Berlin / Hamburg (dpa) - The new corona virus is spreading with enormous dynamism - despite the countermeasures taken by the Chinese authorities. Researchers around the world are trying to infer as many properties of the pathogen from the young development. What you know - and what you don't:
- CORONAVIRES: The 2019-nCoV pathogen is one of the corona viruses - so named because they are surrounded by jagged structures that resemble a crown. Seven representatives of this group cause respiratory diseases in humans. Three of them are known to cause severe symptoms: around 8,000 cases of the Sars virus (severe acute respiratory tract syndrome), also from China, were known in 2002/2003, and around 800 people died. In 2012, the Middle East Respiratory Syndrome (MERS) virus appeared in the Near East. It is less contagious, but more aggressive: from around 2,500 infected people by November 2019, just under 860 died - around one in three. 2019-nCoV is very closely related to Sars.
- INFECTIOSITY: It is so far difficult to assess how contagious the new virus is. Chinese authorities assume that an infected person infects an average of 1.4 to 2.5 people - that would be similar to Sars. "Numbers like this are extremely unreliable," says virologist Christian Drosten of the Berlin Charité. Accordingly, the transmission rate depends on a large number of factors - such as whether people are socially active or tend to stay at home. In Drosten's opinion, this is exactly what the measures in China are aiming for. "I think these measures are working." It is positive that people usually only become infectious with the symptoms - in contrast to the flu, in which people are contagious before they fall ill.
- AGGRESSIVITY: The new corona virus appears to be less aggressive than Sars and Mers. By Monday, 80 out of around 2,800 people had died - this would correspond to a death rate of 2.9 percent. However, the number should be misleading, because it is precisely at the beginning of an outbreak that the more serious cases become known. In Drosten's opinion, a mortality rate of three percent would be very high. The expert assumes that the ten percent usually stated for Sars is too high a value. "There were probably many more back then than the known 8,000 Sars cases," he explains.
- SYMPTOMS: The incubation period - the period between infection and the onset of symptoms - is 2 to 14 days. The lung disease is characterized by fever, dry cough, fatigue and shortness of breath. Because the virus infects the lower respiratory tract, those affected do not have a cold. Ultimately, the symptoms are similar to those of a Sars infection. No wonder, because the new virus docks on the same receptor. The virus test is usually based on an analysis of sputum and takes about two hours.
- THERAPY: There is no special therapy for the lung disease. Seriously ill patients are treated symptomatically: with antipyretic agents, the therapy of any additional bacterial infections and sometimes mechanical ventilation.
- VACCINATION: Vaccination would be the best way to contain the epidemic. According to Jonas Schmidt-Chanasit from the Bernhard Nocht Institute for Tropical Medicine, vaccine candidates against Mers are currently being tested on humans. Assuming successful results, they will be available in a few months at the earliest. "This could then be built on," says Schmidt-Chanasit.
- RESERVOIRE: The reservoirs of various corona viruses are in the animal kingdom. At Mers, camels are the origin, at Sars and the new pathogen the reservoirs are presumably at bats. The Sars pathogen probably spread to humans from sneak cats that are offered in Chinese markets. 2019-nCoV is also likely to assume an animal market in China. The type of animal that the virus jumped over is currently unknown.
- PROTECTION: To protect against this and other viruses, experts recommend regular hygiene measures: regular hand washing, disinfectants and distance from the sick. Schmidt-Chanasit and Drosten rate the benefits of normal breathing masks - as can currently be seen everywhere on the streets in China - as rather low.
- FORECAST: Some experts expect a long breakout. "We should consider this a marathon, not a sprint," said Chris Whitty, who advises the UK government on health issues. "The extent and impact of this outbreak are currently unclear because the situation is developing rapidly," wrote a team led by Anthony Fauci from the US National Health Institute (NIH) in the journal "JAMA". The virologist Drosten, on the other hand, can imagine that the epidemic will end as quickly as the Sars outbreak, which quickly subsided and was declared over in 2004. "I'm inclined to think optimistically because it's a Sars-like disease." In addition to that, there has so far hardly been any further spread outside of China. "It is extremely encouraging." Sars continues to circulate - but only in the animal kingdom.
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"Lancet" study 2
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