Genome Sequencing Helps Determine End of TB Outbreak
News Jun 15, 2016
The research is the first of its kind to demonstrate that genomic analysis can be used to determine when a TB outbreak has ended—valuable knowledge which can assist public health investigators understand an outbreak’s dynamics and guide a real-time public health response. Genomic analysis involves reading the complete genetic instructions of the pathogens causing a disease, and using that data to infer who might have infected whom. By looking for mutations that are shared between the pathogens taken from different people, researchers can see whose pathogens are most closely related to each other, suggesting potential transmission.
“Declaring the end of a TB outbreak is a difficult thing to do,” said senior author Jennifer Gardy, assistant professor in UBC’s school of population and public health and a senior scientist at the British Columbia Centre for Disease Control. “Because the bacterium that causes TB can lie dormant in someone’s lung for months or even years before it causes disease, we had no way of knowing whether a TB case we have just diagnosed was a recent infection – suggesting the outbreak is still going on – or whether the person was infected years ago.”
Using mathematical and statistical techniques, the researchers evaluated a TB outbreak that began in May 2008 and were able to determine when each outbreak case was infected. This provided public health officials with a way to determine when disease transmission had stopped and the outbreak had ended. They were able to declare the outbreak over in January 2015, after the data indicated no disease transmission had occurred since mid-2012.
“By using a series of techniques from the world of mathematics and statistics, we can come up with an estimated time at which each infection occurred,” explained Gardy. “This information is incredibly useful to the public health officials managing an outbreak. Responding to an outbreak requires a lot of effort and resources, and we need to know when we can step down our response.”
“Genomics has been used to monitor infectious disease outbreaks before, but this is the first time it’s ever been possible to declare a complicated outbreak of TB over,” said Gardy. “It really opens up new doors in the world of TB control.”
In a new study in cells, University of Illinois researchers have adapted CRISPR gene-editing technology to cause the cell’s internal machinery to skip over a small portion of a gene when transcribing it into a template for protein building. This gives researchers a way not only to eliminate a mutated gene sequence, but to influence how the gene is expressed and regulated.
Researchers published today a detailed description of the complete genome of bread wheat, the world's most widely-cultivated crop. This work will pave the way for the production of wheat varieties better adapted to climate challenges, with higher yields, enhanced nutritional quality and improved sustainability.