Indoor Residual House Spraying Research Articles

Changing malaria fever test positivity among paediatric admissions to Tororo district hospital, Uganda 2012\u20132019

BackgroundThe World Health Organization (WHO) promotes long-lasting insecticidal nets (LLIN) and indoor residual house-spraying (IRS) for malaria control in endemic countries. However, long-term impact data of vector control interventions is rarely measured empirically.MethodsSurveillance data was collected from paediatric admissions at Tororo district hospital for the period January 2012 to December 2019, during which LLIN and IRS campaigns were implemented in the district. Malaria test positivity rate (TPR) among febrile admissions aged 1 month to 14 years was aggregated at baseline and three intervention periods (first LLIN campaign; Bendiocarb IRS; and Actellic IRS + second LLIN campaign) and compared using before-and-after analysis. Interrupted time-series analysis (ITSA) was used to determine the effect of IRS (Bendiocarb + Actellic) with the second LLIN campaign on monthly TPR compared to the combined baseline and first LLIN campaign periods controlling for age, rainfall, type of malaria test performed. The mean and median ages were examined between intervention intervals and as trend since January 2012.ResultsAmong 28,049 febrile admissions between January 2012 and December 2019, TPR decreased from 60% at baseline (January 2012–October 2013) to 31% during the final period of Actellic IRS and LLIN (June 2016–December 2019). Comparing intervention intervals to the baseline TPR (60.3%), TPR was higher during the first LLIN period (67.3%, difference 7.0%; 95% CI 5.2%, 8.8%, p < 0.001), and lower during the Bendiocarb IRS (43.5%, difference − 16.8%; 95% CI − 18.7%, − 14.9%) and Actellic IRS (31.3%, difference − 29.0%; 95% CI − 30.3%, − 27.6%, p < 0.001) periods. ITSA confirmed a significant decrease in the level and trend of TPR during the IRS (Bendicarb + Actellic) with the second LLIN period compared to the pre-IRS (baseline + first LLIN) period. The age of children with positive test results significantly increased with time from a mean of 24 months at baseline to 39 months during the final IRS and LLIN period.ConclusionIRS can have a dramatic impact on hospital paediatric admissions harbouring malaria infection. The sustained expansion of effective vector control leads to an increase in the age of malaria positive febrile paediatric admissions. However, despite large reductions, malaria test-positive admissions continued to be concentrated in children aged under five years. Despite high coverage of IRS and LLIN, these vector control measures failed to interrupt transmission in Tororo district. Using simple, cost-effective hospital surveillance, it is possible to monitor the public health impacts of IRS in combination with LLIN.

New distribution record of Anopheles rivulorum-like from Sadiola, Mali, with notes on malaria vector insecticide resistance.

The SEMOS gold mine in Sadiola, southwestern Mali, has been implementing a malaria vector control programme for 15y using indoor residual house spraying and sporadic larval control. Periodic screening of the vector populations have been carried out over the years to provide information to the control programme, mainly on vector species present and their insecticide resistance status. The data from five entomological surveys, carried out in 2006, 2011, 2014, 2016 and 2018, are presented. Adult mosquitoes were collected resting on walls inside houses and on verandas. Insecticide susceptibility assays were carried out and mosquitoes subsequently identified by species using molecular assays. The major malaria vector mosquitoes, Anopheles gambiae and Anopheles arabiensis were abundant at each sampling period with Anopheles coluzzii and Anopheles funestus being rare or absent. Anopheles rivulorum was identified in 2006 and Anopheles leesoni in 2016. The presence of Anopheles rivulorum-like, identified for the first time in 2018, was not screened for in previous surveys. Insecticide susceptibility bioassays showed resistance in both A. gambiae and A. arabiensis to pyrethroids, carbamates and dichlorodiphenyltrichloroethane over the 12y. This is the first record of A. rivulorum-like west of Côte d'Ivoire. Resistance levels to the three classes of insecticides were variable but appeared to decrease after pyrethroids were discontinued for house spraying.

