Congenital Tremor

Sporadic disease in which tremors are observed in newborn piglets. They appear at birth and are reduced with age.

Alternative names: Piglets with tremors


This is a sporadic disease seen in newborn piglets. It usually affects more than one piglet per litter. If tremors are so severe they prevent piglets finding a nipple to nurse, then mortality can be high. The mortality in an affected litter or in an outbreak may increase by 3-10% of the normal rate. This problem decreases as the affected piglets grow.

It would be hard to find a farm that throughout its history has not had one or more litters with congenital tremors. Currently 6 different causes are recognized: two are genetic, two viral agents, one due to a chemical substance and another category for unknown causes. In infections cases, few symptoms are observed, probably because an immunity has been established in the population of sows. However in farms with gilts, there may be major outbreaks involving up to 80% of litters during the first farrow. This represents an unquantifiable risk to a farm of gilts.



Sows, transition and fattening stages

  • Not found.

Nursing piglets

  • Nervous symptoms, e.g.  body contractions.
  • Increased mortality.
  • Muscle tremors, which are only observed when piglets walk and not when they sleep.
  • Lack of coordination.
  • Dog sitting posture.


Causes / Contributing Factors

The causes are classified into 4 groups based on the histology of the brain.

  1. Associated with classical swine fever.
  2. Caused by an unknown virus, possibly a circovirus. Most problems in the field are produced by this group.
  3. Associated with hereditary problems observed in breeds like Landrace or Saddleback and organophosphate poisoning.
  4. Toxicosis due to trichlorfon / metrifonate.
  5. Unknown cause.



Diagnoses based on clinical evidence; although histological examination in the laboratory can help differentiate between groups.



  • There is no treatment but careful management can reduce mortality.
  • Ensure that piglets receive colostrum at birth and are helped finding a nipple.
  • Eliminate access to contaminated feed with trichlorfon / metrifonate.
  • Control of infectious cause (if identified).

Atlas of pathology

See images in the Altlas related to Congenital Tremor