Knowledge of tuberculosis transmission among recently infected patients in Glasgow

To examine perceptions and understanding of disease causation in tuberculosis patients with few epidemiological links detected by contact tracing.

An exploratory qualitative study using semi-structured interviews was undertaken. Patients' beliefs were explored against a background of medical thinking about tuberculosis transmission and the current approach to contact tracing.

Interviews were undertaken with patients (n=23) or suitable next of kin (n=3). Study patients were diagnosed with tuberculosis in Glasgow, an urban area of Scotland, between 1997 and 2004. All had a genetically indistinguishable 15-banded IS6110 restriction fragment length polymorphism pattern of the Beijing family of Mycobacterium tuberculosis, suggestive of recently transmitted infection, yet few had epidemiological links detectable as a result of contact tracing (30.8%).

Interviewees had varying levels of knowledge, but most believed that tuberculosis was caused by a pathogen, spread by person-to-person contact. Modes of transmission were thought to include airborne transmission, sharing utensils with an infected individual, consumption of contaminated foods/liquids, and exchange of bodily fluids. Prolonged contact was not thought to be required for transmission to occur. Impaired immunity, social factors and environmental factors were believed to enhance the potential for transmission.

Patients have complex beliefs about tuberculosis transmission and causation, which do not always mirror those of health professionals. Adopting and implementing an approach to contact identification that is aligned with lay beliefs may result in improved contact tracing outcomes.