Each year temporary puddles are formed on compacted earth roads as a consequence of heavy rains and subsequent flooding in the large floodplain forests of the Danube River, Hungary, Central Europe, Hungary. After the receding of floodwaters, the muddy puddles persist from spring to mid-fall, where they are densely populated byGalba truncatulasnails on an annual basis. These snails are the sole intermediate host ofFascioloides magnaliver fluke of deer in the forest. According to field observations,G. truncatulais a very rare species on banks of river branches and lakes within the forest but always appears in large aggregations in these semi-natural potholes. Red deer (Cervus elaphus) leave their droppings in puddles while they wallow in the mud, therefore the snails encounter the miracidia ofF. magnafrequently. Snails are not able to dig themselves into the tamp soil of roads therefore they are destroyed by the wheels of vehicles which drive down the roads from autumn to the end of winter. Therefore, snails colonize these puddles regularly every spring. Since there is no connection between the distant puddles, it is supposed that deer and wild boars repeatedly introduce the snails into the puddles each year carrying snails with the help of mud, which is stuck on their fur while they wallow. This method of transport is supported by the fact that shell remnants of snails can be found on the bark of rubbing trunks situated nearby wallows. It seems that the sequential creation of wallow sites and the repeated introduction ofG. truncatulaenhance the likelihood for the trematode to infect both hosts.