Gastrointestinal kite parasitism (roundworms)
Gastrointestinal parasitism caused by roundworms (nematodes) is a frequent attack in the red kite (Milvus milvus) and the black kite (Milvus migrans). These raptors become contaminated by consuming prey carrying parasitic larvae, in particu...
What is it?
Gastrointestinal parasitism caused by roundworms (nematodes) is a frequent attack in the red kite (Milvus milvus) and the black kite (Milvus migrans). These raptors become contaminated by consuming prey carrying parasitic larvae, in particular rodents, birds or insects. The infestation affects the stomach, intestine or sometimes the esophagus, and can remain discreet or cause a progressive weakening of the bird. It is particularly worrying among young people, injured birds taken into care centers, or individuals already weakened elsewhere.
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:
The signs are often subtle at first. We can observe progressive weight loss despite a preserved or reduced appetite, dull or ruffled feathers, a drop in energy and a reduced flight capacity. In more affected subjects, diarrhea or abnormally soft stools appear, sometimes vomiting of undigested food, and a state of general weakness. Young birds may exhibit stunted growth and poor plumage. In massive infestations, worms may be visible in the droppings or regurgitated. Anemia with pale mucous membranes can be seen in severe forms, particularly linked to blood-sucking parasites.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Several families of gastrointestinal nematodes can infest kites, including worms belonging to genera commonly found in wild raptors, such as those affecting the proventriculus (glandular stomach), gizzard or intestine. Contamination occurs mainly by ingestion of prey (rodents, birds, insects) harboring infesting larvae, which makes the kite a particularly exposed predator due to its varied and sometimes scavenging diet.
Young, inexperienced birds, injured or weakened kites collected in conservation centers, birds living in areas where scavenging feeding is frequent (proximity to landfills, carrion), as well as individuals kept in prolonged captivity in spaces where hygiene is insufficient are more at risk. Stress, a concomitant illness or an unbalanced diet also favor the clinical expression of parasitism.
Transmission
Transmission occurs mainly orally, during the consumption of prey or carrion carrying parasitic larvae. Some cycles involve an intermediate host (insect or small vertebrate) that the kite ingests while feeding. There is no direct transmission between adult birds apart from environmental contamination by droppings.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Diagnosis is based on examining the droppings under a microscope to look for worm eggs or larvae (coproscopy), possibly repeated several days apart. The veterinarian may also look for regurgitated or expelled adult worms. In certain cases, an endoscopic examination or an evaluation of the general condition and blood test (search for anemia) completes the assessment. The bird's dietary history and context of capture also guide the diagnosis.
Treatment
Treatment uses broad-spectrum antiparasitics suitable for birds, prescribed and dosed exclusively by a veterinarian specializing in wildlife or avian medicine, as the safety margin in raptors can be narrow. Nutritional support and rehydration may be necessary if marked weakening occurs. The treatment is often repeated after a coproscopic check to check its effectiveness.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention is mainly based on good health management in care centers: regular cleaning of aviaries, rapid removal of droppings and food remains, quarantine of newly admitted birds, and monitoring of body condition. In the wild, direct prevention is limited, but limiting kites' access to contaminated food sources (open dumps) can reduce exposure. Periodic parasitological checks of droppings are recommended in structures housing raptors undergoing rehabilitation.
Possible complications
A large, untreated infestation can lead to severe anemia, progressive malnutrition, digestive obstruction in extreme cases, and increased vulnerability to other infections. In the young bird, this can compromise growth and flight abilities, reducing the chances of survival in the wild after release.
When to see a veterinarian
Progressive weight loss without apparent cause
Dull, ruffled or poor quality plumage
Diarrhea or persistent abnormal stools
Presence of worms visible in droppings or regurgitation
General weakness, bird unable to fly normally
Any injured or weakened bird collected, before releasing
Prognosis
The prognosis is generally good if the infestation is detected and treated early, particularly in a care center with veterinary monitoring. It becomes more reserved in cases of massive parasitism, severe anemia or concomitant diseases, particularly in birds already weakened before being taken into care.
Frequently asked questions
Can a wild kite carry worms without being sick?
Yes, a light infestation is often well tolerated by a healthy bird. Clinical signs appear especially when the parasite load becomes significant or the bird is already weakened.
Can a commercial antiparasitic be given to a rescued injured kite?
No, treatment should never be administered without veterinary advice. Raptors have a particular sensitivity to certain molecules and an overdose can be dangerous.
Is this parasitism transmissible to humans or domestic animals?
Gastrointestinal kite nematodes are generally specific to birds and pose no known risk to humans or domestic mammals.
How does a care center check that a kite is free of parasites before releasing it?
A coproscopic check (examination of the droppings) is carried out after treatment to ensure the absence of eggs or larvae before considering release.
References
ESCCAP — European Scientific Counsel Companion Animal Parasites
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 29 September 2026
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