An Investigation of Influenza A (H1N1) 2009 Outbreaks among Executive Officials of the Uthaithani Province, Returned from a Studying Visit from China, 3 – 9 June 2014

Abstract

Background: On June 3, 2014 The Surveillance of Rapid Response Teams of Uthaithani conducted an investigation of influenza A (H1N1 2009) in the Uthaithani executive officials and accompanies who returned from a study visit from Hunan, China during May 21 to June 5, 2014. The objectives were to confirm the diagnosis and outbreak, to describe the epidemiological characteristic, to identify the source of outbreak and to control and prevent the outbreak.
Methods: Descriptive epidemiological study was done by obtaining information from medical records and patient interview. We collected throat swab and send to test RT-PCR for influenza.
Results: Totally 46 people were studying visit from China during May 23 – 26, 2014. There were 7 cases met criteria and 2 confirmed and 5 suspected. The first case’s onset was on May 24, 2014 and last case’s onset was on June 2, 2014. The attack rate was 15.2%. There were 4 male and 3 female. The median age was 56 years (range 29-62 years). The clinical presentations were fever 100% following by cough 85.71%, runny nose 57.14%, muscle pain 42.86%, sore throat 28.57%, fatigue 14.28% and dyspnea 14.28%. Two cases were positive for Influenza A (H1N1) 2009. Discussions and
Conclusions: The source of outbreak was from either Thailand or China due to the incubation period. The first case might be infected from Thailand but it lacked of laboratory confirmation. The serological testing such as Influenza A IgM must be applied for confirmed diagnosis particular the first case who recovered. The outbreak was mostly occurring in Thailand after returning from China. There was no additional case after implement the control.