Overview of Novel Coronavirus Pneumonia

Author: AcceGen R&D Team

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A new outbreak of novel coronavirus (2019-nCoV) infected with pneumonia has been reported in China since mid-December 2019, and the WHO officially named it Corona Virus Disease 2019(COVID-19). The epidemic has gradually spread across the world, now the United State and some other countries and regions are facing a challenging situation. AcceGen R&D Team has summarized some published literature to have a systematic understanding of the new coronavirus, which is summarized as follows.

Discovery of the Corona Virus Disease 2019（COVID-19）

Medical institutions around South China Seafood City in Wuhan have successively treated multiple cases of pneumonia of unknown cause since mid-December 2019[1, 2]. Genome sequencing of the virus isolated from the patient’s lower respiratory tract on January 10, 2020, confirmed that this was a new type of coronavirus. Two days later, the World Health Organization (WHO) named it “2019 New Coronavirus (2019-nCoV)“[3].

2019-nCoV continues to spread globally and formed a large scale of the outbreak. Until now, tens of thousands of people have been infected with the 2019‐nCoV[4]. A novel coronavirus (2019-nCoV) has been diagnosed in with an outbreak originating in Wuhan, China[5].

Starting early February 2020, 59 airline companies suspended or limited flights to Mainland China; several countries including the USA, Russia, Australia, and Italy, have also imposed government-issued travel restrictions[6]. As of March 19, 2020, the epidemic situation in China has been effectively restrained. However, the novel coronavirus (2019-nCoV) has spread internationally on a large scale. In response to the current epidemic, Italy has also taken measures to close the city to prevent the large-scale spread of the virus.

The COVID-19 is currently spreading widely in the United States, and the activity levels of new coronaviruses in different regions are various. As it’s reported on by CDC, as of March 20, 2020, 10442 cases have been diagnosed. The outbreaks of the virus in Washington, New York, and California are particularly severe. The U.S. government has adopted a series of unprecedented measures in the areas of travel, medical care, and so on in response to the growing public health threat posed by the novel coronavirus. For example, foreign citizens who have visited China and other 25 countries in the past 14 days are denied entry into the United States, and all elective ambulatory provider visits are delayed.

Features of the Novel Coronavirus

2019-nCoV belongs to the beta coronavirus that genetic characteristics have diversity compared with the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV)[7]. SARS-CoV[8] and MERS-CoV[9] led to more than 10,000 cases in the past two decades, with a mortality rate of 10% in the case of SARS-CoV and 37% in the case of MERS-CoV[10]. In the case of 2019-nCoV, the number of laboratory-confirmed cases still is rising with a reported mortality rate of around 3%[11].

Thousands of coronaviruses that derived from diverse animals in different regions were sequenced. The results show that protein from 2019-nCoV has more than 85% homology compared with bat SARS coronavirus, and the Wuhan Virus Research team confirmed that 2019-nCoV entered cells by binding to Angiotensin-Converting Enzyme 2 cell receptor, which possibly explains its capacity that crosses the species barrier and infects humans [12, 13]. It takes approximately 6 days to isolate and replicate 2019-nCoV in Vero E6 and Huh-7 cell lines. As for primary cells, human respiratory epithelial cells are suitable for research as its susceptible to 2019-nCoV[14].

Epidemiological Characteristics of Novel Coronavirus

Patients with this new type of coronavirus pneumonia are regarded as the principal source of infection, and asymptomatic infection may also become the source[14]. On February 9, 2020, Guan et al. collected 1,099 patients diagnosed with COVID-19 data from the laboratories of 552 hospitals in China as of January 29, 2020. They found that of the 1099 patients with new coronary pneumonia, 43.95% were local, and the remaining 27.85% had contact with Wuhan personnel, 26% of patients have not traveled to Wuhan recently. These results indicate the presence of familial clustered and asymptomatic infections spread[15].

