page_title: Indoor residual spraying
section_title: Residents' opposition to IRS
hierarchical_section_title: Indoor residual spraying / Residents' opposition to IRS
caption_attribution_description: English: The walls of a bathroom on the shores of Lake Victoria, Tanzania, have been sprayed with DDT. Mosquitoes landing on the walls remain there until they die and fall down, instead of flying off to possibly infect people with malaria.
context_page_description: Indoor residual spraying or IRS is the process of spraying the inside of dwellings with an insecticide to kill mosquitoes that spread malaria. A dilute solution of insecticide is sprayed on the inside walls of certain types of dwellings—those with walls made from porous materials such as mud or wood but not plaster as in city dwellings. Mosquitoes are killed or repelled by the spray, preventing the transmission of the disease. In 2008, 44 countries employed IRS as a malaria control strategy. Several pesticides have historically been used for IRS, the first and most well-known being DDT.
context_section_description: For IRS to be effective, at least 80% of homes and barns in an area must be sprayed, and if enough residents refuse spraying, the effectiveness of the whole program can be jeopardized. Many residents resist spraying of DDT in particular. This is due to a variety of factors, including its smell and the stains it leaves on the walls.
  While that stain makes it easier to check whether the room has been sprayed, it causes some villagers to resist the spraying of their homes or to resurface the wall, which eliminates the residual insecticidal effect. Pyrethroid insecticides are reportedly more acceptable since they do not leave visible residues on the walls.
  In addition, DDT is not suitable for this type of spraying in Western-style plastered or painted walls, only traditional dwellings with unpainted walls made of mud, sticks, dung, thatch, clay, or cement. As rural areas of South Africa become more prosperous, there is a shift towards Western style housing, leaving fewer homes suitable for DDT spraying, and necessitating the use of alternative insecticides.
  Other villagers object to DDT spraying because it does not kill cockroaches or bedbugs; rather, it excites such pests making them more active, so that often the use of another insecticide is additionally required. Pyrethroids such as deltamethrin and lambdacyhalothrin, on the other hand, are more acceptable to residents because they kill these nuisance insects as well as mosquitoes. DDT has also been known to kill beneficial insects, such as wasps that kill caterpillars that, unchecked, destroy thatched roofs.
  As a result, Mozambique's chief of infectious disease control, Avertino Barreto, says that resistance to DDT spraying is "homegrown", not due to "pressure from environmentalists". "They only want us to use DDT on poor, rural black people," he says. "So whoever suggests DDT use, I say, 'Fine, I'll start spraying in your house first.'"
caption: Walls on IRS-treated bathroom on the shores of Lake Victoria. The mosquitoes remain on the wall until they fall down dead on the floor.
exif: {"Image ImageDescription": "", "Image Make": "SONY", "Image Model": "DSC-HX100V", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "PaintShop Photo Pro 13,00", "Image DateTime": "2012:10:09 00:35:43", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "286", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "986", "Thumbnail JPEGInterchangeFormatLength": "6119", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/30", "EXIF FNumber": "14/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2012:08:26 06:32:04", "EXIF DateTimeDigitized": "2012:08:26 06:32:04", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "1", "EXIF BrightnessValue": "517/1280", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash fired, auto mode, return light detected", "EXIF FocalLength": "24/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3933", "EXIF ExifImageLength": "2937", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "844", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal"}