Review of the Clinical Characteristics of Coronavirus Disease 2019 (COVID-19)Jiang F, Deng L, Zhang L, et al.
Journal of General Internal Medicine
In December 31, 2019, hospitals reported a cluster of caseswith pneumonia of unknown cause in Wuhan, Hubei, China,attracting great attention nationally and worldwide. On January 1, 2020, Wuhan public health authorities shut down the Huanan Seafood Wholesale Market, where wild and live animals were sold, due to a suspected link with the outbreak.On January 7, 2020, researchers rapidly isolated a novelcoronavirus (SARS-CoV-2, also referred to as 2019-nCoV) from confirmed infected pneumonia patients. Real-time re-verse transcription polymerase chain reaction (RT-PCR) and next-generation sequencing were used to characterize it.
Almost all the patientshad bilateral lung ground glass opacity on computed tomog-raphy imaging. The initial symptoms included fever (98%),cough (76%), dyspnea (55%), myalgia or fatigue (44%), sputum production (28%), headache (8%), hemoptysis (5%), and diarrhea (3%).
Coronaviruses are widespread in humans and several othervertebrates and cause respiratory, enteric, hepatic, and neuro-logic diseases. Notably, the severe acute respiratory syndromecoronavirus (SARS-CoV) in 2003 and Middle East respiratorysyndrome coronavirus (MERS-CoV)
Both SARS-CoVs enter the cell via the angiotensin-converting enzyme 2 (ACE2) receptor.11, 12The SARS-Cov-2 first predominantly infects lower airways and binds to ACE2on alveolar epithelial cells. Both viruses are potent inducers ofinflammatory cytokines. The“cytokine storm”or“cytokinecascade”is the postulated mechanism for organ damage. Thevirus activates immune cells and induces the secretion of inflammatory cytokines and chemokines into pulmonary vas-cular endothelial cells.
The preliminary estimate of R0 (the expected number of cases directly produced by one person in a population susceptible to infection) for COVID-19 is 2.2 (95% CI, 1.4 to 3.9).6Fomitesare suspected as the main source of infectious particles, though some uncertainty remains. Other coronaviruses have beenshown to persist for days on uncleaned surfaces. Additionally, SARS-CoV-2 RNA was detected in the stool specimen in a person who had symptoms while the serum specimen tested negative.13Recently, SARS-Cov-2 was isolated from a swab sample of a confirmed patient’s feces by Chinese re-searchers,14indicating the potential for fecal-oral transmission. Studies have shown effective person-to-person transmission of 2019-nCoVeven in the presence of isolation efforts in medical facilities
Handwashing is the mainstay of viral control. Contact isolation gear such as masks, gowns, and gloves are also recommended. Transmission via ocular surface is possible, so eye protection should also be used.