UV light, fans can curb TB spread

London, March 18: The spread of tuberculosis, an often deadly respiratory infection, can be prevented with the use of ultraviolet light, a new study featuring in the journal PLoS Medicine suggests.

Ultraviolet radiations, typically UVC, together with gentle air mixing helped reduce the spread of tuberculosis in hospital wards and waiting rooms by 70 percent, the animal study highlights.

Tuberculosis, a highly infections bacterial disease, spreads through the air. Respiratory secretions – the mucus, salivadefine and aerosol droplets – are packed with live bacteria particles. When a person already down with TB coughs, sneezes, spits or talks, he lets loose the infected droplets into the air, which other people inhale. Characteristic symptoms of tuberculosis include chronic cough with blood-tinged sputumdefine, fever, night sweats, and weight loss.

"When people are crowded together in a hospital waiting room, it may take just one cough to infect several vulnerable patients," lead author of the study, Roderick Escombe, a researcher at Imperial College London, marked.

In an endeavor to destroy the live bacteria hanging loose in the air, researchers at the Imperial College London conducted a guinea pig study. 900 guinea pigs were picked up for the purpose.

The pigs were placed in cages on the roof of the hospital ward where 69 patients were undergoing active TB treatment. For 535 consecutive days, the air from patient rooms was vented directly into the cages.

By the end of the experiment, 35 percent of guinea pigs exposed to untreated patient room air developed TB infection, opposed to 14 percent who were exposed to air treated with negative air ionizers.

However, only 9.5 percent of guinea pigs exposed to UV-treated air (combination of UVC lights and gentle air mixing by ceiling fans) picked up the TB infection, researchers averred.

"A single shielded ultraviolet C light hanging from the ceiling -- with a fan to mix the air -- disabled the bacteria by damaging DNA so they could no longer infect people, grow or divide," researchers wrote in the PLoS Medicine journal.

But one should ensure proper installation, cautioned co-author Catherine Noakes from the University of Leeds. "The lights must be set high enough to ensure patients and health workers are not overexposed."

Also, careful management of air flow is vital, she pointed. "To be most effective, ventilationdefine systems need to create a constant flow of treated air down to patient level, and potentially infected air up towards the lights."