LISTERIOSIS

  • Also known as circling disease, meningoencephalitis, silage disease
  • It is an acute infectious disease of man and animals characterised by meningoencephalitis, abortion, endometritis, repeat breeding and septicaemia.

Etiology

  • Causative organism: Listeria monocytogenes
  • It is a G+ve, non capsulated, non spore forming rod.
  • It multiplies in silage
  • Mode of transmission
  • Infection may take place through infected feed, soil or silage.
  • Disease also spreads from carrier animals and rodents
  • Spread through infected faeces, urine, aborted foetus, uterine discharge and milk

Clinical findings

  • Listerial meningoencephalitis-
  • Common in case of adult ruminants
  • Animal become dull and anorectic
  • Dummy syndrome
  • Signs like head pressing, unilateral facial paralysis, somnolence, dropped jaw condition, slow prehension and mastication are seen.
  • Animal behaves as maniac
  • Dropping of ear with head held to one side is seen.
  • Protrusion of tongue and excessive salivation occurs
  • Twitching of facial muscles
  • Animal moves in single direction with deviation of head to one side. So, called circling disease
  • Other signs like keratitis, corneal ulceration, recumbency are seen
  • Death may occur due to respiratory failure
  • Temperature lies within 104-106°F
  • Septicaemic listeriosis
  • Acute septicaemia due to L. Monocytogenes
  • Commonly seen in new born lambs and calves.
  • Animals do not exhibit any nervous symptoms.
  • Signs like depression, weakness, emaciation, pyrexia, diarrhoea, gastroenteritis and mild opisthotonus are seen.
  • When eyes are involved signs like corneal opacity and nystagmus are seen.
  • Animal may die within one week.
  • Listerial abortion
  • Temperature may rise upto 105°F
  • Still birth and outbreak of abortion occurs in cattle
  • Listerial mastitis
  • Udder become hard and painful
  • Watery caseated milk discharges from affected quarter.

Diagnosis

  • From clinical signs and symptoms
  • Isolation of organisms from faeces, urine, milk, aborted foetus and vaginal secretion.
  • Clear in silver impregnation with dark field microscopy.
  • Examination of CSF
  • Culture of infected materials in trypticase soya agar, brain heart infusion agar.
  • Animal inoculation using white mice.
  • Other tests like ELISA, CFT, FAT etc.

Differential diagnosis

  • Rabies
  • Lead poisoning
  • Nervous form of ketosis

Treatment

  • Fluid and supportive therapy
  • Chloramphenicol @20-30 mg per kg bwt OR
  • Sulphadimidine @ 100-150 mg per kg bwt OR
  • Penicillin @ 4400 Iu per kg bwt

Prevention and control

  • Proper disposal of infected material should be done
  • Proper sanitation should be practised
  • Excess silage feeding should be avoided.
  • Feeding low doses of chlortetracyclin powder@ 55gm/quintal of feed can be helpful
  • Live attenuated and recombinant vaccine of Listeriolysin-o are useful in prevention of the disease.