Predicting tuberculosis in populations at risk

"Latent TB is not contagious, nor is active TB when it is sucessfully treated", explains Dr. Abhimanyu."If we can identify those at risk of developing the active form of the disease and estimate when it will happen, then we can ensure that they get treated with preventative therapy before they get sick". "This way, not only will we be able to prevent cases, we will also avoid further transmission, which is the only way to eradicate TB", he adds. To discriminate between those latently infected and at risk of progressing to active disease and those who are unlikely to progress, Dr. Abhimanyu will investigate the epigenetic alterations – biological mechanisms that control how our cells interpret our DNA –, involved in the development of active TB. Epigenetic modification of DNA is a regular and natural occurrence but can also be influenced by several factors including age, environment, lifestyle, and disease state. His hypothesis is that a distinct signature in these biological mechanisms can be used both to detect latent TB and to determine the risk of progression to disease. To test his assumption, Dr. Abhimanyu is analysing blood samples collected over a two-year period from a pool of participants highly exposed to Tuberculosis. Studying and comparing how their epigenetic changes evolve, he aims to identify this distinct biological signature, enabling early and reliable diagnosis, hence early treatment.

Tuberculosis and HIV : the twin epidemics

Dr. Abhimanyu's research field is in South Africa, one of the countries with the highest burden of TB in the world, notably because of the high prevalence of HIV. Indeed, latent Tuberculosis is an asymptomatic form of infection where replication of the bacteria is controlled by the immune system but the bacteria is not completely killed. When the immune system is compromised, as is the case with HIV, these latently infected individuals are at greater risk of progressing to disease. "Both diseases are closely intwined", Dr. Abhimanyu explains. "Of those who develop active TB in South Africa, 73% are HIV positive. Individuals with HIV are 26 to 31 times more likely to develop TB than non-infected people." "Never before has the impact of HIV co-infection been studied in the context of epigenetic changes", he points out. By working with participants at high risk of developing the disease, both HIV positive and HIV negative, Dr. Abhimanyu aims to contribute to a better understanding of the mechanisms that trigger the progression from latent to active disease.

More than 4,000 people die from Tuberculosis each day, 95% of which in low and middle income countries. Working on the front line of the battle against Tuberculosis – South Africa having the highest incidence of TB of any country –, the researcher will be studying one of the most exposed populations in the world. By investigating the biological mechanisms of those most likely to develop the disease, his objective is to target potential new cases and provide the means to nip them in the bud. High transmission rates being one of the greatest obstacles to the eradication of Tuberculosis, Dr. Abhimanyu's project will bring us one step closer to ending the disease once and for all.