It may not surprise you to learn that the drama film Contagion has seen a huge spike on download sites amid the coronavirus pandemic, but what you may not know is that microbes have been movie stars since the earliest days of cinema.

Between 1900 and 1930, moviegoers could watch bacteria and other microbes cavort on the silver screen in dozens of films with titles such as On the Trail of the Germs (1912) and The New Microbe (1912).

Cinema was an ideal technology for transforming phenomena that were invisible to the naked eye into spectacular visions. These films were popular because they invoked simultaneous reactions of attraction and repulsion in audiences.

Films of microscopic organisms, such as documentary film pioneer Charles Urban’s The Red Snow Germs (1905) and Typhoid Fever Germs (1905), allowed audiences to see for themselves the previously invisible wriggling, writhing aliens that actually lived around them, on them and in them. Yet, these films were also frightening because of the role these microscopic monsters played in disease. Many fictional films featuring microbes both reflected and fuelled this anxiety with titles such as The Dread of Microbes (1911) and Thomas Edison’s anti-tuberculosis propaganda film The White Terror (1915).

Food was a particularly common subject, as in The Unclean World (1903), The Scientist’s Lunch (1905) and A Bad Case (1909). In The Cheese Mites (1903), the normally invisible mites from a piece of Stilton cheese were made to look like alien invaders when magnified on the screen. The film’s peek into this hidden world was too revealing for some; the British cheesemakers had the film censored because they were afraid it would negatively impact the public’s perceptions of their product.

By 1930, filmmakers began featuring the bacteriologists who studied these killer pathogens in motion pictures. Paul de Kruif’s bestselling 1926 book The Microbe Hunters catalogued the scientific exploits of Louis Pasteur, Paul Ehrlich, Walter Reed and other pioneering microbiologists. As the book’s title suggests, these ‘microbe hunters’ were not feeble old men working in dusty, darkened laboratories. They were idealistic adventurers who travelled to far off locales to establish the truth about microbial dangers. de Kruif had also provided scientific advice for Sinclair Lewis’ 1925 Pulitzer Prize-winning novel Arrowsmith, which followed the exploits of a fictional scientist who studies a plague outbreak in an exotic country and who also conducts bacteriological experiments in the backwoods of the American West.

The popularity of de Kruif’s and Lewis’ books made a film adaptation of Arrowsmith inevitable. However, the critical and financial success of 1931’s Arrowsmith paved the way for a host of films featuring stories of courageous bacteriologists.

Arrowsmith was entirely fictional, but the film had the realistic feel of a ‘bio-pic’ which was also a popular genre at the time. Studios figured that if they were successful with a fictional bacteriologist, then why not make movies about real-life microbe hunters? Like Arrowsmith, The Story of Louis Pasteur (1936) was not only a commercial hit, but it was also a critical triumph – winning three Academy Awards as well as being nominated for best picture. Warner Brothers Studio also tackled the story of Paul Ehrlich with the 1940’s Dr Ehrlich’s Magic Bullet. The film hit a topical sweet spot for producers Harry and Jack Warner. It was an anti-fascist medical picture featuring a Jewish scientist whose research addressed an important social problem (in this case syphilis).

Whether based on real-life scientists or entirely fictional, almost every bacteriologically based movie that followed borrowed narrative elements from Arrowsmith, especially those related to the theme of self-sacrifice. This led to films in which scientists travelled to disease outbreaks in exotic locations or retreated to remote wildernesses in order to conduct experiments in isolation. In The Painted Veil (1934), for example, a bacteriologist travels to a remote part of China to study a cholera epidemic, while Green Light (1937) casts the dashing Errol Flynn as a scientist who leaves the comforts of the big city to work on a cure for Rocky Mountain spotted fever in the wilds of western Montana.

Filmmakers also preferred real-life scientists whose research took place in dangerous locations, such as Yellow Jack (1938), which focused on Walter Reed’s work in Cuba. These films also often featured an ethical dilemma reminiscent of Arrowsmiths moral quandary about inoculating everybody with his potential cure or maintaining his controlled study. In The Crime of Doctor Hallet (1938), for example, the microbiologist commits a crime in order to develop a vaccine for red fever while working in the jungles of Sumatra. Although his indiscretion is the relatively uninteresting crime of forgery, the film highlighted the lengths a microbiologist was willing to go to in order to save humanity from the menace of infectious diseases.

