Diagnosis in a live specimen is possible in the field by palpating the abdomen. As with birds, prominence of the keel could be a determinant in diagnosis, but natural history of the species needs to be understood to avoid potential misdiagnoses. However, the best form of diagnosis still remains as necropsy. During the necropsy, the best diagnosis can be determined by the adult nematodes by scanning them with electron microscopy. Different species of Eustrongylidosis nematodes can be differentiated by specific gender characteristics, i.e. “Male specimens of E. ignotus have a caudal sucker that lacks cuticular cleft, while a cuticular cleft is present in the caudal sucker of male specimens of E. excisus”. “Eustrongylidosis can often be misdiagnosed as starvation in nestling because they are often emaciated at the time of death”.

Before necropsy takes place, diagnosis by palpitation can be used to find tubular lesions. Those tubular lesions are firm, firmly attached to organs, and are felt in the subcutaneous tissue. While palpitation is practical and simple, errors can be made in nestlings’ examinations because their ribs have the potential to present as lesions. Diagnosis is also attainable by examining fecal samples, but has the high potential of false negatives. That possibility is increased in fledging feces “where severe disease may precede appearance of eggs in the feces”.

Because of Eustrongylides species’ complex life cycle with various host species, preventing infection and controlling outbreaks is difficult. Outbreaks of this disease are closely linked to agricultural runoff and urban development Eutrophication of water bodies supports high population levels of oligochaete worms, which causes increased numbers of infected fish that eat the worms, and then the birds who eat the fish.

One way to prevent Eustrongylidosis is to control oligochaete populations. Outbreaks of this parasite are closely linked to high numbers of oligochaete worms in the area’s waterways. This is because the worms are essential for Eustrongylides species to reproduce. Oligochaete populations can be controlled by monitoring nutrient levels in the water, because high nutrient levels support oligochaete populations. They can also be controlled by decreasing the level of oxygen in the water. Encouraging responsible farming practices in order to reduce chemical run-off will help prevent this disease from occurring.

Managers need to be diligent in catching the symptoms of the parasite before it can become an outbreak. Once an outbreak of Eustrongylidosis has occurred, there is little that ecosystem managers can do to stop the spread in oligochaetes, fish and birds. Traditional anthelminthics (dewormers) are not effective in fish because they kill parasites that live inside the gastrointestinal tract, whereas Eustrongylides species live outside the stomach in the body cavity. The parasites can only be removed from fish surgically, which is not feasible. In order to completely stop the Eustrongylides life cycle in fish, all fish in an affected area must be culled.

Surgical removal of the parasite from wading birds is a viable option, but this would also not be feasible for a large number of birds, and it would not stop the cycle of infection.