Editing DDT (section)

===Alternatives===

====Insecticides====
{{Main|Indoor residual spraying}}
[[Organophosphate]] and [[carbamate]] insecticides, e.g. [[malathion]] and [[bendiocarb]], respectively, are more expensive than DDT per kilogram and are applied at roughly the same dosage. [[Pyrethroid]]s such as [[deltamethrin]] are also more expensive than DDT, but are applied more sparingly (0.02–0.3&nbsp;g/m<sup>2</sup> vs 1–2&nbsp;g/m<sup>2</sup>), so the net cost per house per treatment is about the same.<ref name="AmJTrop"/> DDT has one of the longest residual efficacy periods of any IRS insecticide, lasting 6 to 12 months. Pyrethroids will remain active for only 4 to 6 months, and organophosphates and carbamates remain active for 2 to 6 months. In many malaria-endemic countries, malaria transmission occurs year-round, meaning that the high expense of conducting a spray campaign (including hiring spray operators, procuring insecticides, and conducting pre-spray outreach campaigns to encourage people to be home and to accept the intervention) will need to occur multiple times per year for these shorter-lasting insecticides.<ref>{{Cite web|url=https://apps.who.int/iris/bitstream/handle/10665/69386/WHO_HTM_MAL_2006.1112_eng.pdf?sequence=1|title=Indoor Residual Spraying|date=2019|website=World Health Organization|access-date=March 14, 2019|archive-date=July 29, 2020|archive-url=https://web.archive.org/web/20200729031424/https://apps.who.int/iris/bitstream/handle/10665/69386/WHO_HTM_MAL_2006.1112_eng.pdf?sequence=1|url-status=live}}</ref>

In 2019, the related compound difluorodiphenyltrichloroethane ([[DFDT]]) was described as a potentially more effective and therefore potentially safer alternative to DDT.<ref>{{cite journal |last1=Zhu |first1=Xiaolong |last2=Hu |first2=Chunhua T. |last3=Yang |first3=Jingxiang |last4=Joyce |first4=Leo A. |last5=Qiu |first5=Mengdi |last6=Ward |first6=Michael D. |last7=Kahr |first7=Bart |title=Manipulating Solid Forms of Contact Insecticides for Infectious Disease Prevention |journal=Journal of the American Chemical Society |volume=141 |issue=42 |pages=16858–16864 |date=11 October 2019 |doi=10.1021/jacs.9b08125|pmid=31601104 |bibcode=2019JAChS.14116858Z |s2cid=204244148 }}</ref><ref name="NYT 17 October 2019">{{cite news |last1=Chang |first1=Kenneth |title=A Nazi Version of DDT Was Forgotten. Could It Help Fight Malaria? |url=https://www.nytimes.com/2019/10/17/science/nazi-ddt-malaria.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2019/10/17/science/nazi-ddt-malaria.html |archive-date=2022-01-01 |url-access=limited |access-date=18 October 2019 |work=The New York Times |date=17 October 2019}}{{cbignore}}</ref>

====Non-chemical vector control====
Before DDT, malaria was successfully eliminated or curtailed in several tropical areas by removing or poisoning mosquito breeding grounds and larva habitats, for example by eliminating standing water. These methods have seen little application in Africa for more than half a century.<ref>{{cite journal | vauthors = Killeen GF, Fillinger U, Kiche I, Gouagna LC, Knols BG | title = Eradication of Anopheles gambiae from Brazil: lessons for malaria control in Africa? | journal = The Lancet. Infectious Diseases | volume = 2 | issue = 10 | pages = 618–627 | date = October 2002 | pmid = 12383612 | doi = 10.1016/S1473-3099(02)00397-3 }}</ref> According to CDC, such methods are not practical in Africa because "''Anopheles gambiae'', one of the primary vectors of malaria in Africa, breeds in numerous small pools of water that form due to rainfall&nbsp;... It is difficult, if not impossible, to predict when and where the breeding sites will form, and to find and treat them before the adults emerge."<ref>{{cite web |url=https://www.cdc.gov/malaria/malaria_worldwide/reduction/vector_control.html |title=Malaria Worldwide – How Can Malaria Cases and Deaths Be Reduced? – Larval Control and Other Vector Control Interventions |website=CDC.gov |date=January 29, 2019 |access-date=September 9, 2017 |archive-date=July 9, 2017 |archive-url=https://web.archive.org/web/20170709190523/https://www.cdc.gov/malaria/malaria_worldwide/reduction/vector_control.html |url-status=live }}</ref>

The relative effectiveness of IRS versus other malaria control techniques (e.g. bednets or prompt access to anti-malarial drugs) varies and is dependent on local conditions.<ref name="AmJTrop"/>

A WHO study released in January 2008 found that mass distribution of insecticide-treated mosquito nets and [[artemisinin]]–based drugs cut malaria deaths in half in malaria-burdened Rwanda and Ethiopia. IRS with DDT did not play an important role in mortality reduction in these countries.<ref>"[https://web.archive.org/web/20080215004936/http://www.who.int/malaria/docs/ReportGFImpactMalaria.pdf Impact of long-lasting insecticidal-treated nets (LLINs) and artemisinin-based combination therapies (ACTs) measured using surveillance data in four African countries]".  World Health Organization, January 31, 2008.</ref><ref>[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/02/01/MN4EUPS3D.DTL&type=health Malaria deaths halved in Rwanda and Ethiopia Better drugs, mosquito nets are the crucial tools] {{Webarchive|url=https://web.archive.org/web/20080210024708/http://www.sfgate.com/cgi-bin/article.cgi?f=%2Fc%2Fa%2F2008%2F02%2F01%2FMN4EUPS3D.DTL&type=health |date=February 10, 2008 }}, David Brown (Washington Post), ''SF Chronicle'', A-12, February 1, 2008.</ref>

[[Vietnam]] has enjoyed declining malaria cases and a 97% mortality reduction after switching in 1991 from a poorly funded DDT-based campaign to a program based on prompt treatment, bednets and pyrethroid group insecticides.<ref>"[http://www.afronets.org/files/malaria.pdf World Health Organization, A story to be shared: The successful fight against malaria in Vietnam]", November 6, 2000. {{webarchive |url=https://web.archive.org/web/20080226224853/http://www.afronets.org/files/malaria.pdf |date=February 26, 2008 }}</ref>

In Mexico, effective and affordable chemical and non-chemical strategies were so successful that the Mexican DDT manufacturing plant ceased production due to lack of demand.<ref name="PMC1119118">{{cite web |url=http://www.ipen.org/ipenweb/documents/work%20documents/ddt_ipenreport_english.pdf |title=DDT & Malaria |access-date=March 11, 2009 |archive-url=https://web.archive.org/web/20110726185356/http://www.ipen.org/ipenweb/documents/work%20documents/ddt_ipenreport_english.pdf |archive-date=July 26, 2011 |url-status=dead |df=mdy }}</ref>

A review of fourteen studies in sub-Saharan Africa, covering insecticide-treated nets, residual spraying, chemoprophylaxis for children, chemoprophylaxis or intermittent treatment for pregnant women, a hypothetical vaccine and changing front–line drug treatment, found decision making limited by the lack of information on the costs and effects of many interventions, the small number of cost-effectiveness analyses, the lack of evidence on the costs and effects of packages of measures and the problems in generalizing or comparing studies that relate to specific settings and use different methodologies and outcome measures. The two cost-effectiveness estimates of DDT residual spraying examined were not found to provide an accurate estimate of the cost-effectiveness of DDT spraying; the resulting estimates may not be good predictors of cost-effectiveness in current programs.<ref>{{cite journal | vauthors = Goodman CA, Mills AJ | title = The evidence base on the cost-effectiveness of malaria control measures in Africa | journal = Health Policy and Planning | volume = 14 | issue = 4 | pages = 301–312 | date = December 1999 | pmid = 10787646 | doi = 10.1093/heapol/14.4.301 | doi-access = free }}</ref>

