Reservoir Transmission Index
Combine explicitly supplied conditional host-vector-host transmission and vector-survival fractions.
Description
A transmission-chain index can combine reservoir infection, vector contact and onward transmission fractions.
A transmission-chain index can combine reservoir infection, vector contact and onward transmission fractions. Conditional probabilities can be multiplied along a chain when their meanings are consistent.
The tool returns transmissionChainFraction (transmission chain fraction). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Reservoir Transmission Index
Use Reservoir Transmission Index when you already have hostToVectorFraction, vectorSurvivalFraction, vectorToNewHostFraction and want transmissionChainFraction. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Reservoir Transmission Index and understand its results
- Enter hostToVectorFraction, vectorSurvivalFraction, vectorToNewHostFraction using the field table below. Match the units, ordering and data boundaries described in the calculation.
- Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
- Read transmissionChainFraction. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
- Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| hostToVectorFraction | Host to vector fraction | number | Required |
| vectorSurvivalFraction | Vector survival fraction | number | Required |
| vectorToNewHostFraction | Vector to new host fraction | number | Required |
Require each supplied fraction to lie between zero and one, inclusive, then multiply the three factors.
index = reservoirFraction × contactFraction × transmissionFraction The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"hostToVectorFraction": 0.5,
"vectorSurvivalFraction": 0.8,
"vectorToNewHostFraction": 0.25
},
"output": {
"transmissionChainFraction": 0.1
}
}Limitations and assumptions
If the inputs are marginal probabilities with dependencies, their product may be inappropriate. No parameters, infection incidence or causal effects are inferred.
Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.
Alternative or Complementary methods
Vectorial Capacity Model: Evaluate the classical vectorial capacity model m·a²·pⁿ/(−ln p) using explicit caller parameters. Climate Envelope Screen: Screen climate observations against a caller-defined suitability envelope, not a transmission prediction.
Methodological background: Deforestation and Vectorial Capacity of Anopheles gambiae Mosquitoes in Malaria Transmission, Kenya.1
References
-
Deforestation and Vectorial Capacity of Anopheles gambiae Mosquitoes in Malaria Transmission, Kenya — Afrane et al.; Emerging Infectious Diseases
Similar or alternative tools
- Vectorial Capacity Model
Evaluate the classical vectorial capacity model m·a²·pⁿ/(−ln p) using explicit caller parameters.
- Climate Envelope Screen
Screen climate observations against a caller-defined suitability envelope, not a transmission prediction.