Classical swine fever virus in plasma and peripheral blood mononuclear cells of acutely infected swine

The distribution of classical swine fever virus (CSFV) in plasma, monocytes , T and B lymphocytes in peripheral brood was monitored during experimental ly induced acute classical swine fever infection in piglets. Six piglets we re infected with 10(3.8) TCID50 of virus and blood samples taken up to Is d ays postinoculation (p.i.). Infectious virus was detected in monocytes, T a nd B lymphocytes to similar titres in five of the six infected piglets. Inf ectious virus was detected earlier in plasma than in any of the mononuclear cell subpopulations. No significant difference was observed in the period of time in which virus could be isolated from the three cell subpopulations . While a progressive lymphopenia developed, a marked B cell depletion was observed. However, B cells were apparently replaced by non-IgM-bearing mono nuclear cells, as the proportion 'total lymphocyte/total leucocytes' remain ed unaltered throughout the experiment. Virus dues in plasma and peripheral blood mononuclear cells showed a tendency to increase as the disease progr essed to its outcome.