Eustrongylidosis is a parasitic disease that mainly affects wading birds worldwide; however, the parasite's complex, indirect lifecycle involves other species, such as aquatic worms and fish. Moreover, this disease is zoonotic, which means the parasite can transmit disease from animals to humans. Eustrongylidosis is named after the causative agent Eustrongylides, and typically occurs in eutrophicated waters where concentrations of nutrients and minerals are high enough to provide ideal conditions for the parasite to thrive and persist. Because eutrophication has become a common issue due to agricultural runoff and urban development, cases of eustrongylidosis are becoming prevalent and hard to control. Eustrongylidosis can be diagnosed before or after death by observing behavior and clinical signs, and performing fecal flotations and necropsies. Methods to control it include preventing eutrophication and providing hosts with uninfected food sources in aquaculture farms. Parasites are known to be indicators of environmental health and stability, so should be studied further to better understand the parasite's lifecycle and how it affects predator-prey interactions and improve conservation efforts.