Distribution Of Long-lasting Insecticide-treated Nets Research Articles

Assessing afebrile malaria and bed-net use in a high-burden region of India: Findings from multiple rounds of mass screening.

A key obstacle in the fight against malaria is afebrile malaria. It remains undiagnosed and, therefore, is invisible to the health system. Apart from being a serious illness, it contributes to increased transmission. Existing studies in India have not adequately reported afebrile malaria and its determinants, including the use of long-lasting insecticide-treated nets (LLINs). This study used six waves of mass screening, which were conducted by the state government in the high-malaria-burden region of Chhattisgarh, a state in India, in 2020, 2021, and 2022. Each round of data collection included more than 15000 individuals. Descriptive statistics were used to analyse key indicators of malaria prevalence and LLIN use. Multivariate analyses were performed to identify the determinants of afebrile malaria and LLIN use. Malaria prevalence in the afebrile population varied from 0.6% to 1.4% across the different waves of mass screening. In comparison, malaria positivity among febrile individuals was greater than 33% in each wave. Afebrile malaria contributed to 19.6% to 47.2% of the overall malaria burden in the region. Indigenous communities (scheduled tribes) were more susceptible to malaria, including afebrile malaria. Individuals using LLINs were less likely to be affected by afebrile malaria. Overall, 77% of the individuals used LLINs in early monsoon season, and in winter the rate was lower at 55%. LLIN use was significantly associated with the number of LLINs the households received from the government. Although fever continues to be a primary symptom of malaria, afebrile malaria remains a significant contributor to the malaria burden in the region. The free distribution of LLINs should be expanded to include high-burden populations. Global policies must include strategies for surveillance and control of afebrile malaria in high-burden areas.

Bed-nets Hour Density after a Usage of Three Years of Long-lasting Insecticide-treated Nets in Malaria re-elimination Areas in Ngadirejo Village, Purworejo District, Indonesia

Background: Malaria, caused by the genus Plasmodium, is still a global health problem. Its transmission and spread are strongly influenced by the presence of the Anopheles vector. One of the efforts to reduce cases is the distribution of long-lasting insecticide-treated nets to the residents of malaria-endemic areas. This study aims to measure the density of mosquitoes perched on insecticide-treated bed nets after three years of usage. Method: A cross-sectional study was conducted to observe mosquitoes perching on insecticide-treated bed nets at night and calculation of mosquito density data in units of mosquitoes/LLINs/hour. Results: The number of mosquito bites before bedtime in respondents reached 72.5%, while the number of bed nets infested with mosquitoes reached 74.4%. The density of mosquitoes perched varied between 1 and 10 mosquitoes/LLINs/hour with the highest density proportion of 3 mosquitoes/LLINs/hour. Conclusion: LLINs that have been used for three years were found to be less effective at killing and preventing mosquitoes. It is advisable to re-dip with the insecticide doses to match the local vector susceptibility level by officer assistance so that the mosquito nets still function properly

Acceptance and Utilization of Long-Lasting Insecticide-Treated Nets (LLINs) by the Community of Mamboro Sub-district and Katiku Tana Sub-district, Central Sumba Regency, East Nusa Tenggara

Distribution of mosquito nets is one healthcare strategy implemented to control the number of malaria cases in Indonesia. East Nusa Tenggara is one of the provinces contributing to high malaria rates. Cases are high in several areas, including Central Sumba regency. This study aimed to describe the behavior of the people of Mamboro and Katiku Tana sub-districts in using long-lasting insecticide-treated nets (LLINs), the number of LLINs owned, number of beds, number of family members, number of pregnant women and toddlers, distribution of LLINs in families, and LLINs utilization. This is a descriptive quantitative study with a cross-sectional design. The research was conducted in the work area of the Mananga Health Center of Susu Wendewa village of Mamboro sub-district and Malinjak Health Center of Makata Keri village of Katiku Tana sub-district, Central Sumba regency. The research was carried out from 9–19 September 2021 with 341 heads of families as respondents. Data were collected using questionnaires and in-depth interviews. Most families had LLINs (n=287; 94.1%); the total number of LLINs owned was 341, used by 1,220 (94.7%) family members with ten pregnant women and 35 children under five. The number of installed LLINs was 290 units (85%), LLINs obtained from the health centers within 1–3 months was 44% (126 families), 314 units (92%) were used while sleeping, and there were still family members who did not use LLINs every night. We conclude that the acceptance and utilization of LLINs should not stop at the distribution of LLINs to the public and must be supported by an evaluation in the form of regular surveys to ensure that LLINs are correctly used.

