Targeting tuberculosis 'hotspots' could have widespread benefit: study

Reducing tuberculosis transmission in geographic "hotspots" where infections are highest could significantly reduce TB transmission on a broader scale, according to a study led by researchers at the Johns Hopkins Bloomberg School of Public Health. An analysis of data from Rio de Janeiro showed that a reduction in TB infections within three high-transmission hotspots could reduce citywide transmission by 9.8 percent over 5 years, and as much as 29 percent over 50 years. The study was published May 28 by the journal PNAS.

"Targeting treatment of 'core groups' as a way to reduce community-wide transmission is common with diseases like HIV and , but is less accepted as a mantra for ," said David Dowdy, MD, PhD, ScM, lead author of the study and assistant professor in the Bloomberg School's Department of Epidemiology. "Our findings suggest that hotspots containing 6 percent of a city's population can be responsible for 35 percent or more of its ongoing TB transmission. Controlling TB in these hotspots may have a similar impact on long-term, community-wide TB incidence as achieving the same targets in the remaining 94 percent of the population."

For the study, Dowdy and his colleagues developed mathematical models for TB transmission using from Rio de Janeiro. Each model tested different scenarios for TB transmission between the hotspot and the rest of the community. Co-infection with HIV was also factored into the model.

According to the study, reducing TB in the hotspot to those in the general community reduced citywide TB incidence by a mean 2 percent per year over the first 5 years. By year 50, TB incidence was reduced by 29.7 percent, reflecting a 62.8 percent reduction in incidence in the and a 23.1 percent reduction in the remaining community.

Tuberculosis infects more than 8.8 million people worldwide, resulting in 1.4 million deaths each year. The disease is known to cluster in hotspots typically characterized by crowding, poverty and other illnesses such as HIV. Nevertheless, TB transmission appears to be more homogeneous than that of many other infectious diseases, in which 20 percent of the population may generate 80 percent of infections.

According to Dowdy, "TB may not follow the same '80/20' rule that we see in parasitic or sexually transmitted diseases, but the '35/6' rule seen in our study suggests that targeting hotspots is still the best way to control TB in a community."

More information: "Heterogeneity in tuberculosis transmission and the role of geographic hotspots in propagating epidemics", PNAS, May 28, 2012.

Related Stories

New tuberculosis research movement needed

date Nov 30, 2011

In this week's PLoS Medicine, Christian Lienhardt from the WHO in Geneva, Switzerland and colleagues announce that the Stop TB Partnership and the WHO Stop TB Department have launched the TB Research Movement.

HIV/AIDS linked to drug resistant TB

date Nov 16, 2006

U.S. scientists say a highly drug-resistant form of tuberculosis has been linked to HIV/AIDS in a study conducted in rural South Africa.

Recommended for you

Sierra Leone marks grim Ebola anniversary

date 48 minutes ago

On May 24 last year a pregnant woman and an older housewife staggered into Kenema hospital in eastern Sierra Leone and were diagnosed within a day as the country's first Ebola cases.

MSF fighting cholera outbreak in Tanzania refugee camps

date 19 hours ago

Medical charity Medecins sans Frontieres (MSF, Doctors Without Borders) said Sunday it had launched emergency treatment centres in Tanzania, where thousands of Burundians fleeing unrest have been hit by cholera.

Bacteria blamed in indigenous Mexican baby deaths

date May 23, 2015

Bacteria—and not a contaminated vaccine as initially suspected—were to blame for the recent deaths of two Mexican babies and for sickening 29 others, according to an official investigation.

Explainer: What is Chagas disease?

date May 22, 2015

According to an article in the Journal of the American Medical Association (JAMA), in a Los Angeles clinic treating patients with heart failure, about 20% of Latin American patients have Chagas disease. What is that?, y ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.