Laboratory Inspection

The total number of white blood cells in the peripheral blood is regular or decreased, and the lymphocyte count is reduced in the early stage of the onset. The increased liver enzymes, lactate dehydrogenase (LDH), muscle enzymes, or myoglobin are also found in some patients. The increasing troponin can be a crucial index for detecting critically ill patients. The elevated C-reactive protein (CRP) and erythrocyte sedimentation are mostly found in patients.COVID-19 nucleic acid can be detected using RT-PCR technology[16] in specimens such as nasopharyngeal swabs, sputum, lower respiratory tract secretions, blood, and feces[14].

Chest CT Images Features

The early manifestations are mainly sub-pleural patchy ground-glass shadows [17]. As shown in figure 1, the chest CT scan was evaluated for the following characteristics for each patient: (1) presence of ground-glass opacities, (2) presence of consolidation, (3) laterality of ground-glass opacities and consolidation and so on [18, 19]. The lungs of severe patients showed diffuse consolidation. Pulmonary lesions are absorbed, and fibrous foci are formed during recovery[5].

Figure1. Chest CT images. Transverse chest CT images from a 40-year-old man showing bilateral multiple lobular and sub-segmental areas of consolidation on day 15 after symptom onset (A).

Transverse chest CT images from a 53-year-old woman showing bilateral ground-glass opacity and sub-segmental areas of consolidation on day 8 after symptom onset (B) [5].

The 2019-nCoV shows an influential transmission. From the current case data, the minimum reported age is a newborn at 30h, and the maximum reported age is an elderly person over 90 years old. Therefore, the population is generally susceptible[20].

Clinical Typing of Novel Coronaviruses

Patients are divided into 4 types according to the severity of the disease. Light patients have mild clinical symptoms and no pneumonia on imaging. Typical types have symptoms such as fever and respiratory tract. The heavy type meets any of the following: respiratory distress, RR ≥ 30times/min and resting-state mean oxygen saturation ≤ 93%; critically ill those who meet one of the following conditions can be determined as critical: Respiratory failure occurs and requires mechanical ventilation, shock occurs and combined with other organ failures, ICU monitoring and treatment is needed. Doctors will treat patients according to these classification criteria[14]. As shown in figure2, the proportion of mild and asymptomatic cases versus severe and fatal cases is currently unknown for 2019-nCoV that complicates the outbreak response.

Figure2. Surveillance Pyramid and Its Relation to Outbreak Containment[10].

Treatment of 2019-nCoV

Suspected and confirmed cases should be isolated and treated at designated hospitals with effective isolation and protective conditions. Suspected cases should be treated in isolation in a single person. Critical cases should be admitted to the ICU as soon as possible[21]. Unfortunately, no specific coronavirus antivirals or vaccines have been proven to be effective. Remdesivir, a 1′-cyano-substituted adenosine nucleotide analog prodrug with broad-spectrum antiviral activity against several RNA viruses, may be evaluated [22]. In the United States, the first reported patient with COVID-19 infection received treatment with Remdesivir. Remdesivir was given intravenously on the 11th day of illness due to the worsening clinical condition [23]. The drug is currently being used in clinical trials in China, and it is unclear whether it can be used for the diagnosis and treatment of novel coronaviruses. Meanwhile, some national research institutions and pharmaceutical companies announcing the research of the vaccine for the 2019-nCoV is being in pipeline.

Conclusion

In short, in the 2019-nCoV epidemic, China and the international community have responded faster than previous SARS-nCoV. These responses include disease diagnosis, virus isolation, financial support, and temporary hospital construction. However, the normal activities of people are still affected by the spread of the virus.

People need to work hard to reduce panic and economic losses. The current goal is to break the COVID-19 transmission chain, which will require effective procedures to track, diagnose, and cure every infected patient. Besides, we all need to be aware of the risk that zoonotic virus crossing species may infect humans in the future and refuse to eat wild species. We must call for global action to respond to this significant public health emergency.

AcceGen is providing tools that help for fighting against the 2019-nCoV outbreak, include virus RNA/DNA detection kits and cell lines for future diagnostics and therapeutics. For inquiries about the products, please contact inquiry@accegen.com. We wish our resources could support related research to move forward.

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