Abstract:

Objective: To conduct field epidemiological investigation and emergency response to a pulmonary tuberculosis (TB) cluster outbreak in a primary psychiatric hospital in a district of Tianjin, providing scientific basis for formulating TB prevention and control strategies in special settings. Methods: On April 16, 2025, three patients with etiologically-positive pulmonary tuberculosis were reported in a primary psychiatric hospital via the “China Information System for Disease Control and Prevention.” Field epidemiological investigation and outbreak management were conducted. The outbreak was followed up for 12 months, involving four rounds of screening, including detecting suspicious TB symptoms, Mycobacterium tuberculosis infection, and performing chest X-rays and laboratory tests. Descriptive epidemiological methods were used to systematically analyze the characteristics of the outbreak. Results: There were a total of 277 patients and staff in the hospital, including 74 close contacts (26.71%) and 203 general contacts (73.29%). A total of 154 individuals (55.60%) were identified as having latent tuberculosis infection (LTBI). IGRA positivity rate among close contacts was 77.03% (57/74), while that of general contacts was 47.78% (97/203); the difference was statistically significant (χ²=17.568, P<0.001). Comparing IGRA positivity rates across different wards, Ward 3 had the highest rate at 77.03% (57 positive cases) and identified most outbreak-related patients (6 cases); Ward 4 had the lowest rate at 38.36% (28 positive cases) and identified 1 patient. The difference between wards was statistically significant (χ²=20.254, P<0.001). A total of 13 PTB patients were identified in this outbreak. The first round of close contact screening revealed a high number of LTBI cases (154). Follow-up at 3 months identified 2 PTB patients (15.38%, 2/13), and follow-up at 6 months identified 8 patients (61.54%, 8/13). No new patients were found after the 9th month. Among the LTBI individuals, 45 cases (29.22%) received preventive treatment. Conclusion: As a key setting with high risk of PTB epidemic, primary psychiatric hospitals should conduct daily health monitoring for patients and medical staff. Suspected PTB cases should trigger statutory reporting procedures and be prioritized for referral to designated PTB diagnosis and treatment institutions. For individuals with LTBI, standardized pharmacological preventive interventions should be implemented, and the follow-up observation period for LTBI individuals should be extended to 2 years.

Key words: Tuberculosis, Disease outbreaks, Hospitals, psychiatric, Contact tracing