Table 2.
Virus Isolation Rates for Plasma Samples as a Function of Fiebig Stages or Viral Load
| Fiebig stage | Pos | Total | % Pos | Viral load | Pos | Total | % Pos |
|---|---|---|---|---|---|---|---|
| I | 2 | 27 | 7.4% | <1,000 | 0 | 20 | 0.0% |
| II/III | 8 | 11 | 72.7% | 1,000–10,000 | 1 | 14 | 7.1% |
| IV | 2 | 7 | 28.6% | 10,000–100,000 | 10 | 21 | 47.6% |
| V | 9 | 15 | 60.0% | 100,000–1,000,000 | 15 | 20 | 75.0% |
| VI | 9 | 20 | 45.0% | >1,000,000 | 4 | 5 | 80.0% |
| Total | 30 | 80 | 37.5% | Total | 30 | 80 | 37.5% |
Most efficient virus isolation was observed for plasma samples at Fiebig stages II and V, although virus could be isolated at each stage. Efficiency of virus isolation went up as viral load increased. Virus isolation was not achieved for samples with viral loads below 1000 copies/ml.