Intensity and different genes involved in the resistance of An. gambiae s.l. to pyrethroids in four districts representative of the different agricultural production zones of North Benin, West Africa

The different methods used for the control of An. gambiae s.l. have led to the deployment of several defensive weapons by these vectors. Indoor residual spraying (IRS) implemented annually in the northern part of the country, and the national distribution of long-lasting insecticide-treated nets (LLINs) carried out every 3 years are the main malaria vector control tools deployed by the NMCP. The toxicity of insecticides in these tools results from their interaction with their biological target in the insect. Thus, for the effectiveness of vector control tools in an area, the knowledge of different defense weapons of Anopheles present in the area is essential.The characterization of resistance mechanisms present on samples of pyrethroid-resistant Anopheles gambiae s.l. was carried out in four districts of northern Benin taking into account the different agricultural production zones. The different species, resistance gene and enzyme present in these districts were investigated.High resistance of Anopheles gambiae s.l. in the four communes was observed, surviving a high frequency of the kdr resistance gene. Mosquito mortality rates ranged from 56.80% (95% CI: 50.51 - 62.95) in Kandi, to 70.24% (95% CI: 64.61 - 75.45) in N'Dali with deltamethrin, from 57.14% (95% CI: 51.04 - 63.09) in Kandi, to 74.80% (95% CI: 68.94 - 80.06) in N'Dali with permethrin, and from 59.63% (95% CI: 51.76 - 67.17) in Kandi, to 72.90% (95% CI: 66.24 - 78.89) in Parakou with alphacypermethrin. The lowest frequency of the kdr gene was observed in An. coluzzii 64.00% (95% CI: 56.90 - 70.60) in Malanville and the highest frequency in Kandi in An. gambiae 88.33% (95% CI: (82.70 - 92.60). It should also be noted that An. gambiae s.l. from these four districts also use detoxification enzymes to eliminate pyrethroid toxicity. These are: the communes of Parakou, Kandi and N'Dali for α and β esterases (pα < 0.05 and pβ < 0.05), Kandi, Malanville and N'Dali (p

The Potential of Digital Data Collection Tools for Long-lasting Insecticide-Treated Net Mass Campaigns in Nigeria: Formative Study.

BackgroundNigeria has the world’s largest malaria burden, accounting for 27% of the world’s malaria cases and 23% of malaria mortality globally. This formative study describes the operational process of the mass distribution of long-lasting insecticide-treated nets (LLINs) during a campaign program in Nigeria.ObjectiveThis study aims to assess whether and how digital data collection and management tools can change current practices and help resolve major implementation issues.MethodsQualitative data on the technical features and operational processes of paper-based and information and communication technology (ICT)–based systems in the Edo and Kwara states from June 2 to 30, 2017, were collected on the basis of documented operation manuals, field observations, and informant interviews. During the LLIN campaign in Edo State, we recruited 6 local government area focal persons and monitors and documented daily review meetings during household mobilization (9 days) and net distribution (5 days) to understand the major program implementation issues associated with the following three aspects: logistic issues, technical issues, and demand creation. Each issue was categorized according to the expected degree (low, mid, and high) of change by the ICT system.ResultsThe net campaign started with microplanning and training, followed by a month-long implementation process, which included household mobilization, net movement, net distribution, and end process monitoring. The ICT system can improve management and oversight issues related to data reporting and processes through user-centered interface design, built-in data quality control logic flow or algorithms, and workflow automation. These often require more than 50% of staff time and effort in the current paper-based practice. Compared with the current paper-based system, the real-time system is expected to reduce the time to payment compensation for health workers by about 20 days and produce summary campaign statistics for at least 20 to 30 days.ConclusionsThe ICT system can facilitate the measurement of population coverage beyond program coverage during an LLIN campaign with greater data reliability and timeliness, which are often compromised due to the limited workforce capacity in a paper-based system.

Insecticide-treated net distribution in Western Kenya: impacts related to COVID-19 and health worker strikes.

