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Detector can limit spread of tuberculosis infection

Antonio Rothfuchs, senior researcher at the Department of Microbiology, Tumour and Cell Biology at Karolinska Institutet, has created a device for capturing airborne tuberculosis bacteria.

Antonio Rothfuchs, foto: privat. What have you developed and why?
“We have developed a tuberculosis detector called THOR, which stands for TB Hotspot Detector. The device helps us detect airborne bacteria. If it gives a positive reading it means that there is a risk of infection. The aim of the device is to trace and prevent spread of infection.”

How will your detector make a difference?
“A problem with today’s tuberculosis diagnostics is that they are passive. It is only when people start to feel ill and show symptoms that they visit a care centre or hospital to be tested. By then the patients have already passed on the infection to others. And existing screening methods are too expensive to be used in high-risk environments. Our device could then be used for tracing airborne infections. That way, active tracing of infections is made both cost-effective and practical.”

Where would the tracing take place?
“There are several environments where the device could prove useful, for example in prisons, schools and hospital waiting rooms. We are currently running trials in Brazilian prisons. The device will function as a sort of smoke detector for tuberculosis. It would also be possible to have a person cough into the device to test for infection. It will be very cheap to manufacture, but so far only a prototypical version exists.”

Text: Fredrik Hedlund, first published in Swedish in Medicinsk Vetenskap nr 3/2018.

An old story

In the Nordic countries, archaeologist have found tuberculosis bacteria in bones dating back to at least the 12th century. But it was not until the 19th century, when cities grew in size, that the disease started to spread rapidly. First, tuberculosis (TB) affected poor people who lived in overcrowded conditions with little to eat. As the bacterium is airborne and spreads through coughing, the risk of infection increases in overcrowded conditions.

People who are malnourished and in generally poor health have a higher risk of being infected by the active form of the disease. At the end of the century, an offensive was launched against tuberculosis with the building of several sanatoriums all over Sweden. There, the patients were to get rest, breathe “healthy air”, and eat nutritious food. The sanatoriums had limited effect, as did the introduction of BCG vaccinations in 1927. In the early 1940s, over 300 per 100,000 people in Sweden fell ill.

When antibiotics were discovered and began to be used in the late 1940s, the incidence of TB dropped dramatically over a few decades and has since averaged around five cases per 100,000 people, roughly equivalent to 500 cases per year. There has been a slight increase during the 21st century, which reached its peak during the refugee crisis in 2015 when the incidence increased to eight cases per 100,000 people, or 831 cases total. Yet recent statistics show that the incidence has decreased to pre-crisis levels again.

Sources: The Swedish National Archives, Nationalencyklopedin, and the Public Health Agency of Sweden.