• A viral Japanese video used black light to show how fast diseases like COVID-19 can spread
  • Japanese broadcaster NHK worked with health experts to demonstrate the difference hand washing can make
  • The CDC says hand washing is still one of the most effective way to control the spread of diseases.

A black light experiment released by Japanese broadcaster NHK went viral when it showed just how fast disease-causing microbes like bacteria and viruses can spread.

NHK teamed up with health experts in Japan to demonstrate how hand contact can spread an “infection” in a restaurant setting.

The experiment used a substance that glows under ultraviolet light to show how a virus like the novel coronavirus that causes COVID-19 can spread.

The experiment starts with a single “infected” participant coming into the restaurant with nine other people. All of them were asked to take food and eat as they do normally.

The “infected” person had a substance on his hand that glowed under black light and was also asked to eat normally alongside the other “non-infected” persons. The substance represented the “infection.”

A black light was lit at the end of the meal, showing that the “infection” had spread on the food, surfaces, utensils and the participants themselves. Most of the participants had it on their hands while three even had it on their faces.

An alternative version of the experiment was also shown as scientists asked participants to implement measures against infections while enjoying the buffet, most notably hand washing.

There was a striking decrease of 97% in the spread of the substance in black light and no participant had the substance on their face.

John Nicholls, a health expert and professor at Hong Kong University, told CNN that the experiment showed just how important hand hygiene was to stop the spread of the disease.

“What the video demonstrated, is that it will spread to surfaces and to people very efficiently,” Nicholls said. “So the general public gets some concept of the mechanism of how much the use of hand washing can actually reduce the transmission of potentially infectious material.”

The Centers for Disease Control says that hand washing with soap and clean, running water is still one of the most important ways to prevent the spread of infectious diseases.

The CDC also says that good hand washing reduces the incidence of respiratory illnesses like COVID-19 by 16 to 21%.