Within 4 months of its first appearance on November 2019, Coronavirus COVID-19 has become a pandemic across the globe infecting more than 110,000 people in 109 countries. Billions of dollars has already been invested to find reasons behind the rapid spread while also researching any possible methods to contain the infection.
Researchers performing structural analysis of the virus have discovered that it has a unique protein embedded on its outer membrane. This protein has been attributed to be the reason behind the highly infectious nature of the COVID-19, much more than its predecessor the SARS virus that had infected a total of 8098 patients.
The virus also contains a specific receptor on its membrane, which may be used as a target for drugs to attack the virus. However, according to the researchers, the research is still in a preliminary stage and development of any drug to combat the virus could take months to a year.
“Understanding transmission of the virus is key to its containment and future prevention,” said David Veesler, a structural virologist at the University of Washington in Seattle, a researcher among the team that published this finding.
Cardiopulmonary and Liver Failure
The membrane protein contains a spike like structure, which makes it easier for the virus to attach itself to the cell membranes of its hosts. Unlike other viruses, the coronavirus spike protein is activated by furin, an enzyme within the host cell. Furin is found extensively in many tissues of vital organs such as the lungs, liver and small intestines in the human body. Other viruses such as the SARS virus do not contain proteins that are activated by furin.
This finding explains the respiratory and gastrointestinal symptoms experienced by the infected patients. Death results mainly from cardiopulmonary failure and in some cases patients also have fulminant liver failure during the end stages.
Not only does this protein increase the infectivity of the virus, it also makes it more stable within the host environment for further replication.
Multiple research groups around the world have noted the finding of the spike protein, which also enables efficient human-to-human transmission.
Other viruses such as the widespread influenza vaccine also contain a similar activation site on a different protein, haemagglutin. However, as the site is not in a spike like protein, it limits its systemic effects. The influenza virus has a 0.1% mortality rate in comparison to 2% mortality rate of coronavirus.
Skepticism regarding the spike protein
Despite multiple researchers reporting potential use of the activation site as a drug target, skeptics caution that the spike protein may have lesser role in the infectivity of the coronavirus than widely assumed. This thought has been resonated by Jason McLellan, a structural biologist at the University of Texas at Austin who has said, “We don’t know if this is going to be a big deal or not.
Researches pointed out that this seemingly infectious spike protein was not found in the deadliest viral infection, the Spanish viral flu of 1918.
Some virologists including Peter White, a virologist at the University of New South Wales in Sydney, Australia has debated the similarity in the activation sites found in coronavirus to other viruses.
Chinese researchers have already hypothesized possible treatment drugs to fight the Corona virus in the form of a Furin blocker. However, as of yet there has been limited progress in the finding of such a drug and the potential treatment still remains to be just a theory.