Biophysical Society Thematic Meeting - November 16-20, 2015

Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Speaker Abstracts

Novel Approaches to the Aerobiology of Tuberculosis Transmission Robin Wood . Desmond Tutu HIV Centre, IDM, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. South Africa has the highest tuberculosis notification and death rate of any country worldwide. The city of Cape Town alone has more TB notifications annually than USA, Canada, UK and France combined. TB transmission rates have remained at levels recorded in industrial cities of Europe and North America a century ago. Transmission is determined by the combination of the prevalence of infectious TB in the community, the social and environmental factors enabling air exchange from infective individuals, and the concentration of TB bacilli in the exhaled air of infectious. Our knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, these in vivo animal studies may have considerably underestimated the potential infectivity of TB cases. In order to better characterize the factors driving TB transmission in a Cape Township social environments conducive for potential TB transmission in Cape Town were identified using a combination of social mixing studies and the use of carbon dioxide as a natural tracer gas as a proxy for TB exposure. The volumes of air exchanged between individuals were calculated during different activities and seasons. The potential infectivity of TB patients was explored by sampling devices installed in a Respiratory Aerosol Sampling Chamber (RASC) that enabled representative sampling and isolation of airborne particles and organic matter from TB patients. Preliminary results from the first 10 TB patients showed the presence of airborne bacilli on scanning electron microscopy, the presence of culturable TB organisms and high levels of TB DNA in the expired air of these patients.

20