Progress towards malaria elimination in Zimbabwe with special reference to the period 2003\u20132015

BackgroundAn intensive effort to control malaria in Zimbabwe has produced dramatic reductions in the burden of the disease over the past 13 years. The successes have prompted the Zimbabwe’s National Malaria Control Programme to commit to elimination of malaria. It is critical to analyse the changes in the morbidity trends based on surveillance data, and scrutinize reorientation to strategies for elimination.MethodsThis is a retrospective study of available Ministry of Health surveillance data and programme reports, mostly from 2003 to 2015. Malaria epidemiological data were drawn from the National Health Information System database. Data on available resources, malaria control strategies, morbidity and mortality trends were analysed, and opportunities for Zimbabwe malaria elimination agenda was perused.ResultsWith strong government commitment and partner support, the financial gap for malaria programming shrank by 91.4% from about US$13 million in 2012 to US$1 million in 2015. Vector control comprises indoor residual house spraying (IRS) and long-lasting insecticidal nets, and spray coverage increased from 28% in 2003 to 95% in 2015. Population protected by IRS increased also from 20 to 96% for the same period. In 2009, diagnostics improved from clinical to parasitological confirmation either by rapid diagnostic tests or microscopy. Artemisinin-based combination therapy was used to treat malaria following chloroquine resistance in 2000, and sulfadoxine–pyrimethamine in 2004. In 2003, there were 155 malaria cases per 1000 populations reported from all health facilities throughout the country. The following decade witnessed a substantial decline in cases to only 22 per 1000 populations in 2012. A resurgence was reported in 2013 (29/1000) and 2014 (39/1000), thereafter morbidity declined to 29 cases per 1000 populations, only to the same level as in 2013. Overall, morbidity declined by 81% from 2003 to 2015. Inpatient malaria deaths per 100,000 populations doubled in 4 years, from 2/100,000 to 4/100,000 populations in 2012–2015 respectively. Twenty of the 47 moderate to high burdened districts were upgraded from control to malaria pre-elimination between 2012 and 2015.ConclusionsA significant progress to reduce malaria transmission in Zimbabwe has been made. While a great potential and opportunities to eliminate malaria in the country exist, elimination is not a business as usual approach. Instead, it needs an improved, systematic and new programmatic strategy supported strongly by political will, sustained funding, good leadership, community engagement, and a strong monitoring and evaluation system all year round until the cessation of local transmission.

Paludisme : espoir d’un contrôle efficace en Afrique, vers l’élimination du paludisme

The prevalence and morbidity of P. vivax, P. ovale (curisi et wallikeri) and P. malariae remain underestimated. However important progress has been made. According to the WHO World Malaria report between 2000 and 2015 the malaria incidence has decreased by 42% while the incidence of malaria deaths has decreased by 66%. This is the result of the important progress made in scaling up the main interventions such the rapid diagnosis test, Artemisinin-based combination therapies, long lasting insecticide treated nets, indoor residual house spraying, intermittent preventive treatment during pregnancy (IPTp-SP), Seasonal Malaria Chemoprophylaxis with combined antimalarial (SMClAQ-SP). In the Sahel region with a highly seasonal transmission, the use of SMC resulted in a reduction of malaria morbidity for 80% and a reduce mortality for 58%. Malaria elimination efforts are going on in many countries in Swaziland, South Africa, Namibia, Zanzibar (United Republic of Tanzania), Bioko Island (Equatorial Guinea), Sao Tome and Principe, Cape Verde, and maybe Senegal. For the time being only countries in Northern Africa and few in East Africa (Mauritius) have reached the elimination of local transmission. Despite the progress made near 500,000 malaria deaths occur annually in the African Region with 10-15% leading to disabling sequels and low school performance in children. Reaching the target of 80% for preventive and treatment interventions remain a challenge in many countries in Africa. It's important to keep in mind that the Abuja targets and MGDs were not reached by most African countries. In addition, among 12 million children eligible for SMC only 35% were covered despite the availability of resources in 2014. A huge global stock out of ACT. AQ-SP is possible. The development of an effective vaccine has been disappointing with a limited effectiveness of the RTS,S. The emerging resistance to Artemisinin derivate in South-East Asia and its possible expansion to Africa is of big concern. Anopheles gambiae resistance to pyrethroid make to situation even more complex. The situation can worsen because of factor such as climate change and socio-political crisis. Therefore the malaria situation in Africa is still of big concern despite the progress highlighted. Innovative a robust approach is needed with strong government commitment and partners support to lead battle. A new hope is emerging with the development of candidate vaccine from whole sporozoïte, the other candidates vaccines blocking the transmission in phase 1b and the new SMC Plus strategy (AQ-SP+Azithromycine). Conclusion: lessons learnt from the malaria eradication era in the 50s must be factored in while developing the malaria elimination strategy for Africa by 2030.

