Contagion, out in cinemas now and starring Matt Damon, Gwyneth Paltrow and Kate Winslet, is a big-budget thriller by director Steven Soderbergh built around the threat posed by a deadly disease and an international team of doctors recruited to deal with the outbreak.
To mark the film's release, we spoke to David Bhella and Alain Kohl from the University of Glasgow Centre for Virus Research about Contagion, how close we are to such a threat in everyday life, what is the single most germ-riddled object we come into contact with and how we might protect ourselves:
Have we ever been close to this kind of disease in recent years without knowing it?
The requirement of a ‘doomsday scenario’ virus is that it should be both highly pathogenic – causing a high rate of mortality and it should be very infectious. The closest we have come to this was in the Spanish flu outbreak in 1918, which killed more people that the first-world war.
New viruses do sometimes emerge into the human population with devastating consequences, such as Ebola virus which has caused outbreaks of haemorrhagic fever in Africa that were associated with up to 90% fatality rates.
It is not a good strategy for a virus to kill all of its host population as the virus needs its host to survive and go on causing infections. Such viruses emerging in isolated populations are therefore less likely to spread as they would ‘burn themselves out’. Viruses are not however thinking strategic organisms and global travel does make the possibility of a pandemic outbreak more likely. In recent years international surveillance networks have been put in place to monitor outbreaks of unusual disease. We expect therefore that if a virus were to emerge that was very pathogenic, it would be rapidly detected and stringent containment measures put in place to limit transmission as happened with SARS.
How realistic is the kind of threat shown in this film?
The new virus that emerges in Contagion with such dramatic consequences is identified as having come from bats. Bats have been shown to carry several viruses that can be transmitted to other animals including humans. These include Lyssaviruses, a group of viruses that includes rabies virus. Another group of viruses that are transmitted by bats includes two important pathogens; Nipah and Hendra viruses. Hendra virus was discovered in Australia, where it infected horses and their handlers on a farm. Nipah emerged on pig farms in Malaysia infecting both pigs and humans and caused neurological symptoms in humans. This is very similar to the path taken by the MEV-1 virus in the film.
We are of course very familiar with the idea of viruses passing to humans through farm animals such as pigs. We recently saw the emergence of influenza that had certain traits of swine origin. Influenza is particularly liable to evolve in this way because of the way it stores its genetic material. Flu has its genome divided into segments. This means that when two different strains of the virus infect the same cell, new ones can emerge by mixing up the genome segments. This is called reassortment, however bat viruses discovered thus far do not evolve in this way.
Interference with ecosystems has been shown to be responsible for virus outbreaks including those transmitted by bats (which can indeed pass from pigs to humans and human to human) and that is real danger. It is also thought that global warming is starting to facilitate the emergence and spread of tropical diseases in Europe and North America because the insects that carry them can now survive in the warmer climate. For example two tropical viruses, dengue and chikungunya have recently been detected in southern France.
As shown in the recent SARS outbreak, modern techniques would allow scientists to identify new viruses relatively quickly, but the initial lack of a cell line to grow the virus could indeed prove a hindrance for development of vaccines or new antiviral drugs. Once a cell-line that allows the virus to be cultured is discovered it may still prove difficult to produce an attenuated virus (one that doesn’t cause disease and can be used as a vaccine) as described in the film. It might be quicker to produce a chemically inactivated one. Successful vaccine production is not assured however; there are many viruses that have been studied for decades that we cannot vaccinate against.
Once developed, it is unlikely that vaccination would proceed on a lottery basis. Governments would most likely prioritize certain sectors of society such as health care workers and those required for maintaining law and order.
The anthrax that was discovered in the US soon after 9/11, would that have done it?
Unlike the agent described in this movie, anthrax is caused by a bacterial infection and is transmitted from contact with infected farm animals. Anthrax disease can occur in many different ways. If it infects the skin and is detected early then treatment with antibiotics is effective, however infection by inhalation of bacterial spores can be more dangerous.
Anthrax was investigated as a possible bio-weapon during the second world war and is a potent threat as such because the spores can be spread by an explosion. Moreover, once contaminated it is very difficult to remove the spores from an area. There is however a vaccine against the anthrax bacterium and transmission between humans is rare, so it is not likely to cause the sort of outbreak described in this film.
What are some of the most common ways we spread germs between each other without realising it?
Humans are exposed to microorganisms all day every day and our body gives us good protection through the barrier of our skin and our immune systems. Some viruses, bacteria and parasites can cause disease nonetheless and the modes of transmission vary greatly.
Common diseases such as the cold virus or bugs that cause stomach upsets can be transmitted by casual bodily contact (shaking hands for example) or contact with contaminated surfaces such as door handles. They are not able to infect us when they are on our skin however and we usually help them along by rubbing our eyes or putting our fingers in our mouth. Of course someone infected with a cold of flu bug can transmit the germ by sneezing or coughing which produces an aerosol of virus which others can breath in. Drinking sewage-contaminated water is still a major source of illness and death in underdeveloped countries where there is inadequate water treatment.
What is the single most germ-riddled object we come across in everyday life?
Anything commonly touched such as door handles and coins can be a good source of microbial contamination. In particular recent studies have shown that smart phones can be contaminated with e.coli which indicates faecal contamination caused by poor hand washing or perhaps looking at facebook while on the loo!
And how can we best protect ourselves?
Regular hand washing, especially after visiting the lavatory and before preparing food is the best guard we have against everyday infections, as well as keeping food preparation surfaces clean. Also when you have a cold it is a good idea to keep away from other people to limit the spread. While the cold may be a small irritation to you, it may be much more serious to an elderly person or someone with another medical condition.
Tell us about the research that you do at the University of Glasgow Centre for Virus Research
The CVR is a leading international research centre for virology hosting investigators with expertise in human and animal virology, tasked with building our understanding of viruses and viral disease to improve human and animal health. Our research varies from studies of viruses at the molecular and genetic level to the mechanisms with which they cause disease, virus interactions with their hosts, how our immune system responds and how viruses spread through populations. We are also involved in developing new methods for diagnosing viral disease.
David Bhella’s laboratory is focussed on the structure of viruses, how they assemble and how individual components of viruses interact with each other and their host cell. Alain Kohl’s laboratory works on viruses that are spread by mosquitos and ticks, investigating how viruses have adapted to live in both arthropod and mammalian cells.
Contagion is currently on release in cinemas nationwide.