[various sides of influenza. part ii--epidemiology, influenza surveillance and prophylaxis]. | influenza viruses cause epidemics and pandemics. animal reservoir for influenza viruses and repeatedly occurring human infections with avian influenza viruses since 1997 indicate that there is a real threat of pandemic, but it is no possible to predict when this outbreak begins. every year 330-990 millions of people are ill due to influenza worldwide. in poland there are registered from a few hundred to few millions of cases and suspected cases of influenza each epidemic season. who coordinates ... | 2006 | 17163191 |