Diseases / List of Bacterial Diseases / Disease description:

Listeriosis in Waterfowl and Lagomorphs (with notes on Hedgehogs, Bears and Ferrets)









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General and References

Disease Summary

GENERAL Listeria monocytogenes is pathogenic in many animal species, particularly ruminants. Abortion, encephaltitis, and septicaemia may occur in this disease in animals; however, in humans, meningitis is commonly seen. (B614.8.w8)
WATERFOWL Occasional, acute or chronic disease with nervous or septicaemic/diarrhoeal signs, usually in neonates/juveniles.
  • Rabbits: An uncommon septicaemic disease that is characterised by chronic cachexia, abortion, or sudden death. Listeriosis in rabbits is usually only seen in stressed or pregnant animals. (B614.8.w8)
  • Hares: Septicaemia and uterine infections have been described in Lepus europaeus - Brown hare and Lepus timidus - Mountain hare. (B209.28.w28h)
FERRETS Listeriosis is a mildly infectious, but fatal disease.

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Alternative Names (Synonyms)

  • Listeric infection
  • Circling disease
  • Listeria monocytogenes Infection

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Disease Type

 Bacterial Infection

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Infectious/Non-Infectious Agent associated with the Disease

Listeria monocytogenes, (possibly other Listeria spp.)
  • Bacterium monocytogenes is a synonym of Listeria monocytogenes. (B614.8.w8)
Pathogenesis of Listeria monocytogenes
  • Listeria organisms are ingested by the host and enter the gastrointestinal tract where they penetrate the epithelial cells. They are then taken up by macrophages and enter the systemic circulation. (B614.8.w8)
  • The bacteria can then spread to the uterus and there may also be meningeal penetration. (B603.4.w4)
  • Multiplication of this organism is primarily intracellular and is helped by the production of haemolysin. Haemolysin is thought to be important for virulence because the non-haemolytic variants of Listeria monocytogenes are non-pathogenic. (B614.8.w8)
  • Listeria monocytogenes is a facultative intracellular pathogen so the host's cell-mediated immune response plays a more important role in protection than the humoral response. (B614.8.w8)
  • Listeria monocytogenes is a Gram-positive, non-spore-forming rod that is motile at room temperature. This and its haemolytic characteristics separate it from other bacteria. (B627.14.w14, J4.195.w5)

Infective "Taxa"

Non-infective agents


Physical agents

Indirect / Secondary

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Disease Author

Debra Bourne MA VetMB PhD MRCVS (V.w5); Nikki Fox BVSc MRCVS (V.w103); Gracia Vila-Garcia DVM, MSc, MRCVS (V.w67), Bridget Fry BSc, RVN (V.w143)
Click image for main Reference Section


John Chitty BVetMed CertZooMed MRCVS (V.w65); Aidan Raftery MVB CertZooMed CBiol MIBiol MRCVS (V.w122)

Major References / Reviews

Code and Title List

B11.40.w8, B13.33.w4, B16.19.w1, B32.14.w21, B47, B48.15.w15, B220

In Hedgehogs:

In Bears:

In Lagomorphs:
B209.28.w28h, B601.11.w11, B603.1.w1, B603.3.w3, B603.4.w4, B603.5.w5, B606.13.w13, B611.9.w9, B614.8.w8

In Ferrets:

B627.14.w14, B631.28.w28
.173.w4, J4.195.w5

Other References

Code and Title List


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Clinical Characteristics and Pathology

Detailed Clinical and Pathological Characteristics


Keratoconjunctivitis, abortion, septicaemia, meningoencephalitis. (B47)
WATERFOWL Acute disease or chronic wasting, with nervous signs.
LAGOMORPHS Nervous system disease is rare in rabbits in contrast to listeriosis in cattle. Liver disease and reproductive disorders are more likely to be seen in lagomorphs. 