We might think that there was nothing objectionable about stories of heroic scientists, but these films were not exempt from censorship. Some US state censor boards, for example, excised a line of dialogue from The Crime of Doctor Hallet, which had implied that we should be taking our moral cues from bacteria: ‘There’s something to be said for bacteria. They don’t waste time moralising. They eat, breed, die and kill’.

The film facing the biggest struggle with censorship was Dr Ehrlich’s Magic Bullet. The Production Code Administration (PCA)’s restriction on mentioning venereal disease made things difficult for Warner Brothers given that the film was about Ehrlich’s discovery of Salvarsan, the first effective medical treatment for syphilis. In the end, the studio convinced censors that the final film was not about Salvarsan the drug, but about Ehrlich the man. By putting the focus on the scientist and not the science, the story became morally acceptable to the censors.

The fad for movies about heroic bacteriologists did not survive the 1940s. During the Cold War, microbiologists were no longer perceived as brave scientists attempting to cure diseases; instead, the public viewed them as mercenaries betraying their scientific principles by using their knowledge to create horrific biological weapons.

This change in public attitudes was reflected in the movies and by the 1960s microbiologists had turned into movie villains. The success of the James Bond film Dr No in 1962 led to a flood of imitation ‘superspy’ films in the 1960s. A surprising number of these films featured secret agents whose mission was to prevent the release of weaponised infectious agents, whether they were produced in the Soviet Union [Agent for H. A. R. M. (1966); The Nasty Rabbit (1965); Project X (1968)], by Western scientists [The Satan Bug (1965)] or within the lairs of ‘supervillains’ [Billion Dollar Brain (1967)].

Two movies produced in the early 1970s, The Omega Man (1971) and The Crazies (1973), deviated significantly from previous bioweapons films. The effect of these fictional infectious agents was not to cause illness or death. Instead, the weaponised pathogens in these films had a radical transformative effect on the hosts’ minds and bodies. In other words, infected people turned into monsters. Monster-spawning plagues became common in horror films of the next several decades, especially when germs were combined with the theme of genetically modified organisms (GMOs) as in Warning Sign (1985).

By the 2000s, microbial plagues had become what radiation was in the 1950s, the go-to method for creating cinematic monsters. There have been dozens of recent films where viral or bacterial ‘plagues’ have broken out, creating hordes of zombies [28 Days Later (2002); Dawn of the Dead (2004); World War Z (2013)], vampires [Blade (1998); I am Legend (2007); Daybreakers (2009)] and werewolves [Underworld (2003)]. But these films are ultimately not about infectious diseases. In today’s cinema, microorganisms predominantly serve as metaphors for a wide range of social issues such as conformity, consumerism and classism.

Sensationalised news stories about killer E. coli and antibiotic-resistant ‘superbugs’ alongside dire warnings about emerging viruses in popular books, like Laurie Garrett’s The Coming Plague (1994), caused increased anxiety about microbes in the 1990s. In the last two decades, there have been two prominent films that have specifically addressed the serious threat posed by emerging infectious diseases. In many ways, Outbreak (1995) and Contagion (2011) recall the heroic microbiologist films of the 1930s with their plots featuring virologists saving the world from devastating pandemics. Both of these films raised awareness of emerging infectious diseases far more than any popular science book ever could.

Scientists believe that the more realistically a movie catastrophe is visualised, the more motivated the public will be to fund research in order to prevent the event from occurring in the real world. That is why many scientists willingly signed up to act as science consultants on both these films. Outbreak’s filmmakers employed a host of leading microbiologists as advisors including pioneering HIV researcher Donald Francis. Contagion’s producers also utilised prominent microbiologist Ian Lipkin from Columbia University as their main science consultant, along with significant assistance from the Centers for Disease Control and Prevention (CDC) – almost every member of production sought advice from the film’s scientific advisors. Because of this, the scientific elements in the film – the scientists, the laboratories, the source of the virus, the disease’s epidemiology and the response of the CDC – all felt authentic.

Ultimately, the same ‘attraction’ and ‘repulsion’ that drew early cinema audiences to films of microorganisms are the same aspects that still fascinate modern audiences. The technology of cinema adds an unreality to microbes that makes them appear both beautiful and disturbing at the same time. For this reason, it is a good bet that we will continue to see microbes in our movies for years to come.