In our laboratory we are considering serial passaging and perfusion techniques to improve our production capabilities further. From the results reported in this present study we are confident that we have a productive scaleable microcarrier system for our DISC-HSV vaccine that will allow us to produce adequate material for both Phase III studies and commercial product. Diagnosis of influenza viruses with special reference to novel H1N1 2009 influenza virus On 15 April and 17 April 2009, novel swineorigin influenza A (H1N1) virus was identifi ed in specimens obtained from two epidemiologically unlinked patients in the United States. The ongoing outbreak of novel H1N1 2009 influenza (swine influenza) has caused more than 3,99,232 laboratory confi rmed cases of pandemic influenza H1N1 and over 4735 deaths globally. This novel 2009 influenza virus designated as H1N1 A/swine/California/04/2009 virus is not zoonotic swine flu and is transmitted from person to person and has higher transmissibility then that of seasonal influenza viruses. In India the novel H1N1 virus infection has been reported from all over the country. A total of 68,919 samples from clinically suspected persons have been tested for influenza A H1N1 across the country and 13,330 (18.9%) of them have been found positive with 427 deaths. At the All India Institute of Medical Sciences, New Delhi India, we tested 1096 clinical samples for the presence of novel H1N1 influenza virus and seasonal influenza viruses. Of these 1096 samples, 194 samples (17.7%) were positive for novel H1N1 influenza virus and 197 samples (18%) were positive for seasonal influenza viruses. During outbreaks of emerging infectious diseases accurate and rapid diagnosis is critical for minimizing further spread through timely implementation of appropriate vaccines and antiviral treatment. Since the symptoms of novel H1N1 influenza infection are not specifi c, laboratory confi rmation of suspected cases is of prime importance. The current outbreak of swine infl uenza that originated in Mexico in March 2009 has spread to more than 80 countries causing more than 3,99,232 laboratory confi rmed cases of pandemic infl uenza H1N1 globally and over 4735 deaths reported to World Health Organization (WHO)as of 11 October 2009 [1] . The WHO declared pandemic alert stage 6 on 11 June 2009, indicating an ongoing infl uenza pandemic [2] . The 2009 swine fl u virus designated H1N1 A/swine/California/04/2009 is not zoonotic swine fl u and is not transmitted from pigs to humans, but rather from person to person and has higher transmissibility than seasonal infl uenza viruses [3] . In humans, H1N1 swine fl u presents as an infl uenza-like illness (ILI) with symptoms similar to seasonal infl uenza, i.e. fever, cough, sore throat, runny nose, muscle pains, severe headache, however, a considerable proportion of patients reported vomiting or diarrhea which is unusual in seasonal infl uenza [4, 5] . Since these symptoms are not specifi c to swine fl u, early in the pandemic physicians were advised to consider swine infl uenza in the differential diagnosis of patients with acute febrile respiratory illness who had returned from Mexico or been in contact with persons with confi rmed swine fl u [6] . This new strain of H1N1 swine infl uenza has a unique combination of genes from both North American and Eurasian swine lineages that has not been identifi ed previously in either swine or human populations [7] . The virus appears to be a result of reassortment of two swine infl uenza viruses, one from North America and one from Europe with the North American virus itself the product of previous re-assortments, carrying an avian PB2 gene for at least 10 years and a human PB1 gene since 1993. The virus also has genome segments of avian origin. Hence scientists call this novel strain as a "quadruple reassortant" virus. The hemagglutinin (HA) gene is similar to that of swine fl u viruses present in pigs in United States since 1999, where as neuraminidase (NA) and matrix (M) genes resemble viruses present in European pigs. Viruses with this genetic makeup have not previously been found in humans or pigs.