Listeriosis is an infectious disease caused by bacteria of the Listeria genus, most commonly Listeria monocytogenes. In Germany, listeriosis is a notifiable disease, meaning that it must be reported to health authorities when diagnosed.

Transmission/Contagion

It is believed that rabbits primarily become infected with listeriosis through (long-stored) green fodder and other feed. Preventing listeriosis involves providing fresh food to avoid contamination. Listeriosis belongs to sapronoses (decay-based infections) or geonoses (soil-based infections), meaning it is not directly transmitted from animal to animal.

Stress situations can weaken the immune system, making the rabbit more susceptible to infection. Often, rabbits are latent carriers (infected without showing symptoms), and an acute outbreak may occur when their immune system is compromised.

Humans with weakened immune systems, children, and pregnant women are also at risk of contracting listeriosis.

Symptoms

Rabbits affected by listeriosis initially become photophobic (sensitive to light), often seeking dark areas or isolating themselves. Common symptoms include:

  • Loss of appetite or poor food intake
  • Chronic weight loss
  • Fever

If the rabbit has a strong immune system, it may show no symptoms or only the mild ones mentioned above. However, if the immune system is weakened, the pathogen can spread not only into the bloodstream but also into the nervous system and placenta, potentially causing miscarriages.

Neurological symptoms include:

  • Head tilt (torticollis)
  • Paralysis
  • Circling movements
  • Tremors
  • Dizziness

The specific symptoms depend on which organs are affected. Similar to Encephalitozoonosis, listeriosis can impact nearly all organs, including the eyes (e.g., corneal inflammation, conjunctivitis).

Diagnosis

Listeriosis is often not diagnosed because its symptoms are very similar to those of Encephalitozoon cuniculi. Unlike E. cuniculi, however, untreated listeriosis typically leads to sudden death.

A diagnosis can be made through special fecal tests or a blood test. However, this specific test is not included in standard diagnostic procedures and must be specifically requested.

Treatment

Listeriosis can be treated with antibiotics, such as injectable penicillin or tetracyclines. In some cases, an antibiogram may need to be performed to determine the most effective antibiotic.

Additionally, immune-boosting treatments can help support the rabbit’s recovery.

Zinke suggests a homeopathic treatment to support the rabbit, using remedies like Echinacea D30, Lachesis D30, and Engystol. However, it’s important to note that the effectiveness of homeopathic treatments has not been scientifically proven.

In immune-compromised rabbits, the Listeria pathogen can cause head tilt, paralysis, and other neurological symptoms, which is why it is often confused with Encephalitozoon cuniculi (E. cuniculi). Additionally, the weakened immune system can cause both listeriosis and encephalitozoonosis to occur simultaneously.
In such cases, it is crucial to measure the fever. If the temperature is elevated, treatment for listeriosis should begin immediately, as there may not be enough time for prior testing.