The threat of insecticide resistance for vector control
The global community experienced a reduction in malaria cases between 2000 and 2015 due to large scale deployment of LLINs (68% of the reduction in malaria cases) and IRS (10% of the reduction in malaria cases). The World Malaria Report of 2019 indicated these gains have stalled. Widespread insecticide resistance in malaria vectors has led to decreased ability of vector control tools to kill malaria mosquitoes. In areas of high pyrethroid resistance, there is mounting evidence that pyrethroid-only LLINs no longer deliver their intended efficacy.
Dengue, Zika, chikungunya and yellow fever viruses account for over 100 million of the global cases of mosquito borne diseases (CDC, 2016). Prevention, especially in epidemics, relies heavily on insecticide-based vector control. Insecticide resistance in Aedes aegypti and Aedes albopictus, the primary vectors of these mosquito borne viral diseases, challenges their control.
Insecticide resistance is the ability of an insect population to withstand or overcome the effects of an insecticide or insecticides. Resistance is determined by standardized insecticide susceptibility tests. The WHO criteria (for Anopheles and Aedes species) defines confirmed resistance as <90% mortality or resistance ratio (RR)>10, possible resistance is 90-97% mortality or 5-9 RR and susceptibility is 98-100% mortality or RR<5.
Up-to-date information on insecticide resistance must be used to guide the deployment of insecticidal tools to ensure the right tools are used in the right place. Malaria and vector borne disease control policy makers, program managers, and researchers have called for a user-friendly approach to consolidating and visualizing up-to-date information on insecticide resistance.
IR Mapper overview
Updated Anopheles map: Now includes additional features for visualizing modelled insecticide resistance layers and resistance intensity point data.
Conceptualize in 2012, IR Mapper is a tool that interactively displays results from standardized insecticide resistance tests (both phenotypic and resistance mechanisms) on Anopheles species, Aedes aegypti and Ae. albopictus generated using WHO or CDC standard test protocols. The Anopheles map displays resistance data on Anopheles species while the Aedes map displays data on Ae. aegypti and Ae. albopictus. Users have an option for visualizing their own data from insecticide susceptibility and resistance mechanisms tests alongside existing published data.
How It Works
IR Mapper Functions
- Display malaria and arboviral disease endemicity layers
- The Anopheles map displays Anopheles gambiae s.l. and funestus s.l. occurrence layers
- The Anopheles map displays modelled resistance layers on gambiae s.l.
- Zoom feature to view additional map details
- Pop-up boxes for each individual point that show assay details and link to the data source e.g., publication
- Option to change between base maps and switch on/off main menus
- Printing of tailored maps
How to View Own Data
Users can view their own data on the map alongside existing published data. The "View Own Data" tab located at the top left offers the following menu:
- Instructions for filling out the user data template.
- Download template function to download a CSV data template file.
- Add my data to upload the saved CSV file containing the user data or drag and drop the file on the application.
- Clear my data to revert to the online dataset.
Note that user data are not stored or added to the database.
We recognize that users may have varied browser preferences. However, for the best experience on IR Mapper, we recommend using Internet Explorer 11 and above, Firefox 28 and above, Chrome, Opera or Safari browsers.
Data are extracted monthly from peer-reviewed scientific publications and other published reports including the President’s Malaria Initiative Country Insecticide Susceptibility Summaries (for Anopheles map) and VectorBase. The Aedes map includes data provided by Professor Hilary Ranson in 2016.
A new menu was added to the Anopheles map that displays modelled resistance layers from Professor Catherine Moyes’ Geospatial Modelling of Insect Vectors (GMIV) group. The layers bridge insecticide resistance data gaps from surveillance data in sub-Saharan Africa and are made using a published geostatistical ensemble model . The mean mortality of Anopheles gambiae s.l. to alphacypermethrin, lambda-cyhalothrin, deltamethrin, permethrin, and DDT are estimated from 2005 to 2017. Probability layers developed by a collaboration between GMIV, LSTM, CHAI, and IR Mapper are also provided to show the likelihood that pyrethroid resistance in Anopheles gambiae s.l. (at district level) exceeds the WHO thresholds for susceptibility, confirmed resistance, or the 10-80% mortality criteria for deployment of piperonyl butoxide-treated nets that mitigate against the effects of metabolic resistance to pyrethroids.
