Porcine teschoviruses are widely distributed in pig, the disease was initially observed in Czecho Slovakia in 1929, this porcine teschovirus disease is also known as Teschen disease, Talfan disease, Porcine encephalomyelitis, Porcine poliomyelitis.Teschen disease virus was previously classified as enterovirus In 1979. Until 2000, the sequences were aligned and compared.Teschovirus to divided from enterovirus to become a new genus. In 2000, our institute studied a clinical case from a pig farm in Nantou district, this case turned out to be infected by serotype PTV-1; we will do serological surveillance test by VN (virus neutralization) test and ELISA test. Also we try to Identify of the PTV agent by virus isolation and RT-PCR. And try to reconstruct the evolutionary past based on the levels of sequence homology. By comparing sequences of Taiwanese isolates with the others, we may know epidemiology of porcine teschovirus in Taiwan. We will chose 3 months old pig PTV-negative by serum test, the challenge achieve via the oral or nasal cavities. Then sacrifice according to schedule. We will observe gross lesions and collect the specimens, especially from brain, spinal cord, intestines for Histopathology, serology, Isolation of virus, inmunohistochemistry (IHC), RT-PCR. We may know the Pathogenesis of porcine teschovirus, and compared with what is already known. In an area, such as Taiwan with high incidence, vaccine should be an important means for the control of this infection. In development for PTV vaccine, we will Chose suitable PTV-1 strains and pass in the PK-15 cell to obtain attenuated virus, verify virus titer and test efficacy of vaccine.