Clinical Characteristics

  • Chronic wasting, nervous signs: torticollis, muscular spasms; the disease may have a very short time course in juveniles (few hours from first signs to death) (B11.40.w8, B16.19.w1, B48.15.w15).
  • Emaciation and diarrhoea are seen with septicaemic form in birds in general. In the encephalitic form, nervous signs (e.g. depression, incoordination, ataxia, torticollis, opisthotonus) are seen (B32.14.w21).
  • In geese, death occurred within a few hours of the first signs in downies two to three weeks old, while six to eight week old goslings showed nervous signs including spasms and torticollis for a longer period; walking in circles has also been reported from a goose (J5.2.w2).
BEARS Variable clinical signs reported in Ursus arctos - Brown bear [signs not specified]. (B336.51.w51)
LAGOMORPHS In rabbits: non-specific clinical signs of listeriosis include:
  • Sudden death in acute cases. (B603.4.w4, B614.8.w8)
  • Anorexia, depression and weight loss in chronic cases. (B603.4.w4, B614.8.w8)
  • Lethargy (B603.4.w4)
  • Ascites (B603.1.w1)
  • Abortion or vaginal discharge in pregnant females. (B601.11.w11, B603.4.w4, B614.8.w8)
  • Infertility (B601.11.w11)

Note: central nervous system lesions are rare in rabbits (B601.11.w11, B603.4.w4) but the following clinical signs may be seen: 

  • Rolling and torticollis may occur if the bacteria cause a brain stem meningoencephalitis. (B603.3.w3, B606.13.w13, J15.28.w1)
  • Other neurological signs that may occur include:
    • Hind limb paresis (B603.3.w3)
    • Quadriparesis / plegia (B603.1.w1)
    • Seizures (B603.1.w1)

Other possible clinical findings seen in rabbits:

  • Jaundice (B603.1.w1)

In hares:

FERRETS Clinical signs have not been described for ferrets, but are thought to be the same as other species. (B627.14.w14)

Ferrets can often carry and transmit the organism without showing clinical signs. (J4.173.w4)

  • This disease can cause abortion. (J4.173.w4)
  • Septicaemia. (B627.14.w14)
  • Central nervous signs. (B627.14.w14)



Mortality / Morbidity

WATERFOWL Usually sporadic; variable mortality in flock outbreaks (B48.15.w15).
LAGOMORPHS This is a rare disease of rabbits. (B603.4.w4)
  • Rarely reported; the prevalence in ferrets is unknown. B631.28.w28
  • When it occurs, often a fatal disease. (B627.14.w14)


WATERFOWL In birds in general, septicaemia with focal hepatic necrosis and/or myocardial necrosis, sometimes localized encephalitis (J5.2.w2)

N.B. there may be no gross lesions in the encephalitic form/acute disease.

Gross Pathology:


  • Brain - congestion; occasionally in the cerebellum and medulla oblongata, perivascular cuffing and focal necrosis surrounded by polymorphs and lymphocytes;
  • Liver - focal necrosis;
  • Spleen - focal necrosis;
  • Heart - connective tissue fibres and a slight cellular infiltration around a homogeneous faintly staining substance.

(J5.2.w2, B13.33.w4, B16.19.w1, B32.14.w21)

Gross pathology reported in rabbits
  • General:  
    • Peritoneal fluid accumulation. (B603.4.w4)
    • Congestion and ecchymoses of viscera. (B603.4.w4)
  • Liver: 
    • Pin-point ("miliary"), pale grey, foci are seen throughout the parenchyma of the liver. (B603.4.w4, B614.8.w8)
  • Spleen:
    • Pin-point ("miliary"), pale grey, foci are sometimes also seen in this organ. (B603.4.w4, B614.8.w8)
  • Adrenal glands:
    • Pin-point pale grey foci are sometimes also seen in this organ. (B614.8.w8)
  • Uterus: 
    • Fibrinous exudate of the serosal surface. (B603.4.w4)
    • Congestion and ecchymoses. (B603.4.w4)
  • Lymph nodes: 
    • Oedema of mesenteric and cervical lymph nodes. (B603.4.w4)
Histopathology reported in rabbits
  • Focal necrosis of the liver and sometimes also the spleen and/or the adrenal glands.
    • The pin-point pale foci seen on gross pathology are necrotic areas that are surrounded by inflammatory cells, mostly neutrophils. (B614.8.w8)
    • Gram-positive bacteria are easily identifiable adjacent to and within the necrotic lesions. (B614.8.w8)
  • Uterus:  necrotising acute suppurative metritis in pregnant does; dead fetuses may also be present. (B603.4.w4, B614.8.w8)
  • Brain stem meningoencephalitis, however, this is rare. (B603.4.w4, B606.13.w13)
In hares
  • Granulomatous hepatosplenomegaly.
  • Macerated fetuses in the uterus in several hares.



