Coronaviruses bring together seven different types of virus, three of which are very dangerous and which have led to fatal epidemics in humans (Sras, Mers, 2019-nCoV). What are the symptoms of a coronavirus infection? What incubation period? How long is it contagious? Can transmission be avoided?
Coronaviruses form a family of various viruses which can infect both humans and animals. Their name means “virus in crown“and comes from the fact that they all have a crown-like appearance when viewed under a microscope. The coronaviruses have been identified for the first time in humans in the years 1960. These are viruses that cause emerging diseases, that is to say new infections due to modifications or mutations of the virus. Human coronaviruses mainly cause respiratory infections, ranging from cold without gravity to severe pneumonia sometimes lethal. They can also be accompanied by digestive disorders such as gastroenteritis.
The incubation time, duration between exposure to the virus and the manifestation of the first symptoms, is evaluated between 10 and 14 days.
It exists four main subgroups of coronavirus, called alpha, beta, gamma and delta. And seven forms different including four municipalities (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 (beta coronavirus which 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 of over 65, those suffering from respiratory pathologies and the immunosuppressed.
The coronavirus is a RNA virus having a high mutation rate like that of the flu or the HIV virus. Coronaviruses are present in many animal species and move fairly easily from one species to another which can lead to death. Coronaviruses can also infect men.
Coronaviruses are spread from human to human during close contacts (touching or shaking hands for example) and by airway in coughing or in 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 can be done by 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.
Manifestations of coronavirus appear less than 24 hours after infection. Most generally, it results in mild to moderate respiratory disease like colds with symptoms such as:
- sore throat,
- a general feeling of unease.
More seriously, it can cause respiratory diseases of the lower tract such as pneumonia where the bronchitis, especially in people with cardiopulmonary disease, those with weakened immune systems, infants and the elderly.
There is no specific treatment for diseases caused by human coronaviruses. Treatments are symptomatic: take pain and fever medication, rest, do not go out.
There is currently no vaccine available to protect against infection with a human coronavirus. However, scientists at the Institut Pasteur are multiplying initiatives to find a vaccine against the coronavirus. They managed to isolate and culture strains of the new virus 2019-nCov and hopes to develop a vaccine within a year and a half, say researchers from the National Reference Center for Respiratory Viruses in a press release dated January 30, 2020. “Now, researchers at the Institut Pasteur have the virus that causes this infection. This viral isolation opens the way to new diagnostic, therapeutic and prophylactic approaches. “
To reduce your risk of infection with a coronavirus, it is advisable to:
- himself wash hands regularly with water and soap for at least 20 seconds (without forgetting the handy hydro-alcoholic solutions when you cannot wash your hands),
- avoid touching your eyes, nose or mouth when your hands are not washed,
- avoid contact with sick people,
- wear a mask.