Vector life cycle

The following parameters determine the characteristics of the vector life cycle. Set the vector species to include in the simulation and the feeding, egg-laying, migration, and larval development habits of each using these parameters. The parameters for larval development related to habitat and climate are described in Larval habitat.

Note

Parameters are case-sensitive. For Boolean parameters, set to 1 for true or 0 for false. Minimum, maximum, or default values of “NA” indicate that those values are not applicable for that parameter.

EMOD does not use true defaults; that is, if the dependency relationships indicate that a parameter is required, you must supply a value for it. However, many of the tools used to work with EMOD will use the default values provided below.

JSON format does not permit comments, but you can add “dummy” parameters to add contextual information to your files. Any keys that are not EMOD parameter names will be ignored by the model.

Parameter

Data type

Minimum

Maximum

Default

Description

Example

Adult_Life_Expectancy

float

0

730

10

The number of days an adult mosquito survives. The daily adult mortality rate is 1 / Adult_Life_Expectancy, in absence of vector aging. With Enable_Vector_Aging set to 1, Adult_Life_Expectancy equal to 20 days corresponds to a mean adult female mosquito lifespan of 9-9.5 days in calibrated settings. The senescence formula that EMOD uses was described by Styer, et al <https://www.ncbi.nlm.nih.gov/pubmed/17255238>.

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Adult_Life_Expectancy": 18,
            "Enable_Vector_Aging": 1
        }
    }
}

Anthropophily

float

0

1

1

Mosquito preference for humans over animals, measured as a fraction of blood meals from human hosts. This dimensionless propensity is important in differentiating between mosquito species.

 
{
    "Vector_Species_Params": {
        "aegypti": {
            "Anthropophily": 0.95
        }
    }
}

Cycle_Arrhenius_1

float

0

1.00E+15

4.09E+10

The Arrhenius equation, \(a_1^{-a_2/T}\), with T in degrees Kelvin, parameterizes the mosquito feeding cycle rate. This duration is a decreasing function of temperature. The variable a1 is a temperature-independent scale factor on feeding rate. Temperature_Dependent_Feeding_Cycle must be set to ARRHENIUS_DEPENDENCE.

 
{
    "Temperature_Dependent_Feeding_Cycle": "ARRHENIUS_DEPENDENCE",
    "Vector_Species_Params": {
        "arabiensis": {
            "Cycle_Arrhenius_1": 99,
            "Cycle_Arrhenius_2": 88
        }
    }
}

Cycle_Arrhenius_2

float

0

1.00E+15

7740

The Arrhenius equation, \(a_1^{-a_2/T}\), with T in degrees Kelvin, parameterizes the mosquito feeding cycle rate. This duration is a decreasing function of temperature. The variable a2 is a temperature-independent scale factor on feeding rate. Temperature_Dependent_Feeding_Cycle must be set to ARRHENIUS_DEPENDENCE.

 
{
    "Temperature_Dependent_Feeding_Cycle": "ARRHENIUS_DEPENDENCE",
    "Vector_Species_Params": {
        "arabiensis": {
            "Cycle_Arrhenius_1": 99,
            "Cycle_Arrhenius_2": 88
        }
    }
}

Cycle_Arrhenius_Reduction_Factor

float

0

1

1

The scale factor applied to cycle duration (from oviposition to oviposition) to reduce the duration when primary follicles are at stage II rather than I in the case of newly emerged females. Temperature_Dependent_Feeding_Cycle must be set to ARRHENIUS_DEPENDENCE.

 
{
    "Temperature_Dependent_Feeding_Cycle": "ARRHENIUS_DEPENDENCE",
    "Vector_Species_Params": {
        "funestus": {
            "Cycle_Arrhenius_Reduction_Factor": 0.44
        }
    }
}

Days_Between_Feeds

float

0

730

2

The number of days between female mosquito feeding attempts. In the cohort model, this value is converted to a feeding rate, equal to 1/(value of this parameter), and is used to determine the probability that one of each of the various feeding modes (animal host, human host, indoor, outdoor, etc) occurs. In the individual model, this parameter determines the number of days a vector waits between feeds.