Not described. Likely to be CNS lesions or lesions associated with septicaemia. In a ferret with hyperadrenocorticism, pneumonia and hepatitis were attributed to the concurrent Listeria monocytogenes infection. (B627.14.w14)

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Human Health Considerations

  • Zoonotic risk (B32.14.w21, B48.15.w15, B627.14.w14, P1.1997.w11).
  • Pregnant women should not work with ferrets. (J4.195.w5)

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Susceptibility / Transmission

General information on Susceptibility / Transmission

  • Susceptibility: Neonates/young birds may be particularly susceptible. Overcrowding and stress may predispose (B11.40.w8, B32.14.w21, B48.15.w15).
  • Transmitted: by ingestion, inhalation or wound contamination, probably from infected faeces, water and soil (B32.14.w21, B48.15.w15).
  • Listeria monocytogenes is widely distributed in soil, vegetation and faeces. (B47)
  • Based on experimental infection, rabbits [presumably ] appear to be more susceptible than Lepus europaeus - Brown hare. (B58.27.w27)
  • This disease is most likely to be seen in small breeding units of rabbits, but is rarely seen in pet rabbits and large colonies. (B603.4.w4)

Immunosuppression is usually a factor in the development of disease:

  • Pregnancy
    • Pregnant does are more susceptible to listeriosis; one study demonstrated the development of severe disease in pregnant does that were challenged with this organism, whereas this development did not occur in the non-pregnant females and males. The increased susceptibility may be partly due to the physiological stress of pregnancy and partly due to the favourable environment that the pregnant uterus provides for the replication of Listeria organisms. Colonisation of the female reproductive tract is thought to occur readily; Listeria organisms can be isolated from the vagina and uterus even when exposure has occurred by another route. (B614.8.w8)
    • In hares, pregnancy appears to increase susceptibility. Six of nine wild Lepus europaeus - Brown hare in Germany diagnosed with listeriosis were post-abortion or contained macerated fetuses. (J77.112.w1)
  • Stress
    • Stressed animals are reported to be more susceptible to listeriosis. In an outbreak reported in 1926, stress was thought to have been a factor in the development of disease because the affected rabbits were young and not receiving adequate amounts of food and the diet was also of poor quality. (B614.8.w8)
  • Concurrent disease (B603.4.w4)
  • Poor nutrition (B603.4.w4)
Listeriosis is acquired from the external environment rather than being transmissible from animal to animal. (B209.28.w28h)
  • Ingestion: Listeria organisms are a frequent contaminant of food. Once exposed, animals may become asymptomatic carriers shedding bacteria in the faeces. (B603.4.w4, B614.8.w8)
  • Inhalation: Listeria organisms may be recovered from the nasal cavity of humans and ruminants. (B614.8.w8)


  • Ferrets receiving steroid therapy may be immunosuppressed and therefore more susceptible to listeriosis. (B627.14.w14)


The presumed transmission routes for ferrets, as for other species are:

  • Ingestion of contaminated food. (B627.14.w14, B631.28.w28)
  • Inhalation via aerosols. (B627.14.w14, B631.28.w28)
  • Note: Asymptomatic ferrets can be carriers and might transfer Listeria monocytogenes to other animals including ferrets. (B627.14.w14)

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Disease has been reported in either the wild or in captivity in:

  • Geese, wild duck (B16.19.w1, B48.15.w15).
  • Ducks in Germany, Hungary, USSR and Ceylon; geese in Germany and France (J5.2.w2).


  • Listeria monocytogenes was isolated from the liver of a sick hedgehog. (J137.111.w1)




  • Listeria monocytogenes has been recovered from a ferret with hyperadrenocorticism. (B627.14.w14)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

(List does not contain all other species groups affected by this infectious agent)

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Disease has been specifically reported in Free-ranging populations of:

Wild duck (B48.15.w15).


Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

Lagomorphs (Lagomorpha - Lagomorphs (Order))

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General Information on Environmental Factors/Events and Seasonality

Listeria monocytogenes is found commonly in temperate areas. Cold and wet conditions may promote infection (B32.14.w21).

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Regions / Countries where the Infectious Agent or Disease has been recorded

Listeria monocytogenes may be found worldwide. Reported in birds on all continents except Antarctica and Africa, including in waterfowl in Europe, former USSR and Ceylon (J5.2.w2, B48.15.w15).

