Eustrongylidosis

A parasitic disease affecting fish and birds

Eustrongylidosis is a parasitic disease caused by nematodes of the genus Eustrongylides. This disease primarily affects fish and piscivorous birds, leading to significant ecological and economic impacts.

Life Cycle

The life cycle of Eustrongylides involves multiple hosts. The adult nematodes reside in the intestines of piscivorous birds, where they lay eggs that are excreted with the bird's feces. These eggs hatch in aquatic environments, releasing larvae that are ingested by aquatic invertebrates, such as oligochaetes.

A goby infected with Eustrongylidosis

Fish, such as gobies, become infected when they consume these invertebrates. The larvae migrate to the fish's tissues, where they develop into third-stage larvae. Piscivorous birds become infected when they eat infected fish, completing the life cycle.

Symptoms in Fish

Infected fish may exhibit a range of symptoms, including:

• Abdominal swelling
• Hemorrhaging
• Tissue necrosis
• Behavioral changes such as erratic swimming

These symptoms can lead to increased mortality rates in fish populations, affecting both wild and farmed fish.

Impact on Birds

In piscivorous birds, Eustrongylides can cause:

• Gastrointestinal distress
• Weight loss
• Reduced reproductive success

Severe infections may lead to death, impacting bird populations and the ecosystems they inhabit.

Diagnosis and Treatment

Diagnosis of Eustrongylidosis in fish and birds is typically achieved through necropsy and identification of the nematodes in tissues. Treatment options are limited, and control measures focus on managing intermediate host populations and preventing the spread of infection.

Prevention and Control

Preventive measures include:

• Monitoring and managing water quality
• Controlling populations of intermediate hosts
• Implementing biosecurity measures in aquaculture settings

Related pages

• Nematode infections
• Parasitic diseases of fish
• Aquatic parasitology