According to a recent study evaluating how various strains migrate across mixed populations in cosmopolitan cities, the chances of an exposed person becoming infected with TB vary depending on whether the human and the bacterium share a hometown. The study, led by Harvard Medical School scientists provides evidence that pathogen, place, and human host interact in a unique way that affects infection risk and susceptibility. The study strengthens the case for a long-standing hypothesis in the field that specific bacteria and their human hosts likely coevolved over hundreds or thousands of years, the researchers said.
The findings may also help inform new prevention and treatment approaches for tuberculosis, a wily pathogen that, each year, sickens more than 10 million people and causes more than a million deaths worldwide, according to the World Health Organization. ALSO READ: Pulmonary Tuberculosis: Understanding symptoms, risks, treatment and prevention of TB In the current analysis, believed to be the first controlled comparison of TB strains' infectivity in populations of mixed geographic origins, the researchers custom-built a study cohort by combining case files from patients with TB in New York City, Amsterdam, and Hamburg. Doing so gave them enough data to power their models.
The analysis showed that close household contacts of people diagnosed with a strain of TB from a geographically restricted lineage had a 14 per cent lower rate of infection and a 45 per cent lower .