Viral vigilance

the early and accurate diagnosis of an infectious agent is essential for successfully treating individual patients and is even more important at the population or global level. the ability to identify quickly the causative pathogen of an emerging epidemic or pandemic markedly increases the chances of success of any countermeasures to contain the disease. For this reason, many countries together with the World Health Organization (WHO; Switzerland, geneva) have made great efforts to develop integrated surveillance networks for tracking candidate pathogens—such as the bird influenza virus H5N1, human immunodeficiency virus (HiV), West Nile virus, poliovirus and Mycobacterium tuberculosis—and to keep tabs on their genetic structure, geographical distribution and host populations. Moreover, recent advances in molecular biology—DNa chip or new sequencing technologies, for example—are continually improving the diagnosis of a wide range of pathogens and their variants. However, few infectious diseases are likely to cause a devastating pandemic on the scale of the 1918 influenza outbreak, which emerged from nowhere and killed more people than did the First World War. in fact, although the WHO keeps track of a wide range of diseases, one of its primary goals is to snuff out potential pandemics at birth. “Our strategy is to detect an early phase four event”, commented David Heymann, the WHO assistant Director general for communicable Diseases, referring in particular to H5N1. “phase three is where we are now [...] that’s where a novel virus can infect humans, with occasional human-to-human spread. phase four would be sustained human-to-human spread. in that event we would try to ring fence that event by antivirals and vaccines.” H5N1 is now out of control among domestic chickens in many developing countries and is endemic among wild duck populations in parts of asia. although the WHO is responsible for identifying emerging pandemics, most of its activities concentrate on containing and managing the diseases that continue to kill many people, especially in developing countries. On top of its global influenza Surveillance Network, the WHO therefore organizes other networks to monitor yellow fever, Ebola, polio and other major endemic diseases.