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Functionality & Features ‐ Work In Progress
Malaria Threats Map is an online interactive data visualization platform that provides a comprehensive overview of malaria threats worldwide. Users can access data on various factors contributing to malaria risk, including climate, population density, and access to healthcare services. The site offers valuable insights into the distribution of malaria and helps stakeholders identify regions that require targeted interventions. It serves as a valuable tool for researchers, policymakers, and public health professionals in understanding and combating the global malaria burden. The main themes that the platform focuses on are :
- Vector Insecticide Resistance - Vector resistance to the insecticides used for vector control threatens malaria control efforts
- Invasive Vector Species - The spread of certain anopheline vector species and their establishment in new ecosystems poses a threat to malaria control.
- Antimalarial drug efficacy and resistance - Antimalarial drug resistance remains one of the key threats to global malaria control efforts, particularly in the Greater Mekong Subregion
- Parasite pfhrp2/3 gene deletions - Gene deletions among some malaria parasites cause false negative diagnostic test results, complicating case management and control.
The platform is organized into 3 different sections that provides different visualizations of the WHO data as : Maps, Dashboards & Data Download.
Malaria Threats Map application shows visualisations on the various threats to malaria control across the world. The threats are majorly categorised into the 4 below themes :
_NOTE : For each theme, one can view :Interactive Map (with filters), Detailed Drill Down Charts, Time Series Animation. _
This section provides interactive maps with data on insecticide resistance, providing information on the prevalence and distribution of resistance across different vector species. Users can explore trends in insecticide resistance over time and across various geographical regions, aiding in the formulation of targeted intervention strategies.There are 4 map types available
- Insecticide Resistance Status Displays the results of experimental testing(studies) of the biological effectiveness of an insecticide on a vector species across various study sites. The results are categorized as :
- Susceptible - Insecticide is effective and is able to kill >98% of vector population
- Possible - Possibility of insecticide resistance developing as the insecticide is effective in killing only 90-98 % of the population
- Confirmed - Insecticide resistance is confirmed
It is also possible to view charts for each study site that display detailed study results including type of test & mortality rates for each insecticide type.
Uses of insecticide resistance monitoring data
- Inform the selection of appropriate vector control interventions.
- Trigger a change in vector control intervention or insecticide when resistance is detected.
- Guide the introduction of novel or supplementary vector control interventions.
- Inform the development of resistance management strategies in areas where insecticide-based vector control is ongoing.
- Contribute to investigations of unexpected changes in vector-borne disease transmission and disease burden.
- Insecticide Resistance Intensity Displays the result of resistance testing studies that measure the strength of resistance in vector species to insecticides. Resistance intensity is measured by testing the ability of vectors to survive exposure to 5× and 10× a standard discriminating concentration of insecticide.
• Low-intensity resistance: If mosquito mortality (corrected, if necessary) is <90% after exposure to the DC (1×) and ≥98% after exposure to 5× the DC, results indicate low-intensity resistance. In this case, it is not necessary to conduct a bioassay with 10× the DC. • Moderate-intensity resistance: If mosquito mortality (corrected, if necessary) is <90% after exposure to the DC (1×) and <98% after exposure to 5× the DC, results indicate a moderate-intensity resistance. An additional bioassay with 10× the DC should be conducted to determine whether intensity is indeed moderate or high instead. If mortality after exposure to 10× the DC is ≥98%, moderate-intensity resistance is confirmed. • High-intensity resistance: If mosquito mortality (corrected, if necessary) is <90% after exposure to the DC (1×) and <98% after exposure both to 5× and to 10× the DC, results indicate high-intensity resistance.
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Resistance Mechanisms Detection Insecticide resistance in mosquitoes stems from various genetic alterations, enabling survival despite exposure to insecticides used in vector control. These alterations propagate through generations, perpetuating resistance within mosquito populations. While standard bioassays suffice for many programmatic decisions, understanding resistance mechanisms becomes crucial in specific scenarios. Certain mechanisms confer cross-resistance to multiple insecticides, necessitating careful selection of interventions based on identified resistance mechanisms to ensure efficacy.This map displays the results of test conducted to identify whether or not a molecular marker associated with insecticide resistance has been detected in mosquitoes collected on the site.
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Synergist effect in Susceptibility A synergistic effect in susceptibility refers to the combined action of a synergist and an insecticide, enhancing the insecticide's effectiveness against resistant vector populations. Synergist–insecticide bioassays are conducted in mosquito populations resistant to the insecticide that the synergist enhances. When evaluating the synergist's ability to restore susceptibility to the insecticide, mortality in mosquitoes exposed only to the insecticide should be ≥90% for reliable assessment. Interpretation criteria for the effects of the synergist are as follows:
- Full Restoration of Susceptibility: Mortality ≥98% in mosquitoes pre-exposed to synergist and then to insecticide.
- Partial Restoration of Susceptibility:Mortality <98% but at least 10% greater than insecticide-only exposure.
- No Restoration of Susceptibility:Mortality equal to or lower than insecticide-only exposure.
This section contains a vector occurrence map that displays the occurrence of invasive vector species in the study site with a drill down in each site with more details on the types of tests conducted, the species of vectors found, sampling period & method, vector stage & species identification method used for the tests.
Study Results
- Treatment Failure - Displays the results of therapeutic efficacy studies and the percentage of patients with treatment failure at each study site. Additional detailed charts include information on trends across years on treatment failure. {Get more info on significance of 3 dots on the chart}
- Delayed Parasitic Clearance - Displays the results of therapeutic efficacy studies and the percentage of patients with delayed parasitic clearance at each study site.
- Molecular Markers of Drug Resistance - Displays the results of molecular marker studies and the percentage of samples which show molecular mutations. Ongoing & Planned Studies (No Detailed charts)
- Therapeutic efficacy studies - Displays study sites with Planned, Ongoing or Completed Studies
- Molecular marker studies - Displays study sites with Planned, Ongoing or Completed Studies
Study Results - Displays results of hrp2 surveys that indicate if gene deletions have been identified in the sample population tested at the site. There are also additional drill down details available in a chart the displays the type of deletion, number of samples & percentage of confirmed deletions in the sample.
Ongoing & Planned Studies - Displays study sites with Planned, Ongoing or Completed Studies
| Term | Definition |
|---|---|
| bioassay | In applied entomology, experimental testing of the biological effectiveness of a treatment (e.g. insecticide) by deliberately exposing insects to it. |
| insecticide discriminating concentration | The concentration of an insecticide that, when a sample of mosquitoes is exposed to a surface treated with it for a standard period of time,reliably kills susceptible mosquitoes so that any survivors may be assumed to be resistant |
| insecticide resistance | Property of mosquitoes to survive exposure to a standard dose of insecticide; may be the result of physiological or behavioural adaptation |
| resistance intensity | Strength of resistance in mosquitoes to insecticides, resulting from the level of expression of resistance phenotype(s). Resistance intensity is measured by testing the ability of mosquitoes to survive exposure to 5× and 10× a standard |
| discriminating concentration of insecticide | |
| susceptible population | A mosquito population is considered to be susceptible to an insecticide when 98% or more of the mosquitoes in a sample taken from the population die after being exposed to a discriminating concentration of the insecticide |
| synergist | A substance that does not itself have insecticidal properties, but that, when mixed and applied with insecticides of a particular class, considerably enhances their potency by inhibiting an enzyme that normally acts to detoxify the insecticide in the insect |
https://iris.who.int/bitstream/handle/10665/356964/9789240051089-eng.pdf?sequence=1