Seronegative Myasthenia Gravis with Concomitant SARS-CoV-2 Infection in a Dog

SIMPLE SUMMARY: Myasthenia gravis is a disorder of neuromuscular transmission affecting neuromuscular junction. Both congenital and acquired forms are described in dogs. Usually, the acquired form might be induced by an autoimmune attack against specific acetylcholine receptors. Viral infection is incriminated to be a trigger for myasthenia gravis occurrence and, in a limited number of papers, infection with SARS-CoV-2 was found to be associated with myasthenia gravis expression in humans. In this case report, we describe a 2-year old crossbred, female dog case of seronegative generalized myasthenia gravis and concomitant SARS-CoV 2 infection due to close exposure to an infected owner. Despite the viral particles were not identified in our dog, the presence of anti SARS-CoV 2 antibodies and the epidemiological context were highly suggestive for a new recent infection with SARS-CoV 2. Our data complete the limited number of reports which document the SARS-CoV 2 passage from owners to pets and underline the role of serological screening for specific anti-SARS-CoV 2 antibodies as an indirect marker of infection especially when the viral detection fail to PCR test. ABSTRACT: Myasthenia gravis (MG) is a disorder of neuromuscular transmission affecting the neuromuscular junction. The majority of cases involve an autoimmune attack against AChR, but a limited number of patients are seronegative for AChR antibodies. Viral infection is incriminated as a trigger for MG occurrence, and in a limited number of reports, infection with SARS-CoV-2 was found to be associated with MG expression in humans. In this report, we describe case of seronegative generalized MG in a 2-year-old crossbred female dog associated with SARS-CoV-2 infection due to close exposure to an infected owner.