Gastrointestinal parasitism in rhinoceroses (roundworms)

What is it?

Gastrointestinal parasitism caused by roundworms (nematodes) is very common in white rhinoceroses, whether living in the wild, zoos, or reserves. Worms from several families live in the animal's intestines and stomach, feeding at its expense. In small numbers, these parasites are usually well tolerated. However, when their numbers increase—especially in young animals or those in poor health—they can cause significant digestive disease, sometimes severe.

Commonly observed signs

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

Causes and risk factors

The disease results from the presence of large numbers of roundworms (nematodes) in the digestive tract. In white rhinoceroses, several genera are described, notably digestive strongyles similar to those found in equines and other large herbivores. These worms lay eggs that are shed in droppings, contaminating pasture or enclosures; the animal reinfects itself by grazing on contaminated grass.

Young rhinoceroses, with less developed immunity, are more vulnerable than adults. Overcrowding in an enclosure or reserve, high humidity, poor pasture rotation, and chronic stress (transport, environmental change, concurrent illness) promote parasite accumulation. Unbalanced nutrition or immunosuppression—for instance related to age or another disease—also increases the risk.

Transmission

Infection occurs through ingestion: the animal takes in infective larvae present on grass or in water contaminated by infected feces. There is no direct transmission between animals without passage through the environment.

Diagnosis and care

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

Treatment

Treatment uses antiparasitic drugs (dewormers) chosen by the veterinarian according to the type of parasite identified. Nutritional support and rehydration may be necessary in severe cases. Environmental management (cleaning, enclosure rotation) routinely accompanies medical treatment to prevent rapid reinfestation.

Prevention

Possible complications

Heavy untreated infestation can cause severe weight loss, anaemia, dehydration, and general weakness that makes the animal more susceptible to other diseases. In young animals, lasting growth retardation is possible. In extreme cases, intestinal obstruction or digestive perforation may occur, putting the animal's life at risk.

When to see a veterinarian

Prognosis

The prognosis is generally good if the infestation is detected early and treated appropriately. Young animals, elderly animals, or those already weakened by another disease have a more guarded prognosis. Without treatment, a severe infestation can lead to a gradual decline in the animal's overall condition and, in extreme cases, to the animal's death.

Frequently asked questions

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 30 August 2026