We examined the impact of coronavirus disease (COVID) mitigation, supply and distribution interruptions on the delivery of long-lasting insecticide-treated nets (LLINs) in Western Kenya. The median monthly distribution of LLINs declined during COVID mitigation strategies (March–July 2020) and during the health worker strikes (December 2020–February 2021). Recovery periods followed initial declines, indicative of a ‘catching up’ on missed routine distribution. Mass community campaigns were delayed by 10 months. These observations offer encouragement for routine net distribution resilience, but complete interruptions of planned mass distributions require alternate strategies during pandemics.

The Epidemiology of Plasmodium falciparum Malaria in the Bijagos Islands of Guinea-Bissau.

.Distribution of long-lasting insecticide-treated nets (LLINs), passive detection and treatment with artemisinin-based combination therapy (ACT), and intermittent preventive treatment in pregnancy (IPTp) are the mainstay malaria control measures of Guinea-Bissau’s national control programme. This study aimed to estimate the prevalence of Plasmodium falciparum on Bubaque, the most populous island of the country’s remote Bijagos archipelago. A cross-sectional survey was performed at the start of the rainy season in August 2017. Participants were recruited using systematic random sampling in a two-stage stratified cluster design. Malaria parasitemia was detected using rapid diagnostic tests (RDTs) and quantitative PCR (qPCR). Data on housing, education, larval source management, socioeconomic status, anemia, and malaria preventive measures were collected. Multivariable logistic regression models were constructed to identify associations with P. falciparum infection. Four hundred four persons (aged 6 months–79 years, median 17 years) were enrolled in the study. The prevalence of P. falciparum parasitemia was 5.8% by RDT (95% CI: 3.55–9.33) and 16.9% by qPCR (95% CI: 13.09–21.71). The prevalence of anemia was 74.3% (95% CI: 69.04–78.85) as defined by the WHO criteria. All sampled houses were found to have open eaves; 99.5% of the surveyed population reported sleeping under a bednet (95% CI: 97.8–99.9). Although reported LLIN use is high, there remains an appreciable prevalence of malaria, suggesting that transmission is ongoing and further tools are required to reduce the burden of the disease.

Monitoring Plasmodium falciparum and Plasmodium vivax using microsatellite markers indicates limited changes in population structure after substantial transmission decline in Papua New Guinea.

Monitoring the genetic structure of pathogen populations may be an economical and sensitive approach to quantify the impact of control on transmission dynamics, highlighting the need for a better understanding of changes in population genetic parameters as transmission declines. Here we describe the first population genetic analysis of two major human malaria parasites, Plasmodium falciparum (Pf) and Plasmodium vivax (Pv), following nationwide distribution of long-lasting insecticide-treated nets (LLINs) in Papua New Guinea (PNG). Parasite isolates from pre- (2005-2006) and post-LLIN (2010-2014) were genotyped using microsatellite markers. Despite parasite prevalence declining substantially (East Sepik Province: Pf=54.9%-8.5%, Pv=35.7%-5.6%, Madang Province: Pf=38.0%-9.0%, Pv: 31.8%-19.7%), genetically diverse and intermixing parasite populations remained. Pf diversity declined modestly post-LLIN relative to pre-LLIN (East Sepik: Rs =7.1-6.4, HE =0.77-0.71; Madang: Rs =8.2-6.1, HE =0.79-0.71). Unexpectedly, population structure present in pre-LLIN populations was lost post-LLIN, suggesting that more frequent human movement between provinces may have contributed to higher gene flow. Pv prevalence initially declined but increased again in one province, yet diversity remained high throughout the study period (East Sepik: Rs =11.4-9.3, HE =0.83-0.80; Madang: Rs =12.2-14.5, HE =0.85-0.88). Although genetic differentiation values increased between provinces over time, no significant population structure was observed at any time point. For both species, a decline in multiple infections and increasing clonal transmission and significant multilocus linkage disequilibrium post-LLIN were positive indicators of impact on the parasite population using microsatellite markers. These parameters may be useful adjuncts to traditional epidemiological tools in the early stages of transmission reduction.