 
{
    "Vector_Species_Params": {
        "gambiae": {
            "Days_Between_Feeds": 3
        }
    }
}

Drought_Egg_Hatch_Delay

float

0

1

0.33

Proportion of regular egg hatching that still occurs when habitat dries up. Enable_Drought_Egg_Hatch_Delay must be set to 1.

 
{
    "Enable_Drought_Egg_Hatch_Delay": 1,
    "Drought_Egg_Hatch_Delay": 0.33
}

Egg_Arrhenius1

float

0

1.00E+10

6.16E+07

The Arrhenius equation, \(a_1^{-a_2/T}\), with T in degrees Kelvin, parameterizes the daily rate of mosquito egg hatching. This duration is a decreasing function of temperature. The variable a1 is a temperature-independent scale factor on hatching rate. Enable_Temperature_Dependent_Egg_Hatching must be set to 1.

 
{
    "Enable_Temperature_Dependent_Egg_Hatching": 1,
    "Egg_Arrhenius1": 61599956,
    "Egg_Arrhenius2": 5754
}

Egg_Arrhenius2

float

0

1.00E+10

5754.03

The Arrhenius equation, \(a_1^{-a_2/T}\), with T in degrees Kelvin, parameterizes the daily rate of mosquito egg hatching. This duration is a decreasing function of temperature. The variable a2 is a temperature-dependent scale factor on hatching rate. Enable_Temperature_Dependent_Egg_Hatching must be set to 1.

 
{
    "Enable_Temperature_Dependent_Egg_Hatching": 1,
    "Egg_Arrhenius1": 61599956,
    "Egg_Arrhenius2": 5754
}

Egg_Batch_Size

float

0

10000

100

Number of eggs laid by one female mosquito that has fed successfully. The value of Egg_Batch_Size is used for both the number of female eggs and for the number of male eggs. For example, the default value of 100 means that there are 100 female eggs and 100 male eggs.

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Egg_Batch_Size": 100
        }
    }
}

Egg_Hatch_Delay_Distribution

enum

NA

NA

NO_DELAY

The distribution of the delay from oviposition to egg hatching. Possible values are:

NO_DELAY

No delay between oviposition and egg hatching.

EXPONENTIAL_DISTRIBUTION

There is a delay that follows an exponential distribution. Set the mean delay in Mean_Egg_Hatch_Delay.

 
{
    "Egg_Hatch_Delay_Distribution": "EXPONENTIAL_DISTRIBUTION",
    "Mean_Egg_Hatch_Delay": 2
}

Egg_Hatch_Density_Dependence

enum

NA

NA

NO_DENSITY_DEPENDENCE

The effect of larval density on egg hatching rate. Possible values are:

DENSITY_DEPENDENCE

Egg hatching is reduced when the habitat is nearing its carrying capacity.

NO_DENSITY_DEPENDENCE

Egg hatching is not dependent upon larval density.

 
{
    "Egg_Hatch_Density_Dependence": "NO_DENSITY_DEPENDENCE"
}

Egg_Saturation_At_Oviposition

enum

NA

NA

NO_SATURATION

If laying all eggs from ovipositing females would overflow the larval habitat capacity on a given day, the means by which the viable eggs become saturated. Possible values are:

NO_SATURATION

Egg number does not saturate; all eggs are laid.

SATURATION_AT_OVIPOSITION

Eggs are saturated at oviposition; habitat is filled to capacity and excess eggs are discarded.

SIGMOIDAL_SATURATION

Eggs are saturated along a sigmoidal curve; proportionately fewer eggs are laid depending on how oversubscribed the habitat would be.

 
{
    "Egg_Saturation_At_Oviposition": "SATURATION_AT_OVIPOSITION"
}

Enable_Egg_Mortality

boolean

0

1

0

Controls whether or not to include a daily mortality rate on the egg population, which is independent of climatic factors.

