A case of infectious tuberculosis on two long-haul aircraft flights: contact investigation

Abstract

Aim: During a five-week period in 1996, a passenger with highly infectious tuberculosis travelled on five long-haul aircraft flights. We investigated passengers and crew on two of these flights to identify whether transmission of Mycobacterium tuberculosis had occurred.

Methods: Crew and passengers were identified from airline and immigration records. Contacts were notified of their exposure and invited to attend their local public health clinic. At the clinic, a questionnaire was administered by a public health worker, and a Mantoux skin test was performed. When indicated, a second test was carried out twelve weeks later. Test positivity and conversion were defined according to the 1996 New Zealand tuberculosis control guidelines.

Results: Data were obtained on 206 (87%) of the 238 contacts. Twenty four contacts had a positive Mantoux test result, four of which were conversions. All of these contacts had at least one other major risk factor for a positive result, such as a previous BCG vaccination (n=17) or having lived in a country in which tuberculosis is endemic (n=15). To our knowledge, no contacts have subsequently developed tuberculosis disease.

Conclusions: The investigation produced inconclusive evidence about the hypothesis that Mycobacterium tuberculosis was transmitted on one or both of these flights.