The important role of early diagnosis and preventive management during a large-scale outbreak of hepatitis A in Thailand

Abstract

Introduction: Acute hepatitis A is a worldwide public health problem especially in developing countries. Recently, a large, community-wide outbreak of hepatitis A occurred in the northeast part of Thailand.

Methods: Demographic and clinical data as well as blood samples were collected and analyzed from patients with acute hepatitis who attended the Buengkan Provincial Hospital from June to September 2012. About 1619 patients with clinical symptoms of hepatitis A visited the hospital during the outbreak which manifested in three waves. Blood samples were collected from 205 patients.

Results: One hundred and seventy eight patients had hepatitis A confirmed by the presence of anti-hepatitis A virus (HAV) IgM and/or HAV-RNA. The sensitivities for anti-HAV IgM and HAV-RNA were 95·5% (170/178) and 61·8% (110/178), respectively. When HAV-RNA was combined with anti-HAV IgM test, this increased the diagnostic yield by 7·2% (8/111) in the early phase of the acute infection (less than 5 days). Investigation of the molecular structure of the detected viruses indicated that all of the infections were caused by HAV genotype IA. There were no fatalities from this outbreak. Rapid detection, health education, sanitation campaigns, and vaccination offered on a voluntary basis have steadily reduced the number of infected patients and stopped the outbreak.

Conclusion: Occasionally a large-scale outbreak of HAV genotype IA can occur. A combination of HAV-RNA and anti-HAV IgM tests can increase the diagnostic yield during the early phase of the acute infection. Early diagnosis and preventive management campaigns can slow down and stop the outbreak.

Keywords:

• Hepatitis A
• HAV
• Genotype IA
• Thailand
• Outbreaks

The study was supported by grants from The Higher Education Research Promotion and National Research University Project of Thailand Office of the Higher Education Commission (HR1155A-55); the National Research Council of Thailand, Center of Excellence in Clinical Virology, Chulalongkorn University; Chulalongkorn University Centenary Academic Development Project, Integrated Innovation Academic Center; Chulalongkorn University Centenary Academic Development Project (CU56-HR01); Outstanding Professor of the Thailand Research Fund (DPG5480002); and by generous support from the National Research Council of Thailand and King Chulalongkorn Memorial Hospital. The authors would like to thank the staff of Buengkan Provincial Hospital for taking care of the patients and collecting the data and Ms Petra Hirsch for reviewing the manuscript.