NADIS Health Bulletin for South West England - Listeriosis

Economic implications

• Less than two per cent clinically involved in an outbreak

• Mortality rate greater than 70 per cent

• In exceptional circumstances may reach 10 per cent in a flock.

Clinical signs

You will detect the following signs of infection:

• Not eating

• Depressed, disoriented

• Propel themselves into corners, into fences, under gates and feed troughs

• Lean against objects

• Profuse salivation

• Food material impacted in the cheek of the affected side

• Drooping ear, deviated muzzle, flaccid lip on the affected side

• Lowered eyelid on the affected side

• Weakness along affected side of body

Diagnosis

Your veterinary surgeon may also consider the other diseases including pregnancy toxaemia; peripheral vestibular lesions (middle ear infections); brain abscesses or gid (coenurosis, tapeworm cyst in the brain) as well as Listeriosis. Diagnosis is based on a thorough veterinary examination.

Treatment

To effectively treat listeriosis requires early detection of the illness and prompt, aggressive antibiotic treatment prescribed by the veterinary practitioner with high doses of antibiotic. Plus:

• Oral propylene glycol to prevent development of a severe energy deficit

• Fresh palatable foods and clean water must always be available

• A topical antibiotic eye ointment should be applied twice daily

Prevention/control

The disease can be kept at bay through adopting the following controls.

• Discard spoiled silage (or feed to cattle)

• Clean feed troughs daily

• Avoid soil/manure contamination of feed troughs from tractor wheels etc.

• Discard refusals

• Clean water troughs regularly

Silage making:

• Use silage additives

• Silage clamps must be rolled continuously

• Silage clamps must be sheeted to prevent entry of air

• Use a block cutter

• Cut across a narrow silage face

• Seal punctures immediately

• Fence against farm stock and vermin