Theiler's Disease 
Clinical signs
Fever
Ataxia
Diarrhea
Icteric
Weight loss
Photosensitisation
Anorexia
Respiratory distress
Lethargy
Clotting abnormalities
Neurologic signs
Central blindness
Aggression
Post-mortem findings
Diagnosis
Differential diagnosis
Prevention
Treatment - not specific
Icterus
Ascites
Pale and enlarged liver 
Bile duct proliferation
Mottled and bile-stained liver
History
Clinical signs
Complete blood count (CBC) and chemistry panel
Ultrasonographic examination
Pyrrolizidine toxicosis
Hepatotoxins
Acute infectious hepatitis
Acute mycotoxicosis
Cerebral disease
Hemolytic disease.
Fluid therapy (IV crystalloid fluids with glucose and potassium)
Minimize stress
Administer B vitamins intravenously slowly and vitamin E orally
Pentoxifylline 10 mg/kg PO or IV
Nontoxic bactericidal antibiotic
Mannitol, 0.5 to 1.0 g/kg,
4 to 8 mg/kg neomycin sulfate orally q8h mixed in molasses
Restricted TAT to situations necessitating tetanus prophylaxis
Routine administration of TAT to parturient mares is strongly discouraged
Liver biopsy
Any equine biological products must be screened for any possible diseases
Epidemiology
Outcomes
Acute hepatitis
Liver failure
Other names
Acute hepatitis necrosis
Idiopathic acute hepatitis disease ( IAHD)
Postvaccinal hepatitis
Serum-associated hepatitis
Serum sickness
Etiology
Equine parvovirus-hepatitis (EqPV-H)
After receiving an equine origin biologic agent
come into contact with a horse that has received TAT
‘Theiler’s disease-associated virus’ (TDAV); Genus: Pegivirus
Colic signs
References
Conditions of the liver, spleen and pancreas. (2014). Knottenbelt and Pascoe’s Color Atlas of Diseases and Disorders of the Horse, 84–104. doi:10.1016/b978-0-7234-3660-7.00002-x
Sturgeon, B. (2017). Theiler’s disease. Veterinary Record, 180(1), 14–15. doi:10.1136/vr.j8
Divers, T. J. (2014). Liver Failure, Anemia, and Blood Transfusion. Equine Emergencies, 268–288. doi:10.1016/b978-1-4557-0892-5.00020-9
Hepatoencephalopathy (head pressing)
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Pathophysiology
virus both circulates in the serum and has trophism for the live
administration of serum/biologic products
antigen-antibody reactions may attempt to clear the virus causing an immune-related apoptosis and necrosis of hepatocyte
clinical signs of acute hepatic failure appears after 60% of functional mass is destroyed
Other horses with TDAV infection may not have any biochemical or clinical effects from the virus and some may become healthy persistent carriers
Time course
Recovered horses do not have chronic liver disease
die of hepatic failure or gradually recover over 5-10 day
4-10 weeks after equine biologic administration
onset of liver disease 1-7 days