The past, present and future use of epidemiological intelligence to plan malaria vector control and parasite prevention in Uganda.

BackgroundAn important prelude to developing strategies to control infectious diseases is a detailed epidemiological evidence platform to target cost-effective interventions and define resource needs.MethodsA review of published and un-published reports of malaria vector control and parasite prevention in Uganda was conducted for the period 1900–2013. The objective was to provide a perspective as to how epidemiological intelligence was used to design malaria control before and during the global malaria eradication programme (GMEP) and to contrast this with the evidence generated in support of the Roll Back Malaria (RBM) initiative from 1998 to date.ResultsDuring the GMEP era, comprehensive investigations were undertaken on the effectiveness of vector and parasite control such as indoor residual house-spraying (IRS) and mass drug administration (MDA) at different sites in Uganda. Nationwide malariometric surveys were undertaken between 1964 and 1967 to provide a profile of risk, epidemiology and seasonality leading to an evidence-based national cartography of risk to characterize the diversity of malaria transmission in Uganda. At the launch of the RBM initiative in the late 1990s, an equivalent level of evidence was lacking. There was no contemporary national evidence-base for the likely impact of insecticide-treated nets (ITN), no new malariometric data, no new national cartography of malaria risk or any evidence of tailored intervention delivery based on variations in the ecology of malaria risk in Uganda.DiscussionDespite millions of dollars of overseas development assistance over the last ten years in ITN, and more recently the resurrection of the use of IRS, the epidemiological impact of vector control remains uncertain due to an absence of nationwide basic parasite and vector-based field studies.ConclusionReadily available epidemiological data should become the future business model to maximize malaria funding from 2015. Over the next five to ten years, accountability, impact analysis, financial business cases supported by a culture of data use should become the new paradigm by which malaria programmes, governments and their development partners operate.

Towards making efficient use of household resources for appropriate prevention of malaria: investigating households’ ownership, use and expenditures on ITNs and other preventive tools in Southeast Nigeria

BackgroundMany households own, use and spend money on many malaria preventive tools, some of which are inappropriate and ineffective in preventing malaria. This is despite the promotion of use of effective preventive methods such as Insecticide treated nets (ITNs) and indoor residual house spraying (IRHS). The use of these ineffective methods imposes some economic burden on households with no resultant reduction in the risk of developing malaria. Hence, global and national targets in use of various effective malaria preventive toools are yet to be achieved in Nigeria. This paper presents new evidence on the differential use and expenditures on effective and non-effective malaria preventive methods in Nigeria.MethodsSemi-structured interviewer administered pre-tested questionnaire were used to collect data from 500 households from two communities in Enugu state, Nigeria. The two study communities were selected randomly while the households were selected systematically. Information was collected on demography, malaria status of children under 5 within the past month, types of malaria preventive tools used by households and how much was spent on these, the per capita household food expenditure and assets ownership of respondents to determine their socio-economic status.ResultsThere was high level of ownership of ITNs (73%) and utilization (71.2%), with 40% utilization by children under 5. There were also appreciable high levels of use of other malaria preventive tools such as window and door nets, indoor spray, aerosol spray and cleaning the environment. No significant inequity was found in ownership and utilization of ITNs and in use of other preventive methods across socioeconomic groups. However, households spent a lot of money on other preventive tools and average expenditures were between N0.83-N172 ($0.005-$1.2) The richest households spent the most on window and door nets (P = 0.04).ConclusionHigh levels of use and expenditure on ITNs and other malaria preventive tools exist. A programmatic challenge will involve designing ways and means of converting some of the inefficient and inappropriate expenditures on many ineffective malaria preventive tools to proven cost-effective methods such as ITNs and IRHS. This will help to achieve universal coverage with malaria preventive tools.