 
{
    "Enable_Egg_Mortality": 1
}

Enable_Temperature_Dependent_Egg_Hatching

boolean

0

1

0

Controls whether or not temperature has an effect on egg hatching, defined by Egg_Arrhenius_1 and Egg_Arrhenius_2.

 
{
    "Enable_Temperature_Dependent_Egg_Hatching": 1,
    "Egg_Arrhenius1": 61599956.864,
    "Egg_Arrhenius2": 5754.033
}

Enable_Vector_Aging

boolean

0

1

0

Controls whether or not vectors senesce as they get older. When enabled, the daily mortality rate (1/Adult_Life_Expectancy) is modified by environmental conditions such as dry heat, feeding on humans, etc. With vector aging enabled, Adult_Life_Expectancy equal to 20 days corresponds to a mean adult female mosquito lifespan of 9-9.5 days in calibrated settings. The senescence formula that EMOD uses was described by Styer, et al <https://www.ncbi.nlm.nih.gov/pubmed/17255238>.

 
{
    "Enable_Vector_Aging": 1,
    "Adult_Life_Expectancy": 20
}

Enable_Vector_Mortality

boolean

0

1

1

Controls whether or not vectors can die. Vector_Sampling_Type must be set to TRACK_ALL_VECTORS.

 
{
    "Vector_Sampling_Type": "TRACK_ALL_VECTORS",
    "Enable_Vector_Mortality": 1
}

Human_Feeding_Mortality

float

0

1

0.1

The fraction of mosquitoes, for all species, that die while feeding on a human.

 
{
    "Human_Feeding_Mortality": 0.15
}

Immature_Duration

float

0

730

2

The number of days for larvae to develop into adult mosquitoes. The value is used to calculate mosquito development rate, which equals 1 / (value of this parameter). Development from immature to adult is not dependent on temperature.

 
{
    "Vector_Species_Params": {
        "funestus": {
            "Immature_Duration": 4
        }
    }
}

Indoor_Feeding_Fraction

float

0

1

1

The fraction (dimensionless) of feeds in which mosquitoes feed on humans indoors; the fraction of feeds on humans that occur outdoors equals 1 - (value of this parameter).

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Acquire_Modifier": 0.2,
            "Adult_Life_Expectancy": 10,
            "Anthropophily": 0.95,
            "Aquatic_Arrhenius_1": 84200000000,
            "Aquatic_Arrhenius_2": 8328,
            "Aquatic_Mortality_Rate": 0.1,
            "Cycle_Arrhenius_1": 0,
            "Cycle_Arrhenius_2": 0,
            "Cycle_Arrhenius_Reduction_Factor": 0,
            "Days_Between_Feeds": 3,
            "Egg_Batch_Size": 100,
            "Immature_Duration": 4,
            "Indoor_Feeding_Fraction": 0.5,
            "Infected_Arrhenius_1": 117000000000,
            "Infected_Arrhenius_2": 8336,
            "Infected_Egg_Batch_Factor": 0.8,
            "Infectious_Human_Feed_Mortality_Factor": 1.5,
            "Larval_Habitat_Types": {
                "TEMPORARY_RAINFALL": 11250000000
            },
            "Nighttime_Feeding_Fraction": 1,
            "Transmission_Rate": 0.5
        }
    }
}

Infected_Egg_Batch_Factor

float

0

10

0.8

The dimensionless factor used to modify mosquito egg batch size in order to account for reduced fertility effects arising due to infection (e.g. when females undergo sporogony).

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Acquire_Modifier": 0.2,
            "Adult_Life_Expectancy": 10,
            "Anthropophily": 0.95,
            "Aquatic_Arrhenius_1": 84200000000,
            "Aquatic_Arrhenius_2": 8328,
            "Aquatic_Mortality_Rate": 0.1,
            "Cycle_Arrhenius_1": 0,
            "Cycle_Arrhenius_2": 0,
            "Cycle_Arrhenius_Reduction_Factor": 0,
            "Days_Between_Feeds": 3,
            "Egg_Batch_Size": 100,
            "Immature_Duration": 4,
            "Indoor_Feeding_Fraction": 0.5,
            "Infected_Arrhenius_1": 117000000000,
            "Infected_Arrhenius_2": 8336,
            "Infected_Egg_Batch_Factor": 0.8,
            "Infectious_Human_Feed_Mortality_Factor": 1.5,
            "Larval_Habitat_Types": {
                "TEMPORARY_RAINFALL": 11250000000
            },
            "Nighttime_Feeding_Fraction": 1,
            "Transmission_Rate": 0.5
        }
    }
}

