Listeriosis

Description

Listeriosis is a bacterial infection caused by Listeria species. It affects a wide range of animals and is also a zoonosis.

References

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

• Occurs in North and East Europe and North America

Outbreaks of listeriosis often linked to silage feeding

Treatment and control

• Ampicillin or amoxycillin in early stages of septicaemic listeriosis
• Sub-conjuntival antibiotics and corticosteroids for ocular listeriosis
• Avoid poor quality silage and discontinue silage-feeding in an outbreak

Causes abortions in cattle and sheep last third of pregnancy. Foetal membranes often retained leading to metritis. The placenta is covered by purulent exudate and there are focal pinpoint yellow lesions in foetal liver.

• Neural listeriosis:
  • Incubation period 14-40 days
  • Meningoencephalitis
  • Dullness, circling, head tilt, facial paralysis, drool saliva, droop of eyelid and ear
  • Exposure keratitis
  • Fever during early stages
  • Recumbency and death within a few days in sheep and goats
  • Abortion up to 12 days after infection in cattle; usually recover but may get septicaemia
• Septicaemic listeriosis:
  • Incubation period 2-3 days
  • Lambs and occasionally pregnant sheep
  • Occurs in newborn piglets, foals, poultry, adult sheep
• Keratoconjunctivitis in cattle and sheep - direct contact with silage via eye
• Pneumonia, myocarditis, enodcarditis
• Zoonosis - consumption of contaminated unpasteurised milk; memingitis and meningoencephalitis; abortion