A fatal influenza A (H1N1) and influenza outbreak investigation in a bank, Muang District, Phuket, Thailand, May–June 2016

Abstract

Background: On 14 June 2016, Muang Phuket district public health office was notified a fatal influenza A (H1N1) and a suspected influenza outbreak in a bank office. Phuket Surveillance and Rapid Response Team conducted outbreak investigation during 14–26 June 2016. The objectives were to describe a prognostic, to confirm outbreak, to describe the epidemiological characteristic, to identify the source factor and risk of outbreak and to control and prevent the outbreak.
Methods: Epidemical descriptive and retrospective cohort studies were conducted. Active case finding was also done in the bank where fatal case was working. A case definition was a bank personnel who had fever with myalgia and of the respiratory symptom during May 12 to June 26, 2016. Laboratory testing was also carried out by influenza PCR and ELISA IgM.
Results: A fatal lab-confirmed influenza A (H1N1) 2009 was a 48 years old female. She was no underlying disease. The patient took some medicine by herself and then was seeking medical care at a clinic without Oseltamivir. The clinical was worsening and hospitalized with pneumonia, septic shock and acute renal failure and then was expired. There were 8 suspected cases in the fatal case’s working place (attack rate 22.50%) but there was only case detected on third floor where the fatal case was working (specific attack rate 64.29%). All 5 cases were negative influenza A IgM and 2 cases were negative PCR. The epidemic happened during the seasonal epidemic in Muang Phuket district. The significant risk factors were attending parties in both first and second time.
Conclusions and discussions: A prognostic risk was a delaying to antiviral treatment at hospital. The group activities or meeting or aggregation of people was a risk factor of the outbreak. Early detection and treatment of severe form of influenza particularly high risk group is crucial. Warning message of influenza to the clinicians in the area by district health office should be emphasized.