eradicable disease (Webster, 1998). During the development of this report, it was reported that H5N1 avian influenza had been discovered in migratory birds in the Novosibirskaya region of Russia (ProMED-mail, 2004t). Preliminary data indicate that the virus was brought from south east Asia by migratory birds, such as ducks and geese (ProMED-mail, 2004t). Workshop discussants concurred that the best chance of averting a pandemic lies in stopping the further spread of epidemics in poultry populations, thereby reducing human exposure to the virus and limiting its opportunities for reassortment (Trampuz et al., 2004; Barclay and Zambon, 2004).

Live poultry markets provide near-optimal conditions for amplifying and perpetuating viruses due to the continuous movement of many bird species through the market (Webster, 2004b). These risks are multiplied when livestock and poultry are kept in close proximity and in crowded conditions, as is often the case in “wet markets” and in livestock (especially swine) and poultry feeding operations (Liu et al., 2003). Because neither practice is likely to end soon, participants agreed, the immediate focus of preventive efforts should be on making farms and markets safer through measures and regulations that reduce the possibility of contact between domestic and wild animals and between domestic mammals and poultry, as well as through efforts to protect workers from infection (see Swayne and Sibartie in Chapter 4).

Surveillance

Influenza surveillance at all levels—from global to local—has a common, practical goal: to detect events indicating unusually large or severe outbreaks of influenza as early as possible, and to determine the intensity and impact of influenza on populations. The first step toward this goal is to determine normal conditions, so that an unusual event can be recognized for what it is. Thus influenza surveillance must be stable, ongoing, and representative of populations on the basis of geography, demography, and severity of disease. The vital data that emerge determine vaccine strain selection and public health resource allocation and drive influenza prevention and control policy and planning for pandemic preparedness.

Surveillance findings also contribute to epidemiological research, most often as a springboard for more detailed investigation. In the case of influenza, surveillance has clarified essential questions regarding the clinical epidemiology of pandemics and the biological causes of epidemiological phenomena. Pursuing answers to these questions will require investment in planning research, designing protocols, and establishing networks of scientists ready to engage in these studies in advance of the next pandemic (Stöhr, 2004).



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