Nasopharyngeal Tuberculosis: Characterization of Transmissibility in a College Classroom Setting

Background:Nasopharyngeal tuberculosis is an unusual presentation of tuberculosis disease that is usually pulmonary. Due to its rare presentation, the transmissibility of nasopharyngeal tuberculosis is not well characterized. This investigation sought to identify contacts of a 28 year old foreign born female college student with a six month history of misdiagnosed nasophayngeal tuberculosis to determine if spread occurred in the months prior to proper diagnosis.

Methods: A contact investigation was initiated. Due to the student's daily routine, a small circle of contacts was unable to be established. The smallest circle identified was 4 classes with a total of 69 students with which the ill student had contact an average of 3-4 hours each week. Contacts were offered tuberculosis education and a single baseline PPD test that was read ~48 hours later. Demographics and a risk factor panel were collected from those tested.

Results: Sixty-nine people were identified at risk. All were offered PPD testing through the county health department, however only 18 people chose to have baseline testing. One contact tested positive. This individual had significant travel history to countries where tuberculosis is endemic.

Conclusions: In this setting, it does not appear that nasopharyngeal tuberculosis was easily transmitted. The one positive contact had potential exposure from travel. The investigation was limited by both the lack of a small circle of close contacts and few students wishing to be tested. Follow up testing three months from the last exposure will be offered to 18 contacts that had baseline testing.