Challenges for malaria elimination in Zanzibar: pyrethroid resistance in malaria vectors and poor performance of long-lasting insecticide nets

BackgroundLong-lasting insecticide treated nets (LLINs) and indoor residual house spraying (IRS) are the main interventions for the control of malaria vectors in Zanzibar. The aim of the present study was to assess the susceptibility status of malaria vectors against the insecticides used for LLINs and IRS and to determine the durability and efficacy of LLINs on the island.MethodsMosquitoes were sampled from Pemba and Unguja islands in 2010–2011 for use in WHO susceptibility tests. One hundred and fifty LLINs were collected from households on Unguja, their physical state was recorded and then tested for efficacy as well as total insecticide content.ResultsSpecies identification revealed that over 90% of the Anopheles gambiae complex was An. arabiensis with a small number of An. gambiae s.s. and An. merus being present. Susceptibility tests showed that An. arabiensis on Pemba was resistant to the pyrethroids used for LLINs and IRS. Mosquitoes from Unguja Island, however, were fully susceptible to all pyrethroids tested. A physical examination of 150 LLINs showed that two thirds were damaged after only three years in use. All used nets had a significantly lower (p < 0.001) mean permethrin concentration of 791.6 mg/m2 compared with 944.2 mg/m2 for new ones. Their efficacy decreased significantly against both susceptible An. gambiae s.s. colony mosquitoes and wild-type mosquitoes from Pemba after just six washes (p < 0.001).ConclusionThe sustainability of the gains achieved in malaria control in Zanzibar is seriously threatened by the resistance of malaria vectors to pyrethroids and the short-lived efficacy of LLINs. This study has revealed that even in relatively well-resourced and logistically manageable places like Zanzibar, malaria elimination is going to be difficult to achieve with the current control measures.

Molecular Systematics and Insecticide Resistance in the Major African Malaria Vector Anopheles funestus

Anopheles funestus is one of three major African vectors of malaria. Its distribution extends over much of the tropics and subtropics wherever suitable swampy breeding habitats are present. As with members of the Anopheles gambiae complex, An. funestus shows marked genetic heterogeneity across its range. Currently, two unnamed species are recognized in the group, with molecular and cytogenetic data indicating that more may be present. The control of malaria vectors in Africa has received increased attention in the past decade with the scaling up of insecticide-treated bed nets and indoor residual house spraying. Also in the past decade, the frequency of insecticide-resistant mosquitoes has increased exponentially. Whether this increase is in response to vector control initiatives or because of insecticide use in agriculture is debatable. In this article we examine the progress made on the systematics of the An. funestus group and review research on insecticide resistance and its mechanisms.

Entomological indices of malaria transmission in Chikhwawa district, Southern Malawi

BackgroundAlthough malaria is highly prevalent throughout Malawi, little is known of its transmission dynamics. This paper describes the seasonal activity of the different vectors, human biting indices, sporozoite rates and the entomological inoculation rate in a low-lying rural area in southern Malawi.MethodsVectors were sampled over 52 weeks from January 2002 to January 2003, by pyrethrum knockdown catch in two villages in Chikhwawa district, in the Lower Shire Valley.ResultsIn total, 7,717 anophelines were collected of which 55.1% were Anopheles gambiae sensu lato and 44.9% were Anopheles funestus. Three members of the An. gambiae complex were identified by PCR: Anopheles arabiensis (75%) was abundant throughout the year, An. gambiae s.s. (25%) was most common during the wet season and Anopheles quadriannulatus occurred at a very low frequency (n=16). An. funestus was found in all samples but was most common during the dry season.Anopheles gambiae s.s. and An. funestus were highly anthropophilic with human blood indices of 99.2% and 96.3%, respectively. Anopheles arabiensis had fed predominantly on humans (85.0%) and less commonly on cattle (10.9%; 1.2% of blood meals were of mixed origin). Plasmodium falciparum (192/3,984) and Plasmodium malariae (1/3,984) sporozoites were detected by PCR in An. arabiensis (3.2%) and An. funestus (4.5%), and in a significantly higher proportion of An. gambiae s.s. (10.6%)(p<0.01). All three vectors were present throughout the year and malaria transmission occurred in every month, although with greatest intensity during the rainy season (January to April). The combined human blood index exceeded 92% and the P. falciparum sporozoite rate was 4.8%, resulting in estimated inoculation rates of 183 infective bites/ person per annum, or an average rate of ~15 infective bites/person/month.ConclusionsThe results demonstrate the importance of An. gambiae s.s., An. arabiensis and An. funestus in driving the high levels of malaria transmission in the south of Malawi. Sustained and high coverage or roll out of current approaches to malaria control (primarily insecticide-treated bed nets and indoor residual house spraying) in the area are likely to reduce the observed high malaria transmission rate and consequently the incidence of human infections, unless impeded by increasing resistance of vectors to insecticides.