Larval_Density_Dependence

enum

NA

NA

UNIFORM_WHEN_OVERPOPULATION

The functional form of mortality and growth delay for mosquito larvae based on population density. Possible values are:

UNIFORM_WHEN_OVERPOPULATION

Mortality is uniformly applied to all larvae when the population exceeds the specified carrying capacity for that habitat.

GRADUAL_INSTAR_SPECIFIC

Mortality and delayed growth are instar-specific, where the younger larvae are more susceptible to predation and competition from older larvae.

LARVAL_AGE_DENSITY_DEPENDENT_MORTALITY_ONLY

Mortality is based only on larval age.

DENSITY_DELAYED_GROWTH_NOT_MORTALITY

There is no mortality, only delayed growth in larvae.

NO_DENSITY_DEPENDENCE

There is no additional larval density-dependent mortality factor.

 
{
    "Larval_Density_Dependence": "GRADUAL_INSTAR_SPECIFIC"
}

Larval_Density_Mortality_Offset

float

0.0001

1000

0.1

An offset factor in the formula determining the larval-age-dependent mortality for the GRADUAL_INSTAR_SPECIFIC and LARVAL_AGE_DENSITY_DEPENDENT_MORTALITY_ONLY models.

 
{
    "Larval_Density_Mortality_Offset": 0.001
}

Larval_Density_Mortality_Scalar

float

0.01

1000

10

A scale factor in the formula determining the larval-age-dependent mortality for the GRADUAL_INSTAR_SPECIFIC and LARVAL_AGE_DENSITY_DEPENDENT_MORTALITY_ONLY models.

 
{
    "Larval_Density_Mortality_Scalar": 1.0
}

Mean_Egg_Hatch_Delay

float

0

120

0

The mean delay in egg hatch time, in days, from the time of oviposition. Set the delay distribution with Egg_Hatch_Delay_Distribution.

 
{
    "Egg_Hatch_Delay_Distribution": "EXPONENTIAL_DURATION",
    "Mean_Egg_Hatch_Delay": 2
}

Nighttime_Feeding_Fraction

float

0

1

1

The fraction of feeds on humans (for a specific mosquito species) that occur during the nighttime. Thus the fraction of feeds on humans that occur during the day equals 1 - (value of this parameter).

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Acquire_Modifier": 0.2,
            "Adult_Life_Expectancy": 10,
            "Anthropophily": 0.95,
            "Aquatic_Arrhenius_1": 84200000000,
            "Aquatic_Arrhenius_2": 8328,
            "Aquatic_Mortality_Rate": 0.1,
            "Cycle_Arrhenius_1": 0,
            "Cycle_Arrhenius_2": 0,
            "Cycle_Arrhenius_Reduction_Factor": 0,
            "Days_Between_Feeds": 3,
            "Egg_Batch_Size": 100,
            "Immature_Duration": 4,
            "Indoor_Feeding_Fraction": 0.5,
            "Infected_Arrhenius_1": 117000000000,
            "Infected_Arrhenius_2": 8336,
            "Infected_Egg_Batch_Factor": 0.8,
            "Infectious_Human_Feed_Mortality_Factor": 1.5,
            "Larval_Habitat_Types": {
                "TEMPORARY_RAINFALL": 11250000000
            },
            "Nighttime_Feeding_Fraction": 1,
            "Transmission_Rate": 0.5
        }
    }
}

Temperature_Dependent_Feeding_Cycle

enum

NA

NA

NO_TEMPERATURE_DEPENDENCE

The effect of temperature on the duration between blood feeds. Possible values are:

NO_TEMPERATURE_DEPENDENCE

No relation to temperature; days between feeds will be constant and specified by Days_Between_Feeds for each species.

