Teschen disease is a viral disease caused by a the highly virulent strain of the virus of of the Picornaviridae family from the Enterovirus genus, serotype 1 (PEV1). The virus causes a virulent manifestation of porcine polioencephalomyelitis with a high morbidity and high mortality.
In addition further porcine enteroviruses from the serotype 1 cause porcine polioencephalomyelitis, including Talfan virus and begign enzootic paresis which cause a milder, more sporadic and less contagious disease. There are 11 serotypes of porcine enterovirus potentially causing encephalomyelitis (PEV 1-7 and PEV 11-13) and, recently, they have been grouped under enterovirus encephalomyelitis.
Classification
OIE List B disease
Susceptible species
Pigs
Distribution
Central and Eastern Europe, Madagascar and Uganda have the highly virulent strain of PEV1 (Teschen disease).
Talfan disease is more widely distributed, it is present in Australia as well as PEV2, PEV5 and PEV8. Some forms of the disease were suspected in the Cooks Islands and in Wallis and Futuna.
Clinical signs
The highly virulent strain of PEV1 (Teschen disease) can occur in pigs of all ages, with the highest incidence in piglets up to 3 months.
Symptoms include:
The lower virulent viruses cause a milder disease. They usually affect piglets and do not cause a total paralysis.
Post-mortem findings
No characteristic gross lesions. Histologically, lesions are confined to the central nervous system.
Differential diagnosis
Specimens required for diagnosis
For virus identification a range of samples from brain and spinal cord from pigs that have just died or been killed for post-mortem. Both fresh and preserved (in solution of equal part of phosphate buffered isotonic saline pH 7.4 and glycerol) samples should be collected. techniques include virus neutralisation and indirect fluorescent antibody test.
Serological diagnosis, based virus neutralisation or ELISA can be performed from serum collected from sick or recumbent animals.
Transmission
The virus is a gut inhabitant. Virus is excreted in faeces and oral secretions. Clinically recovered animals may continue to shed the virus for up to 7 weeks. Virus can survive in the environment for 3 months.
Transmission is made by direct or indirect contact, swill feeding and fomites
Risk of introduction
The disease could be introduced through the importation of infected pigs, or through contaminated product being fed to pigs (swill feeding) or husbandry material. Because of its limited world distribution and lack of imports from these countries, the risk of introducing Teschen disease would appear low. However the risk to introduce other strain of the virus from Australia must be subject to a risk analysis.
Control / vaccines
Live attenuated and inactivated vaccines are effective in controlling the disease. Quarantine and hygienic measures should be applied.
Swills should be sterilised before fed to pigs.
References
GEERING WA, FORMAN AJ, NUNN MJ, Exotic Diseases of Animals, Aust Gov Publishing Service, Canberra, 1995, p. 189-192
DERBYSHIRE JB (1999), Enterovirus, In Diseases of Swine, Iowa state University Press, Ames, Iowa, USA, p. 145-150
Office International des Epizooties, 2002
Porcine Enteroviral Encephalomyelitis, In Merck Veterinary Manual, National Publishing Inc. Eight ed, 1998, Philadelphia, p 963-964
Viral Encephalomyelitis of Pigs, In Veterinary Medicine, Saunders, Eight ed, 1997, London p. 1103-1105