Can coronaviruses mutate to an extent to get as dangerous as fliovirusues such as Marburg viruses, Ravn or Ebola Zaire?
Each existing virus can mutate until it becomes ready to affect new species, organisms, cells or whatever.
Coronaviruses too are capable of mutating, so they could become more dangerous.
But can coronaviruses (which cause respiratory tract diseases) mutate into filoviruses (which cause hemorrhagic fevers)?
Of course not.
Filoviridae and coronaviridae are two different families of viruses, like felidae and canidae are two different families of mammals, in the order carnivora.
And you would never ask if cats can mutate in dogs!
'Dangerous' is quite a subjective term, and can be defined in different ways.
Viruses vary in their
pathogenicity, which is essentially the ability of the virus to cause a disease in a single individual. This can influence other factors, such as the
case fatality rate, which is the proportion of people who die from the disease once they have contracted it. For example, the Ebola virus has a very high case fatality rate of up to 90%.
However, those aren't the only ways in which you could define 'dangerous'. We might also consider the total number of people that the virus can kill. This often isn't a linear relationship with the case fatality rate. Often, viruses with a high case fatality rate 'burn out' before than can inflict a global pandemic, because people die before they can spread the disease on to others. Vice versa, viruses with a relatively low case fatality rate, such as the Spanish Flu (2-3%) can be extremely 'dangerous' and kill millions of people.
But there is no hard and fast rule, as the propensity of a virus to cause a global pandemic is influenced by many, many other factors.
So to answer your question: is it possible for the Covid-19 to mutate into something as dangerous as Ebola? Well, if we are thinking about it's pathogenicity - Influenza A H5N1 (bird flu) had a case fatality rate of about 60%, which is pretty high for a flu virus. For context, the seasonal flu which has a case fatality rate of about 0.1%. I'm not an expert in Virology, so it would be great if someone with more knowledge could confirm this, but it seems very unlikely that the Covid-19 virus could acquire mutations to the degree where it would kill as high as 90% of the people who acquire it, like Ebola does. Ebola is a hemorrhagic virus, which is a totally different mechanism of pathogenicity to the Coronavirus family.
It's plausible that Covid-19 could obtain mutations which allow it to transfer more quickly between humans. For example, we know that the Spanish Flu acquired mutations in hemagglutinin subtype which allowed it to be more transmissible between humans. Generally, Coronaviruses have relatively lower R0 rates than other disease (~2/3 compared to Measles which is 12-18). The total number of people killed by the Ebola outbreak was about 11,000. Covid-19 has already killed ~3000 (although the exact figure is hard to quantify), so it seems like on the global level, Covid-19 will be more dangerous than Ebola, if we consider the total number of people killed.