Atypical canine infectious respiratory disease complex

Atypical canine infectious respiratory disease complex (aCIRDC) is a proposed novel respiratory disease in dogs^[1] of unknown cause. It has been recorded in 19 US states, with more cases on the West Coast.^{[citation needed]}

It has also been referred to as respiratory syndrome of unknown aetiology in dogs and as canine respiratory disease of unknown origin.^[2]

History

It was first described in summer 2023 as a cluster of 200 cases around Portland, Oregon.^[3]

Characteristics

Symptoms include a cough, fever, lethargy, sneezing and watery eyes. In some cases, the illness proceeds to death.^[1] Cases tend to fit three clinical syndromes: chronic mild/moderate tracheobronchitis of prolonged duration (6+ weeks),^[4] with coughing, sneezing, and watery eyes; chronic pneumonia that is minimally responsive to antimicrobials, possibly including dyspnea; and, rarely, acute pneumonia that rapidly becomes severe and can lead to death.^[5][6] Most cases are self-limiting and respond well to supportive care.^[7] Antibiotics may be indicated.^[6]

Diagnosis should rule out known forms of canine infectious respiratory disease complex (CIRDC; also known as kennel cough). aCIRDC does not respond to regular treatment protocols for CIRCD and the course of the disease is longer and more severe.^[8]

There is no evidence that it can spread to humans.^{[citation needed]}

Cause

The cause is currently unknown.^{[citation needed]}

The Veterinary Diagnostic Laboratory at the University of New Hampshire have put forth a possible bacterium as the cause.^[5] They have tentatively identified this as IOLA KY405,^[9] which was previously identified in humans in 2021.^[10] This is similar to Mycoplasma in lacking a cell wall and having a small genome.^[9]

However, other vets have suggested that this might just represent a peak in CIRDC cases and not involve any new pathogens. This could be due to changes in human behaviour following the end of COVID-19 lockdowns and other COVID-19-related disruption to veterinary care (e.g. frequency of vaccination), as well as to the general increase in dog numbers in the US.^[11][6]

See also

• 2022 hepatitis of unknown origin in children