Please cite this paper as: Chadha et al. (2011) Multi site Virological Influenza Surveillance in India: 2004–2008. Influenza and Other Respiratory Viruses 6(3), 196–203.
Background Influenza surveillance is important to identify circulating, emerging/reemerging strains and unusual epidemiological trends. With these objectives, a multisite human influenza surveillance network was initiated in India in 2004.
Methods Epidemiologic data and throat swabs for laboratory testing were collected from patients with influenza‐like illness (ILI) and severe acute respiratory infections (SARI). Virus isolation was carried out in Madin–Darby canine kidney cells and strains identified by hemagglutination inhibition assay. Meteorological data were collected.
Results From September 2004 to December 2008, 617 (4·43%) of 13928 cases yielded isolates: 27·8% were influenza A(H1N1), 29·8% were type A(H3N2), and 42·3% were type B. The yearly type and subtype distribution varied significantly from site to site. Peak influenza activity was observed from June to August in Delhi, Pune, and Kolkata and October to December in Chennai. Maximum influenza activity was seen during the rains in Delhi, Pune, Chennai, and Kolkata in correlation with virus isolations. Multivariate analysis of ILI cases showed chill/rigors, cough, fatigue, and ILI in family, correlated positively with isolation. Genetic analysis of Indian isolates revealed that viruses matched with vaccine strains by and large. Overlapping between circulating and vaccine component strains of consecutive years was also observed.
Conclusions Seasonal influenza A(H1N1), H3N2, and type B co‐circulated in all regions without any particular pattern of movement of any subtype. Year‐round limited influenza activity with peaks during rains was observed. Genetic drifts and varying seasonality in different parts of the country suggest that a staggered timing of vaccination may be appropriate for India.
India has made appreciable progress and continues to demonstrate a strong commitment for establishing and operating a disease surveillance programme responsive to the requirements of the International Health Regulations (IHR[2005]). Within five years of its launch, India has effectively used modern information and communication technology for collection, storage, transmission and management of data related to disease surveillance and effective response. Terrestrial and/or satellite based linkages are being established within all states, districts, state-run medical colleges, infectious disease hospitals, and public health laboratories. This network enables speedy data transfer, video conferencing, training and e-learning for outbreaks and programme monitoring. A 24x7 call centre is in operation to receive disease alerts. To complement these efforts, a media scanning and verification cell functions to receive reports of early warning signals. During the 2009 H1N1 outbreak, the usefulness of the information and communication technology (ICT) network was well appreciated. India is using ICT as part of its Integrated Disease Surveillance Project (IDSP) to help overcome the challenges in further expansion in hard-to-reach populations, to increase the involvement of the private sector, and to increase the use of other modes of communication like e-mail and voicemail.
Circulatory immune complexes were estimated in the sera of 25 patients and 20 age and sex matched controls by precipitation with 8% polyethylene glycol (PEG). Characterization of the immune complexes, thus obtained, was performed by the double immuno-diffusion method. The mean protein content of the PEG precipitates was significantly higher in the patients of thromboangiitis obliterans than in the controls. The immunoglobulins in the immune complexes were predominantly of mixed type in contrast to mainly single class immunoglobulins in the controls. C3 complement distribution in immune complexes of patients and control sera was 64% and 45% respectively. The immune complexes in patients were found to be biologically active. The mechanism of formation of circulatory immune complexes and their role in the pathogenesis of arteritis in relation to smoking of tobacco has been postulated.
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