Corona virus affected countries. Covid-19 (formerly known as 2019-nCoV) appeared in China in late December 2019. This infectious disease is caused by SARS-CoV-2, a virus that belongs to a large family, the corona viruses. Very frequent, they can cause a simple cold as well as a serious respiratory infection such as pneumonia, causing fatal epidemics as was the case with Sras or Mers and now with Covid-19. Symptoms, transmission, number of cases, preventive measures.
What is a corona virus?
Corona virus, which owe their name to the crown shape of the proteins that coat them, are part of a large family of viruses, some of which infect different animals, others humans. They are likely to be the cause of a wide range of diseases. In humans, these diseases range from the common cold to a severe lung infection, responsible for acute respiratory distress.
Corona viruses cause deadly epidemics
On the subject, Inserm recalls that two deadly epidemics have already occurred in the 21st century, involving emerging corona viruses, hosted by animals and suddenly transmitted to humans:
- the SARS-CoV (2002-2003), or corona viruses cause of severe acute respiratory syndrome (SARS) appeared in China more than 8000 cases have been reported in 30 countries and 774 people died (nearly 10% mortality).
- the MERS-CoV (2012-2013), or respiratory syndrome corona virus in the Middle East, so called because it was detected for the first time in Saudi Arabia. 1,589 cases and 567 deaths in 26 countries have been recorded (representing a mortality rate of around 30%).
The third fatal epidemic is that related to SARS-CoV-2, which appeared in China in December 2019. The first cases identified are people who went to a local market, in Wuhan, in Hubei province. corona virus affected countries
How are emerging corona viruses transmitted?
Corona viruses are of animal origin: one species (“reservoir”) harbors a virus without being sick and transmits it to another species, which then transmits it to humans. In the cases of SARS-CoV and MERS-CoV, the reservoir animal was the bat. As Inserm explains, “the virus is asymptomatic in this animal. An intermediate host is therefore necessary for the transmission of these viruses to humans: the masked palm civet for SARS-CoV, sold on the markets and consumed in southern China, and the dromedary for MERS-CoV. “
With regard to SARS-CoV-2, the reservoir could also be the bat. In early February, a team of Chinese researchers from the University of Agriculture in southern China estimated that the missing link could be the pangolin, a small mammal with scales, in danger of extinction. But caution is advised, pending a final confirmation. The virus is said to pass into humans via animal secretions, under specific conditions which have yet to be identified.
The SARS-CoV corona virus and MERS-CoV are transmitted not only from animals to humans but also from humans to humans. Human-to-human transmission is also known to occur in Covid-19 disease. The disease is transmitted by postlets (droplets of saliva) projected by coughing or sneezing. Close and prolonged contact is therefore necessary to transmit it (family, same hospital or boarding room) or to have had contact within 1 meter of the patient, in the absence of effective protective measures.
One of the most important transmission factors seems to be contact with unwashed hands. So-called “barrier” measures are therefore essential to limit the impact of the virus: wash your hands frequently with soap or hydro-alcoholic gel, sneeze or cough in your elbow, and use disposable tissues.
If the health authorities insist that the objects coming from them (such as letters and cardboard) do not allow the virus to survive for a sufficient period of time. Depending on temperatures and humidity, the virus can nevertheless survive for a few hours or even a few days on various surfaces if they are not disinfected. This is why it is essential to avoid touching your eyes, nose or mouth (which are possible entry points for the virus in your body) with dirty hands.
What are the symptoms of Covid-19?
The most common symptoms of the virus are fever, the tiredness and a dry cough. Some people may also experience body aches, headaches, tightness or shortness of breath. These symptoms suggest an acute respiratory infection or radio-logically detectable lung abnormalities. In more severe cases, the infection can cause “respiratory distress, acute renal failure, or even multiple organ failure that can lead to death,” said the Ministry of Health.
As a reminder: the disease remains mild in 80% of cases and the researchers estimate the overall mortality rate from the virus at around 3.4%. Some patients also have an asymptomatic form of the virus: they carry the virus, but do not report the symptoms.
Given that these symptoms can also be confused with those of the flu, the only way to confirm the diagnosis is to perform a biological test by taking samples from the nasal or respiratory tract. The result can usually be obtained in 3 or 5 hours. In anticipation of a possible transition to stage 3 of the epidemic in France, the government has indicated that this test will no longer be systematic and may be available in the city laboratory (no longer only in reference health establishments).
Is there a vaccine for Covid-19?
Vaccines against pneumonia, such as the pneumococcal vaccine and the Hemophilus influenzae type B (Hib) vaccine, unfortunately do not protect against the corona virus. The Covid-19 is so new and specific that it is necessary to develop a vaccine of its own. Dozens of clinical trials are currently underway. According to the Pasteur Institute, the vaccine, if found, would not be available until the fall of 2021.
Are there people at risk of developing a more severe form of the disease?
The available information suggests that the virus can cause symptoms similar to those of a moderate flu, but also more severe symptoms. As with many infectious diseases, people with pre-existing chronic diseases (hypertension, cardiovascular disease, diabetes, liver disease, respiratory disease …) seem more likely to develop severe forms, as are the elderly and immunocompromised.
Patients with chronic obstructive pulmonary disease (COPD) are particularly vulnerable. Children under the age of fifteen are unlikely to trigger a severe form of coronavirus. A study published in the journal Jama at the end of February also indicates that men could be more affected by the virus.
How to treat an infection with the new corona virus?
The treatment is said to be symptomatic (it aims to relieve symptoms): fever medication (antipyretics)… In severe forms, sick people can receive antibiotics when a bacterial co-infection is present, be put on respiratory assistance…
Drugs that have been proven to treat other diseases, including viral diseases, are currently being tested against the corona virus. The idea of a treatment based on chloroquine, used against malaria, was advanced at the end of February by Professor Didier Raoult, director of the Mediterranean Infection Institute in Marseille. The latter is based on the work of three Chinese researchers published in the journal Bioscience Trends and carried out on cells cultured in vitro. Tests and clinical trials involving infected patients have yet to be performed.
As for the development of a specific antiviral drug for Covid-19, research is underway, but it would take at least a year to create a new drug.
How many people are affected by Covid-19?
Corona Virus Affected Countries
According to March 10 estimates, nearly 119,200 cases have been reported, 65,800 people have been cured and 4,290 people have died, mostly in China, where the epidemic appears to be slowing. A total of 106 Corona virus affected countries and territories on five continents are now affected by the epidemic. The most affected countries, excluding China, are Italy, Iran and South Korea. “Believing yourself safe from the disease would be a fatal mistake,” said Tedros Adhanom Ghebreyesus, director general of the World Health Organization. Corona virus affected countries
France is the fifth most Corona virus affected countries list by the epidemic in the world. The latest report shows 1,784 people infected with the new SARS-CoV-2 corona virus. Since the first cases were detected on the territory, thirty-three patients have died.
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