Update on the Wuhan Coronavirus 2019-nCoV
This post is an extension to the previous one on Origin and Evolution of Coronaviruses. We have based this update on an article on the epidemiology and clinical features of 99 confirmed patients of 2019-nCoV in Wuhan. The report – updated till Jan 25th – was published online in the Lancet yesterday on January 30, 2020. Our motive is to present to the non-technical readers a summary of the findings in a simpler and shorter format. We want the general readers to keep themselves updated.
Although the new Coronavirus has created a public health emergency in the current month of January 2020, several cases of pneumonia of unknown aetiology came to the fore in Wuhan in the Hubei province of China beginning the second week of December 2019. The patients in general showed acute respiratory distress syndrome (ARDS). The novel coronavirus was identified exactly after a month on Jan.7, 2020 by the Chinese Center for Disease Control and Prevention (CDC) and subsequently named 2019-nCoV by WHO. Yes, the “n” in the name stands for “Novel”.
Human coronaviruses are the main pathogens of respiratory infection. Two of these – SARS-CoV and MERS-CoV – are highly pathogenic and cause severe respiratory syndrome. Four others viz. HCoV-OC43, HCoV-229E, HCoV-NL63, HCoV-HKU1 also induce mild upper respiratory disease. The mortality of SARS-CoV was reportedly more than 10% and that of MERS-CoV more than 35%. At data cutoff for this study, 11 of the 99 patients of 2019-nCoV had succumbed. Over 200 persons have died so far.
The sequence of 2019-nCoV is relatively different from the above six coronavirus sub-types but can be classified as β-coronavirus. The origin and transmission of 2019-nCoV need further investigation. Nevertheless, like SARS and MERS the novel one is supposed to have originated in bats and transmitted through animals.
Club-shaped glycoprotein spikes in the envelope give 2019-nCoV a crown-like or coronal appearance like the other coronaviruses. Transmission rates are unknown for 2019-nCoV; however, there is evidence of human-to-human transmission.
These are highly infectious and due to modern aero-connectivity spread fast to other countries. For example, SARS-CoV had in 2002-03 spread to not less than 29 countries. The major SARS-CoV outbreak involving 8422 patients occurred during 2002–03 and spread to 29 countries globally. Similarly, MERS-CoV had emerged in Middle Eastern countries in 2012 but spread to China, among other several countries. So, viral attacks are global.
The absolute value of lymphocytes in most patients was found to be reduced. 2019-nCoV might mainly act on lymphocytes, especially T lymphocytes, as does SARS-CoV. Coronavirus consumes many immune cells and inhibits the body’s cellular immune function. As such, low absolute value of lymphocytes could be used as a reference index in the diagnosis of new coronavirus infections in the clinic.
Mortality almost follows the MuLBSTA score. The MuLBSTA score system contains six indexes, which are multilobular infiltration, lymphopenia, bacterial co-infection, smoking history, hypertension, and age.
As in the case of SARS and MERS, in the current Wuhan scenario too, a greater number of men than women have got affected. The reduced susceptibility of females to viral infections could be attributed to the protection from X chromosome and sex hormones. These play an important role in innate and adaptive immunity.
At Wuhan, about half of patients additionally have had chronic underlying diseases, mainly cardiovascular and cerebro-vascular diseases and diabetes. This pattern also follows MERS. Thus, SARS, MERS and Wuhan suggest that 2019-nCoV is more likely to infect older adult males with chronic co-morbidities as a result of the weaker immune functions of these patients. Some patients, especially severely ill ones, had bacterial and fungal co-infections of A baumannii, K pneumoniae, A flavus, C glabrata, and C albicans. Of these, A baumannii shows high drug resistance.
In cases of severe mixed infections, in addition to the virulence factors of pathogens, the patient’s immune status is the deciding factor. Old age, obesity, diabetics, HIV infection, people with long-term use of immunosuppressive agents, and pregnant women, and presence of co-morbidity might increase mortality. Prompt administration of antibiotics may not cure the Novel Coronavirus, but it surely will boost the immune system of the patients suffering from multiple infections and having low immune function.
Use of intravenous immunoglobulin is recommended to enhance the ability of anti-infection for severely ill patients and steroids are recommended for patients with ARDS, for as short a duration of treatment as possible. Patients infected severely suffer from ARDS, may have septic shock followed by multiple organ failure resulting in death. Early identification and timely treatment can only save their lives hopefully. To conclude, the infection of 2019-nCoV is of clustering onset and more likely to attack older men with low-immunity and co-morbidities resulting in severe and even fatal respiratory diseases such as ARDS.