Coronavirus

Coronavirus: SARS, MERS and nCoV, here’s what’s similar about these diseases

When the virus was first identified, several health officials were worried that it would start a chain of reactions similar to the SARS outbreak of 2002.

Written by : Dr Nimeshika Jayachandran

On Sunday morning, health officials from the People’s Republic of China announced that the death toll from the Novel Coronavirus (2019-nCoV) has risen to 56, with the death of 15 more individuals in Shanghai.

The city of Wuhan in Hubei province is one of the most populated cities in China, with over 11 million people. It is the heart of the recent outbreak of a coronavirus, which has now been detected in several countries across the world, including India, the US, and Japan. A city-wide shut down and ban on travel has been imposed by the government in an effort to contain any further spread of the virus.

Human infection by Coronavirus is not new. A previous epidemic, which occurred in 2003, has also been attributed to a virus from this family of pathogens. According to the Center for Disease Control (CDC), over 8,000 people were infected during the Severe Acute Respiratory Distress (SARS) outbreak caused by what was termed the SARS-CoV. Of these infected individuals, over 700 died.

Why are officials comparing current outbreak to SARS?

While the World Health Organisation (WHO) opted to not declare the current outbreak a ‘global health emergency', the decision came after some debate.

“On January 22, the members of the Emergency Committee expressed divergent views on whether this event constitutes a PHEIC (Public Health Emergency of International Concern) or not. At the time, the advice was that the event did not constitute a PHEIC, but the Committee members agreed on the urgency of the situation and suggested that the Committee should be reconvened in a matter of days to examine the situation further,” reads the statement issued by the organisation.

This came amidst concerns that the nCoV outbreak was strikingly similar and even potentially as fatal as SARS.

The SARS outbreak started in November 2002 in Guangdong, China. The virus, another coronavirus, had been transmitted to humans via animals at a market. In a span of eight months, over 8,000 people were infected and more than 700 lives were lost. Its widespread manifestation in 29 countries led health experts to deem it “the first pandemic of the 21st Century”.

However, since July 2003, no case has been reported.

MERS: Why it's significant

SARS may have been last seen in 2003. However, nearly a decade later, another coronavirus causing a similar respiratory illness caught the attention of scientists: the Middle East Respiratory Syndrome (MERS). It was first identified in Saudi Arabia in 2012 and was caused by a virus called MERS‐CoV.

According to the WHO, it cannot be transmitted between humans, and it is transmitted from animals to people (termed a zoonotic virus). The virus is only transmitted via close contact with an infected individual. Twenty-seven countries in the world (mostly in the Middle Eastern regions) have reported cases of MERS.

No vaccine is available and treatment comprises easing an individual’s symptoms until the virus self-limits its replication.

Animals, virus mutation, difficulty in producing vaccine

Animals have been identified as being the primary source of all three mentioned coronavirus infections. While SARS was thought to have been spread from an animal, officials are yet to determine the original source. MERS was also transmitted from animals to humans. While SARS was spread via an infected person, MERS was only transmitted from animals to people.

Similarly, officials initially thought that 2019-nCoV was also being spread via animals. An initial study pointed towards snakes, which were sold at the now-closed and quarantined market in Wuhan. Later, reports, however, pointed to bats being the source of the viruses.

While a lot of questions remain unanswered, global experts are working on trying to produce a vaccine. This can be challenging as the pathogen is relatively new in this virulent form. Furthermore, a rapid adaptation of viral DNA can cause the virus to mutate into a more potentially aggressive form, even before a vaccine can be developed to tackle the initial strain of the virus.

China has issued a strict travel advisory against visiting Wuhan. The city remains on lockdown as well.

Several airports in India, including in Kochi, Hyderabad, Chennai, Bengaluru and Mumbai, have begun screenings of passengers arriving from China. Suspected cases have been reported across the world, with three confirmed cases in the US as well as a “presumptive” case reported from Toronto. among others.

Prevention, symptoms, testing, treatment

Maintaining personal hygiene, including frequently washing hands with soap and water and using an alcohol-based sanitiser are some good early measures to take. Avoid contact with others if ill and cover your face and mouth. Rest at home and visit a doctor at once if symptoms worsen.

The most commonly seen symptoms are fever, cough, cold, runny nose and breathing difficulties in more severe cases. The infection may not even present as anything more than a common cold, therefore measures should be taken even at the earliest appearance of symptoms.

Situation in India

The Health Ministry in India has issued a travel advisory, cautioning those who may be travelling to exposed regions of the world.

Suspected cases have been reported in Mumbai, Kerala, and Hyderabad. Over 100 people have been asked to remain under home isolation in Kerala following fears of transmission of the virus.

The incubation period of the virus is said to be anywhere between eight days to two weeks. A recent report in Lancet observed a family which had recently holidayed in Wuhan. It is speculated that an individual can be a carrier of the virus without actually being infected by it, though it is unclear if carriers can transmit the virus to a healthy individual.

However, what does seem to be a pressing cause for concern is that the virus appears to have the ability to rapidly mutate, possibly at a rate faster than a vaccine could potentially be developed.

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