A decade-long study found passengers on certain Metro bus routes were more likely to have tuberculosis, raising the question of whether they contracted the disease on the bus.
“We see a higher prevalence of clustering with bus riders,” said Edward Graviss, an epidemiologist who collected the data. “It’s not direct evidence that transmission occurred on the bus per se, but from a biological standpoint, it makes sense.”
Graviss, director of the molecular tuberculosis laboratory at the Methodist Hospital Research Institute, said he believes the study is the first published to find public transportation as a possible risk factor for tuberculosis.
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In 2010, 10.4 cases were reported in Houston for every 100,000 residents, more than double the 3.6 cases per 100,000 residents nationally. Harris County had 340 cases reported in 2010; statewide, there were 1,385 cases.
The study was conducted between 1995 and 2004, and the findings published in the journal Tuberculosis last month.
Houston residents diagnosed with tuberculosis were asked detailed questions, including whether they rode public buses and, if so, what routes.
After distilling the findings, Graviss said researchers determined people infected with the same strain but living in different parts of town were connected by certain bus routes.
A team of Rice engineering students is working on a way to improve air filtration on buses and to use ultraviolet light to help kill airborne bacteria, which is what causes TB. Given that it was a ten-year study that identified and confirmed the problem, it may be awhile before anyone can say if the mitigation efforts are working. Be that as it may, as the story notes any enclosed space carrier an increased risk of contagion. Do your part to combat that by covering your mouth when you cough or sneeze, and be sure to do so into your elbow, as it’s the best way to contain germs.