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Abstract
The Teschen-Talfan disease is also known as “Ansteckende Schweinelähmung”, Teschen disease, polioencephalomyelitis enzootica suum, poliomyelitis suum or porcine enterovirus encephalomyelitis. The disease is caused by certain strains of viruses classified to the family Picornaviridae. Teschoviruses are widely distributed in pigs and wild boars. The disease was initially observed in Czechoslovakia in 1929. The nucleotide and derived amino acid sequences of the RNA-dependent RNA polymerase (RdRp) region, the capsid VP2 region and the 3' non-translated region (3'-NTR) were compared among PTVs and PEVs and with other picornaviruses. The sequences were obtained by RT–PCR and 3'-RACE with primers based on the sequences of Talfan and available porcine enteroviruses (PEVs) strains. Phylogenetic analysis of RdRp/VP2 and analysis of the predicted RNA secondary structure of the 3'-NTR indicated that PEVs should be reclassified genetically into at least three groups, one that should be assigned to PTVs and two PEV subspecies. Comparison of 11 serotypes and analysis of their nucleotide sequences have prompted reclassification of them into a new genus, Teschovirus, within the family Picornaviridae. Teschoviruses specifically infect pigs and are shed in pig feces. Hence, their presence in water should indicate contamination with pig fecal residues. To assess this hypothesis, it is necessary to develop a real-time reverse transcriptase PCR (RT-PCR) method for quantitative detection of pig teschovirus RNA. In 2000, The Animal Health research Institute investigated a clinical case of pig farm in Nantou and the viral isolate was identified as serotype PTV. From the viruses isolated from diseased pigs in various districts of Taiwan in years 2003, 2004 and 2005, it suggests that this disease is distributed widely in Taiwan. In this study, we will perform antibodies detection from serum samples in field farms and identify diseased pigs. Based on the results of serological surveillance and virus isolation, we would know epidemiology of porcine teschovirus in Taiwan. We will design an experimental model to study the pathogenesis of porcine teschovirus. Our final goal is to develop a feasible vaccine to control the disease.
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