However, a study in Thailand found the cost per malaria case prevented of DDT spraying ([[United States dollar|US$]]1.87) to be 21% greater than the cost per case prevented of [[lambda-cyhalothrin]]–treated nets (US$1.54),<ref>{{cite journal | vauthors = Kamolratanakul P, Butraporn P, Prasittisuk M, Prasittisuk C, Indaratna K | title = Cost-effectiveness and sustainability of lambdacyhalothrin-treated mosquito nets in comparison to DDT spraying for malaria control in western Thailand | journal = The American Journal of Tropical Medicine and Hygiene | volume = 65 | issue = 4 | pages = 279–284 | date = October 2001 | pmid = 11693869 | doi = 10.4269/ajtmh.2001.65.279 | doi-access = free }}</ref> casting some doubt on the assumption that DDT was the most cost-effective measure. The director of Mexico's malaria control program found similar results, declaring that it was 25% cheaper for Mexico to spray a house with synthetic pyrethroids than with DDT.<ref name="PMC1119118"/> However, another study in South Africa found generally lower costs for DDT spraying than for impregnated nets.<ref>{{cite journal | vauthors = Goodman CA, Mnzava AE, Dlamini SS, Sharp BL, Mthembu DJ, Gumede JK | title = Comparison of the cost and cost-effectiveness of insecticide-treated bednets and residual house-spraying in KwaZulu-Natal, South Africa | journal = Tropical Medicine & International Health | volume = 6 | issue = 4 | pages = 280–295 | date = April 2001 | pmid = 11348519 | doi = 10.1046/j.1365-3156.2001.00700.x | s2cid = 28103584 | doi-access = free }}</ref>

A more comprehensive approach to measuring the cost-effectiveness or efficacy of malarial control would not only measure the cost in dollars, as well as the number of people saved, but would also consider ecological damage and negative human health impacts. One preliminary study found that it is likely that the detriment to human health approaches or exceeds the beneficial reductions in malarial cases, except perhaps in epidemics. It is similar to the earlier study regarding estimated theoretical infant mortality caused by DDT and subject to the criticism also mentioned earlier.<ref>{{cite journal |url=http://www.jcu.edu.au/jrtph/vol/v04corin.pdf |vauthors=Corin SE, Weaver SA |year=2005 |title=A risk analysis model with an ecological perspective on DDT and malaria control in South Africa |journal=Journal of Rural and Tropical Public Health |volume=4 |issue=4 |pages=21–32 |access-date=January 30, 2006 |archive-date=March 6, 2006 |archive-url=https://web.archive.org/web/20060306003634/http://www.jcu.edu.au/jrtph/vol/v04corin.pdf |url-status=live }}</ref>

A study in the [[Solomon Islands]] found that "although impregnated bed nets cannot entirely replace DDT spraying without substantial increase in incidence, their use permits reduced DDT spraying".<ref>{{cite journal | vauthors = Over M, Bakote'e B, Velayudhan R, Wilikai P, Graves PM | title = Impregnated nets or DDT residual spraying? Field effectiveness of malaria prevention techniques in solomon islands, 1993–1999 | journal = The American Journal of Tropical Medicine and Hygiene | volume = 71 | issue = 2 Suppl | pages = 214–223 | date = August 2004 | pmid = 15331840 | doi = 10.4269/ajtmh.2004.71.214 | doi-access = free }}</ref>

A comparison of four successful programs against malaria in Brazil, India, Eritrea and Vietnam does not endorse any single strategy but instead states, "Common success factors included conducive country conditions, a targeted technical approach using a package of effective tools, data-driven decision-making, active leadership at all levels of government, involvement of communities, decentralized implementation and control of finances, skilled technical and managerial capacity at national and sub-national levels, hands-on technical and programmatic support from partner agencies, and sufficient and flexible financing."<ref>{{cite journal | vauthors = Barat LM | title = Four malaria success stories: how malaria burden was successfully reduced in Brazil, Eritrea, India, and Vietnam | journal = The American Journal of Tropical Medicine and Hygiene | volume = 74 | issue = 1 | pages = 12–16 | date = January 2006 | pmid = 16407339 | doi = 10.4269/ajtmh.2006.74.12 | doi-access = free }}</ref>

DDT resistant mosquitoes may be susceptible to pyrethroids in some countries. However, pyrethroid resistance in ''Anopheles'' mosquitoes is on the rise with resistant mosquitoes found in multiple countries.<ref>{{cite journal | vauthors = Mint Mohamed Lemine A, Ould Lemrabott MA, Niang EH, Basco LK, Bogreau H, Faye O, Ould Mohamed Salem Boukhary A | title = Pyrethroid resistance in the major malaria vector Anopheles arabiensis in Nouakchott, Mauritania | journal = Parasites & Vectors | volume = 11 | issue = 1 | pages = 344 | date = June 2018 | pmid = 29895314 | pmc = 5998517 | doi = 10.1186/s13071-018-2923-4 | doi-access = free }}</ref>