Gastrointestinal parasitism in stilts (roundworms)
Gastrointestinal parasitism caused by roundworms (nematodes) is a common condition in black-winged stilts, wading birds that live in wetland areas such as Tunisian lagoons and salt marshes. These worms establish themselves in the bird's in...
What is it?
Gastrointestinal parasitism caused by roundworms (nematodes) is a common condition in black-winged stilts, wading birds that live in wetland areas such as Tunisian lagoons and salt marshes.
These worms establish themselves in the bird's intestine or stomach, feeding at its expense. A light infection often goes unnoticed, but a heavy parasite burden can seriously weaken the bird, especially young or already compromised individuals.
This disease affects both wild stilts and those kept in rehabilitation centers or captivity (zoos, wildlife rehabilitation facilities).
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Signs are often subtle at first. Progressive weight loss may occur despite a sometimes preserved appetite, along with dull and ruffled feathers, decreased activity, and lethargy.
Digestive disturbances such as abnormally soft or liquid droppings may develop. In severe infestations, worms may sometimes be visible in the feces.
In young stilts, stunted growth and abnormal feather development are important warning signs. Dehydration can develop if digestive problems persist.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The disease is caused by nematodes (roundworms) that parasitize the digestive tract. Several genera may be involved depending on the region and habitat, particularly worms belonging to families commonly found in wading birds and shorebirds.
Infection usually occurs through ingestion of eggs or larvae present in the environment (mud, water, sediments) or through consumption of prey items (small aquatic invertebrates) that serve as intermediate hosts for certain parasites.
Young stilts have less developed immunity and are more vulnerable to infection. Birds gathering in high numbers at the same location—such as busy wetland areas or wildlife rehabilitation centers—increases transmission risk.
Poor environmental conditions, stagnant water contaminated with droppings, and stress from injury, prior weakness, or difficult weather all increase the likelihood and severity of infestation.
Transmission
Transmission occurs mainly through the fecal-oral route: the bird ingests worm eggs present in contaminated water, mud, or soil. For certain nematode species, an invertebrate intermediate host (small crustaceans, mollusks, or aquatic insects) is necessary before the parasite becomes infective to the bird.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian or wildlife care specialist performs a thorough physical examination and assesses the bird's body condition. Diagnosis is confirmed by fecal analysis (coproscopy), which detects and identifies worm eggs.
In some cases, a post-mortem examination of a deceased bird can also confirm the diagnosis and identify the specific parasites involved.
Treatment
Treatment involves administering antiparasitic drugs (dewormers) suitable for wild birds, selected and dosed only by a veterinarian experienced in wildlife medicine.
Nutritional support and rehydration may be needed in addition for weakened birds, as part of comprehensive care at a rehabilitation center.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
In the wild, prevention depends mainly on maintaining the quality of wetland habitats and reducing overcrowding at water points.
In captivity or at rehabilitation centers, good sanitation of pools and enclosures, regular cleaning of feeding and water areas, and periodic parasite screening (fecal examination) help limit infestations.
Quarantining new arrivals and checking them for parasites before introducing them to an established group is recommended at wildlife care facilities.
Possible complications
Severe, untreated infestation can lead to extreme weight loss, anemia, and immunosuppression that makes the bird susceptible to other infections. Death may occur, especially in young birds or those already in poor condition.
When to see a veterinarian
The bird shows visible weight loss or decline in overall condition.
Abnormal droppings, loose stools, or visible worms are seen.
A young stilt shows poor growth or abnormal feathering.
The bird appears depressed, lethargic, or refuses to eat.
Any stilt found weakened in the field should be brought to a wildlife rehabilitation center.
Prognosis
The outlook is generally good if the infestation is detected early and treated by a wildlife professional. Without prompt care, particularly in young or already weakened birds, the outlook becomes guarded due to the risk of severe decline and complications.
Frequently asked questions
Can roundworm parasitism in the stilt pass to humans?
No, these nematodes are specific to birds and pose no known risk to humans.
How to tell if a wild stilt is parasitized?
Signs such as weight loss, dull plumage, or abnormal droppings should raise concern, but only a professional examination of droppings can confirm the presence of worms.
Should stilts be systematically dewormed in care centers?
Regular parasite screening is recommended, but treatment should always be decided by a veterinarian based on test results.
Are wild stilts often infested?
A low parasitic burden is common and generally well tolerated; it is above all a massive infestation that becomes problematic.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
ESCCAP — European Scientific Counsel Companion Animal Parasites
Content reviewed by the TunisieVet editorial team · Updated 23 August 2026
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