A qualitative study on the use of long-lasting insecticidal nets (LLINs) for the prevention of malaria in the Peruvian Amazon

BackgroundMalaria is a huge global health burden due to its mortality, morbidity and cost to economies. It is necessary to eliminate the disease in all countries where possible to achieve the World Health Organization target of > 90% reduction by 2030. Successful previous campaigns suggest elimination is feasible in Peru. However, the incidence has recently been rising, focalized to the region of Loreto. Currently, the distribution of long-lasting insecticide-treated nets (LLINs) is a major part of Peru’s malaria control strategy, however these may be having a limited effect in Loreto, because of the recent behavioural adaption of the mosquito vector, Anopheles darlingi, to earlier biting times, as well as local perceptions and practices towards LLINs. It was, therefore, necessary to investigate how perceptions, practices and lifestyle factors affect the efficacy of LLINs in Loreto.MethodsQualitative research was carried out in 5 rural communities along the Iquitos-Nauta Road in Loreto, which have increased exposure and have received nets in a distribution scheme prior to the study. Twenty semi-structured interviews as well as observations of the bed nets were conducted in participants’ homes, using a topic guide. Thematic content analysis was used to produce the findings.ResultsAll participants viewed malaria prevention as a high priority, and the use of bed nets was deeply embedded in the culture. They expressed preference for LLINs over traditional-type nets. However there were too few LLINs distributed, participants did not maintain the nets correctly, washed them too frequently and did not repair holes. The earlier mosquito biting times were also problematic. Additionally, poor housing construction and proximity to mosquito breeding sites further increased transmission.ConclusionThe positive findings in attitudes of the respondents can be used to improve malaria control in these communities. Interventions providing education on effective LLIN use should be implemented. A change in strategy away from vector control methods is also necessary, as these do not provide long-term protection due to the adaptability of An. darlingi. Interventions focusing on parasite control are recommended, and socio-economic factors which increase malaria risk should be addressed.

Mapping and enumerating houses and households to support malaria control interventions on Bioko Island

BackgroundHousing mapping and household enumeration are essential for the planning, implementation, targeting, and monitoring of malaria control interventions. In many malaria endemic countries, control efforts are hindered by incomplete or non-existent housing cartography and household enumeration. This paper describes the development of a comprehensive mapping and enumeration system to support the Bioko Island Malaria Control Project (BIMCP).ResultsA highly detailed database was developed to include every housing unit on Bioko Island and uniquely enumerate the associated households residing in these houses. First, the island was divided into a virtual, geo-dereferenced grid of 1 × 1 km sequentially numbered map-areas, each of which was in turn subdivided into one hundred, 100 × 100 m sequentially numbered map-sectors. Second, high-resolution satellite imagery was used to sequentially and uniquely identify all housing units within each map-sector. Third, where satellite imagery was not available, global positioning systems (GPS) were used as the basis for uniquely identifying and mapping housing units in a sequential manner. A total of 97,048 housing units were mapped by 2018, 56% of which were concentrated in just 5.2% of Bioko Island’s total mapped area. Of these housing units, 70.7% were occupied, thus representing uniquely identified households.ConclusionsThe housing unit mapping and household enumeration system developed for Bioko Island enabled the BIMCP to more effectively plan, implement, target, and monitor malaria control interventions. Since 2014, the BIMCP has used the unique household identifiers to monitor all household-level interventions, including indoor residual spraying, long-lasting insecticide-treated nets distribution, and annual malaria indicator surveys. The coding system used to create the unique housing unit and household identifiers is highly intuitive and allows quick location of any house within the grid without a GPS. Its flexibility has permitted the BIMCP to easily take into account the rapid and substantial changes in housing infrastructure. Importantly, by utilizing this coding system, an unprecedented quantity and diversity of detailed, geo-referenced demographic and health data have been assembled that have proved highly relevant for informing decision-making both for malaria control and potentially for the wider public health agenda on Bioko Island.

Assessment of the Status of Awareness, Ownership, and Usage of Long-Lasting Insecticide Treated Nets after Mass Distribution in Ekiti State, Nigeria.

Vector control with long-lasting insecticide treated nets (LLINs) has been identified as a major component of malaria prevention and control. The study examined present status of awareness, ownership, and utilization of LLINs in malaria high-risk areas of Ekiti State, Nigeria. Data were obtained from 352 copies of semistructured interviewer-guided questionnaire distributed to participants of each household in the four Local Government Areas (LGAs) of Ekiti State, where malaria is endemic after mass distribution of LLINs. Findings in this study showed that awareness was high (91.8%) in the Local Government Areas (LGAs) with mass media contributing largely (44.3%) to awareness. Also, LLINs ownership was found to be high (71.3%) with 72.9% of the nets being supplied by the government. Of the owners of LLINs, usage rate was observed to be 67.6%. Multivariate analysis result showed that statistically significant sociodemographic characteristics of respondents predicting the usage of LLINs included age greater than 50 years (p value = 0.008), female gender (χ2 = 8.2014, p value = 0.004), being married (χ2 = 24.721, p value <0.001), civil servants (χ2 = 12.739, p value = 0.005), and average income above poverty line (χ2 = 13.576, p value = 0.004). The study concluded that although not all households surveyed owned LLINs, nevertheless, the level of usage of LLINs among net-owning households was high. The study recommended continuous free distribution, periodic household survey, and expanding public knowledge on the benefits of LLINs usage especially through social media.

