Tuberculosis contact tracing within a school environment: lessons for the future.

Contact tracing plays a large role in the everyday work of chest clinics in NSW. It is a routine procedure that follows the ‘concentric circle’ method of screening. When a chest clinic becomes aware of a confirmed case of tuberculosis (TB), the inner ring of the circle (which comprises those with the highest risk of infection, including family and others in close contact with the index case) are screened first. If infection is detected in this group, screening proceeds to the medium-risk group and then, if necessary, to low-risk contacts, until no new infections are found. When explained, this methodis usuallyreadily understood and accepted by contacts. However, screening can become disrupted when contacts and others become fearful. This paper highlights the case of a complex school screening which involved both screening all rings of the concentric circle (i.e. high, medium and low-risk contacts) and screening outside the circle (i.e. non-contacts). In 2007 an overseas-born casual infants/primary school teacherinNSWwasdiagnosedwithinfectiouscavitaryTB disease by sputum smear, culture and chest X-ray. She had originallybeendiagnosedwithpneumoniaandwasonsick leave for 1 month. One hour into the second day of her return to work, she had a massive haemoptysis (coughing up of blood) and was hospitalised. Her household contacts were an overseas-born husband who was tuberculin skin test (TST) positive with a clear chest X-ray, and an Australian-born child who was TST negative. No other contacts were provided to the TB Coordinator at the Chest Clinic. Because of the teacher’s smear and chest X-ray results, the TB Coordinator consulted with the then NSW Department of Health and local Public Health Unit (local units which work to identify, prevent and minimise public health risks tothe community). Following this consultation, it was agreed to notify the school.