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Understanding Coronavirus pandemic
By Dr. Wahied Khawar Balwan. Dated: 3/31/2020 11:22:36 PM
On December 31, 2019, China informed the World Health Organization of a cluster of cases of pneumonia of an unknown cause in Wuhan City in Hubei province. On January 9, 2020, the WHO issued a statement saying Chinese researchers have made "preliminary determination" of the virus as a novel coronavirus.
Since then, more than 33,000 deaths have been reported due to COVID-19 across the world till March 30, 2020. Cases have been reported from more than 203 countries, including India, where till date about 1071 positive cases have been reported and death toll has reached to about 30. Lockdowns, curfews, massive airport screenings, quarantines, and social distancing have become the norm across the globe.
Coronaviruses are a large family of viruses with some causing less severe common cold to more severe diseases such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). The SARS-CoV-2 is a coronavirus very similar to the one that caused SARS. Many coronaviruses are zoonotic, meaning they are transmitted from animals to humans. While the SARS coronavirus is thought to be an animal virus from an as-yet-uncertain animal reservoir, perhaps bats, that spread to other animals (civet cats) and first infected humans in the Guangdong province of southern China in 2002, the MERS coronavirus was passed on from dromedary camels to humans in Saudi Arabia in 2012. There is evidence that the SARS-CoV-2 has also been transmitted from bats.
Like other coronaviruses, SARS-CoV-2 virus particles are spherical and have mushroom shaped proteins called spikes protruding from their surface, giving the particles a crown like appearance. The spike binds and fuses to human cells, allowing the virus to gain entry.
The spike protein of the novel coronavirus shares 98% sequence identity with the spike protein of the bat coronavirus, the researchers say. The results were published in the journal Science. The researchers also found that like in the case of the SARS coronavirus, the spike protein of the SARS-CoV-2 that causes Coronavirus Disease 19 (COVID-19) binds to the cellular receptor called angiotensin-converting enzyme 2 (ACE2), which serves as the entry point into human cells. But unlike in the case of SARS, the spike protein of the novel coronavirus binds to the cell receptor with much higher affinity about 10 to 20 fold higher.
The much greater binding affinity to the cell receptor explains the apparent high human to human transmissibility of the virus compared with the SARS coronavirus. "The high affinity of the 2019-nCoV S for human ACE2 may contribute to the apparent ease with which the 2019-nCoV can spread from human to human," the researchers write.
The World Health Organisation has declared COVID-19 to be a pandemic. The symptoms of COVID-19 appear within 2 to 14 days after exposure and include fever, cough, a runny nose and difficulty in breathing. It primarily spreads through the respiratory droplets of infected people. If a person touches a surface or object that has been infected by the virus and then touches his own mouth, nose, or eyes, he may get infected.
While people of all ages can be affected by the disease, people aged 80 and above are at the highest risk of dying due to COVID-19, according to case records analyzed by the Disease Control and Prevention Centers in China and South Korea. Victims of the virus with pre-existing medical conditions such as cardiovascular disease and diabetes have a higher fatality rate than others. Also the rate of fatalities was relatively higher for retirees.
Regarding Symptoms, the guidelines from the Union Health Ministry for early recognition of COVID-19 patients are those who come in with Severe Acute Respiratory Infection (SARI) who also have a history of foreign travel or close contact with another COVID-19 patient. As per the guidelines, COVID-19 may present with mild, moderate, or severe illness; the latter includes severe pneumonia, ARDS [Acute Respiratory Distress Syndrome], sepsis and septic shock.
Regarding Detection, the virus can be detected using a RT-PCR test. An RT-PCR or reverse transcription polymerase chain reaction test is DNA-based and can quickly tell if someone harbours the virus. In India, the government facilities to test for the virus include many labs belonging to the Viral Research and Diagnostic Laboratories network of the Indian Council of Medical Research (ICMR), labs under the National Centre for Disease Control (NCDC), and the NIV.
Regarding Treatment, there is no current evidence from randomised controlled trial to recommend any specific treatment for suspected or confirmed COVID19 patients. No specific antivirals are recommended for treatment of those suffering from respiratory ailment due to lack of adequate evidence from medical literature.
In India, the Union Health Ministry guidelines has recommended use of anti-HIV drug combinations Lopinavir and Ritonavir on a case to case basis depending upon the severity of the condition of a person having coronavirus infection. The Ministry recommended Lopinavir-Ritonavir for high-risk groups: patients aged above 60, suffering from diabetes mellitus, renal failure, chronic lung disease and are immuno-compromised. However, the use of Lopinavir-Ritonavir in PEP regimens for HIV is also associated with significant adverse events which many times leads to discontinuation of therapy. The guidelines advise the treating doctors to closely monitor patients with severe acute respiratory infection for signs of clinical deterioration, such as rapidly progressive respiratory failure and sepsis, and apply supportive care interventions immediately. "Application of timely, effective, and safe supportive therapies is the cornerstone of therapy for patients that develop severe manifestations of COVID-19," it said.
Regarding the development of vaccine for COVID-19, According to Raman. R. Gangakhedkar, head of the Epidemiology and Communicable Diseases-I (ECD-I), Division of ICMR, there are two ways of going for vaccine preparation- either you look at the sequences of the gene which then may lead to development of antibodies, or you actually have the strain and then you try to develop a vaccine which is always an easier option. He said Indian scientists have managed to successfully isolate the COVID-19 virus and about 11 isolates are available which is a prime requisite for doing any kind of research related to viruses and developing the vaccine. Internationally, several institutes and pharmaceutical companies are in various stages of developing the vaccine with some set to go on clinical trials soon.
Guidelines by the World Health Organization specify that one of the ways to reduce the risk of infection is by regularly and thoroughly cleaning one's hands with an alcohol based hand rub or washing them with soap and water. Regular washing becomes important as the virus tends to be viable from hours to more than a day on different surfaces that are regularly touched with hands. So protection include washing hand with soap or cleaning with alcohol based sanitizers, using a medical mask, social distancing, avoid touching eyes, nose and mouth and practice respiratory hygiene.
There have been several myths around the disease, like consuming more garlic, curry leaves or cow's urine would treat or protect one from the disease or COVID-19 virus cannot be transmitted in areas with hot and humid climates or the new coronavirus can be transmitted through mosquito bites. The World Health Organisation has busted such misleading claims. On garlic, WHO said it is a healthy food that may have some antimicrobial properties but there is no evidence that it has prevented people from contracting the 2019 nCoV.
"Any Error in this manuscript is silent testimony of the fact that it was a human effort". The article has been compiled from various resources like Journals, Wikipedia, News Papers and other annals.
*(Dr. Wahied Khawar BalwanSr. Assistant Professor Department of Zoology Govt. Degree (PG) College Bhaderwah