Electron Microscopy, National Institute of Virology, 20A Dr Ambedkar Road, Pune-411001.
After more than five decades of continuous evolution the science of electron microscopy has become a state-of-art tool in infectious disease research. The applications are broad spectrum ranging from providing the first-key clues of virus discovery to ultrastructural characterization of mechanisms of virus induced cell damage and imaging the virus particle at near-atomic resolution. The advent of cryoelectron microscopy methods has further expanded our knowledge about native virus structures, morphogenesis pathways in cells and volume reconstructions through cellular tomography. A fundamental and perhaps the most important application of EM have been the science of virus morphodiagnosis that enables a rapid and accurate detection and identification of viruses within families using TEM. The use of advanced immunolabeling methods, coupled with ultra-high resolution modern TEMs can now track viruses at every level of interaction with the host cell. With changes in global climatic factors, human demography and looking at a slice of time-pathogens are evolving and emerging out of previously unknown niches resulting in newer diseases and pandemics. In 1984, the human immunodeficiency virus; in 1990, the Sin Nomre virus; in 2001, the SARS virus; and in 2003 Chandipura virus are few examples. Importantly, in all these cases the first identity of a virus as a suspect etiologic agent was provided by TEM data. The stage is set for more future plagues. Anticipating the threat, an unique effort was initiated in 1999 by a consortium of global EM facilities to network and develop an efficient grid to provide frontline rapid-response in the use of diagnostic electron microscopy in emerging situations. This includes unknown disease investigations and biosecurity responses. The core issues, complexity of data analysis and future trends will be collectively discussed.
