A brief summary of the spread of COVID-19

Written By : Dr. Ananya Mukherjee
Department of Plant Science and innovation University of Nebraska-Lincoln, USA

The novel corona virus or COVID-19 has affected, as per recent statistics, 1,356,354 and caused nearly 75,760 deaths. The scary aspect of this enormous statistic is that, it will change when you get your hands on this article and it did change while I was writing the article.COVID-19which is now a global pandemic is a respiratory illness which is not the flu but is characterized by flu like symptoms such as fever, dry cough, fatigue, diarrhea in some cases and in severe cases shortness of breath coupled with pneumonia. It has been reported so far that this disease originated in Wuhan, China in December of 2019 and has spread from bats via possibly pangolins- ant eating mammal, to humans. However, it has not been conclusively proven if the pangolin theory is true. It was suspected to have spread from a seafood market in Wuhan, but recent reports found earlier cases of the novel coronavirus in individuals who had no connection to the alleged market.

Some scientists like Richard Ebright, from Rutgers University who is a biosecurity expert, suggested that a natural accident such as a leak from a laboratory where bat coronaviruses were being studied, maybe a cause for this outbreak. Such labs such as Wuhan Center for Disease Control are generally biosafety level 2 which offers only minimal protection to its researchers. Ebright pointed out that one such bat virus RaTG13 has a 96% similarity with the novel coronavirus. This suggests that maybe a bat virus has evolved to become dangerous for humans. A study in Nature Medicine did refute Ebright’s claim which was backed up by Thomas Gallagher, a virus expert and professor at Loyola University of Chicago.However another study on Researchgate- a paper/study sharing website, from South China University of Technology, also suggested an accidental lab release. The South China study has since then been removed but it is curious that the Wuhan [Center for Disease Control] is a mere 280 meters from the seafood market which is currently being held responsible for the spread. However, there is no evidence that the virus is engineered by a lab or that it was released as a bioweapon, as many rumors falsely suggest. Yanzhong Huang, a senior fellow for Global Health at the Council on Foreign Relations rubbished claims of bioweapons and deliberate virus release but did cite the South China study. The origin story has several conflicting reports but the story needs to be determined. If animal virus truly are capable of evolving this fast then more disease threats might be in store for humans. This also means lab safety levels need to be tightened for any labs working with animal viruses. There is no real consensus about the origin story even amongst experts but racist suggestions of bioweapons and repeated reference of COVID-19 as “Wuhan” or “China virus” certainly needs to stop.

COVID-19 is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). It belongs to the same family as SARS and Middle Eastern Respiratory Syndrome( MERS) viruses both of which are zoonotic viruses as well. Zoonotic viruses originate in animals and make their way to infect humans.Chinese scientists have sequenced the genome of the virus shortly after it’s widening spread which has shown that the spike protein, arm like structures on a virus that targets hosts, is very efficient in targeting receptor proteins on human cells. Receptor proteins are like a gateway inside a cell and SARS-CoV-2 effectively fuses its membranes to the human cell membrane. This is mainly due to a more compact molecular ridge on the spike protein of SARS-CoV-2 as compared to the regular SARS virus, which cements theinfection better and spread faster. Thus the tighter the bond is between the virus and human cells, less the amount of virus needed to cause the disease.

It has been suggested that the spread of SARS-CoV-2 occurs from respiratory droplets of an infected person. So far it has also been found that the virus can survive on various surfaces such as plastic, cardboard etc. for several hours. This virus has an incubation period of 14 days and belongs to a family of coronaviruses some of which are dangerous for humans. The major obstacle in the detection of this disease is the fact that most carriers are asymptomatic. This makes it harder to trace and very easy to spread as unsuspecting individuals are spreading it to more and more immunocompromised, high risk people. Thus strict lockdowns have been placed across the globe where governments are forcing individuals to work from home and maintain social distancing.

Social distancing is essentially maintaining a distance of at least 6ft from everyone you do not live with and stay indoors other than performing essential tasks. So far the U.S. Centers for Disease Control and Prevention (CDC) has asked people to only wear masks if they are currently a carrier or caring for someone with COVID-19 but a recent report may change things. A report in the national academy of sciences encourages a disturbing idea that breathing and talking may spread the virus too. The CDC and other health organizations around the world have thus far maintained, that the spread of the disease occurs via large respiratory droplets from coughs or sneezes, upto a millimeter across. The spread can also occur via touching infected surfaces and then touching one’s nose, mouth eyes etc. However if the new study is to be believed then the spread of the disease can occur via the ultrafine mist that is produced when we exhale. In such a scenario masks will become mandatory for public safety. If this study is indeed true, then the rapid spread of the disease can be explained. In a study by researchers led by Yuan Liu at Wuhan University, it has been observed that virus particles have been in air upto 3 hours even after health care workers have disinfected and cleaned the contaminated surfaces. However experts are still divided on the results of these studies. This is because in studies of 75000 patients carrying the disease in China, no evidence of airborne transmission was found conclusively. It is being suspected that airborne transmission may only occur in severely ill patients who are intubated with tubes.

The main roadblock in preventing the spread of the novel coronavirus has been the people who are asymptomatic. The asymptomatic carriers have ended up spreading the disease far and wide. For instance in Italy young professionals are known to travel to and from Milan for their work and then go back to their remote cities where there are more elderly people. This has caused carriers, possibly young people, to spread the disease to the compromised and elderly. However this kind of virus which is now a global pandemic, was not completely unanticipated. Experts have written many books and opinion pieces on this inevitability. However despite having information abut the outbreak in China western countries mainly USA failed to prepare itself in time. It started with the manufacture and distribution of faulty kits for testing the virus from CDC which caused a huge setback to early detection. The FDA at the same time did not approve independent kits. By the time the right kit was available and testing had started the actual case numbers had already shot up. This was coupled with the regular flu season which had the healthcare system in a tizzy.

Right now the numbers have risen almost exponentially in USA, Italy and Spain. The best plan of action is of course test, test and test as the World health organization have themselves pointed out. This needs to be followed up with proper protective gear for both healthcare professionals and scientists who are working on developing a vaccine and testing drugs. The issue here too is the fact that many of the PPE manufacturing comes from China where business is still on its way to get back to normal. Its imperative at a time like this, to start increasing distribution of test kits so everyone who wants a test can get one. However it’s extremely crucial to test the healthcare professionals first. Keeping them in good health a time like this when they are literally battling the disease every day tirelessly, is vital. Many local companies and factories have started making their own homemade PPE and supplying the same to hospitals and elderly homes. The different states in USA need to reach a consensus and issue a countrywide stay at home order, state by state. As of now 8 governors have still not issued such an order despite USA being the country with 311,637 cases, the highest in the world. While scientists try their best to come up with a vaccine and the healthcare workers lose sleep over accommodating more patients USA needs to come together and enforce a country wide lockdown. Complete and enforced social distancing is the only way to brake and break this vicious virus cycle.

About the author :
Dr. Ananya Mukherjee
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803