The residual effect of lambda-cyhalothrin, deltamethrin and dichlorodiphenyltrichloroethane in Zhombe, Kwekwe district, Zimbabwe

Indoor residual house spraying using lambda-cyhalothrin, deltamethrin and dichlorodiphenyltrichloroethane (DDT) was conducted in Zhombe Resettlement area, Zimbabwe. A total of 204/219 (93.1%), 224/260 (86.2%) and 257/325 (79.1%) rooms were sprayed with lambda-cyhalothrin, deltamethrin and DDT wettable powders respectively. Bioassays were conducted on sprayed walls and roofs using 3-5 day old laboratory reared susceptible &lt;em&gt;Anopheles gambiae sensu lato &lt;/em&gt;mosquitoes placed in World Health Organization cones. &lt;br /&gt;Bioassays conducted on sprayed walls (1 month), showed that efficacy of lambda-cyhalothrin was the same with DDT but different with deltamethrin and this trend continued in the 2&lt;sup&gt;nd&lt;/sup&gt; month. During the 3rd month, lambda-cyhalothrin killed more mosquitoes than deltamethrin (P=1.931x10&lt;sup&gt;-14&lt;/sup&gt;), DDT killed more mosquitoes than deltamethrin (P=0.0001) and lambda-cyhalothrin killed more mosquitoes than DDT (walls). Efficacy of lambda-cyhalothrin and DDT was the same 4 months post spray (P=0.487), notable differences were seen in lambdacyhalothrin and deltamethrin (P=2.57x10&lt;sup&gt;-6&lt;/sup&gt;), DDT and deltamethrin (P=2.17-10&lt;sup&gt;-8&lt;/sup&gt;). Efficacy of lambda-cyhalothrin and DDT was the same 5 months post spray (P=0.244), major differences were found in lambdacyhalothrin and deltamethrin (P=0.000), DDT and deltamethrin (P=5.18x10&lt;sup&gt;-5&lt;/sup&gt;) and this trend continued in the 6&lt;sup&gt;th&lt;/sup&gt; month. One month after spraying roofs, mortality of mosquitoes due to lambdacyhalothrin/ deltamethrin (P=2.56x10&lt;sup&gt;-5&lt;/sup&gt;), lambda-cyhalothrin/DDT (P=1.2x10&lt;sup&gt;-7&lt;/sup&gt;) and deltamethrin/DDT (P=0.013) were significantly different and this continued in the 2&lt;sup&gt;nd&lt;/sup&gt; month. However, 3 months after spraying, mortality due to lambda-cyhalothrin/deltamethrin (P=1.46x10&lt;sup&gt;-6&lt;/sup&gt;), lambda-cyhalothrin/DDT (P=0.048), and deltamethrin/DDT (P=0.004) were significantly different and this continued in the 4&lt;sup&gt;th&lt;/sup&gt; month. Five months after spraying roofs, mortality due to lambda-cyhalothrin/ deltamethrin (P=0.000) and deltamethrin/DDT (P=6.6x10&lt;sup&gt;-7&lt;/sup&gt;) were significantly different. Six months after spraying, lambdacyhalothrin/ deltamethrin (P=0.34), lambda-cyhalothrin/DDT (P=0.982), and deltamethrin/DDT (P=0.64) were not significantly different. When using exit window traps, no mosquitoes were collected from rooms sprayed with each of the insecticides over a 6-month period. However, 17, 6, 14, 7, 2 and 3 fed &lt;em&gt;An. gambiae sl &lt;/em&gt;mosquitoes were collected in the 1&lt;sup&gt;st&lt;/sup&gt;, 2&lt;sup&gt;nd&lt;/sup&gt;, 3&lt;sup&gt;rd&lt;/sup&gt;, 4&lt;sup&gt;th&lt;/sup&gt;, 5&lt;sup&gt;th&lt;/sup&gt; and 6&lt;sup&gt;th&lt;/sup&gt; month respectively from unsprayed rooms and none of them died after 24 h.

