Tutorial 3: Interventions

This tutorial adds two interventions that represent a standard malaria control package: treatment-seeking care and insecticide-treated nets (ITNs). It introduces the campaign file and shows how to compare scenarios with and without interventions.

File: tutorials/tutorial_3_interventions.py

The campaign file

The campaign file defines what interventions to distribute, to whom, and when. In emodpy-malaria a build_campaign() function constructs this file and is passed to EMODTask via campaign_builder=:

task = emod_task.EMODTask.from_default2(
    ...
    campaign_builder=build_campaign,   # previously None
    ...
)

Interventions

build_campaign() adds the two interventions using emodpy-malaria helper functions:

def build_campaign():
    campaign.set_schema(manifest.schema_file)

    if use_treatment_seeking:
        add_treatment_seeking(campaign,
                              start_day=365,
                              targets=[{"trigger": "NewClinicalCase", "coverage": 0.7},
                                       {"trigger": "NewSevereCase",   "coverage": 0.9}])

    if use_itn:
        add_itn_scheduled(campaign,
                          start_day=365,
                          demographic_coverage=0.5,
                          receiving_itn_broadcast_event="Received_ITN")

    return campaign

Treatment seeking covers people who develop new clinical cases (70% coverage) and severe cases (90% coverage). The drug defaults to artemether-lumefantrine, the standard first-line therapy. Both interventions start on day 365, giving the population one year to reach a baseline before any control begins.

ITN distribution distributes insecticide-treated nets to 50% of the population on day 365. receiving_itn_broadcast_event causes EMOD to fire a Received_ITN event for each person who receives a net, which can be used to trigger follow-up events in more complex campaigns.

Comparing scenarios

Two boolean flags at the top of the script control which interventions are active:

use_treatment_seeking = True
use_itn = True

Toggle these and re-run to compare each intervention separately against the no-intervention baseline. Each combination writes to its own output directory:

`use_treatment_seeking`	`use_itn`	Output directory
True	True	`tutorial_3_results`
True	False	`tutorial_3_results_ts`
False	True	`tutorial_3_results_itn`
False	False	`tutorial_3_results_no_interventions`

Plotting with a baseline reference

plot_results() looks for tutorial_2_results/ from the previous tutorial and, if found, uses it as the no-intervention reference (plotted in red) so the intervention impact is visible directly. If you are starting here without having run Tutorial 2, the plot will still work — the reference line simply will not appear.

reference = None
if os.path.exists("tutorial_2_results"):
    t2_files = get_filenames(dir_or_filename="tutorial_2_results",
                             file_prefix="InsetChart", file_extension="json")
    if t2_files:
        reference = t2_files[0]

plot_inset_chart(dir_name=output_path,
                 reference=reference,
                 title="Tutorial 3 - InsetChart",
                 output=output_path)

Treatment seeking reduces the fraction of people infected; ITNs reduce the daily biting rate and vector population. Running each combination separately lets you see each effect in isolation.