ARRHENIUS_DEPENDENCE

Use the Arrhenius equation with parameters Cycle_Arrhenius_1 and Cycle_Arrhenius_2.

BOUNDED_DEPENDENCE

Use an equation bounded at 10 days at 15C and use Days_Between_Feeds to set the duration at 30C.

 
{
    "Temperature_Dependent_Feeding_Cycle": "BOUNDED_DEPENDENCE"
}

Vector_Migration_Food_Modifier

float

0

3.40E+38

0

The preference of a vector to migrate toward a node currently occupied by humans, independent of the number of humans in the node. Used only when Vector_Sampling_Type is set to TRACK_ALL_VECTORS. Enable_Vector_Migration must be set to 1.

 
{
    "Vector_Migration_Food_Modifier": 1.0
}

Vector_Migration_Modifier_Equation

enum

NA

NA

LINEAR

The functional form of vector migration modifiers. Enable_Vector_Migration must be set to 1. Possible values are: LINEAR EXPONENTIAL

 
{
    "Vector_Migration_Modifier_Equation": "EXPONENTIAL"
}

Vector_Migration_Stay_Put_Modifier

float

0

3.40E+38

0

The preference of a vector to remain in its current node rather than migrate to another node. Used only when Vector_Sampling_Type is set to TRACK_ALL_VECTORS. Enable_Vector_Migration must be set to 1.

 
{
    "Vector_Migration_Stay_Put_Modifier": 1.0
}

Vector_Species_Names

array of strings

NA

NA

[]

An array of vector species names for all species that are present in the simulation. You may provide any species names you desire, but the same names must be used in Vector_Species_Params.

 
{
    "Vector_Species_Names": [
        "arabiensis",
        "funestus",
        "gambiae"
    ]
}

Vector_Species_Params

JSON object

NA

NA

NA

A JSON object that lists each vector species, as defined in Vector_Species_Names, and the parameters that define them.

 
{
    "Vector_Species_Params": {
        "arabiensis": {
            "Acquire_Modifier": 1,
            "Adult_Life_Expectancy": 10,
            "Anthropophily": 0.95,
            "Aquatic_Arrhenius_1": 84200000000,
            "Aquatic_Arrhenius_2": 8328,
            "Aquatic_Mortality_Rate": 0.1,
            "Days_Between_Feeds": 3,
            "Egg_Batch_Size": 100,
            "Immature_Duration": 4,
            "Indoor_Feeding_Fraction": 0.5,
            "Infected_Arrhenius_1": 117000000000,
            "Infected_Arrhenius_2": 8336,
            "Infected_Egg_Batch_Factor": 0.8,
            "Infectious_Human_Feed_Mortality_Factor": 1.5,
            "Larval_Habitat_Types": {
                "TEMPORARY_RAINFALL": 10000000000.0,
                "WATER_VEGETATION": 1000000.0
            },
            "Transmission_Rate": 0.5
        }
    }
}

Vector_Sugar_Feeding_Frequency

enum

NA

NA

VECTOR_SUGAR_FEEDING_NONE

The frequency of sugar feeding by a female mosquito. Used is used in conjunction with the SugarTrap and OvipositionTrap interventions. Vector_Sampling_Type must be set to TRACK_ALL_VECTORS or SAMPLE_IND_VECTORS. Possible values are:

VECTOR_SUGAR_FEEDING_NONE

No sugar feeding.

VECTOR_SUGAR_FEEDING_ON_EMERGENCE_ONLY

Sugar feeding once at emergence.

VECTOR_SUGAR_FEEDING_EVERY_FEED

Sugar feeding occurs once per blood meal.

VECTOR_SUGAR_FEEDING_EVERY_DAY

Sugar feeding occurs every day.

 
{
    "Vector_Sugar_Feeding_Frequency": "VECTOR_SUGAR_FEEDING_NONE"
}