What are Pinworms?
Pinworms can live undetected in a rabbit’s colon, cecum, and small intestines, even in large amounts. They are usually only found by the erratic itching behavior they may cause, or the visible worms in feces that can sometimes be seen. The only way to transmit this parasite is through direct contact with the feces of an infected rabbit. Generally, if an infected rabbit lives alone, it probably became infected at the pet store or breeder. It can be contracted at any age, and is a common parasite found worldwide.
Pinworms, or Passalurus ambiguus, are an intestinal parasite that infects only rabbits. While not lethal, they can cause secondary symptoms, such as itching, skin irritation, and intestinal problems, making your rabbit uncomfortable.
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Symptoms of Pinworms in Rabbits
Though many rabbits infested with pinworms will show no visible signs of the infestation, some symptoms to look for include:
- Constant itching
- Biting and scratching of infected areas
- Irritated anus
- Rectal prolapse
- Inflammation and redness in infected areas
- Self-inflicted trauma
- Visible small white worms near anus or in feces
- Poor weight gain
- Slow growth
- Decrease in activity
- Increase in stickiness of feces
- Coat in poor condition
- Lack of appetite
- Diarrhea and enteritis around the time of weaning
- General poor body condition
Causes of Pinworms in Rabbits
A pinworm infestation is caused by the ingestion of pinworm eggs, usually by way of your rabbit eating the feces of an infected rabbit. After ingestion of pinworm eggs, the larvae can begin to hatch after only 30 hours. The eggs can remain active and in the environment for years, even at room temperature. Rabbits with diminished immunity may be more susceptible to pinworm infestation.
Infestation can occur from:
- Ingestion of pinworm contaminated feces
- Ingestion of pinworm contaminated food, water or debris
- Ingestion of pinworm eggs
Diagnosis of Pinworms in Rabbits
After a physical exam, and taking into consideration any symptoms that may be present, your veterinarian may suspect a pinworm infestation. A sample of your rabbit’s feces will then be tested by a microscopic smear, fecal float test, or centrifuge technique to determine the presence of eggs. Eggs can sometimes be collected by pressing clear tape to the skin near the anus. Adult pinworms, which can range from 2-11 mm in length, may also be visible near the anus of your rabbit, or directly in its feces.
Treatment of Pinworms in Rabbits
Fatal cases of pinworms in rabbits are very rare, and treatment is easy to obtain. Treatment can prove difficult, however, because rabbits are coprophagic, meaning they eat their own feces, thus re-infestation can easily occur. A common occurrence among rabbits is the ingestion of night pellets, or cecotropes, nutrient dense pellets that come from the cecum and are essential for your rabbit’s health. The time of day this occurs varies, and is often out of sight of caregivers. Either type of pellet ingestion can cause a re-infestation. Therefore, treatment of the rabbit and its environment must occur simultaneously.
Antiparasitic drugs are usually prescribed, and can often be dosed by adding to food or water. These may include piperazine dosed in water, fenbendazole dosed in food, or ivermectin as a topical treatment. The treatment regimen may need to be repeated to completely eradicate all pinworms and their eggs. Some antiparasitic drugs can be toxic to some of the new breeds of rabbits, or run the risk of altered reproduction and behavior in treated animals, so discuss these issues with your veterinarian if they are a concern.
Then, to prevent reinfection, all the areas in which your rabbit lives, plays and roams need to be diligently cleaned. By keeping up with this cleaning, and eliminating all eggs present in your rabbit’s environment, re-infestation can be prevented, and the elimination of the pinworm infestation in your rabbit can be successful.
If any secondary symptoms are causing malnourishment or digestive complaints, an altered diet may be suggested, or assisted care to get your rabbit back to a healthy state may be administered. Pinworms in rabbits are species specific, and are not transmittable to humans.
Recovery of Pinworms in Rabbits
Keeping your rabbit’s environment clean and sanitary is the best chance to avoid re-infestation and ensure a complete recovery. If your rabbit shares any spaces with other rabbits, make sure to have them tested as well, as they have likely been infested too. Diets high in fiber have been known to reduce pinworm populations. An altered diet may also be prescribed to help with any secondary symptoms.