Island and Massachusetts in 2023, based on genetic sequencing. However, this finding has not been confirmed by other laboratories, and it is unclear whether this bacterium is the primary cause of the disease or a secondary opportunistic infection.

Because the cause of ACIRDC is unknown, there is no specific treatment or prevention for the disease. Veterinarians recommend that owners of affected dogs provide supportive care, such as hydration, nutrition, and oxygen therapy, and monitor their dogs closely for signs of worsening. Antibiotics may be prescribed to treat secondary bacterial infections, but they may not be effective against the underlying cause of the disease. Anti-inflammatory drugs, such as steroids, may also be used to reduce inflammation, but they may have side effects and should be used with caution. In some cases, dogs may require hospitalization and intensive care.

To prevent the spread of the disease, owners of affected dogs should isolate them from other dogs and avoid contact with other people, as the disease may be contagious through respiratory secretions. Owners should also practice good hygiene, such as washing their hands and disinfecting surfaces, and consult their veterinarians before traveling with their dogs to other states. Owners of healthy dogs should avoid exposing them to dogs that may be sick, and make sure they are up to date on their vaccinations for CIRD. However, it is important to note that the current vaccines for CIRD may not protect against ACIRDC, as they target different pathogens.

Is ACIRDC a threat to human health?

One of the main concerns about ACIRDC is whether it can infect humans, as some respiratory diseases can cross the species barrier and cause zoonotic infections. However, there is currently no evidence that ACIRDC has zoonotic potential, meaning that it cannot be transmitted from animals to people. According to the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, which is working with state animal health officials and diagnostic laboratories to investigate the disease, no human cases of ACIRDC have been reported, and no human pathogens have been detected in the samples from affected dogs. The Centers for Disease Control and Prevention, which is also monitoring the situation, has stated that there is no public health risk associated with ACIRDC at this time.

However, experts advise that people who have contact with sick dogs should take precautions, such as wearing masks and gloves, and seek medical attention if they develop any respiratory symptoms, as they may be exposed to other infectious agents that can cause illness in humans. People who have underlying health conditions, such as asthma, COPD, or immunodeficiency, may be more susceptible to respiratory infections and should avoid contact with sick dogs. People who have questions or concerns about their health or their pets’ health should consult their doctors or veterinarians.

What are the next steps to solve the mystery of ACIRDC?

The investigation of ACIRDC is ongoing, and experts are collaborating to find answers and solutions to this emerging disease. Some of the goals of the investigation are:

To collect more data and samples from affected dogs and compare them with those from healthy dogs
To perform more advanced diagnostic tests, such as whole genome sequencing, to identify the cause or causes of the disease
To develop new tests and vaccines that can detect and prevent the disease
To monitor the epidemiology and the spread of the disease
To educate and inform the public and the veterinary community about the disease and its prevention

The experts are asking for the cooperation and the participation of the dog owners and the veterinarians who are dealing with the disease, as they are the key sources of information and samples. They are also asking for the patience and the understanding of the public, as the investigation may take time and resources, and the results may not be conclusive or definitive. They are hopeful that with the combined efforts of the scientific and the veterinary communities, they will be able to unravel the mystery of ACIRDC and protect the health and the welfare of the dogs and their owners.