A Comprehensive Study of Cellular and Humoral Immunity in Dogs Naturally Exposed to SARS-CoV-2

Area of Science:

• Veterinary Immunology
• Zoonotic Diseases
• Infectious Disease Epidemiology

Background:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the COVID-19 pandemic.
• Understanding the role of domestic dogs in SARS-CoV-2 transmission is crucial due to close human-animal contact.

Purpose of the Study:

• To investigate the presence of SARS-CoV-2 and its long-term immune effects in naturally exposed domestic dogs.
• To assess the potential of dogs as reservoirs or transmitters of SARS-CoV-2.

Main Methods:

• Analysis of humoral (IgM, IgG) and cellular (IFN-γ secreting cells) immune responses in 24 dogs.
• Monitoring immune markers and blood parameters over an 8-month period.
• Assessment of viral shedding to determine transmissibility.

Main Results:

• Approximately 17% of dogs had IgM and 33% had IgG antibodies against SARS-CoV-2.
• SARS-CoV-2-specific IFN-γ secreting cells were identified in about half of the dogs.
• Humoral response persisted in 56% of dogs at 8 months, while cellular response was maintained in 22%.

Conclusions:

• The canine immune system effectively controls SARS-CoV-2 replication in some domestic dogs.
• Dogs with specific immune responses showed no viral shedding, indicating they are unlikely transmitters.
• Findings suggest companion dogs may not contribute significantly to SARS-CoV-2 epidemiology.