How Viruses And Diseases Get Named

You may be using the terms interchangeably, but SARS-CoV-2 is the name of the novel coronavirus, while COVID-19 refers to the disease that it causes in humans.

AsianScientist (Apr. 22, 2020) – In the past two decades, two major epidemics were caused by coronaviruses—a family of enveloped single-stranded RNA viruses with a genome no larger than 30 kilobases.

The first epidemic happened in 2002 with severe acute respiratory virus-related coronavirus (SARS-CoV), known simply as SARS. A decade later, it was followed by the Middle East respiratory syndrome coronavirus (MERS-CoV), known simply as MERS.

In December 2019, Chinese authorities identified a new type of coronavirus from an outbreak at one seafood market in the city of Wuhan. Tentatively called the 2019 novel coronavirus, or 2019-nCoV, it has since gone on a rampage around the globe with confirmed cases surpassing 1.2 million and a death toll of nearly 68,000.

Most people may have at some point used the terms SARS-CoV-2 and COVID-19 interchangeably to describe this virus, but they aren’t the same thing—SARS-CoV-2 refers to the virus, while COVID-19 refers to the disease that it causes in humans. But who gets to decide on what a disease is called?

The little sister of SARS

The main players here are the World Health Organization (WHO), which comes up with the official name for the disease based on best practices, and in consultation and collaboration with the World Organization for Animal Health (OIE) and the Food and Agriculture Organization of the United Nations (FAO).

In February 2020, WHO director-general Dr. Tedros Adhanom Ghebreyesus announced the official name for the disease caused by the novel coronavirus would be COVID-19—‘co’ for corona, ‘vi’ for virus, ‘d’ for disease, and ‘19’ for the year the outbreak began.

That same month, the Coronavirus Study Group (CSG) of the International Committee on Taxonomy of Viruses, which is responsible for developing the official classification of viruses and taxonomy of the Coronaviridae family, published their assessment of the novelty of 2019-nCoV.

Drawing upon phylogeny, taxonomy and established practice, the international team formally designated the novel coronavirus as ‘severe acute respiratory syndrome coronavirus 2’ (SARS-CoV-2), and recognized it to be a sister to the species ‘severe acute respiratory syndrome-related coronavirus’ (SARS-CoV).

While viruses are typically classified by genomic sequence, the authors noted that sequence alone cannot be used to reliably ascertain virus novelty or identity, since nucleotide changes may attenuate a deadly virus or cause a host switch.

In addition, as RNA viruses are constantly evolving, they persist as a swarm of co-evolving closely related entities, or ‘quasispecies.’ Their genome sequence may therefore vary within a single infected person and over time in an outbreak.

“If the strict match criterion of novelty was to be applied to RNA viruses, it would have qualified every virus with a sequenced genome as a novel virus, which makes this criterion poorly informative,” the authors wrote. “To get around the potential problem, virologists instead may regard two viruses with non-identical but similar genome sequences as variants of the same virus.”

Nicknames can hurt

At the onset of an outbreak, the virus and associated disease are given names by people outside of the scientific community. But once established in common usage in online articles and social media, these names are difficult to change, even if later deemed inappropriate.

The SARS-CoV-2 novel coronavirus, for example, was quickly nicknamed ‘Wuhan virus’ after the capital city of Hubei province where it was discovered. As expected, there have been an increase in reports of xenophobic behavior towards people of Asian descent outside of China since the outbreak.

It is therefore important that whoever first reports on a newly identified human disease uses an appropriate name that is scientifically sound and socially acceptable, the WHO advised.

“Having a name matters to prevent the use of other names that can be inaccurate or stigmatizing,” said the WHO director-general during a press conference. “It also gives us a standard format to use for any future coronavirus outbreaks.”

To get a disease name right, one can refer to a set of best practice guidelines issued by the WHO in 2015 for naming new human infectious diseases.

As a start, a new disease name should consist of generic descriptive terms based on the symptoms that the disease causes, such as respiratory disease or watery diarrhea. More specific descriptive terms such as how the disease manifests, who it affects, its severity or seasonality, can also be included.

In the case of SARS-CoV-2, ‘severe’ was used to indicate that the disease has a very high initial case fatality rate (CFR), recognizing that the CFR may decrease over time. If the pathogen that causes the disease is known, such as coronavirus, it should be part of the disease name. Potential acronyms should also be easy to pronounce, the guidelines advised.

Terms that should be avoided in disease names include geographic locations, such as the Middle East for Middle East Respiratory Syndrome (MERS). Likewise, people’s names (Creutzfeldt-Jakob disease, Chagas disease), animal names (swine flu, bird flu, monkey pox) groups of people (legionnaires disease), and terms that incite undue fear (unknown, fatal, epidemic) should also be avoided.

Why is MERS not renamed?

While the name COVID-19 certainly complies with WHO best practices, the latest guidelines do not apply to diseases for which there is already a name in common usage. Media outlets and healthcare authorities will thus continue to refer to Ebola virus after a river near the Ebola village in the Democratic Republic of Congo (formerly Zaïre), and Zika virus after the Zika forest in Uganda, places where the viruses were first identified.

“The use of names such as swine flu and Middle East Respiratory Syndrome has had unintended negative impacts by stigmatizing certain communities or economic sectors,” said Dr. Keiji Fukuda, WHO assistant director-general for health security.

“This may seem like a trivial issue to some, but disease names really do matter to the people who are directly affected. We’ve seen certain disease names provoke a backlash against members of particular religious or ethnic communities, create unjustified barriers to travel, commerce and trade, and trigger needless slaughtering of food animals. This can have serious consequences for peoples’ lives and livelihoods.”

Newer guidelines will also not correct historical inaccuracies in naming. The 1918 influenza pandemic was widely called the Spanish flu, even though its geographic origins are unclear and it was simply better reported by the Spanish press. German measles is another misnomer—the rubella infection did not originate in Germany; German physicians were just the first to describe it.


Copyright: Asian Scientist Magazine; Illustration: Lam Oikeat/Asian Scientist Magazine.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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