Cause
This pneumonia is an infectious disease caused by a virus belonging to the coronavirus family, currently identified as SARS-Cov2.
The virus reservoir is probably animal. Although SARS-Cov2 is very close to a virus detected in a bat, the animal responsible for transmission to humans has not yet been identified with certainty.
Several publications suggest that the pangolin, a small mammal consumed in southern China, could be implicated as an intermediate host between the bat and humans.
Symptoms
- The duration of the incubation is on average 5 days, with extremes of 2 to 12 days. The onset of symptoms is done gradually over several days, unlike the flu which starts suddenly.
- The first symptoms are not very specific: headache, muscle pain, fatigue. Fever and respiratory signs occur secondarily, often two or three days after the first symptoms.
- In the first descriptive studies from China, an average of one week elapsed between the onset of the first symptoms and admission to hospital in the disease phase. At this stage, the symptoms combine fever, cough, chest pain and respiratory discomfort and the performance of a chest scanner almost always shows pneumonia affecting both lungs.
- The severity of the clinical signs requires that approximately 20% of patients remain in hospital and 5% require admission to intensive care. The most serious forms are observed mainly in people who are vulnerable because of their age (over 70 years) or associated diseases.
- Privileged observational studies (such as that carried out on passengers on the Diamond Princess cruise ship ) as well as modeling work have shown that the infection can be asymptomatic or paucisymptomatic (causing little or no clinical manifestations) in 30 to 60% of infected subjects.
Transmission
The majority of the cases initially described concerned people who had visited a live animal market. The hypothesis of a zoonosis (disease transmitted by animals) is therefore preferred.
Human-to-human transmission is established and it is estimated that in the absence of control and prevention measures, each patient infects between 2 and 3 people.
How is the diagnosis made?
A diagnostic test for the COVID-19 coronavirus is carried out in all referral health establishments, in the event of suspicion of the disease validated by the SAMU and by a referent infectiologist.
This test concerns any person with signs of acute respiratory distress syndrome for which no etiology could be identified, without any notion of travel / stay in a risk exposure area or close contact with a confirmed case of Covid- 19.
In addition, the definition of close contact now includes all contact from 24 hours before the onset of symptoms in a confirmed case of Covid-19.
These definitions are subject to change at any time, depending on the information available, and can be viewed on the Public Health France website .
The specific diagnostic test, developed by the National Reference Center for respiratory infection viruses (including influenza) of the Institut Pasteur in order to detect this new virus on samples of respiratory origin, is available in many hospitals in the national territory French.
Precautions / Prevention
- Refrain from any non-essential outing in a public place.
- Do not participate in any grouping, whether of a professional, social or family nature.
- Avoid contact with vulnerable people (pregnant women, the chronically ill, the elderly, etc.).
- Avoid frequenting places where there are fragile people (hospitals, maternity hospitals, accommodation facilities for the elderly, etc.).
Barrier gestures are effective:
- Wash your hands regularly (water + soap) or use a hydroalcoholic solution.
- Cough or sneeze into your elbow, or into a tissue.
- Use disposable tissues (and throw them in the trash after the first use).
- Greet without shaking hands, without hugging.
- Keep a distance of at least 1.5 meters from any contact person.
The predictions about the coronavirus catastrophe grow more ominous by the day, and despite the best efforts of countries like Australia in enacting emergency action plans to contain the disease, its spread continues at a worrying rate.
Even the World Health Organisation forecasts a world of pain. It says the virus poses a greater global threat than terrorism. That’s bad enough, but medical experts tell 60 MINUTES it’s actually even more terrifying.
Professor Gabriel Leung, who led the fight against the SARS virus, believes 60 per cent of the world’s population could become infected with COVID-19 and that up to 45 million people might die from it.
For this story, Liam Bartlett has travelled to Hong Kong and Thailand to find out the likely cause of the disease, as well as the latest ongoing efforts to combat it.
At all times he and his crew have followed medical advice and undertaken strict protocols to limit their exposure to potential danger.
Some Frequently Asked Questions
- What is the animal reservoir?
A 96% virus identical to SARS-Cov-2 has been identified in bats caught in China, so the bat is most likely the reservoir of the virus. Coronavirus
- How was the transition from animal to man made?
It is very likely that a mammal served as an intermediate host between the bat and humans. This intermediate animal is not identified with certainty, but the pangolin is suspected.
- Can the virus persist in the environment? And if so, for how long?
In view of the available data, the survival of coronaviruses in the outdoor environment is only a few hours on dry inert surfaces.
Given the times and conditions of transport between France and China, the risk of being infected with SARS-CoV2 by touching an object imported from China is considered to be extremely low. Standard hygiene measures (hand washing, surface cleaning) are effective. Coronavirus
- How long is the incubation?
The duration of incubation is on average 5 to 6 days, with extremes of 2 to 12 days, which justifies the quarantine period of 14 days.
- How is COVID-19 diagnosed in patients?
The diagnosis is suspected in the face of signs of respiratory infection in a person returning from an area of circulation of the virus in the 14 days preceding the onset of symptoms, in accordance with the case definition of Public Health France. Coronavirus
- What is the period of contagiousness?
Contagiousness seems to start with the onset of symptoms, or even a few days before for some subjects, and would be more important in symptomatic people, especially when they cough.
An international research effort is continuing, including the Pasteur Institute in Paris and the International Network of Pasteur Institutes, to refine the answers to these questions.