Congenital Tremor

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

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 preventing piglets to find a nipple and then nurse, then mortality can be high. The mortality in a litter or in an outbreak may increase by 3-10% of the normal rate. This problem decreases as affected piglets grow.

It would be hard not 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 causes, two viral agents, one due to a chemical substance and another category for unknown causes. During an infection 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 stage

  • It is not present.

Lactating piglets

  • Nervous symptoms, e.g.  body contractions.
  • Increased mortality in piglets.
  • 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 to 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.



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



  • There is no treatment but a 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 etiology (if identified).

Atlas of pathology

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