Financing and delivery mechanisms for mosquito control tools in Sudan: A Strengths Weaknesses Opportunities and Threats (SWOT) analysis.

Background: Malaria is a major public health problem in Sudan and causes an enormous burden of morbidity in the country. Malaria is generally controlled in Sudan using five main approaches, which are environmental management, space spraying (SS), insecticide-treated nets (ITNs), larviciding with abate (LWA) and indoor residual house spraying (IRHS). However, it is not clear which options or mix of options present the most economically viable means in terms of financing and delivery, for malaria control.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Methods: The study used an interviewer-administered questionnaire administered to malaria control managers at national and sub-national levels, as well as the review of documents to collect information at three levels of service delivery: National, State and Local. Three localities were selected from each state to represent an urban, peri-urban and rural area. Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis is undertaken on the financing and delivery schemes. The respondents assigned scores based on several SWOT indicators, which were: dependability, sustainability, timeliness, equity, sufficiency, and affordability. The scores for the different SWOT indicators were added-up for each vector control mechanism.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Findings: The funding for the four strategies was dependable but only the funding for ITNs was rated highest on the sustainability criterion and financing of IRHS and SS were deemed not to be sustainable. Overall, financing of LWA followed by ITNs had the highest SWOT analysis scores on the financing criterion. The delivery strategies of three out of four vector control activities were rated poorly efficient, integrated, and timely. Only the delivery of ITNs and LWA were rated by the control managers as optimally sustainable. Overall, the delivery of LWA, followed by ITNs, was rated highest on the delivery criterion.Conclusion: SWOT analysis revealed critical issues with financing and delivery of the different malaria vector control interventions. These issues need to be resolved for optimal malaria control activities in Sudan.Keywords: Financing and delivery mechanisms; mosquito control tools; SWOT analysis; Sudan.

Implementation of an insecticide-treated net subsidy scheme under a public-private partnership for malaria control in Tanzania--challenges in implementation.

BackgroundIn the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs) and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM), the President's Malaria Initiative and the World Bank Booster programme.MethodsThe case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control – 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 – 2004) and implementation phases (2004 – 2005). Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs.ResultsThe major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative.ConclusionThe lessons gleaned from this synthesis include: (a) the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b) senior politicians often steered the policy agenda when the policy in question was a 'crisis event', the stakes and the visibility were high, (c) national stakeholders in policy making have an advantage in strengthening alliances with international organizations, where the latter can become extremely influential in solving bottlenecks as the need arises, and (d) conflict can be turned into an opportunity, for example the Presidential initiative has inadvertently provided Tanzania with important lessons in the organization of 'catch-up' campaigns.

DDT is back: let us spray!

DDT is back: let us spray!

Socio-economic inequity in demand for insecticide-treated nets, in-door residual house spraying, larviciding and fogging in Sudan

BackgroundIn order to optimally prioritize and use public and private budgets for equitable malaria vector control, there is a need to determine the level and determinants of consumer demand for different vector control tools.ObjectivesTo determine the demand from people of different socio-economic groups for indoor residual house-spraying (IRHS), insecticide-treated nets (ITNs), larviciding with chemicals (LWC), and space spraying/fogging (SS) and the disease control implications of the result.MethodsRatings and levels of willingness-to-pay (WTP) for the vector control tools were determined using a random cross-sectional sample of 720 householdes drawn from two states. WTP was elicited using the bidding game. An asset-based socio-economic status (SES) index was used to explore whether WTP was related to SES of the respondents.ResultsIRHS received the highest proportion of highest preferred rating (41.0%) followed by ITNs (23.1%). However, ITNs had the highest mean WTP followed by IRHS, while LWC had the least. The regression analysis showed that SES was positively and statistically significantly related to WTP across the four vector control tools and that the respondents' rating of IRHS and ITNs significantly explained their levels of WTP for the two tools.ConclusionPeople were willing to pay for all the vector-control tools, but the demand for the vector control tools was related to the SES of the respondents. Hence, it is vital that there are public policies and financing mechanisms to ensure equitable provision and utilisation of vector control tools, as well as protecting the poor from cost-sharing arrangements.

