Coronaviruses bring together seven different types of virus, three of which are very dangerous and have led to fatal epidemics in humans (Sras, Mers, 2019-nCoV). What are the symptoms of a coronavirus infection? Can transmission be avoided? Are there treatments?

Definition: what is a coronavirus?

Coronaviruses are a family of various viruses affecting both humans and animals. Their name means “crown virus” and comes from the fact that they all have a crown-shaped appearance when viewed under a microscope. Coronaviruses were first identified in humans in the 1960s. They are viruses that cause emerging diseases, that is, new infections caused by changes or mutations in the virus. Human coronaviruses mainly cause respiratory infections, ranging from mild colds to severe, sometimes lethal, lung disease. They can also be accompanied by digestive disorders such as gastroenteritis.


Types of coronavirus: SARS, MERS …

There are four main subgroups of coronaviruses, called alpha, beta, gamma, and delta. And seven different forms including four commons (less serious than the others):

229E (alpha coronavirus)
NL63 (alpha coronavirus)
OC43 (beta-coronavirus)
HKU1 (beta-coronavirus)
And three more serious:
SARS-CoV (the beta-coronavirus that causes Severe Acute Respiratory Syndrome, or SARS, identified in China in 2002).
MERS-CoV (the beta coronavirus that causes Middle East respiratory syndrome, or MERS discovered in 2012 in Saudi Arabia).
New Coronavirus 2019 (2019-nCoV) identified in China in December 2019.
2,300 cases of MERS-CoV identified between 2012 and 2018, 35% of which died.
The mortality rate is relatively high for SARS and MERS-CoV, with nearly 15% and more than 36% of deaths of people affected, respectively. The most sensitive people are those over 65, those suffering from respiratory pathologies and immunocompromised.

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Coronavirus mutation
The coronavirus is an RNA virus with a high mutation rate like that of the flu or the HIV virus.

Coronaviruses are present in very many animal species and circulate fairly easily from one species to another which can lead to death. Coronaviruses can also infect men.


Coronaviruses are transmitted from humans to humans during close contact (touching or shaking hands for example) from air coughing or sneezing. Touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands can also spread the coronavirus. Finally, more rarely contamination is from fecal contact.

In the case of the SARS epidemic in 2002, the coronavirus responsible resulted from an adaptation of a coronavirus initially present in the bat to a small carnivore (the masked palm civet, consumed in China) at first, then to the human race.
Incubation time
The incubation time, duration between exposure to the virus and the manifestation of the first symptoms is evaluated between 10 and 14 days.


Manifestations of coronavirus appear less than 24 hours after infection. Most commonly, it causes mild to moderate respiratory illnesses like the common cold with symptoms such as:

headache, cough, sore throat, fever, a general feeling of unease.
More seriously, it can cause respiratory diseases of the lower tract such as pneumonia or bronchitis, especially in people with cardiopulmonary disease, in those with weakened immune systems, in infants and the elderly.


There is no specific treatment for coronaviruses diseases . Treatments are symptomatic: take pain and fever medication, rest, do not go out.

To reduce your risk of infection with a coronavirus, it is advisable to:

wash your hands regularly with soap and water for at least 20 seconds (without forgetting very practical hydro-alcoholic solutions when you cannot wash your hands),
avoid touching your eyes, nose or mouth.
avoid contact with sick people,
wear a mask.


Coronaviruses, Anses, July 25, 2018.
National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases