In their paper published in the latest issue of Journal of Swine Health and Productivity, S.R. Baker of St Paul, Minnesota and co–authors from Boehringer Ingelheim Vetmedica, Inc. in St Joseph and Pipestone Veterinary Clinic in Pipestone, Minnesota, explain that their objective was to evaluate the ability of a needle-free injection device (NFID) to prevent haematogenous transmission of PRRSV.

They used 88 five–week–old gilts from a PRRSV-negative source, organised into five groups and individually housed by group in isolation rooms (four replicate trials, 22 pigs per trial). On day 0, pigs in Group 1 (PRRSV source population) were inoculated with PRRSV isolate MN-184, and pigs in Group 4 (sham-inoculated group) were inoculated with virus-free medium. On days 4, 5 and 6 post–inoculation, each pig in Groups 1, 2 and 3 was vaccinated with a Mycoplasma hyopneumoniae bacterin using the needle-syringe and the NFID. First, a needle-syringe and NFID were both used to vaccinate pigs in Group 1, and then the same needle–syringe and NFID were used to vaccinate pigs in Group 2 (needle–syringe) and Group 3 (NFID), respectively.

On day 11, the researchers report that all pigs in Group 2 tested positive for PRRSV RNA, suggesting that transmission of PRRSV had occurred between Groups 1 and 2 by repeated use of the same needle. On day 21, all pigs in one replicate of Group 3 tested positive for PRRSV RNA, suggesting that transmission of PRRSV had occurred between Groups 1 and 3 by repeated use of the same NFID.

Under the conditions of this study, haematogenous transmission of PRRSV can occur from infected pigs to susceptible pigs via repeated use of the same needle, concluded Baker and co-authors, and use of NFIDs does not prevent haematogenous transmission of PRRSV.

Reference

Baker S.R., E. Mondaca, D. Polson, and S.A. Dee. 2012. Evaluation of a needle-free injection device to prevent hematogenous transmission of porcine reproductive and respiratory syndrome virus. J. Swine Health Prod. 20(3):123–128.

Further Reading

-

You can view the full report by clicking here.

Further Reading

-

Find out more information on porcine reproductive respiratory syndrome (PRRS) by clicking here.

May 2012