Today, the world is suffering from a pandemic of a respiratory disease which outbreaks in Wuhan, China in December 2019 and the causative agent of which was identified in January 2020 as novel beta coronavirus of the same subgenus as SARS-CoV and named as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV2) and the disease is named as COVID-19.
COVID-19 rapidly promulgated worldwide with clinical tokens from mild respiratory symptoms to severe pneumonia and fatality rate of about 3%.
World Health Organization (WHO) has affirmed COVID-19 as Public Health Emergency of International Concern, a pandemic on 11th March, pointing to over 118,000 cases in over 110 countries and territories around the world at that time. Now the sheer number of entrenched cases in the world has crossed 1 million with 1,204,055 and annihilation- 64,791 and in India, the cases are above 4,000 with the annihilation of above 100.
Many studies have shown the virus commencement is akin to the seafood market in Wuhan, China but unequivocal associations have not been confirmed, reported clinical findings to include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis and dyspnea.
In the antiphon to ebullition of COVID-19, WHO along with the Chinese CDC investigated the epidemiological and etiological facet of the disease and confirmed that the convulsion was linked with the Huanan South China seafood market place, but no peculiar animal association was identified.
Scientists forthwith initiated the pursuit of the antecedent of COVID-19 and the first genome of it was divulged by a research team led by Prof. Yong-Zhen-Zhang on 10th Jan 2020.
It was scrutinized that most of the early cases had some sort of contact antiquity with the original seafood market. Soon, a collateral cause of infection i.e. human to human transmission was found which led to radical cumulation in the population of infected people with no antiquity of jeopardy to wildlife or visiting Wuhan and among them, the majority were medical professionals. It became evident that COVID-19 infection occurs through jeopardy to the virus and both immune-suppressed & normal people emerge impressionable.
Some studies have also an age apportioning of adult patients between 25-89 years old and few were children & infants. It was propounded that the population most at risk may be people with a poor immune function such as older people and those with renal and hepatic dysfunction.
Coronavirus is an enveloped virus with single-stranded positive-sense RNA and 60nm-140nm in diameter, zoonotic in nature and causes manifestations ranging from that common cold to more severe respiratory, enteric, hepatic and neurological symptoms.
To detect infection antecedent, China CDC researchers collected 585 environmental samples from the seafood market and found 33 samples encompassing SARS CoV-2 and marked its provenance from the seafood market. Scientists used the lung fluid, blood, and throat swabs samples of 15 patients for a laboratory test and found that the virus unambiguous nucleic acid sequence in the sample are divergent from those of known human coronavirus species. Laboratory results also showed that SARS-CoV-19 is similar to some of the beta-corona viruses genera determined in bats.
This virus can remain viable on surfaces for days in benign conditions but are wrecked in less than a minute by prevalent disinfectants such as sodium hypochlorite and hydrogen peroxide, etc. The virus is also present in stools and contamination of water supply and subsequent hauling via aerosolization/feco-oral route is also hypothesized.
Research has found angiotensin receptor enzyme 2 (AGE2) as the receptor through which the virus infiltrates the respiratory mucosa. AGE2 primary physiological role is the maturation of Angiotensin, a peptide hormone that controls vasoconstriction and blood pressure. AGE2 found in several tissues involved with cardiovascular directly, but in the brain, including brain nuclei involved with cardio-respiratory regulation. Hence, it may directly or indirectly cause neurological problems in infected patients/populations.
Peculiar diagnosis can be done by unambiguous molecular tests on respiratory samples which encompass throat swabs, sputum, nasopharyngeal swabs, endotracheal aspirates, and bronchoalveolar lavage. The virus can also be uncovered in stool and in severe cases- in blood. Other laboratory tests are usually nonspecific.
Treatment is substantially ancillary and emblematic. Adequate solitude is paramount to prevent transmission. It is essential to follow the usual principles which are perpetuating hydration and nutrition and controlling fever & cough. Routine use of antibiotics and antivirals such as oseltamivir should be shunned in confirmed cases. In hypoxic patients, the accouterment of oxygen is registered through nasal prongs, face mask, high flow nasal cannula (HFNC) or noninvasive ventilation. As of now, there is no approved treatment for COVID-19.
Antivirals like- ribavirin, lopinavir-ritonavir have been used based on the experience with SARS & MERS.
In the case array of 99 hospitalized patients with COVID-19 in Wuhan, oxygen was given to 76%, noninvasive ventilation to 13%, mechanical ventilation to 4%, extracorporeal membrane oxygenation (ECMO) to 3%, continuous renal replacement therapy (CRRT) to 9%, intravenous immunoglobulin therapy to 27%, antibiotics to 71%, antifungals to 15%, glucocorticoids to 19%, and antiviral therapy having oseltamivir, ganciclovir & lopinavir-ritonavir to 75% of the population.
Other drugs contemplated for therapy are arbidol (an antiviral developed in Russia and China), intravenous immunoglobulin, interferon, chloroquine and plasma of patients retrieved from COVID-19.
Since at this time there is no ratified remedy for this infection, hence, forestalling is crucial. Many properties of virus make forestalling difficult, they are-
• Nonspecific features of the disease.
• Infectivity even before the onset of symptoms in the incubation period.
• Transmission from asymptomatic people
• Long incubation period
• Tropism for mucosal surfaces like conjunctiva
• Prolonged duration of illness
• Transmission even after clinical recovery
The greatest risk in COVID-19 is transmission to health workers. A Chinese doctor who first warned about the virus has died too.
Patients should be settled in separate rooms or cohorted together. Rooms, surfaces, and equipment should undergo regular decontamination preferably with sodium hypochlorite.
Airborne hauling anticipations should be taken during aerosol-generating procedures such as intubation, suction & tracheotomies.
People should be asked to practice cough hygiene by coughing in sleeves/tissues rather than hands and also to practice hand hygiene frequently every 15-20 minutes. Patients of respiratory symptoms should be asked to use surgical masks.
This new virus insurrection has challenged the economic, medical and public health infrastructure of the world. Time alone will tell how the virus will impact our lives, social distancing and self-quarantine is the need of the hour for everyone worldwide to forestall the proliferation of this infectious virus and save mankind. More so, future insurrections of viruses and pathogens of zoonotic provenance are likely to outlast. Therefore, apart from cribbing this ebullition, efforts should be made to devise comprehensive measures to prevent future insurrections of zoonotic origin.