Gregarines (Apicomplexa) and microsporidians (Microsporidia) of native and invasive gammarids (Amphipoda, Gammaroidea), occurring in Poland.

The goal of our study was to recognize microparasites of alien gammarids inhabiting Polish inland and coastal waters versus those infecting local species. Twenty two localities including the Vistula, Oder and Bug Rivers, Vistula Lagoon, Gosławskie Lake, littoral of the Baltic Sea, as well as small rivers draining directly to the sea were investigated. In total, over 5000 individuals of 14 species of gammarids were collected and analyzed using light and electron microscopy.