Abstract: To survey the indigenous flies to carry porcine reproductive and respiratory syndrome virus (PRRSV) in the porcine farm, in 2010, the indigenous flies in the Guizhou porcine farm were collected to detect the pathogeny of PRRSV by RT-PCR. The positive indigenous flies were chosen to isolate and cultivate the virus by inoculating in the cells of Marc-145, and the genes of the isolated PRRSV were cloned and analysed by testing the sequences. The findings indicate that the length of the PRRSV N gene fragments in the flies is 377 bp and the cytopathic effects appear in the cells of Marc-145. The cells were inoculated by the PRRSV. The length of the PRRSV Nsp2 gene fragments in the cells is 1064 bp. By analyzing the consequences of the sequences of the PCR products that were cloned, the findings indicate that the fragment of PRRSV Nsp2 gene in the cells that inoculated by the virus of PRRS and in the swine of Guizhou province are similar and the rate of the similarity is 97.1%—98.5%. So the initial inference is that the indigenous flies may be the carriers of PRRSV.

Key words: indigenous fly; porcine reproductive and respiratory syndrome virus (PRRSV); RT-PCR; isolation and identification