A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012
In May 2012, a teacher of a nursing school with about 300 staff members and students in Japan was diagnosed with sputum smear-positive pulmonary tuberculosis (TB), leading to an investigation involving nearly 300 contacts. We describe the contacts’ closeness to the index TB patient and the likelihoo...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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World Health Organization Regional Office for the Western Pacific
2018-09-01
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| Series: | Western Pacific Surveillance and Response |
| Subjects: | |
| Online Access: | https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/584/833 |
| _version_ | 1818450203512930304 |
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| author | Masako Tasaka Tamae Shimamura Mami Iwata Takahiro Toyozawa Masaki Ota |
| author_facet | Masako Tasaka Tamae Shimamura Mami Iwata Takahiro Toyozawa Masaki Ota |
| author_sort | Masako Tasaka |
| collection | DOAJ |
| description | In May 2012, a teacher of a nursing school with about 300 staff members and students in Japan was diagnosed with sputum smear-positive pulmonary tuberculosis (TB), leading to an investigation involving nearly 300 contacts. We describe the contacts’ closeness to the index TB patient and the likelihood of TB infection and disease.
A case of TB was defined as an individual with positive bacteriological tests or by a physician diagnosis of TB. A latent TB infection (LTBI) case was defined as an individual who had a positive interferon-gamma release assay (IGRA).
A total of 283 persons screened with IGRA were analysed. Eight persons (2.8%, 95% confidence interval [CI]: 1.2–5.4) tested positive by IGRA; one student who had intermediate (less than 10 hours) contact with the index patient was found to have pulmonary TB by chest X-ray. The positivity in IGRA among staff members with very close contact with the index patient (4 of 21, 19%, 95% CI: 5.4–42%) with a statistically significant relative risk of 17 (95% CI: 2.0–140) was high compared with that of the intermediate contacts (1 of 88, 1.1% [95% CI: 0.028–6.2]). There was a statistically significant trend in the risk of TB infection and closeness with the index patient among the staff members and students (P < 0.00022).
In congregate settings such as schools, the scope of contact investigation may have to be expanded to detect a TB case among those who had brief contact with the index patient. |
| first_indexed | 2024-12-14T20:47:34Z |
| format | Article |
| id | doaj.art-f562f799b5564bb6864ce11c53d071b7 |
| institution | Directory Open Access Journal |
| issn | 2094-7321 2094-7313 |
| language | English |
| last_indexed | 2024-12-14T20:47:34Z |
| publishDate | 2018-09-01 |
| publisher | World Health Organization Regional Office for the Western Pacific |
| record_format | Article |
| series | Western Pacific Surveillance and Response |
| spelling | doaj.art-f562f799b5564bb6864ce11c53d071b72022-12-21T22:47:58ZengWorld Health Organization Regional Office for the Western PacificWestern Pacific Surveillance and Response2094-73212094-73132018-09-01934810.5365/wpsar.2018.9.1.001A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012Masako Tasaka0Tamae Shimamura1Mami Iwata2Takahiro Toyozawa3Masaki Ota4Kanagawa Prefectural Institute of Public Health, Kanagawa, JapanResearch Institute of Tuberculosis, Tokyo, Japan.Naka Welfare and Health Office, Yokohama, Japan.Yokohama City Health Department, Yokohama, Japan.Research Institute of Tuberculosis, Tokyo, Japan.In May 2012, a teacher of a nursing school with about 300 staff members and students in Japan was diagnosed with sputum smear-positive pulmonary tuberculosis (TB), leading to an investigation involving nearly 300 contacts. We describe the contacts’ closeness to the index TB patient and the likelihood of TB infection and disease. A case of TB was defined as an individual with positive bacteriological tests or by a physician diagnosis of TB. A latent TB infection (LTBI) case was defined as an individual who had a positive interferon-gamma release assay (IGRA). A total of 283 persons screened with IGRA were analysed. Eight persons (2.8%, 95% confidence interval [CI]: 1.2–5.4) tested positive by IGRA; one student who had intermediate (less than 10 hours) contact with the index patient was found to have pulmonary TB by chest X-ray. The positivity in IGRA among staff members with very close contact with the index patient (4 of 21, 19%, 95% CI: 5.4–42%) with a statistically significant relative risk of 17 (95% CI: 2.0–140) was high compared with that of the intermediate contacts (1 of 88, 1.1% [95% CI: 0.028–6.2]). There was a statistically significant trend in the risk of TB infection and closeness with the index patient among the staff members and students (P < 0.00022). In congregate settings such as schools, the scope of contact investigation may have to be expanded to detect a TB case among those who had brief contact with the index patient.https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/584/833EpidemiologyContact investigationInterferon-gamma release assayDisease outbreakTuberculosis |
| spellingShingle | Masako Tasaka Tamae Shimamura Mami Iwata Takahiro Toyozawa Masaki Ota A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 Western Pacific Surveillance and Response Epidemiology Contact investigation Interferon-gamma release assay Disease outbreak Tuberculosis |
| title | A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 |
| title_full | A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 |
| title_fullStr | A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 |
| title_full_unstemmed | A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 |
| title_short | A tuberculosis contact investigation involving a large number of contacts tested with interferon-gamma release assay at a nursing school: Kanagawa, Japan, 2012 |
| title_sort | tuberculosis contact investigation involving a large number of contacts tested with interferon gamma release assay at a nursing school kanagawa japan 2012 |
| topic | Epidemiology Contact investigation Interferon-gamma release assay Disease outbreak Tuberculosis |
| url | https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/584/833 |
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