Gastrointestinal parasitism of crows (roundworms)
Gastrointestinal parasitism by roundworms (nematodes) is a common condition in crows, whether wild, injured in a care center or held in captivity. Roundworms such as roundworms (genus Ascaridia or Porrocaecum) or capillaries (genus Capilla...
What is it?
Gastrointestinal parasitism by roundworms (nematodes) is a common condition in crows, whether wild, injured in a care center or held in captivity.
Roundworms such as roundworms (genus Ascaridia or Porrocaecum) or capillaries (genus Capillaria) settle in the stomach or intestine of the bird. They feed at the expense of their host and disrupt digestion.
This parasitosis is often silent in healthy adult birds, but it becomes worrying in young, weakened or stressed birds (captivity, injury, other illness), where it can worsen the general condition.
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 discreet and non-specific.
We can observe progressive weight loss despite a sometimes retained appetite, dull and ruffled feathers, diarrhea or loose stools, general depression and a drop in activity.
In young birds or in the event of a significant infestation, growth retardation, a distended or sensitive stomach, or even vomiting may appear.
Sometimes, entire worms are visible in the droppings, which makes it possible to suspect the diagnosis even before the consultation.
In severe cases, intestinal obstruction or digestive perforation may occur, putting the bird's life in danger.
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 species of nematodes (roundworms) can infest the crow's digestive tract. The most common are roundworms which live in the small intestine and the capillaries which reside in the esophagus, the jarabot (crop) or the intestine.
These worms lay eggs which are eliminated in the droppings. These eggs become infective in the external environment after a certain time, or after being ingested by an intermediate host such as an earthworm or an insect.
Young crows, still immature in terms of immunity, are more sensitive.
Living in dense groups, prolonged captivity in a care center or aviary, and an environment soiled by droppings increase the risk of reinfestation.
Stress linked to an injury, convalescence or captivity favors the clinical expression of the disease in a carrier bird without symptoms.
A poor diet or an already weakened body condition aggravates the consequences of the disease. parasitism.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian relies on the clinical examination of the bird and especially on an analysis of the droppings called coproscopy, which makes it possible to search for and identify parasite eggs under a microscope.
In certain cases, an endoscopy or an x-ray can be useful to visualize worms or assess the digestive consequences of a significant infestation.
Treatment
Treatment is based on the administration of an antiparasitic agent adapted to the species of worm identified, prescribed and dosed exclusively by a veterinarian competent in wild avifauna.
Nutritional support and rehydration may be necessary in weakened birds.
Monitoring the effectiveness of the treatment by a new coproscopy is often recommended.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
In care centers or in captivity, regular cleaning of floors, feeders and aviaries limits the accumulation of infective eggs.
Avoiding overpopulation and isolating newly arrived birds for parasite control reduces transmission.
Regular veterinary monitoring with examination of droppings (coproscopy) makes it possible to detect an infestation before the appearance of symptoms, particularly in birds kept in captivity for a long time.
Possible complications
Untreated massive infestation can lead to intestinal obstruction, digestive perforation, anemia or severe growth retardation in the young.
The resulting general weakening makes the bird more vulnerable to further infections and compromises the chances of survival, particularly before release.
When to see a veterinarian
Unexplained progressive weight loss in a crow in care or captivity
Persistent diarrhea or abnormal stools
Presence of worms visible in the droppings
Marked depression or refusal to feed
Swollen belly or painful to the touch
Retardation of growth in a young bird
Prognosis
The prognosis is generally good when the infestation is detected early and treated by a veterinarian, especially in otherwise healthy adult birds.
It becomes more reserved in young birds, in the event of a massive infestation or digestive complications, especially when the bird must be released quickly.
Frequently asked questions
Can a crow have worms without showing symptoms?
Yes, it's even common. Many wild crows harbor roundworms without visible signs, especially if their immune systems control them well. Symptoms appear especially in cases of stress, captivity or significant infestation.
How does a crow get roundworms?
Most often by ingesting eggs present in the contaminated environment, or by eating earthworms or insects carrying infective larvae.
Can you treat a crow yourself with an antiparasitic purchased without a prescription?
No, this is not recommended. The choice of product, dose and duration depend on the species of parasite identified and the weight of the bird. Inappropriate treatment can be ineffective or even toxic.
Is this parasitosis transmissible to humans?
Roundworms specific to birds such as crows are not considered transmissible to humans under usual conditions.
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 30 October 2026
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