COVID-19: SARS-CoV-2 Infection Causes Neurodegeneration in Dogs and Humans

A Korean study shows that the Delta variant of SARS-CoV-2 can infect dogs and cause cellular damage in the brain and lungs, even in the absence of neurological or respiratory clinical signs. Furthermore, the coronavirus spreads between dogs or to humans through direct contact and can then cause pathological changes in the brain and upper respiratory tract, contrary to the findings of previous studies. The study demonstrated that the COVID-19 virus damages the blood-brain barrier, allowing it to cross it, thereby explaining the lesions in the cerebral vascular system—more prominent in the white matter—observed in dogs infected either experimentally via the intranasal route or through direct viral transmission. Analysis of nasopharyngeal and oropharyngeal swabs revealed an inflammatory response of varying severity depending on the stage of infection, and immunofluorescence tests confirmed the presence of viral particles in the canine brain. SARS-CoV-2 was thus detected in the lungs and brains of both inoculated dogs and those that had been in contact with them. However, none of the dogs exhibited apparent neurological disorders or respiratory symptoms of COVID-19. The abnormalities identified reveal that even asymptomatic animals infected with the coronavirus can develop both a neurodegenerative condition in the brain (small-vessel disease) and lung lesions (interstitial pneumonia). Furthermore, these lesions are persistent, suggesting the development of a long-term syndrome—similar to “long COVID” in humans—in affected dogs. SARS-CoV-2 could thus induce pathological reactions in the brains of various hosts, including humans, although the underlying mechanisms remain unclear. The observations made in dogs are indeed applicable to human infection. Compared to other animal models, dogs are genetically closer to humans and have a similar brain structure, making this extrapolation relevant. The results of this study also suggest that SARS-CoV-2 infection of the brain, even in asymptomatic human patients with COVID-19, could lead to a neurodegenerative disease in the short or long term, such as Alzheimer’s disease. Thus, animal owners are potentially at risk of contracting the virus through direct contact with their pets and subsequently developing neurological disorders, even without showing any symptoms.   https://vetitude.fr/les-animaux-errants-egalement-exposes-a-la-covid-19/ https://vetitude.fr/au-bresil-31-de-chiens-et-40-de-chats-testes-positifs-a-la-covid-19/ https://vetitude.fr/covid-19-comprendre-linfectivite-du-sars-cov-2-chez-lhomme-et-lanimal/