A Domestic Cat with Respiratory Symptoms Caused by Severe Acute Respiratory Syndrome Coronavirus 2 Infection

A 12-year-old indoor cat showed severe respiratory symptoms such as sneezing, nasal discharge and cough. On Day 5 after disease onset, an oral swab was collected and a real-time RT-PCR test was performed to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), indicating that the sample from the cat was positive for SARS-CoV-2 genes. Since the symptoms worsened on Day 8, a general physical examination, blood tests, chest x-rays and treatment were carried out and oral, nasal and rectal swabs were collected. Mild bronchitis and increased serum amyloid A (SAA) were observed, but it did not lead to pneumonia. In addition, whole-genome analysis revealed that it was the delta variant of SARS-CoV-2. Then the cat recovered, and a significant increase of virus-neutralizing antibody titer was observed in the convalescent serum. In conclusion, this is the first report on a cat with respiratory symptoms caused by SARS-CoV-2 infection in Japan.