Temporal dynamics of Campylobacter and Arcobacter in a freshwater lake that receives fecal inputs from migratory geese

Migratory geese could influence the microbiological water quality; however, their impacts on pathogen dynamics remain largely unknown. In this study, we analyzed the population dynamics of Campylobacter and Arcobacter group bacteria (AGB) in a freshwater lake in Japan over two years. The bacteria were quantified by using both culture-dependent and-independent methods. The potential sources of these bacteria were examined by a highthroughputflaA sequencing approach. Campylobacter was abundantly detected both by culture-dependent and-independent methods in the lake, especially when migratory geese were present in the lake. High-throughput flaA sequencing suggests that geese were the likely source of Campylobacter in the lake. The viable population of Campylobacter exceeds the concentrations that can potentially cause 10(-4) infections per person per year when water is used to grow fresh vegetables. The occurrence of AGB, on the other hand, was not directly related to the population of migratory geese. AGB were not detected in geese fecal samples. Diverse AGB flaA genotypes occurred in the lake over multiple seasons. Our results suggest that AGB likely comprise a part of the indigenous microbial population of the lake and grow in response to high nutrient, warm temperature, and low dissolved oxygen concentrations in the lake. Geese therefore can indirectly impact the AGB population by providing nutrients to cause eutrophication and lower the dissolved oxygen concentration. Since geese travel long-distance and disperse their fecal microbiota and nutrients to wide areas, they may have significant impacts on water quality and public health.

Automated summary

Migratory geese can have significant impacts on water quality and public health by affecting the microbiological composition and nutrient levels in freshwater lakes. They are likely to be a major source of Campylobacter bacteria in the lake, while the occurrence of Arcobacter group bacteria is not directly related to the presence of geese. The nutrient inputs provided by geese can lead to eutrophication and lower dissolved oxygen concentrations, indirectly impacting the indigenous microbial population of the lake.