Regional Activity and Spread of Influenza Viruses in Poland in the Context of Neighboring Countries in the Epidemic Season 2017-2018: An Epidemiological Review

This article reviews the epidemiological situation in Poland during the 2017-2018 influenza season in the context of viral spread from the neighboring countries. There were 5793 specimens tested for the presence of influenza virus. The specimens were collected from patients with suspected upper airway infection. The presence of influenza virus was confirmed in 2454 specimens. The data were used to determine the extent of morbidity and the possible direction of spread of influenza virus. It was found that virus type B predominated in 13 out of the 16 Polish provinces, type A predominated in just 1 province, and both types predominated equally in another 2 provinces. Data on influenza type B virus did not enable the drawing of a clear-cut conclusion on the way of its spread. Presumptively, the route of type B virus spread originated in the Ukraine and moved westward, with the transmission enhanced, to some extent, by migration of Ukrainian citizens. Virus type A, on the other side, spread from the Southwest Europe eastward. Reviewing the epidemiological situation plays an important role in gaining more knowledge on influenza morbidity and its differentiation from other similar infections, which helps counteract future infections.