Retroviruses that quietly multiply unnoticed, spread through communities and threaten humanity. Robots that mutate into semi-conscious beings and go on the run from their human masters.

Television screenwriters all over the world are taking our darkest fears and turning them into popular entertainment.

From the American series "Helix" and South Korea's "The End of the World" to Sweden's "Real Humans", these dramas explore anxieties generated by a technologically inter-connected world in which medical science is constantly being outstripped by new threats.

Biotech is even edging out terrorism as a theme of choice for television writers, after a post-9/11 decade marked by pulse-raising dramas in the vein of the hit action series "24".

"We have many strong trends this year including... contamination by a virus that spreads and is going to have an impact on society," said Laurence Herszberg, from the Forum des Images cultural centre in Paris, during the forum's annual television drama festival.

"What is interesting, is that we find these themes in television series that have nothing to do with each other from very different parts of the world," she added.

In "Helix", one of a string of series shown at the "Series Mania" festival in Paris which ended earlier this week, a team of scientists investigate the outbreak of a retrovirus with potentially catastrophic consequences for humanity at a research centre in the Arctic.

Fear of contagion is also the theme of "The End of the World" in which a researcher battles to find the source of a mysterious epidemic.

And Belgium's "Cordon" tackles the same subject in a drama in which part of the city of Antwerp is sealed off to prevent the spread of a deadly virus.

"The virus is a very interesting way of tackling a number of themes... The human virus has a strong metaphorical power," said Pierre Langlais, a journalist for French television listings magazine Telerama, adding that the series were "trying to reflect contemporary anxieties".

- 'Fragile frontier between man and machine' -

In a twist on the contamination theme, "Real Humans" throws in technological developments that run of control.

Set in modern-day Sweden, it depicts a world in which humanoid robot workers and servants are commonplace.

Known as "hubots" they are programmed via a USB-type port in the back of their necks, although some form a group of "free hubots" after being reprogrammed to enable them to experience human emotions.

"Today we have the feeling that information technologies, computers, the Internet, are difficult to control, and are almost living their own life. It's something that didn't used to exist 15 years ago," said the series creator Lars Lundstroem, adding that it was both a potential "dream and a nightmare".

Britain's "Black Mirror", meanwhile, explores the possible consequences of an addiction to technology, from implants to playback memories, forced exposure to advertising and relatives brought back from the dead using synthetic flesh and computer-generated personalities.

Creator Charlie Brooker has described it as being "about the way we live now -- and the way we might be living in 10 minutes' time if we're clumsy".

The drama won an International Emmy for best mini-series in 2012.

But if all this sounds a bit too bleak, British director Danny Boyle has managed to inject some humour.

In his police comedy-drama "Babylon", the action alternates between police and the force's "ultra-connected" all-tweeting public relations department.

"The fragile frontier between man and machine is a strong theme at the moment," added Langlais.

"We are starting to take notice of the dangers of our addiction to new technologies and the pitfalls into which they could lead us," he said.