Suspected Tuberculosis Outbreak and Workplace Contact Investigation at Food Processing Plant in Northeast Georgia, 2022
Abstract
Background: Over the course of less than six weeks, three employees at a food processing plant were hospitalized with pulmonary symptoms and diagnosed with active tuberculosis (TB) disease. Concern of a TB outbreak quickly grew, and public health agencies and the plant worked together to screen exposed employees and determine whether an outbreak was truly occurring.
Methods: Local health departments conducted contact investigation interviews with each case. The plant confirmed work dates and departments and identified a total of 151 current and former employees who were potentially exposed. The local health department held nine testing events from July through October 2022. The Georgia Public Health Laboratory conducted genotype testing on isolates from each of the three cases.
Results: All three cases were from TB-endemic countries, and one had been diagnosed with latent tuberculosis infection (LTBI) more than 10 years prior but did not complete preventative treatment. A total of 122 plant employees were evaluated for TB infection, and 17 were positive, for a positivity rate of 13.9%. Nine of these were found to have previous LTBI diagnoses, and seven had already received preventative treatment. All positives were originally from high-incidence countries. No additional active TB cases were found. Genotyping did not match between the three current cases or previous cases from the same plant.
Conclusion: Many of the employees who tested positive for TB infection had previously been diagnosed with LTBI, which was unknown before testing and accounted for the relatively high positivity rate. Because none of the three cases had the same genotype, and none of the genotypes matched a group of cases from the same plant a few years prior, there was little evidence that transmission was taking place within the plant, indicating an outbreak was not confirmed and a workplace-wide screening of remaining employees was unnecessary.
Keywords
tuberculosis, outbreak, contact investigation, genotyping
Suspected Tuberculosis Outbreak and Workplace Contact Investigation at Food Processing Plant in Northeast Georgia, 2022
Background: Over the course of less than six weeks, three employees at a food processing plant were hospitalized with pulmonary symptoms and diagnosed with active tuberculosis (TB) disease. Concern of a TB outbreak quickly grew, and public health agencies and the plant worked together to screen exposed employees and determine whether an outbreak was truly occurring.
Methods: Local health departments conducted contact investigation interviews with each case. The plant confirmed work dates and departments and identified a total of 151 current and former employees who were potentially exposed. The local health department held nine testing events from July through October 2022. The Georgia Public Health Laboratory conducted genotype testing on isolates from each of the three cases.
Results: All three cases were from TB-endemic countries, and one had been diagnosed with latent tuberculosis infection (LTBI) more than 10 years prior but did not complete preventative treatment. A total of 122 plant employees were evaluated for TB infection, and 17 were positive, for a positivity rate of 13.9%. Nine of these were found to have previous LTBI diagnoses, and seven had already received preventative treatment. All positives were originally from high-incidence countries. No additional active TB cases were found. Genotyping did not match between the three current cases or previous cases from the same plant.
Conclusion: Many of the employees who tested positive for TB infection had previously been diagnosed with LTBI, which was unknown before testing and accounted for the relatively high positivity rate. Because none of the three cases had the same genotype, and none of the genotypes matched a group of cases from the same plant a few years prior, there was little evidence that transmission was taking place within the plant, indicating an outbreak was not confirmed and a workplace-wide screening of remaining employees was unnecessary.
