Genetic and clinical assessment of 2009 pandemic influenza in southern China

Amber Farooqui; Yanchang Lei; Pusheng Wang; Jianyun Huang; Jie Lin; Guishuang Li; Alberto J Leon; Zhen Zhao; David J Kelvin

doi:10.3855/jidc.2251

Authors

Amber Farooqui Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, China
Yanchang Lei Division of Viral Hepatitis and Liver Failure, Infectious Disease Hospital, Nanchang University, Nanchang 9th Hospital, 167 Hongdu Middle Road, Nanchang 330002, Jiangxi
Pusheng Wang Center for Disease Control and Prevention of Shantou, 58 Shanfen Road, Shantou 515041, Guangdong
Jianyun Huang Center for Disease Control and Prevention of Shantou, 58 Shanfen Road, Shantou 515041, Guangdong
Jie Lin Center for Disease Control and Prevention of Shantou, 58 Shanfen Road, Shantou 515041, Guangdong
Guishuang Li International Institute of Infection and Immunity, Shantou University Medical College, Shantou
Alberto J Leon Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, 101 College Street, Toronto, ON M5G 1L7
Zhen Zhao International Institute of Infection and Immunity, Shantou University Medical College, Shantou
David J Kelvin International Institute of Infection and Immunity, Shantou University Medical College, Shantou

DOI:

https://doi.org/10.3855/jidc.2251

Keywords:

Pandemic H1N1 influenza, genetic characterization, clinical presentation, Hemagglutinin, Neuraminidase

Abstract

Introduction: South China has a proven role in the global epidemiology of previous influenza outbreaks due to its dual seasonal pattern. We present the virologic, genetic and clinical characterization of pandemic H1N1 influenza infection (pH1N1) in Shantou and Nanchang, cities in southern China, during the second wave of the 2009-2010 pandemic.

Methodology: Nasopharyngeal swabs were collected from 165 individuals with influenza-like illness (ILI) who presented to the hospitals in Shantou and Nanchang. Laboratory diagnosis and characterization was performed by real-time PCR, virus isolation in embryonated chicken eggs, and sequencing.

Results: pH1N1 activity was sustained in three different temporal patterns throughout the study period. The overall positivity rate of pH1N1 was 50% with major distribution among young adults between the ages of 13 and 30 years. High fever, cough, expectoration, chest pain, myalgia, nasal discharge and efficient viral replication were observed as major clinical markers whereas a substantial number of afebrile cases (17%) was also observed. Rate of hospitalization and disease severity (39%) and recovery (100%) were also high within the region. Furthermore, severe complications were likely to develop in young adults upon pH1N1 infection. Genetic characterization of the HA and NA genes of pH1N1 strains exhibited homogenous spread of pH1N1 strains with 99% identity with prototypic strains; however, minor unique mutations were also observed in the HA gene.

Conclusion: The study illustrates the detailed characteristics of 2009 influenza pandemic in southern parts of China that might help to strategize preparedness for future pandemics and subsequent influenza seasons.