SARS-CoV-2 isn’t the only coronavirus known to humankind. But how many are there?

·4-min read
The ultrastructural morphology exhibited by the 2019 Novel Coronavirus (2019-nCoV) is seen in an illustration released by the Centres for Disease Control and Prevention in Atlanta January 29, 2020.— CDC handout via Reuters
The ultrastructural morphology exhibited by the 2019 Novel Coronavirus (2019-nCoV) is seen in an illustration released by the Centres for Disease Control and Prevention in Atlanta January 29, 2020.— CDC handout via Reuters

KUALA LUMPUR, May 23 — Researchers recently announced the discovery of a canine coronavirus — not linked to Covid-19 — in children.

The finding was a result of Duke University’s Global Health Institute research aimed at developing a pan-species coronavirus test in order to help prevent the next pandemic.

Professor Gregory Gray, the lead researcher, said several lab tests found canine coronavirus was present in a group of mostly children patients admitted to hospital for pneumonia in Malaysia in 2017 and 2018.

The data was released on Thursday in Clinical Infectious Diseases, a peer review journal.

Should we be worried about this latest finding? Well, while Gray’s team had suspicions that the canine coronavirus may have caused illness in the children, as opposed to merely being present in the patients’ airways, they weren’t able to conclusively prove it.

Plus humans have been living with coronaviruses — which the World Health Organization (WHO) defines as a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS) — for decades, or maybe even centuries.

According to the United States Centers for Disease Control and Prevention, considered the most authoritative agency on infectious diseases, human coronaviruses were first discovered in the mid-1960s, while the medical website NBI said symptoms shown by those who carried the virus were first recorded in the 1930s.

Below is a list of the most common human or animal coronaviruses found by experts to date:

HCoVs — 229E, OC43, NL63, and HKU1

These four coronaviruses are commonly associated with the common cold.

The website sciencedirect.com said symptoms are typically characterised by rhinorrhea, nasal congestion, sore throat, sneezing and cough that may be associated with fever.

The HCoVs put together are the second most common cause of the common cold after rhinoviruses.

Veterinary science journal Frontiers said all HCoVs likely had zoonotic origins from bats, mice or domestic animals, with ample “evidence suggesting that the evolutionary origin of all HCoVs lies in bats, which are well-adapted and non-pathogenic but show great genetic diversity.”

MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)

The Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus named the Middle East respiratory syndrome coronavirus, or MERS‐CoV. It was first identified in Saudi Arabia in 2012.

There was scientific evidence suggesting that dromedary camels are a major reservoir host for MERS-CoV which could have infected humans. — Reuters pic
There was scientific evidence suggesting that dromedary camels are a major reservoir host for MERS-CoV which could have infected humans. — Reuters pic

Most human cases of MERS-CoV infections have been attributed to human-to-human infections in healthcare settings, but there was scientific evidence suggesting that dromedary camels are a major reservoir host for MERS-CoV which could have infected humans, according to the WHO.

But unlike the coronavirus that causes Covid-19, the world body said MERS-CoV does not seem to pass easily from person to person unless there is close contact, such as occurs when providing unprotected care to a patient.

“Healthcare associated outbreaks have occurred in several countries, with the largest outbreaks seen in Saudi Arabia, United Arab Emirates, and the Republic of Korea,” it said.

SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS)

SARS-CoV 1 causes severe acute respiratory syndrome (SARS), a viral respiratory illness first reported in Asia in February 2003.

The illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained.

The European Science Media Hub, part of the European Parliamentary Research Service, said while coronaviruses are infectious viral diseases agents of zoonotic origin, it cited a study that suggests the SARS-coronavirus to be “moderately” related to other known coronaviruses.

SARS-CoV 1 causes severe acute respiratory syndrome (SARS), a viral respiratory illness first reported in Asia in February 2003. — AFP pic
SARS-CoV 1 causes severe acute respiratory syndrome (SARS), a viral respiratory illness first reported in Asia in February 2003. — AFP pic

Analysis also indicated that they do not closely resemble any of the three previously known groups of coronaviruses, which will be explained below.

SARS-CoV 1 infection typically causes severe symptoms related to the lower respiratory tract.

What are the three major coronavirus groups?

Experts initially found three major known coronavirus groups before the discovery of SARS-related viruses, according to Frontiers. Based on the names, all of the coronaviruses from the three groups have zoonotic origins.

The first group consists of the Porcine Transmissible Gastroenteritis Virus (TGEV), Feline Coronavirus (FCoV), Canine Coronavirus (CCoV), HCoV-229E, and Porcine Epidemic Diarrhea Virus (PEDV).

The second group comprises Murine Hepatitis Virus (MHV), Bovine Coronavirus (BCoV), HCoV-OC43, Porcine Hemagglutinating Encephalomyelitis Virus (HEV), Rat Coronavirus (RtCoV), and Equine Coronavirus (ECoV).

The third group comprises IBV, Turkey Coronavirus (TCoV), and Pheasant Coronavirus.

But the journal said the three groups have been reclassified recently into four genera — the Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus.

Scientists continue to learn more about coronaviruses and along the way discover new ones. There is no denying the one we are most familiar with right now is the SARS-CoV-2 as its spread has led to a worldwide pandemic.

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