Molecular pathology of emerging coronavirus infections

Abstract

Respiratory viruses can cause a wide spectrum of pulmonary disease ranging from mild, upper respiratory tract infections to severe and life‐threatening lower respiratory tract infection including development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Viral clearance and subsequent recovery from infection require activation of an effective host immune response; however, many immune effector cells may also cause injury to host tissues. Severe Acute Respiratory Syndrome (SARS) Coronavirus and Middle East Respiratory Syndrome (MERS) Coronavirus cause severe infection of the lower respiratory tract with 10% and 35% overall mortality rates respectively; however, >50% mortality rates are seen in the aged and immunosuppressed populations. While these viruses are susceptible to interferon treatment in vitro, they both encode numerous genes that allow for successful evasion of the host immune system until after high virus titres have been achieved. In this review we discuss the importance of the innate immune response and the development of lung pathology following human coronavirus infection.