parasitic disease Raccoon Transmissible to humans

Gastrointestinal roundworm infection in raccoons

Gastrointestinal parasitism caused by roundworms refers to infestation of the raccoon's intestine by nematodes, particularly Baylisascaris procyonis, a roundworm very common in this species. This parasite lives in the small intestine of the...

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Zoonosis Prognosis FAQ Sources Affected species

What is it?

Gastrointestinal parasitism caused by roundworms refers to infestation of the raccoon's intestine by nematodes, particularly Baylisascaris procyonis, a roundworm very common in this species.

This parasite lives in the small intestine of the animal and produces highly resistant eggs that are shed in large quantities in the feces.

In adult raccoons, the infestation often goes unnoticed, but it represents a significant health risk to other species, including humans, if eggs are accidentally ingested.

Key point

Although generally mild in the raccoon itself, this infection carries major public health significance because of its zoonotic potential, notably through Baylisascaris procyonis, which can cause serious neurological disease in humans.

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:

Diarrhea Vomiting Weight loss Loss of appetite Dull coat Stunted growth Bloating Visible worms in stools Dehydration Seizures Head tilted Staggering gait

In young raccoons, a heavy parasite burden can cause a swollen belly, diarrhea, vomiting, dull coat, and poor growth.

The animal may appear lethargic, lose weight despite a preserved appetite, or conversely eat less.

In rare cases of very heavy infestation, intestinal obstruction may occur with marked bloating and abdominal pain.

Whitish worms, resembling small spaghetti, are sometimes visible in the feces or vomit.

Adults are most often carriers without visible signs.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

Infestation is mainly caused by Baylisascaris procyonis, a roundworm specific to raccoons, but other intestinal nematodes may also be involved.

Contamination occurs through ingestion of eggs present in the environment (soil, bedding, vegetation soiled by feces), or by eating small animals (rodents, birds) carrying encysted larvae in their tissues.

Young raccoons are most susceptible, as they typically carry higher parasite loads.

Group living, use of communal latrines (areas where several raccoons deposit feces) and contact with other wild animals promote transmission.

A contaminated or poorly cleaned environment, or contact with wild raccoons increases risk, particularly in captivity or at wildlife rehabilitation centers.

Transmission

Transmission occurs mainly through the fecal-oral route: ingestion of eggs present in the environment contaminated by raccoon feces, or consumption of prey (rodents, birds) carrying encysted larvae. Eggs can survive for a long time in soil and resist many common disinfectants.

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 animal's history, clinical examination, and particularly fecal analysis (coproscopy) to detect worm eggs.

In some cases, imaging (abdominal radiography or ultrasound) may be useful if bowel obstruction is suspected.

Precise identification of the parasite species may require specialist examination, particularly if Baylisascaris procyonis is suspected due to its zoonotic potential.

Treatment

Treatment involves administering broad-spectrum antiparasitic drugs prescribed and dosed only by a veterinarian.

Support care (rehydration, appropriate diet) may be needed in weakened animals.

In severe intestinal obstruction, surgical intervention may be required.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Prevention relies on good environmental hygiene: regular cleaning of enclosures, safe disposal of feces, and disinfection of surfaces with products effective against resistant eggs.

Regular deworming, supervised by a veterinarian, is recommended for captive animals or those admitted to wildlife care centers.

Limiting direct contact with feces and wearing gloves when cleaning reduces the risk of human contamination.

Possible complications

High parasite load in young animals can lead to intestinal obstruction, severe dehydration, or lasting growth delay.

In other species (including humans), accidental ingestion of Baylisascaris procyonis eggs can cause larval migration through tissues, particularly the nervous system or eyes, with potentially serious consequences.

When to see a veterinarian

The animal experiences persistent diarrhea or repeated vomiting.

The abdomen appears swollen, firm, or painful when touched.

Worms are visible in the stool or vomit.

A young raccoon fails to grow normally or remains thin despite adequate food intake.

Neurological signs (tremors, abnormal gait, head tilt) appear in an animal that has been in contact with raccoons.

Transmission to humans

Baylisascaris procyonis is a concerning zoonotic parasite: accidental ingestion of its eggs, found in raccoon feces or on contaminated surfaces, can cause visceral or ocular larval migration in humans (particularly young children), or in rare cases severe neurological involvement.

Strict hygiene practices (hand washing, wearing gloves when cleaning feces, avoiding direct contact with raccoon latrines) are essential to reduce this risk, especially for those working in wildlife rehabilitation centers or in contact with captive raccoons.

Prognosis

Prognosis is generally good in adults, often carrying the parasite without major symptoms.

In heavily infested young animals, prognosis depends on how quickly treatment begins: early treatment allows complete recovery in most cases.

Severe complications such as intestinal obstruction are rare but require prompt management.

Frequently asked questions

Is a raccoon carrying roundworms dangerous for my pets or my family?

Yes, potentially. Eggs from certain roundworms found in raccoons, particularly Baylisascaris procyonis, can contaminate the environment and pose a risk to other animals and humans. Strict hygiene is essential when handling raccoons or their feces.

How do you know if a raccoon has intestinal worms?

Diagnosis is made by a veterinarian, usually through fecal analysis. In adults, infestation may cause no visible symptoms.

Can wormer be given without veterinary advice?

No. The choice of product, dosage, and frequency must be determined by a veterinarian, as misuse can be ineffective or dangerous for the animal.

Are young raccoons at higher risk?

Yes, young people generally carry a higher parasite load and are more susceptible to developing marked digestive symptoms.

References

CDC — Centers for Disease Control and Prevention

AVMA — American Veterinary Medical Association

ESCCAP — European Scientific Counsel Companion Animal Parasites

Content reviewed by the TunisieVet editorial team · Updated 26 August 2026

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AT A GLANCE

AgentParasite

SpeciesRaccoon

VaccineNo

Transmissible to humansYes

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