We recognize that An. funestus s.l. is also an important malaria vector in Africa, however, data on An. funestus s.l. were insufficient to produce modelled pyrethroid resistance estimates. In areas where An. funestus s.l. are present, the layers showing resistance in An. gambiae s.l. should be considered alongside data on resistance in An. funestus s.l.
Additionally, the Anopheles map includes a menu that allows for download of analysis ready data. These are a series of geospatial datasets for insecticide resistance in malaria vectors that can be used to quantify insecticide resistance trends in time and space. To request the up-to-date dataset displayed on the site, contact us via firstname.lastname@example.org.
- Moyes CL, Athinya DK, Seethaler T, et al. Evaluating insecticide resistance across African districts to aid malaria control decisions. Proc Natl Acad Sci. August 2020:202006781.
- Hancock, P. A., Hendriks, C., Tangena, J. A., Gibson, H., Hemingway, J., Coleman, M., Gething, P. W., Cameron, E., Bhatt, S., & Moyes, C. L. (2020). Mapping trends in insecticide resistance phenotypes in African malaria vectors. PLoS Biology, 18(6), e3000633.
- Weiss, D. J., Lucas, T. C., Nguyen, M., Nandi, A. K., Bisanzio, D., Battle, K. E., ... & Gibson, H. S. (2019). Mapping the global prevalence, incidence, and mortality of Plasmodium falciparum, 2000–17: a spatial and temporal modelling study. The Lancet, 394(10195), 322-331.
- Battle, K. E., Lucas, T. C., Nguyen, M., Howes, R. E., Nandi, A. K., Twohig, K. A., ... & Gibson, H. S. (2019). Mapping the global endemicity and clinical burden of Plasmodium vivax, 2000–17: a spatial and temporal modelling study. The Lancet, 394(10195), 332-343.
- Messina, J. P., Kraemer, M. U., Brady, O. J., Pigott, D. M., Shearer, F. M., Weiss, D. J., ... & Brownstein, J. S. (2016). Mapping global environmental suitability for Zika virus. Elife, 5, e15272.
- Bhatt, S., Gething, P. W., Brady, O. J., Messina, J. P., Farlow, A. W., Moyes, C. L., ... & Myers, M. F. (2013). The global distribution and burden of dengue. Nature, 496(7446), 504-507.
- Nsoesie, E. O., Kraemer, M. U., Golding, N., Pigott, D. M., Brady, O. J., Moyes, C. L., ... & Hay, S. I. (2016). Global distribution and environmental suitability for chikungunya virus, 1952 to 2015. Eurosurveillance, 21(20), 30234.
IR Mapper is a joint initiative. Data collection and collation is performed by Vestergaard, data proofreading is conducted by KEMRI-CGHR and the interactive map platform was developed by ESRI Eastern Africa (collectively “IR Mapper”).
Disclaimer: Data provided by the IR Mapper application is to the best of IR Mapper’s knowledge correct and true. However, the data has been produced by using, and in reliance on, information furnished by third parties and such information has not been independently validated, verified or confirmed by IR Mapper. Thus, IR Mapper makes no representation or warranty (express or implied) to any User of this website in relation to the data, and IR Mapper’s expressly disclaims any liability whatsoever (whether in contract, tort or otherwise) to any User. If published data appear to be missing or there are errors, kindly contact us with further information.
Data and maps from the IR Mapper application may not be used for any commercial purpose whatsoever without IR Mapper’s prior express written approval for each use. If such data and maps are to be used for non-commercial purposes (including without being limited to publications), the following citation shall be conspicuously provided by User of the IR Mapper application: