Swine Flu: An overview of recent outbreak in India

Pages: 354-356
Vinod Chayal and Pardeep Khanna (Department of Community Medicine PGIMS, Rohtak, Haryana)
Pooja (Medical Officer, Health Department, Haryana)
Anuradha (Medical Officer Indian Army)
Mukesh Nagar (Medical Officer, VMMC & Safadarjang Hospital, New Delhi)
Shweta Goswami (Department of Community, Medicine KPC Medical College & Hospital, Kolkata)

Influenza Subtype A has caused various pandemics; in 1918-19 Spanish flu [A (H1N1)], Asian Flu [A (H2N2)] 1957-59, Hongkong Flu [A (H3N2)] 1968-69 and “Swine Flu” [A (H1N1)] 2009-10. H1N1 flu virus causes respiratory illness in people, affecting the nose, throat and lungs. Influenza can be transmitted through airborne route by droplets from infected human beings or direct contact or contact with fomites. Agent H1N1 influenza derives Segments from four influenza viruses; North American Swine, North American Avian, Human Influenza and Eurasian Swine. Pigs Infected with Influenza virus from different host of human or bird origin may act as “mixing vessel” which may lead to reassortment of influenza genes and can create a new strain of influenza virus. Subtype A of Influenza virus can Undergo mutation that can take place within the genome (Antigenic drift) / or re- assortment among the genetic materials of subtypes (Antigenic Shift) resulting in a new virus. Antigenic analyses of the recent circulating A (H3N2) viruses have shown differences from the A (H3N2) virus used in the influenza vaccines for 20142015. Recently, countries in Northern Africa, Middle East, and India reported an increase in influenza A (H1N1) pdm09 activity. The predominant strain in western countries has been seasonal influenza A (H3N2) where as in India the California strain of 2009 is prevailing. It has been reported that the recent 2014-2015 H1N1A outbreak in India has resulted in >30,000 cases with over 2000 deaths. These recent spurt of cases and deaths which was even higher than the original H1N1 2009 outbreak in India resulted in a widespread debate that this strain H1N1A 2009 has mutated or not. Improved surveillance and monitoring of the influenza outbreak is need of the hour to both treat as well as prevent spread of the virus. Due to better connectivity world over and high infectious nature of influenza, there is an urgent need to develop a comprehensive and a standardized response to influenza epidemic outbreaks. There is a need of genetic and phenotypic analysis of the virus as and when cases are reported world over and general dissemination of the data is needed to ensure access to this data source in case of any outbreak.