Determination of reproductive properties of virulent and vaccine classical swine fever virus strains in primary and continuous cell cultures

Classical swine  fever  (CSF) is a highly dangerous porcine disease. CSF outbreaks are annually notified in several countries. Despite the availability of specific prevention tools, the disease spread risk still persists both at country level and at world level. Hence, the disease surveillance and eradication require highly sensitive methods for early diagnosis of the infection and for tests for the virus circulation in the environment.  Development of up-to-date  diagnostic methods is based on well-established  virus cultivation system; therefore, CSF virus reproduction enhancement,  tests of new cell lines without  endogenous  contamination  for their possible use are still of current importance. The said study was aimed at testing of primary and continuous cell cultures for their susceptibility to classical swine fever virus (vaccine virus strains and some field virus isolates recovered in the Russian Federation) and detection of the virus reproduction dynamics with real-time polymerase chain reaction with fluorescent hybridization probes used for detection. Virus replication intensity in primary and continuous cell cultures was also analyzed. The CSF virus was found incapable of replicating in some cell cultures without  its preliminary adaptation.  Primary porcine and lamb testicle cell cultures grown in minimal essential medium supplemented  with 10% normal CSFV-negative porcine serum instead  of fetal bovine serum were shown to be useful for the virus accumulation, both for vaccine strains and field isolates. Cultivation parameters and optimal minimal essential medium composition contributing to the 4–10-fold  increase in the virus accumulation  both in primary and continuous  cell cultures were determined.

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