Researchers at Boston Medical Center (BMC), the primary teaching affiliate of Boston University School of Medicine in the US, have developed a real-time surveillance system that uses routinely collected laboratory data to identify communities experiencing a high burden of drug-resistant TB.
The aim of the system is to help the public health system improve targeted interventions to reduce the number of people who could contract the contagious disease.
“It is critically important that we understand how drug-resistant TB impacts people in specific areas over time,” said Assistant Professor of Infectious Diseases and Epidemiology at Boston University School of Medicine and Boston University School of Public Health, Karen Jacobson, MD, MPH.
“By locating emerging and chronic hotspots of the disease in real-time, public health providers can evaluate the most effective interventions and monitor progress towards TB reduction goals,” continued Jacobson.
South Africa not only has the highest rate of TB in the world, but it also has a centrally collected laboratory database that includes TB tests, making it the ideal location to test the system to track drug-resistant TB cases by clinic location.
As part of a study published in PLOS Medicine, the team of researchers used data from the Western Cape’s National Health Laboratory Services (NHLS) database to track changes of the prevalence of drug-resistant TB over a five year period, between 2008 and 2013. The surveillance system includes an algorithm that identifies unique patients and episodes of disease from the data, and creates heat maps of the region to see which areas were most afflicted during this time period.
The study identified 799,779 individuals who had specimens submitted for TB tests from clinics during the study period; 28% of which were diagnosed with TB, and of those 4.6% were resistant to first line TB treatment.
The spread of these cases was geographically diverse, ranging from 0 to 25% of TB cases having drug resistance in different parts of the region. There were also significant annual fluctuations in drug-resistant TB percentages at several locations. The communities that saw the highest rates of drug-resistant TB were Cape Town townships and informal settlements, the rural region of the west coast, and areas bordering the Eastern Cape.
The researchers concluded that routinely collected laboratory data plays an important role in identifying both ongoing and short-term TB outbreaks, and is an important tool for researchers and providers to ensure a more accurate allocation of resources to treat TB.
The study also found that constant monitoring of TB patients could lead to more effective public health interventions, resulting in fewer cases of medication-resistant TB.
“Our model of mapping high-burden communities can serve as a roadmap for regions working to reduce TB incidence by initiating treatment as soon as possible,” concluded Jacobson.