BACKGROUND: In August 2016, a local health department was notified of a patient clinically diagnosed with active tuberculosis (TB) disease. The patient reported persistent cough, fever, fatigue and chest pains; abnormal chest x-ray, positive gene expert, and positive TB culture confirmed diagnosis. The patient was placed under droplet precautions and restricted from their workplace. The exact period of communicability could not be determined, as the patient had been exhibiting symptoms for nearly a year prior to diagnosis (dating back to August 2015).
METHODS: After the index patient was diagnosed, a contact investigation was initiated at the patient’s workplace. Employees at the firm were reported as itinerant; employees moved between buildings for meetings and social activities. In addition, during the potential exposure period, the firm restructured, thus employees were moved from one building to another or laid off. Employees were interviewed for risk factors and screened for TB by interferon-gamma release assays (IGRA) or tuberculin skin test, based on employee preference. A second round of screening was conducted 10 weeks after the initial screening.
RESULTS: One hundred forty-nine (149) employees were screened for TB exposure and interviewed for risk factors. The employee population of the firm was diverse: 72% of those screened were originally from the U.S, followed by 9% from India, 6% from China and 8% from other countries. Eight (5%) employees reported undergoing immunosuppressive therapy, 7 (4%) reported high-risk medical conditions such as diabetes and cancer and 1 employee was HIV positive. Out of 149 employees screened, 8 (5%) screened positive for TB. Of the 8, 1 employee was a U.S. born citizen; the others were originally from countries where TB is endemic. Only the U.S. born employee reported sitting directly next to the index patient.
CONCLUSIONS: The transitionary nature of the firm led to a larger than anticipated contact investigation. The total employee population exposed could not be determined. TB was likely transmitted from the index patient to the U.S. born employee. DNA-fingerprints of TB isolates from the employees that tested positive would be needed to definitively associate cases to the index case. In Virginia, over 60% of TB cases are diagnosed in foreign born individuals. Due to the diversity of this employee population, routine TB screening at the start of employment should be implemented, with testing done for those at risk, to prevent future exposures.