BY: SAMANTHA BARTLETT, DVM

Konkuk University in South Korea recently published a study in Emerging Infectious Diseases. The study found  that dogs experimentally infected with SARS-CoV-2 Delta variant that were not showing any neurologic or respiratory signs of the disease did have pathologic evidence of degenerative brain disease on necropsy. 

The researchers infected six dogs with the virus intranasally. The dogs were placed in shared cages with six non-infected dogs. The control group was three uninfected dogs treated with placebo. Blood, nose-throat, mouth-throat, and fecal samples were tested at 10, 12, 14-, 38-, 40- and 42-days post infection. 

Viral titers appeared higher in the nasal and oral mucosa of contact dogs than infected dogs. Dogs in the contact group had more severe inflammation in the trachea and bronchioles in early stages of infection. This is consistent with previous studies showing that contact transmission has higher viral concentrations in the upper respiratory tract. 

SARS-CoV-2 DNA was detected in the brain at weeks 10, 12, and 14 postinfection. Necropsies at all time points showed the virus had caused abnormal changes and damage to the blood-brain barrier and evidence that the virus had crossed the barrier. 

Researchers conclude that this study suggests a potential for a long COVID-like syndrome in infected dogs. This research can also help with studies of how the disease affects humans.