Clinical Aspects of Veterinary Listeriosis

Dr. David Larson, DVM, MSIowa State Veterinary Diagnostic Laboratory

Dr. Arach Wilson, DVM, MSUSDA-APHIS-VS, National Center for Animal Health, Pathobiology Laboratory, Special Pathology Services

Irene V. Wesley, DrPHUSDA-ARS-National Animal Disease Center

ListeriaListeria monocytogenesmonocytogenes• All livestock species

• Cattle, sheep, goats

• Three clinical manifestations

Encephalitis

Abortion

Septicemia

Listeriosis cases 2000-2007 ISU Veterinary Diagnostic Lab

0

20

4060

80

100

120

140

Bovine Ovine Camelid Caprine

AbortionBacterial IsoEncephalitisSepticemia

Num

ber o

f Cas

es

Courtesy of Randy Berghefer, ISU

Seasonal Distribution

Wesley et al. 2002. J Vet Diagn Invest.14: 314-321

Diagnostic flow chart

Wesley et al. 2002. Microbial Food Safety In Animal Agriculture pp.233-241

Encephalitis: Clinical Symptoms

• Depressed/disoriented• Head pressing• Circling• Ataxia• Head tilt• Facial paralysis• Facial hypoalgesia• Paresis of jaw muscles

Copyright NADIS 2004

Differential Diagnosis

ListeriosisRabiesThromboembolic meningoencephalitis(TEME) PolioencephalomalaciaTransmissible Spongiform Encephalopathies(TSE)etc.

Methods ComparisonBact Isol Gram (+) IHC (+)

YES 17/25 17 9/17 16/17

NO 8/25 8 3/8 5/8

NO ATTEMPT

13/38 13 6/13 10/13

TOTAL 17/25(68%)

13/38 (34.2%)

31/38 (81.5%)

Johnson et al. 1995. J Vet Diagn Invest 7:223-228

Immunohistochemistry (IHC)Listeria in brain micro-abscess

Johnson et al. 1995. J Vet Diagn Invest 7:223-228

Gram stain of ovine brainstem

Johnson et al. 1995. J Vet Diagn Invest 7:223-228

IHC of Listeria in bovine brainstem

Loeb 2004. J. Vet Med 51: 453-455.

Case Histories

• Clinically healthy carriers!

• Bovine• Sheep• Alpaca

Encephalitis

• No gross lesions in brain• Perviascular cuffing of vessels in brain stem• Microabscesses in the neuropil• Leptomeningitis may be present• Ocular iritis and keratoconjunctivitis RARE

IHC of Listeria in ovine brainstem

Wesley et al. 2002. J. Vet Diagn Invest. 14: 314-321

Septicemia (generalized listeriosis)

Most common in neonatesFeverDepressionEmaciationDiarrheaNystagmusOpisthotonos

Courtesy of Deb Hoyt, ISU

Abortion

•Sporadic or up to 15% of herd

•Usually in last trimester without clinical signs (~280 day gestation-bovine)

•Fetus dies in utero, stillbirths, neonatal deaths

•Dystocia, retained placenta

Conclusion

• Progress since 1926!• Molecular methods complement

diagnostic assays

Acknowledgements

James Fosse, Visual ServicesRandy Berghefer, Computer

SpecialistDeb Hoyt, Medical Technologist

Dr. Amir Hamir, Pathologist