Calculator
Example data table
| Parameter | Example value | Notes |
|---|---|---|
| Eclipse period | 6 hours | Intracellular replication becomes detectable. |
| Latent period | 12 hours | First extracellular release begins. |
| Release duration | 2 hours | Time to complete one production cycle. |
| Burst size | 100 virions/cell | Average released virions per infected cell. |
| Initial infected cells | 1,000 | Starting infected cell count. |
| Infection efficiency | 20% | Fraction of virions initiating new infections. |
| Target cumulative virions | 1×109 | Stop simulation when the total reaches this value. |
Formula used
How to use this calculator
- Choose multi-cycle for spread, or single-cycle for one burst.
- Select the time unit, then enter eclipse, latent, and release.
- Enter burst size and initial infected cells from your scenario.
- Set infection efficiency to reflect successful new infections.
- Enter the target cumulative virions and a max cycle cap.
- Press Calculate to view summary results and the cycle table.
- Use CSV or PDF to export values for documentation.
Replication timing concepts
Viral replication time is described as a sequence of intracellular and extracellular stages. The eclipse period is the interval after entry when new genome copies and proteins accumulate, but infectious particles are not yet released. The latent period ends at first detectable release. For planning, one production cycle is approximated as latent time plus the active release duration.
Key inputs and measurement sources
Eclipse and latent values are commonly estimated from time‑of‑addition experiments, qPCR growth curves, immunostaining time series, or one‑step growth assays at controlled multiplicity of infection. Burst size is calculated as total released particles divided by infected cells, often using plaque assays, TCID50, or particle counts. Infection efficiency summarizes how many released virions initiate new infections under the same temperature, cell line, and medium constraints.
Interpreting cycle-by-cycle outputs
Each simulated cycle reports virions produced, cumulative output, and a next infected‑cell estimate. With burst size B and efficiency η, the model uses Vk=Ik×B and Ik+1=Vk×η. Time is reported at the end of the cycle, enabling comparisons against targets such as 107, 109, or a lab‑specific detection threshold. If η is low, growth stalls quickly and the target may not be reached within the maximum cycles.
Sensitivity and uncertainty handling
Replication timing is typically most sensitive to the cycle length because total time scales linearly with cycles. Burst size and η act multiplicatively, so small percentage shifts can change the cycle count by whole integers. When parameter estimates vary, run low, central, and high scenarios and report ranges for total time and cumulative release. Document sampling intervals, assay limits, and whether values reflect intracellular particles, extracellular particles, or infectious units.
Practical reporting and export workflow
Use single‑cycle mode to summarize a one‑burst experiment, then switch to multi‑cycle mode to explore propagation under assumed re‑infection conditions. Record unit choices and keep eclipse less than or equal to latent. Export CSV for spreadsheet auditing and PDF for stakeholder review. In reports, include strain, cell line, incubation temperature, and any antiviral exposure, because these factors shift both timing and burst size materially.
FAQs
1) What does the calculator mean by replication time?
It estimates time needed to accumulate released virions over one or more cycles, using latent time plus release duration as a simplified cycle length.
2) Why is eclipse period shown if it does not change cycle length?
Eclipse helps interpret early intracellular events and assay timing. It provides context within the latent phase, even when cycle length is summarized as latent plus release.
3) How should I choose infection efficiency?
Set it to the fraction of released virions that successfully start new infections in your setup. Use conservative values when target cells are limited or antiviral pressure is present.
4) What is the difference between particle count and infectious units?
Particle counts include noninfectious virions, while infectious units represent functional infections measured by plaque or TCID50 assays. Keep burst size and targets consistent with the measurement type.
5) Why might the target not be reached?
Low efficiency, small burst size, short max cycles, or declining infected cells can prevent growth. Increase max cycles or adjust assumptions, and report that the scenario does not meet the target.
6) Is this suitable for clinical prediction?
No. It is a planning and education model that ignores immunity, spatial limits, and host dynamics. Use it for comparative scenarios and document assumptions clearly.