Exploring the gap between coverage, access, and utilization of long-lasting insecticide-treated nets (LLINs) among the households of malaria endemic districts in Bangladesh

BackgroundMalaria is still a major public health concern in Bangladesh in spite of mass distribution of long-lasting insecticide-treated nets (LLINs) as a key preventive strategy. There might be a considerable gap between coverage and actual use of nets by the population in endemic areas. This study intended to assess the gap between coverage, access to and use of LLINs among the households in malaria-endemic settings in Bangladesh.MethodsThis cross-sectional study collected data from 2640 households of 13 endemic districts of Bangladesh through three-stage cluster random sampling. The gap between coverage, access and use of LLINs were calculated using the procedure established by the Roll Back Malaria Monitoring and Evaluation Reference Group. To support the quantitative findings, qualitative data were also collected through in-depth interview, focus group discussion and key informant interview and analysed accordingly.ResultsOf 2640 total households, 77.4% (n = 2044) possessed at least two LLINs, 56.8% (n = 1499) had insufficient access, and 18.8% (n = 495) had excess LLINs. Members of 77.9% (n = 2056) households had used LLINs the previous night and 6.0% (n = 68) did not use LLINs despite having sufficient access. LLIN use was lower in non-hill track areas, in Bengali community, in richer households and households with more than four members. Moreover, qualitative findings revealed that the major reasons behind not using LLINs were insufficient access, sleeping outside the home, migration, perceived low efficacy of LLINs, or fear of physical side effects.ConclusionClosing the access gap by providing enough nets through solid investment and well-designed behavioural change interventions are crucial for achieving and sustaining universal coverage.

Utilization of Long-Lasting Insecticide Treated Nets and Parasitaemia at 6 Months after a Mass Distribution Exercise among Households in Mbarara Municipality, Uganda: A Cross-Sectional Community Based Study.

Background Utilization of long-lasting insecticide treated nets (LLINs) after free and mass distribution exercise has not been adequately studied. The objectives of this study were to assess ownership and utilization of LLINs following a mass distribution campaign in a Ugandan urban municipality. Methods We conducted a cross-sectional study in western Uganda among households with children under 5 years, at 6 months after a mass LLIN distribution exercise. We administered a questionnaire to measure LLIN ownership and utilization. We also measured parasitaemia among children under five years. Results Of the 346 households enrolled, 342 (98.8%) still owned all the LLINs. LLIN use was reported among 315 (91.1%) adult respondents and among 318 (91.9%) children under five. Parasitaemia was detected among 10 (2.9%) children under five. Males (OR=2.65, 95% CI 0.99-7.07), single respondents (OR=10.35, 95% CI 1.64-65.46), having a fitting bed net size (OR= 3.59, 95% CI 1.71-7.59), and no childhood malaria episode reported in the home in the last 12 months (OR=1.69, 95% CI 1.02-2.83) were all associated with LLIN use. Conclusions Ownership of LLIN is very high, and parasitaemia among the children was very low. Low parasitaemia may be attributed to high LLIN utilization. Long term follow-up should be done to determine durability of the ownership and utilization.

Combination of indoor residual spraying with long-lasting insecticide-treated nets for malaria control in Zambezia, Mozambique: a cluster randomised trial and cost-effectiveness study protocol

BackgroundMost of the reduction in malaria prevalence seen in Africa since 2000 has been attributed to vector control interventions. Yet increases in the distribution and intensity of insecticide resistance and...

Insecticide-treated nets and malaria prevalence, Papua New Guinea, 2008-2014.

