1Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
2Employees Health Service Clinic, All India Institute of Medical Sciences, New Delhi, India.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Influenza viruses are among the most common causes of human respiratory infections because it causes high morbidity and mortality in both children and adults. Three times in the last century, the influenza viruses have undergone major genetic changes in their Hemagglutinin and Neuraminidase component, resulting in global pandemics. The aim of this study is to report the preliminary data on circulating strains of influenza viruses from national capital territory, India. Nasal and Throat swabs were collected in viral transport medium from patients of influenza like illness (ILI) Samples were collected from two sites (a) Comprehensive Rural Health Service Project (CRHSP) of AIIMS, Ballabhgarh. (b) Employees Health Service Clinic of AIIMS, New Delhi. Each sample was passaged at least twice in MDCK cell line. The presence of influenza virus was detected by Hemagglutinin assay (HA). If HA was positive, further sub typing was done by Hemagglutinin Inhibition assay (HI) using anti-sera provided by WHO. Two thousand eight hundred twenty one (2821) samples have been collected from December 2004–September 2008. Influenza viruses were isolated in 168 (6%) of 2821 samples. HI WAS done on 168 samples, 39 (23%) have been identified as subtype H3N2, 48 (29%) as H1N1 and 81 (48%) as influenza B. Maximum number of influenza positive cases were seen during winter months of December–March and rainy months of July-August. The pattern of circulating influenza strains needs to be closely monitored as with new influenza strains emerging each year, identification of circulating strains by coordinated global surveillance is crucial to vaccine development.
