New Method For Diagnosis Of Pestivirus Infections In Swine

Infections in swine with pestiviruses other than CSF virus (CSFV) can give rise to a clinical disease that is indistinguishable from CSF. The rapid and accurate differentiation of CSFV from non-CSFV pestiviruses is decisive because whereas CSFV infection of domestic pigs demands strict control measures to prevent vast economic losses for other pestivirus infections in pigs, no immediate zoo-sanitary measures are prescribed. Since different pestiviruses are closely related, both immunologically and genetically, the ruminant's pestivirus infections in swine can result into a false CSF diagnosis.

Here we describe the development and evaluation of a novel multiplex, highly sensitive and specific RT-PCR for the simultaneous detection and rapid differentiation between CSFV and other pestivirus infections in swine.

The universal and differential detection was based on primers designed to amplify a fragment of the 5' non-coding genome region for the detection of pestiviruses and a fragment of the NS5B gene for the detection of classical swine fever virus. The assay proved to be specific when different pestivirus strains from swine and ruminants were evaluated.

The assay analysis of 30 tissue homogenate samples from naturally infected and non-CSF infected animals and 40 standard serum samples evaluated as part of two European Inter-laboratory Comparison Tests conducted by the European Community Reference Laboratory, Hanover, Germany proved that the multiplex RT-PCR method provides a rapid, highly sensitive, and cost-effective laboratory diagnosis for classical swine fever and other pestivirus infections in swine.

The multiplex RT-PCR assay described here provides a sensitive tool for simultaneous detection and rapid differentiation between CSFV and other pestiviruses infections in swine. The reaction can be performed in a rapid and cost-effective manner. This method could be a good alternative for diagnostic laboratories with limited economic resources probably located in developing nations where CSF outbreaks occur frequently.