ObjectiveTo investigate changes in malaria prevalence in Papua New Guinea after the distribution of long-lasting Insecticide-treated nets, starting in 2004, and the introduction of artemisinin-based combination therapy in 2011.MethodsTwo malaria surveys were conducted in 2010–2011 and 2013–2014. They included 77 and 92 randomly selected villages, respectively. In each village, all members of 30 randomly selected households gave blood samples and were assessed for malaria infection by light microscopy. In addition, data were obtained from a malaria survey performed in 2008–2009.ResultsThe prevalence of malaria below 1600 m in altitude decreased from 11.1% (95% confidence interval, CI: 8.5–14.3) in 2008–2009 to 5.1% (95% CI 3.6–7.4) in 2010–2011 and 0.9% (95% CI 0.6–1.5) in 2013–2014. Prevalence decreased with altitude. Plasmodium falciparum was more common than P. vivax overall, but not everywhere, and initially the prevalence of P. vivax infection decreased more slowly than P. falciparum infection. Malaria infections were clustered in households. In contrast to findings in 2008–2009, no significant association between net use and prevalence was found in the later two surveys. The prevalence of both fever and splenomegaly also decreased but their association with malaria infection became stronger.ConclusionLarge-scale insecticide-treated net distribution was associated with an unprecedented decline in malaria prevalence throughout Papua New Guinea, including epidemic-prone highland areas. The decline was accompanied by broader health benefits, such as decreased morbidity. Better clinical management of nonmalarial fever and research into residual malaria transmission are required.

Evaluation of community-based continuous distribution of long-lasting insecticide-treated nets in Toamasina II District, Madagascar

BackgroundContinuous distribution of insecticide-treated nets (ITNs) is thought to be an effective mechanism to maintain ITN ownership and access between or in the absence of mass campaigns, but evidence is limited. A community-based ITN distribution pilot was implemented and evaluated in Toamasina II District, Madagascar, to assess this new channel for continuous ITN distribution.MethodsBeginning 9 months after the December 2012 mass campaign, a community-based distribution pilot ran for an additional 9 months, from September 2013 to June 2014. Households requested ITN coupons from community agents in their village. After verification by the agents, households exchanged the coupon for an ITN at a distribution point. The evaluation was a two-stage cluster survey with a sample size of 1125 households. Counterfactual ITN ownership and access were calculated by excluding ITNs received through the community pilot.ResultsAt the end of the pilot, household ownership of any ITN was 96.5%, population access to ITN was 81.5 and 61.5% of households owned at least 1 ITN for every 2 people. Without the ITNs provided through the community channel, household ownership of any ITN was estimated at 74.6%, population access to an ITN at 55.5%, and households that owned at least 1 ITN for 2 people at only 34.7%, 18 months after the 2012 campaign. Ownership of community-distributed ITNs was higher among the poorest wealth quintiles. Over 80% of respondents felt the community scheme was fair and simple to use.ConclusionsHousehold ITN ownership and population ITN access exceeded RBM targets after the 9-month community distribution pilot. The pilot successfully provided coupons and ITNs to households requesting them, particularly for the least poor wealth quintiles, and the scheme was well-perceived by communities. Further research is needed to determine whether community-based distribution can sustain ITN ownership and access over the long term, how continuous availability of ITNs affects household net replacement behaviour, and whether community-based distribution is cost-effective when combined with mass campaigns, or if used with other continuous channels instead of mass campaigns.

Cost analysis of a school-based comprehensive malaria program in primary schools in Sikasso region, Mali

BackgroundThe expansion of malaria prevention and control to school-aged children is receiving increasing attention, but there are still limited data on the costs of intervention. This paper analyses the costs of a comprehensive school-based intervention strategy, delivered by teachers, that included participatory malaria educational activities, distribution of long lasting insecticide-treated nets (LLIN), and Intermittent Parasite Clearance in schools (IPCs) in southern Mali.MethodsCosts were collected alongside a randomised controlled trial conducted in 80 primary schools in Sikasso Region in Mali in 2010-2012. Cost data were compiled between November 2011 and March 2012 for the 40 intervention schools (6413 children). A provider perspective was adopted. Using an ingredients approach, costs were classified by cost category and by activity. Total costs and cost per child were estimated for the actual intervention, as well as for a simpler version of the programme more suited for scale-up by the government. Univariate sensitivity analysis was performed.ResultsThe economic cost of the comprehensive intervention was estimated to $10.38 per child (financial cost $8.41) with malaria education, LLIN distribution and IPCs costing $2.13 (20.5%), $5.53 (53.3%) and $2.72 (26.2%) per child respectively. Human resources were found to be the key cost driver, and training costs were the greatest contributor to overall programme costs. Sensitivity analysis showed that an adapted intervention delivering one LLIN instead of two would lower the economic cost to $8.66 per child; and that excluding LLIN distribution in schools altogether, for example in settings where malaria control already includes universal distribution of LLINs at community-level, would reduce costs to $4.89 per child.ConclusionsA comprehensive school-based control strategy may be a feasible and affordable way to address the burden of malaria among schoolchildren in the Sahel.

