From cholera in London to a plague in Manchuria, engineers have played important roles in responding to past pandemics.
They called it the Great Stink.
Throughout the 19th century, the population of London had been growing – and with that growth came sewage.
Some of it went into cesspits. Some of it travelled through poorly constructed pipes from centuries previous. A lot of it went into the Thames.
And in the summer of 1858, the stench bubbled up to intolerable levels. The British Parliament was forced to soak its curtains in lime so politicians could continue to meet there. Queen Victoria was forced to cancel a pleasure cruise after minutes, the stench was so odious.
And, Londoners had noticed the city had suffered through a number of cholera epidemics over the past few decades, killing between 6000 and 14,000 people in each wave.
Was there a connection?
Yes – although not in the way they thought. But when civil engineer Joseph Bazalgette turned his attention to saving London from the terrible tang of the Thames, he also saved the city from the disease striking its population at regular intervals.
Just as engineers have helped respond to the current coronavirus pandemic – by 3D-printing protective equipment, by devising safer surface material, by putting robots to work in cleaning and care – previous outbreaks of disease have also inspired technological and infrastructure responses.
When Joseph Bazelgette saved the day in Victorian London, the prevailing consensus on how diseases like cholera spread was known as miasma theory. Infection, people supposed, wafted through the air much the way the malodorous scent of the city’s river did.
So when Bazelgette put forward a grand plan to remake London’s sewer system, it was under the expectation that his scheme would do something about the apparently cholera-causing miasma that helped him secure approval.
You know something, John Snow
Actually, during a cholera outbreak in 1854, a physician by the name of John Snow had advanced an alternate theory: cholera, he said, was caused not by “bad air,” but by contaminated drinking water.
Snow demonstrated his theory by removing the handle from a water pump that had been placed less than a metre away from an old cesspit, thus preventing anyone from drinking the water. But it wasn’t until Bazelgette constructed his ambitious sewer scheme, thus ensuring that drinking water and sewage would remain separate for good, that Snow’s theory was accepted.
Bazelgette started his career as a railway engineer, but by the late 1850s, he had become chief engineer of London’s Metropolitan Board of Works.
The board raised £3 million for Bazelgette to work with. He used pumping stations to direct waste downstream, relied on gravity for the main drainage sewers, and, for the smaller conveyances, created egg-shaped chambers that encouraged flow towards the narrower bottom end. He also used his experience in railways to build embankments on the river.
Importantly, Bazelgette went overboard in his design. He gave each London resident the maximum allotment of sewer space when he was making his calculations, then he doubled the diameter of the pipes – just in case.
As a result, when London’s population density grew with the construction of high-rises in the 20th century, Bazelgette’s oversized sewers could accommodate the extra people. They are still in use today.
And its health value was proved almost immediately. In 1866, London’s East End was hit by another cholera outbreak. It was the only part of the city not connected to the sewers. The rest of the residents were safe.
A face covering, a bra, an infection-preventing mask
In protecting health workers from exposure to infection during the current coronavirus pandemic, one of the most straightforward yet vital pieces of equipment has been the face mask.
One of the most advanced versions of these is the N95 respirator, which, with its tight seal and advanced filter, provides far more effective protection than standard surgical masks.
But the story of the N95 dates back more than a century, to an epidemic in northern China.
The debunked miasma theory of disease common in Bazelgette’s day had been replaced by the germ theory by this time, but face coverings are still useful in protecting against airborne pathogens.
It was one of these that hit Manchuria and Mongolia in the winter of 1910. Wu Lien-Teh, a doctor from what is now Malaysia, had been sent there to treat the horrific pneumonia outbreak, which killed 99.9 per cent of the people who were infected with the disease.
Wu ascertained that the virus was spread through the air and designed a surgical mask out of gauze and cotton to protect himself. One French doctor, also there to treat the stricken, refused Wu’s offer of a mask, quickly fell ill and died two days later.
Wu survived – and so did his mask. But it took the development of World War II-era respirators, a savvy industrial designer and an engineer to develop the product into the N95 we know today.
The industrial designer was a woman named Sara Little Turnbull, who would go on to work as a consulting professor at the Stanford School of Engineering. Working for 3M during the 1950s, she was assigned to work on developing products made from a non-woven material originally used for ribbons.
She used the material for shoulder pads and a moulded bra cup. Inspired particularly by the latter of these, she began to adapt the cup into a medical mask.
“I did a number of things,” Turnbull said of her role in the design. “I asked questions in the laboratory, questions coloured by my own experience. I acted as a catalyst bringing together the most current technology on non-woven fabrics. I took direction, gave direction, expressed concerns.”
But Little’s mask, upon testing, proved unable to filter out pathogens, even though it was effective as a dust mask. The creation of the true N95 came at the hands of Peter Tsai, a Taiwanese engineer.
“Tsai used a method called corona electrostatic charging,” explains the University of Tennessee, Knoxville, where Tsai worked in the Department of Material Science and Engineering.
“The technique, which earned him a US patent in 1995, uses an electric field to ionize the neutral air to generate ions and electrons, which then charge the nonwoven fibers through field and induction. Using his innovative approach, the charged nonwoven fabric can filter particles in the air ten times more efficiently than uncharged fabrics without adversely increasing the air resistance.”
And although Tsai is now retired, he is still working on the N95. His latest research involves finding a way to clean and re-use the mask, in hope of addressing the shortages facing many hospitals at the moment.
“We are going to use heat, [158 degrees Fahrenheit (70 degrees Celsius)], for 30 minutes, to see if we can kill COVID-19,” he told Vice earlier this month.