Year: 2020
Type: article
Abstract: A n infectious disease with a new viral pathogen has garnered the world's attention over the past 3 months in ways that no other human infection has to date.Coronavirus disease 2019, also known as COVID-19, is accelerating around the world in pandemic proportions.This infectious disease is caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 [SARS CoV 2 (1)], which was first detected in China and has now spread to over more than 150 countries.On March 17, the WHO announced that the number of confirmed cases outside of China had exceeded those inside of China (2), and counts on March 25, showed 413,467 confirmed cases and 18,433 associated deaths, globally (3).The latest global count updates can be found at: https://www.who.int/ emergencies/diseases/novel-coronavirus-2019/situation-reports/.SARS-CoV-2 is a positive-sense, single-stranded RNA virus belonging to the genus Betacoronavirus, and phylogenetically related (88%-89% similarity) to the two bat-derived SARS-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21.Coronaviruses are capable of rapid mutation and recombination leading to novel coronaviruses that have differing transmission profiles, as was witnessed in the 2002 epidemic of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV), and the Middle East Respiratory Syndrome coronavirus (MERS-CoV) in 2012.Genetic analysis suggests that SARS-CoV-2 is a novel coronavirus (4) that enabled its initial transmission from an animal source, possibly bats to humans, either directly or via dropping-contaminated materials, in a local seafood and wild animal market in Wuhan, Hubei Province, China (5,6), and now is being transmitted in exponentially rising numbers between humans.The virus enters the human host cell via angiotensinconverting enzyme-2 receptors that are expressed on the outer membrane of tissue-specific cells found in the heart, lungs, small intestine, kidneys, testes, as well as other organs to a lesser degree.Early in the epidemic, individuals who had contact with travelers to China or other geographical hot-spots were deemed at risk.With evolution of the epidemic into a pandemic, community contacts, with no obvious exposure, now account for the majority of the viral spread.Unlike SARS-CoV and MERS-CoV, however, the human-to-human transmission of SARS-CoV-2 is far more efficient.The reproduction number (R 0 ) of an infection is the expected number of cases resulting directly from 1 case, in a population where all individuals are susceptible to the infection.Whereas SARS-CoV and MERS-CoV had R 0 overall values of 0.3 to 2.9 and 0.5 to 3.5, respectively, the R 0 for SARS-CoV-2 is currently estimated at 2.7 (7,8).The mean incubation period for COVID-19 is 5 to 6 days, ranging from 2.1 to 11.1 days (2.5-97.5thpercentile) (9), with both symptomatic and asymptomatic human-to-human transmission now causing local, regional, and global spread of the virus.Despite the efficient spread, the case-fatality rate, which could change as the total number of infected cases accumulates, is currently at or less than 4.3% (3), with different rates based on age, sex, geographical region (10) and other yet to be identified factors.Regardless, despite a much more efficient infection transmission rate, the SARS-CoV-2 fatality rate overall is much lower than either SARS (10%, 8098 cases and 774 deaths) or MERS-CoV (34%, 2494 cases and 858 deaths) (11).Clinical presentation: Although adults tend to present stereotypically with acute respiratory symptoms, the presentation of children appears more variable.Adults are suspected as having COVID-19 when they have an acute respiratory infection with fever, cough and/or shortness of breath, and no other etiology that fully explains the clinical presentation (WHO, February 27, 2020, and the European Centre for Disease Prevention and Control [ECDC] case definition).Additionally, there is growing experience that anosmia, hyposmia, and dysgeusia are associated with COVID-19, and may be present before any other symptoms of infection present (12).In contrast, the symptoms in children are sometimes indistinguishable from those associated with common respiratory infections.One case series of 34 children from the Province of Shenzhen, China described the clinical manifestations of the previously well children, with 65% having common respiratory symptoms (fever [50%] and cough [38%]), 26% only mild disease, and 9% as asymptomatic (13).In a series of 20 children from the Province of Zhejiang, China, they described the presenting symptoms of low-to-moderate or no fever, rhinitis, cough, fatigue, headache, and diarrhea, and only in the more severe cases were dyspnea, cyanosis, and poor feeding observed (14).Although gastrointestinal symptoms are considered rare with coronaviral infections, prior studies of other coronaviruses (15), as well as the experience with SARS-CoV-2 suggest that vomiting and diarrhea may be among the presenting symptoms in adults and in up to 10% of children (16,17).In 204 adults (mean age 54.9 years) from China with COVID-19, 48.5% experienced 1 or more digestive symptoms, including: lack of appetite (40.1%), diarrhea (14%), vomiting (4%), and abdominal pain (2%).More importantly, 3.4% of the patients with COVID-19 had no respiratory symptoms but did experience digestive symptoms (18).Despite mild or no symptoms, there is evidence that transmission of the infection is still possible by these infected individuals (19).
Institutions: Cleveland Clinic, GI Care for Kids, Tel Aviv University, Schneider Children's Medical Center, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Zagreb, Children's Hospital Zagreb, Seattle Children's Hospital, Children's Hospital of Zhejiang University, Zhejiang University
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,780
OpenAlex ID: W3015085447