Basil intestinal parasitism (roundworms)

What is it?

Intestinal parasitism caused by roundworms (nematodes) is a very common condition in the basilisk, an arboreal lizard from Central America often kept in terrariums. These parasites live in the intestine of the reptile and feed at its expense. A light infestation sometimes goes unnoticed, but a high parasite load can seriously weaken the animal, especially in captivity where stress and reduced space favor the multiplication of eggs.

Commonly observed signs

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

Causes and risk factors

The infestation is caused by intestinal nematodes (roundworms), including pinworms and roundworms specific to reptiles. The life cycle often takes place in a closed circuit in the terrarium: the animal ingests eggs present in its environment, soiled by its own excrement, or consumes prey (insects) themselves carrying larvae.

A poorly cleaned terrarium, insufficient substrate hygiene, overpopulation of animals, chronic stress linked to unsuitable breeding conditions (temperature, hygrometry) and a diet based on uncontrolled insects increase the risk. Young basilisks and immunocompromised animals are more vulnerable to severe forms.

Transmission

Contamination occurs orally, by ingesting parasite eggs present on the substrate, terrarium decorations, contaminated water or directly in the stools. Live prey (crickets, locusts) caught in the wild or poorly raised can also carry larvae. The cohabitation of several animals in the same terrarium promotes propagation.

Diagnosis and care

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

Treatment

Treatment is based on the administration of antiparasitics suitable for reptiles, prescribed and dosed only by a veterinarian familiar with exotic animals. Nutritional support and rehydration may be necessary if weakened. Complete cleaning of the terrarium systematically accompanies the treatment to avoid immediate reinfestation.

Prevention

Possible complications

A massive and untreated infestation can cause intestinal obstruction, severe dehydration, significant weight loss and, in extreme cases, the death of the animal, particularly in young, fragile animals.

When to see a veterinarian

Prognosis

The prognosis is generally good if the infestation is detected and treated early, with a return to normal after treatment and improvement of terrarium hygiene. On the other hand, an old and severe infestation in an already weakened animal darkens the prognosis.

Frequently asked questions

References

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

Content reviewed by the TunisieVet editorial team · Updated 27 September 2026