Rapid reduction of malaria following introduction of vector control interventions in Tororo District, Uganda: a descriptive study

BackgroundIn 2012, Tororo District had the highest malaria burden in Uganda with community Plasmodium prevalence of 48%. To control malaria in the district, the Ministry of Health introduced universal distribution of long lasting insecticide-treated nets (LLINs) in 2013 and added indoor residual spraying (IRS) in 2014. This study assessed malaria incidence, test positivity rates and outpatient (OPD) attendance due to malaria before and after vector control interventions.MethodsThis study was based on analysis of Health Management Information System (HMIS) secondary malaria surveillance data of 2,727,850 patient records in OPD registers of 61 health facilities from 2012 to 2015. The analysis estimated monthly malaria incidence for the entire population and also separately for <5- and ≥5-year-olds before and after introduction of vector control interventions; determined laboratory test positivity rates and annual percentage of malaria cases in OPD. Chi square for trends was used to analyse annual change in malaria incidence and logistic regression for monthly reduction.ResultsFollowing universal LLINs coverage, the annual mean monthly malaria incidence fell from 95 cases in 2013 to 76 cases per 1000 in 2014 with no significant monthly reduction (OR = 0.99, 95% CI 0.96–1.01, P = 0.37). Among children <5 years, the malaria incidence reduced from 130 to 100 cases per 1000 (OR = 0.98, 95% CI 0.97–1.00, P = 0.08) when LLINs were used alone in 2014, but declined to 45 per 1000 in 2015 when IRS was combined with LLINs (OR = 0.94, 95% CI 0.91–0.996, P < 0.0001). Among individuals aged ≥5 years, mean monthly malaria incidence reduced from 59 to 52 cases per 1000 (OR = 0.99, 95% CI 0.97–1.02, P = 0.8) when LLINs were used alone in 2014, but reduced significantly to 25 per 1000 in 2015 (OR = 0.91, 95% CI 0.88–0.94, P < 0.0001). Malaria test positivity rate reduced from 57% in 2013 to 30% (Chi = 15, P < 0.0001) in 2015. Slide positivity rate reduced from 45% in 2013 to 21% in 2015 (P = 0.004) while RDT positivity declined from 69 to 40%.ConclusionsA rapid reduction in malaria incidence was observed in Tororo District following the introduction of IRS in addition to LLINs. There was no significant reduction in malaria incidence following universal distribution of LLINs to communities before introduction of IRS.

Interventions that effectively target Anopheles funestus mosquitoes could significantly improve control of persistent malaria transmission in south-eastern Tanzania.

Malaria is transmitted by many Anopheles species whose proportionate contributions vary across settings. We re-assessed the roles of Anopheles arabiensis and Anopheles funestus, and examined potential benefits of species-specific interventions in an area in south-eastern Tanzania, where malaria transmission persists, four years after mass distribution of long-lasting insecticide-treated nets (LLINs). Monthly mosquito sampling was done in randomly selected households in three villages using CDC light traps and back-pack aspirators, between January-2015 and January-2016, four years after the last mass distribution of LLINs in 2011. Multiplex polymerase chain reaction (PCR) was used to identify members of An. funestus and Anopheles gambiae complexes. Enzyme-linked immunosorbent assay (ELISA) was used to detect Plasmodium sporozoites in mosquito salivary glands, and to identify sources of mosquito blood meals. WHO susceptibility assays were done on wild caught female An. funestus s.l, and physiological ages approximated by examining mosquito ovaries for parity. A total of 20,135 An. arabiensis and 4,759 An. funestus were collected. The An. funestus group consisted of 76.6% An. funestus s.s, 2.9% An. rivulorum, 7.1% An. leesoni, and 13.4% unamplified samples. Of all mosquitoes positive for Plasmodium, 82.6% were An. funestus s.s, 14.0% were An. arabiensis and 3.4% were An. rivulorum. An. funestus and An. arabiensis contributed 86.21% and 13.79% respectively, of annual entomological inoculation rate (EIR). An. arabiensis fed on humans (73.4%), cattle (22.0%), dogs (3.1%) and chicken (1.5%), but An. funestus fed exclusively on humans. The An. funestus populations were 100% susceptible to organophosphates, pirimiphos methyl and malathion, but resistant to permethrin (10.5% mortality), deltamethrin (18.7%), lambda-cyhalothrin (18.7%) and DDT (26.2%), and had reduced susceptibility to bendiocarb (95%) and propoxur (90.1%). Parity rate was higher in An. funestus (65.8%) than An. arabiensis (44.1%). Though An. arabiensis is still the most abundant vector species here, the remaining malaria transmission is predominantly mediated by An. funestus, possibly due to high insecticide resistance and high survival probabilities. Interventions that effectively target An. funestus mosquitoes could therefore significantly improve control of persistent malaria transmission in south–eastern Tanzania.

