Roundworm infection in marabou storks (gastrointestinal parasitism)

What is it?

Gastrointestinal parasitism caused by roundworms (nematodes) is a common condition in the African marabou stork, a large scavenging wading bird often housed in zoos or aviaries. These parasites live in the intestines and sometimes in the gizzard or oesophagus. They feed at the bird's expense and in large numbers can cause significant digestive disease. Young marabous and birds that are weakened or stressed are most susceptible to severe infestations.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

The disease is caused by gastrointestinal nematodes, a group of roundworms parasitizing the digestive tract of wading birds. Several genera may be involved depending on region and management conditions, including worms similar to those affecting other large wading birds (storks, herons). Birds become infected by ingesting eggs or larvae present in the environment, contaminated water, feed, or prey (small animals, insects) that serve as intermediate hosts for some parasites.

Young birds, recently relocated or stressed individuals, and high bird densities in the same enclosure favour parasite spread. Contaminated ground, poor hygiene of water basins and feeders, accumulation of droppings, or limited water changes increase infestation risk. Birds weakened by another illness or unbalanced diet are more susceptible to severe forms.

Transmission

Transmission occurs mainly through ingestion of infective eggs or larvae present in soil, stagnant water, or feed contaminated with droppings from infected birds. Some nematodes require passage through an intermediate host (insect, mollusc, small vertebrate) that the marabou naturally consumes as part of its varied and scavenging diet.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Treatment

Treatment involves administering antiparasitic drugs specific to roundworms, prescribed and adapted by your vet based on the parasite species identified. Nutritional support and sometimes rehydration may accompany treatment in weakened birds. In complicated cases with intestinal obstruction, surgical management may be considered.

Prevention

Possible complications

Untreated heavy infestation can lead to anaemia, severe weight loss, intestinal blockage or even digestive perforation in extreme cases. In young marabous, lasting growth retardation is possible. Chronic parasitism also weakens immune defences, making the bird more vulnerable to other infections.

When to see a veterinarian

Prognosis

The outlook is generally good if the infestation is detected early and treated with an appropriate antiparasitic medication. It becomes more guarded in cases of heavy infestation, complications such as intestinal blockage, or in a bird already weakened by another health problem.

Frequently asked questions

References

WOAH — Organisation mondiale de la santé animale (ex-OIE)

FAO — Organisation des Nations unies pour l'alimentation et l'agriculture

Content reviewed by the TunisieVet editorial team · Updated 08 September 2026