Abstract

Coronaviruses (CoVs) are important RNA viruses that affect respiratory, gastrointestinal and urinary system of human being and birds. These viruses originated from the subfamily Coronavirinae which genetically includes Alphacoronavirus, Beta coronavirus, Gamma coronavirus and Delta coronavirus. The sequencing analysis of the genome showed that COVID-19 caused by SARS-CoV-2 belongs to Beta coronavirus genus and avian infectious bronchitis caused by IBV comes from Gamma coronavirus genus. Over the past few decades and until now, the world showed that endemic outbreaks of infectious bronchitis in avian caused by IBV. Once more, the world sees the emergence of another new human coronavirus COVID-19 outbreak due to a new strain called SARS-CoV-2. Whole genetic material and comparative genomic analysis exhibited that IBV and SARS-CoV-2 have particularly same genomic structures and characteristics. Both have a spike protein in the genome structure which allows that SARS-CoV-2 attaches to their human select cells throughout ACE₂ receptors, that are notably reported in the lung and kidney. While IBV uses alpha (2,3) linked sialic acids-dependent manner for bind to the avian tissues which is notably reported in the lung and kidney. The two diseases are produced a pulmonary and urinary infection that lead to sneezing, gasping, respiratory massive destruction, severe pneumonia and renal failure. This review will introduce a general overview of two diseases and describe the phylogeny, epidemiology, pathogenesis, clinical features, autopsy report and microscopic lesions.