The Impact of Hotspot-Targeted Interventions on Malaria Transmission in Rachuonyo South District in the Western Kenyan Highlands: A Cluster-Randomized Controlled Trial

BackgroundMalaria transmission is highly heterogeneous, generating malaria hotspots that can fuel malaria transmission across a wider area. Targeting hotspots may represent an efficacious strategy for reducing malaria transmission. We determined the impact of interventions targeted to serologically defined malaria hotspots on malaria transmission both inside hotspots and in surrounding communities.Methods and FindingsTwenty-seven serologically defined malaria hotspots were detected in a survey conducted from 24 June to 31 July 2011 that included 17,503 individuals from 3,213 compounds in a 100-km2 area in Rachuonyo South District, Kenya. In a cluster-randomized trial from 22 March to 15 April 2012, we randomly allocated five clusters to hotspot-targeted interventions with larviciding, distribution of long-lasting insecticide-treated nets, indoor residual spraying, and focal mass drug administration (2,082 individuals in 432 compounds); five control clusters received malaria control following Kenyan national policy (2,468 individuals in 512 compounds). Our primary outcome measure was parasite prevalence in evaluation zones up to 500 m outside hotspots, determined by nested PCR (nPCR) at baseline and 8 wk (16 June–6 July 2012) and 16 wk (21 August–10 September 2012) post-intervention by technicians blinded to the intervention arm. Secondary outcome measures were parasite prevalence inside hotpots, parasite prevalence in the evaluation zone as a function of distance from the hotspot boundary, Anopheles mosquito density, mosquito breeding site productivity, malaria incidence by passive case detection, and the safety and acceptability of the interventions. Intervention coverage exceeded 87% for all interventions. Hotspot-targeted interventions did not result in a change in nPCR parasite prevalence outside hotspot boundaries (p ≥ 0.187). We observed an average reduction in nPCR parasite prevalence of 10.2% (95% CI −1.3 to 21.7%) inside hotspots 8 wk post-intervention that was statistically significant after adjustment for covariates (p = 0.024), but not 16 wk post-intervention (p = 0.265). We observed no statistically significant trend in the effect of the intervention on nPCR parasite prevalence in the evaluation zone in relation to distance from the hotspot boundary 8 wk (p = 0.27) or 16 wk post-intervention (p = 0.75). Thirty-six patients with clinical malaria confirmed by rapid diagnostic test could be located to intervention or control clusters, with no apparent difference between the study arms. In intervention clusters we caught an average of 1.14 female anophelines inside hotspots and 0.47 in evaluation zones; in control clusters we caught an average of 0.90 female anophelines inside hotspots and 0.50 in evaluation zones, with no apparent difference between study arms. Our trial was not powered to detect subtle effects of hotspot-targeted interventions nor designed to detect effects of interventions over multiple transmission seasons.ConclusionsDespite high coverage, the impact of interventions targeting malaria vectors and human infections on nPCR parasite prevalence was modest, transient, and restricted to the targeted hotspot areas. Our findings suggest that transmission may not primarily occur from hotspots to the surrounding areas and that areas with highly heterogeneous but widespread malaria transmission may currently benefit most from an untargeted community-wide approach. Hotspot-targeted approaches may have more validity in settings where human settlement is more nuclear.Trial registrationClinicalTrials.gov NCT01575613