Historical review of malarial control in southern African with emphasis on the use of indoor residual house-spraying.

Indoor residual house-spraying (IRS) mainly with dichlorodiphenyltrichloroethane (DDT) was the principal method by which malaria was eradicated or greatly reduced in many countries in the world between the 1940s and 1960s. In sub-Saharan Africa early malarial eradication pilot projects also showed that malaria is highly responsive to vector control by IRS but transmission could not be interrupted in the endemic tropical and lowland areas. As a result IRS was not taken to scale in most endemic areas of the continent with the exception of southern Africa and some island countries such as Reunion, Mayotte, Zanzibar, Cape Verde and Sao Tome. In southern Africa large-scale malarial control operations based on IRS with DDT and benzene hexachloride (BHC) were initiated in a number of countries to varying degrees. The objective of this review was to investigate the malarial situation before and after the introduction of indoor residual insecticide spraying in South Africa, Swaziland, Botswana, Namibia, Zimbabwe and Mozambique using historical malarial data and related information collected from National Malaria Control Programmes, national archives and libraries, as well as academic institutions in the respective countries. Immediately after the inception of IRS with insecticides, dramatic reductions in malaria and its vectors were recorded. Countries that developed National Malaria Control Programmes during this phase and had built up human and organizational resources made significant advances towards malarial control. Malaria was reduced from hyper- to meso-endemicity and from meso- to hypo-endemicity and in certain instances to complete eradication. Data are presented on the effectiveness of IRS as a malarial control tool in six southern African countries. Recent trends in and challenges to malarial control in the region are also discussed.

Malaria prevention in highland Kenya: indoor residual house-spraying vs. insecticide-treated bednets.

This study compares the effectiveness and cost-effectiveness of indoor residual house-spraying (IRS) and insecticide-treated bednets (ITNs) against infection with Plasmodium falciparum as part of malaria control in the highlands of western Kenya. Homesteads operationally targeted for IRS and ITNs during a district-based emergency response undertaken by an international relief agency were selected at random for evaluation. Five hundred and ninety homesteads were selected (200 with no vector control, 200 with IRS and 190 with ITNs). In July 2000, residents in these homesteads were randomly sampled according to three age-groups: 6 months-4 years, 5-15 years, and > 15 years for the presence of P. falciparum antigen (Pf HRP-2) using the rapid whole blood immunochromatographic test (ICT). The prevalence of P. falciparum infection amongst household members not protected by either IRS or ITN was 13%. Sleeping under a treated bednet reduced the risk of infection by 63% (58-68%) and sleeping in a room sprayed with insecticide reduced the risk by 75% (73-76%). The economic cost per infection case prevented by IRS was US$ 9 compared to US$ 29 for ITNs. This study suggests that IRS may be both more effective and cheaper than ITNs in communities subjected to low, seasonal risks of infection and as such should be considered as part of the control armamentarium for malaria prevention.

A field evaluation study on the effects of residual spray of Bifenthrin and Deltamethrin on Anopheles minimus population in Mae Hong Son Province, northern Thailand.

A field study was conducted to evaluate the effects of indoor residual house spraying of Bifenthrin and Deltamethrin on malaria vector population of Anopheles minimus s.l., from April 1999 to April 2001 at rural vil- lages in Mae Hong Son province, northern Thailand. Nine villages in Mae Hong Son province were selected for the present study (three villages for control and three villages each for insecticide spray). The residual spray of Bifen- thrin (25 mg/m 2 ) showed greater adulticiding effects on An. minimus s.l. population than Deltamethrin (20 mg/m 2 ). In Bifenthrin treated villages, a clear decrease in biting density of An. minimus s. l. was found in human bait col- lection as well as animal bait collection after the insecticide spray. In all of the three villages, the average density after insecticide spray was significantly lower than that observed before the spray. The effects of Deltamethrin on An. minimus s. l. density was found only in one village out of the three treated villages. A significant decrease in parous rate after insecticide spray was found in all the villages sprayed with Bifenthrin, whereas no significant changes were observed in control villages. The average parous rate in the villages treated with Deltamethrin be- came significantly higher after the insecticide spray. These results clearly suggested that the residual spray of Bifenthrin (25 mg/m 2 ) was more effective than Deltamethrin (20 mg/m 2 ).