Influenza outbreak in a psychiatric ward of a general hospital, Thailand

Abstract

Background: On 2^nd September 2015, Bureau of Epidemiology was notified of 17 influenza-like illness (ILI) cases at a psychiatric ward in Provincial Hospital, Northern Thailand. An investigation was conducted to confirm a diagnosis, describe the epidemiological characteristics, identify precipitating factors of transmission and provide proper recommendations to control the outbreak.
Methods: Descriptive study including active case finding was conducted among healthcare workers, their relatives, and patients in the psychiatric ward. An ILI case was defined as a person who developed at least two of the following symptoms: fever, cough, sore throat, rhinorrhea, dyspnea and headache/muscle ache. Confirmed Influenza case was ILI cases with founding Influenza virus by Real-time RT-PCR technique. A retrospective cohort study was undertaken to identify risk factors of infection among psychiatric patients. Result was shown in rate ratios with 95% confidence intervals.
Results: Of 135 healthcare workers, their relatives and psychiatric patients in the psychiatric ward, 20 cases met the case definition (Overall attack rate 14.7%) including 16 ILI and 4 confirmed influenza A (H3) cases (3 male patients and 1 healthcare worker). The transmission started from male psychiatric patients to healthcare workers and then their relatives. Influenza outbreak was detected approximately 2 weeks after first cases developed symptoms. There were no explicit prevention and control measures, including mask using, screening, and isolation, were implemented before being detect. The analytical study suggested that being restrained was a statistically significant risk factor [Crude rate ratio 9.44 (1.73-51.52)] due to increasing body contact from healthcare workers and other psychiatric patients.
Conclusions: There was an Influenza A (H3) outbreak in a psychiatric ward of a general hospital. While being an essential procedure for caring psychiatric patients, restraint was founded to be a risk of respiratory infection. Therefore early detection, prompt isolation, and strict hand hygiene are particularly indispensable measures for Influenza prevention and control.