Journal of Current Biomedical Reports jcbior.com Volume 1, Number 2, 2020 eISSN: 2717-1906 1 Review Coronavirus disease 2019 (COVID-19): A New Pandemic and its Challenges Davood Mansury 1 , Sharareh Moghim 1,* 1 Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Abstract Emerging of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide outbreak and a major public health problem. The present review was conducted to provide brief information about the origin, symptoms, transmission, pathogenesis, diagnosis, and treatment of the virus. A search was performed in the databases of PubMed, Scopus, Science Direct, and Google scholar with English keywords including 2019-nCoV, Coronavirus disease 2019 (COVID-19), SARS-CoV-2, and novel coronavirus from December 2019 to 15 March 2020, and the search results were evaluated. Selected studies have shown that the virus may have originated from the bat. It has also been shown that the virus receptor is angiotensin-converting enzyme 2 (ACE2) which is also the SARS virus receptor and is expressed in most human tissues. The most common way of virus transmission was suggested through respiratory droplets and close contact. It is also transmitted by asymptomatic patients, but vertical transmission from mother to fetus has not been confirmed. Real-time reverse transcriptase (RT)-PCR is the gold standard for SARS-CoV-2 detection, but chest computed tomography (CT) can be more sensitive to detect positive cases. Since no effective vaccine or drug for prevention and treatment of this disease has not yet been identified and also because of the high incubation and infection period, easy transmission, and the lack of complete recognition of the characteristics and stability in different environments, the best way to control of COVID-19 is to prevent the spread of the infection in different ways and take seriously personal and public hygiene. Keywords: Coronavirus, COVID-19, SARS-CoV-2, Emerging viruses, Pathogenesis 1. Introduction Coronaviruses are one of the most important pathogens in the human respiratory system. Severe Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) have previously been identified as risk factors for general health [1]. In late December 2019, a report was published on pneumonia in a group of patients with unknown cause, possibly related to contact with the seafood market in Wuhan, China [2]. In January 2020, the World Health Organization (WHO) temporarily * Corresponding author: Dr. Sharareh Moghim, Ph.D Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Tel/Fax: +98 31 37929038 Email: moghim@med.mui.ac.ir http://orcid.org/0000-0002-7134-3145 Received: September, 30, 2020 Accepted: November, 11, 2020 named this virus the 2019 novel coronavirus (2019- nCoV). Later, in February 2020, they officially named it severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [3, 4]. The coronaviruses are a class of coated single-stranded RNA viruses that are genetically and serologically subdivided into four subfamilies, including alpha, beta, gamma, and delta. In this regard, most human infections are caused by alpha and beta subfamilies. Phylogenetic analyses show that the etiology of coronavirus disease 2019 (COVID-19), like SARS and MERS, belongs to the