In recent months, a perplexing respiratory syndrome has been plaguing dogs across the country, with a focus on the New England region. Termed "Respiratory Syndrome of Unknown Etiology in Dogs 2022-3," this enigmatic illness has veterinarians and researchers on high alert, as affected animals display upper respiratory symptoms resistant to conventional treatments, all while eluding identification through standard diagnostic tests for common respiratory pathogens.

The Challenge of the Unknown

Veterinarians routinely encounter and address typical canine respiratory pathogens. However, the cases under scrutiny have tested negative for these standard pathogens, prompting a comprehensive investigation to explore the possibility of emerging pathogens previously unidentified as causes of respiratory disease. It is crucial to note that any findings at this stage are preliminary, and ongoing investigations are essential for conclusive determinations.

Clinical Presentation

Clinically, the affected dogs exhibit symptoms akin to other canine respiratory diseases like kennel cough. Strikingly, these cases prove refractory to standard medical treatments and often yield negative results on syndromic canine respiratory disease PCR testing. The duration of illness is prolonged, with some cases progressing to pneumonia. While anecdotal reports in New Hampshire suggest mortalities, submissions of carcasses or excised lung tissue have been minimal.

Timeline of Investigation

The investigative journey began in late summer and autumn of 2022 in New Hampshire. Prompted by anecdotal reports, the New Hampshire Veterinary Diagnostic Lab (NHVDL) and Hubbard Center for Genomic Studies (HCGS) at the University of New Hampshire initiated the analysis of respiratory specimens from NH cases using cutting-edge metagenomic techniques. In 2023, samples from southeastern Massachusetts and northern Rhode Island, reporting increased cases, were also included in the analysis. Preliminary findings were shared with veterinarians in New Hampshire and neighboring New England states, where similar reports of infection were emerging.

Widening the Scope

The investigation has since expanded its reach, with samples arriving from Oregon and anticipated arrivals from Colorado, Illinois, and other states. This broader scope aims to determine if the identified findings in the New England region are consistent across the nation.

Preliminary Findings

Initial metagenomic analysis did not identify known canine respiratory pathogens, RNA or DNA viruses of concern, or typical fungal or bacterial respiratory pathogens. Notably, a non-culturable, bacterial-like organism resembling Mycoplasma was detected in a subset of respiratory samples. However, caution is advised, as distinguishing between correlation and causation is challenging with the detection of DNA sequences.

To further validate these findings, canine respiratory tissues from the NHVDL necropsy biobank archive from 2018, presumed to be prior to the current outbreak, were tested as negative and temporal controls. These older negative control samples have, so far, tested negative for this newly identified organism.

Ongoing Investigations

It is imperative to emphasize that these findings are preliminary, and further testing and analysis are essential before conclusively connecting this syndrome to a specific cause. For additional information, refer to the frequently asked questions (FAQs) provided below.

As veterinarians, researchers, and pet owners anxiously await more answers, the collaboration and diligence of the scientific community remain paramount in unraveling the mystery behind this respiratory syndrome affecting our beloved canine companions.