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Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

  • Sweden; most outbreaks in wild birds in general have been in Europe (B48.15.w15)
  • In lagomorphs: various countries of Europe and the former USSR. (B58.27.w27, J77.112.w1)

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General Investigation / Diagnosis

General Information on Investigation / Diagnosis

WATERFOWL Post mortem findings: serofibrinous pericarditis and myocardial necrosis (note: there may not be visible lesions in acute disease). Bacterial isolation (B13.33.w5, B16.19.w1, B48.15.w15).
  • Serological screening techniques including a microagglutination test and an immunofluorescence assay. However, apparently there is a high percentage of normal animals that have positive titres indicating either prior exposure to the organism or a carrier state. (B614.8.w8)
  • Culture of CSF, blood and vaginal exudates, may be useful in the live rabbit. (B611.9.w9, J213.2.w3)
  • Diagnosis in the individual animal is not usually possible and is usually made by culture of Listeria organisms at post mortem examination. (B603.4.w4)
    • Culture from blood, brain and visceral organs. (B611.9.w9)
  • A presumptive diagnosis can be made based on gram-positive organisms being identified in typical lesions. (B614.8.w8)
  • Note: Isolation of Listeria organisms from clinical cases may be difficult and so selective procedures or special enrichment are often necessary. "A cold enrichment technique has been described, and chemicals such as potassium thicyanate, thallous acetate, and nalidixic acid can be added to media to help facilitate isolation". (B614.8.w8)
  • Listeria monocytogenes can be isolated from the central nervous system or infected tissue of symptomatic animals. Cerebral spinal fluid culture can be performed and cold enrichment may help increase sensitivity in isolating the Listeria monocytogenes. (B627.14.w14, B631.28.w28)
  • Other tissues from which the organism has been isolated include the lungs, spleen and pleural fluid. (B627.14.w14, B631.28.w28)
  • Listeria monocytogenes can be distinguished from other diphtheroid bacteria by the following characteristics: a Gram-positive, spore-forming rod, non-motile and haemolytic. (B627.14.w14)
Related Techniques
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Similar Diseases (Differential Diagnosis)

WATERFOWL Other causes of septicaemia and nervous signs. (V.w5, V.w6)
LAGOMORPHS Other causes of focal hepatocellular necrosis:

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Treatment and Control

Specific Medical Treatment

  • In vitro, most antibiotics are reportedly active against Listeriosis monocytogenes apart from cephalosporins; in humans, ampicillin plus an aminoglycoside is thought to be the most effective combination. (B614.8.w8)
WATERFOWL Broad-spectrum antibiotics (B48.15.w15). High dose tetracyclines or parenteral chloromycetin may be effective (B16.19.w1, B32.14.w21).
  • Treatment efficacy is hampered by the intracellular location of this organism. (B209.28.w28h, B614.8.w8)
  • Tetracyclines may be effective in the early stage of disease if ante mortem or colony diagnosis is made. (B209.28.w28h, B603.3.w3)
  • Enrofloxacin is reported to be effective against Listeria monocytogenes. (B603.5.w5)
Related Techniques
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General Nursing and Surgical Techniques

  • Minimal handling is recommended, until rabies is ruled out. (B627.14.w14)
  • Personnel protective clothing should be worn when handling a susceptive case. (J4.195.w5)
Related Techniques
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Preventative Measures

Vaccination WATERFOWL --
LAGOMORPHS Vaccinations have not been used in rabbits, but in ruminants a killed vaccine has been used and reported to be partially effective. (B614.8.w8)
Prophylactic Treatment


Probiotics for the first 14 days in neonates (B11.40.w8)
Related Techniques
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Environmental and Population Control Measures

General Environment Changes, Cleaning and Disinfection


Good general hygiene, minimal stress (B11.40.w8).
  • Good husbandry and nutrition to avoid immunosuppression. (B603.4.w4, B614.8.w8)
  • Only high quality feed should be used (particularly in breeding colonies) because food is a common source of Listeria monocytogenes. (B614.8.w8)
  • Gloves, masks and protective clothing should be worn when handling immunosupressed or infected ferrets. (J4.195.w5)
Population Control Measures WATERFOWL Avoid overcrowding (B11.40.w8).
Isolation, Quarantine and Screening WATERFOWL --
  • Potentially infected ferrets should be isolated from other animals. (B627.14.w14)
Related Techniques
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