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A new study to be published in tomorrow's New England Journal of Medicine shows that United States investment in tuberculosis (TB) treatment abroad saves lives and money at home. Most cases of TB in the US and Canada occur among immigrants, refugees, visitors and other migrants from countries where this disease remains common.

An international team led by Ï㽶ÊÓƵ Health Centre researchers Dr. Dick Menzies, Dr. Kevin Schwartzman and Ms. Olivia Oxlade predicts that better TB control in high-incidence countries would reduce transmission there, and result in fewer migrants developing TB disease in the US, fewer TB-related deaths in the US, and financial savings in the US. This research was funded by the Rockefeller Foundation.

The current US approach to TB screening of immigrants and refugees depends on chest X-rays obtained before or on arrival, with treatment of tuberculosis when detected. The research team predicted the number of TB cases, related deaths and costs over the next 20 years that would occur as a result of this strategy in migrants arriving in the US from Mexico, the Dominican Republic and Haiti. They compared these results with expected outcomes if TB control programs in these three countries received US funding to improve diagnosis and treatment in the home country — to the standard recommended by the World Health Organization.

Particularly striking were the findings regarding Mexico, which is the single largest source of migrants to the United States. "Our results show that if the US government spent US$35 million to strengthen Mexican tuberculosis control, this would result in net savings of $108 million over 20 years within the US," says Dr. Menzies, Director of the Respiratory Division at the MUHC, professor of Medicine, Epidemiology and Biostatistics at Ï㽶ÊÓƵ, and team leader. "There would also be 2,591 fewer TB cases in the US and 349 fewer TB-related deaths than if the current approach were continued. And these figures do not even account for the fact that preventing these cases will prevent transmission of TB from them to other US citizens." Similar US government assistance for TB control in Haiti and the Dominican Republic would also lead to long-term savings in the US.

If the US instead elected to expand detection of dormant tuberculosis among immigrants and refugees from Mexico by the addition of tuberculosis skin tests to chest X-rays, TB-related costs would increase by $329 million, while preventing only 401 tuberculosis cases and 30 deaths, over the same 20-year period. "This strategy is less effective because many obstacles limit the successful use of preventive treatment for people with dormant TB infection," says Dr. Schwartzman, a researcher in the Respiratory Division of the MUHC, assistant professor of Medicine at Ï㽶ÊÓƵ, and lead author of the study. "In addition, many entrants, such as visitors and undocumented migrants, simply cannot be tested."

"In a world of ever-increasing travel and migration, global control of infectious diseases like TB is in everyone's interests," notes Dr. Menzies. "It is not surprising that investment abroad can result in improvements in the health of citizens in these other countries. But what is surprising is the substantial health and economic benefits for the US, Canada and other immigrant-receiving countries. When it comes to TB, doing the right thing turns out to be the smart thing."

The Ï㽶ÊÓƵ Health Centre (MUHC) is a comprehensive academic health institution with an international reputation for excellence in clinical programs, research and teaching. The MUHC is a merger of five teaching hospitals affiliated with the Faculty of Medicine at Ï㽶ÊÓƵ — the Montreal Children's, Montreal General, Royal Victoria, and Montreal Neurological Hospitals, as well as the Montreal Chest Institute. Building on the tradition of medical leadership of the founding hospitals, the goal of the MUHC is to provide patient care based on the most advanced knowledge in the health care field, and to contribute to the development of new knowledge.