We carried out subgroup analyses to explore causes of heterogeneity, grouping by co-interventions (vector control versus no vector control), endemicity level (≤ 5%, 6-39% and ≥ 40%), co-administration of 8-aminoquinoline plus schizonticide drug treatments, and plasmodium species (P. falciparum or P. vivax).
The state of a network under intervention, i.e., a GAP, is determined by the control signal, the state prior to the intervention and the intervention vector.
An intervention vector can be obtained by various methods; in this paper, a control policy using the steady state distribution (SSD) [ 40] is used to obtain u.
World over, malaria control has focused on pharmacological intervention, vector control, curtailing irrational and indiscriminate use of antimalarials, and the development of vaccines.
Various methods have been proposed for deriving control vectors for an effective intervention [ 29, 40]; in this study the SSD algorithm proposed in [ 40] is used to determine an intervention vector.
An intervention vector is defined as u = u 1, u 2, u 3, …, u 2 n, u j ∈ {0, 1} for any j ∈ {1, 2, …, 2 n }, where u j = 1 (or 0) indicates a flipping (or remaining) of the state of a control gene at GAP j.
Malaria was eliminated in North America by the 1950s through several different interventions, including vector control by changes in vector habitat, introduction of new antimalarial medications (such as quinine) for improved treatment, and decreased contact between humans and mosquitoes, in part because of changes in housing conditions (3 ).
The most effective interventions affecting vector indices for multiple diseases were found to be intradomiciliary residual spraying, insecticide-treated materials (especially insecticide-treated nets or curtains), and treatment of larval habitats with biological and chemical methods.
This could be explained at municipality level by heterogeneity of reproductive numbers that would have been very sensitive to local interventions in vector control [ 33].
One way to tackle this complex issue is to study how each intervention affects vector and disease transmission in different locations, says van den Berg.
