Malaria control needs mass distribution of insecticidal bednets

Using donor funding to catalyse investment in malaria prevention in Ghana: an analysis of the potential impact on public and private sector expenditure

Background

An estimated 1.5 billion malaria cases and 7.6 million malaria deaths have been averted globally since 2000; long-lasting insecticidal nets (LLINs) have contributed an estimated 68% of this reduction. Insufficient funding at the international and domestic levels poses a significant threat to future progress and there is growing emphasis on the need for enhanced domestic resource mobilization. The Private Sector Malaria Prevention (PSMP) project was a 3-year intervention to catalyse private sector investment in malaria prevention in Ghana.

Methods

To assess value for money of the intervention, non-donor expenditure in the 5 years post-project catalysed by the initial donor investment was predicted. Non-donor expenditure catalysed by this investment included: workplace partner costs of malaria prevention activities; household costs in purchasing LLINs from retail outlets; domestic resource mobilization (public sector financing and private investors). Annual ratios of projected non-donor expenditure to annualized donor costs were calculated for the 5 years post-project. Alternative scenarios were constructed to explore uncertainty around future consequences of the intervention.

Results

The total donor financial cost of the 3-year PSMP project was USD 4,418,996. The average annual economic donor cost per LLIN distributed through retail sector and workplace partners was USD 21.17 and USD 7.55, respectively. Taking a 5-year post-project time horizon, the annualized donor investment costs were USD 735,805. In the best-case scenario, each USD of annualized donor investment led to USD 4.82 in annual projected non-donor expenditure by the fifth-year post-project. With increasingly conservative assumptions around the project consequences, this ratio decreased to 3.58, 2.16, 1.07 and 0.93 in the “very good”, “good”, “poor” and “worst” case scenarios, respectively. This suggests that in all but the worst-case scenario, donor investment would be exceeded by the non-donor expenditure it catalysed.

Conclusions

The unit cost per net delivered was high, reflecting considerable initial investment costs and relatively low volumes of LLINs sold during the short duration of the project. However, taking a longer time horizon and broader perspective on the consequences of this complex catalytic intervention suggests that considerable domestic resources for malaria control could be mobilized, exceeding the value of the initial donor investment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04218-2.

Slow-DEET-Release Mosquito-Repellent System Based on Poly(butylene succinate)

Bio-sourced and biodegradable poly(butylene succinate) (PBS) strands containing up to 40 m% mosquito-repellent N,N-diethyl-3-methylbenzamide (DEET) were obtained by extrusion, for an initial evaluation of the DEET evaporation characteristics and the possible application of such strands as biodegradable slow-release repellent-delivery devices. For DEET concentrations up to 20 m%, DEET is entrapped in the semicrystalline spherulitic superstructure of PBS. In contrast, at higher DEET concentrations, the liquid repellent, at least partially, is not fully incorporated in the PBS spherulites rather than segregates to form an own macrophase. Quantification of the release of DEET to the environment by thermogravimetric analysis at different temperatures between 60 and 100 °C allowed estimation of the evaporation rate at lower service temperatures, suggesting an extremely low release rate with a time constant of the order of magnitude of 1-2 years at 25 °C, independent of the initial concentration.

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

Background

Nigeria 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.

Objective

This study aims to assess whether and how digital data collection and management tools can change current practices and help resolve major implementation issues.

Methods

Qualitative 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.

Results

The 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.

Conclusions

The 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.

Information and cooperation in preventive health behavior: The case of bed net use in rural Kenya

This paper assesses whether providing people with information on the public benefits of bed net use, and on other people's bed net use, changes their bed net use behavior. I use a survey experiment from rural Kenya, where randomly selected households are provided with information on the public benefits generated by bed net use, and on the consequences of an individual's own bed net use on the health of the immediate neighbor. The results show that information increased willingness to use bed nets, and that people are more willing to use bed nets when they know other people are using them as well. Results are robust to the inclusion of a broad set of controls, including risk aversion; number of household members to have suffered from malaria in the past 12 months; and number of children in the household who are below five years age. Overall, these results suggest that in addition to free distribution of bed nets, informing people on the private and public benefits of bed net use could potentially save many more lives.

Insecticide resistance profiles in malaria vector populations from Sud-Kivu in the Democratic Republic of the Congo

BACKGROUND

Insecticide resistance has become a widespread problem causing a decline in the effectiveness of vector control tools in sub-Saharan Africa. In this situation, ongoing monitoring of vector susceptibility to insecticides is encouraged by the WHO to guide national malaria control programmes. Our study was conducted from April to November 2018 in Tchonka (Sud-Kivu, Democratic Republic of the Congo) and reported primary data on the resistance status of Anopheles funestus and Anopheles gambiae.

METHODS

Insecticide susceptibility bioassays were performed on wild populations of A. funestus and A. gambiae using WHO insecticide-impregnated papers at discriminating concentration. In addition, PCR was performed to identify mosquito species and to detect kdr and ace-1R mutations involved in insecticide resistance.

RESULTS

Bioassay results show resistance to all tested insecticides except pirimiphos-methyl, propoxur, fenitrothion and malathion with a mortality rate ranging from 95.48 to 99.86%. The addition of piperonyl butoxide (PBO) increased the susceptibility of vectors to deltamethrin and alpha-cypermethrin by exhibiting a mortality ranging from 91.50 to 95.86%. The kdr mutation was detected at high frequencies (approximately 0.98) within A. gambiae while ace-1R was not detected.

CONCLUSIONS

This study provides useful data on the insecticide resistance profiles of malaria vector populations to better manage vector control. Our results highlight that, despite the high level of resistance, organophosphorus compounds and pyrethroids + PBO remain effective against the vectors.

The fabric of life: what if mosquito nets were durable and widely available but insecticide-free?

BACKGROUND

Bed nets are the commonest malaria prevention tool and arguably the most cost-effective. Their efficacy is because they prevent mosquito bites (a function of physical durability and integrity), and kill mosquitoes (a function of chemical content and mosquito susceptibility). This essay follows the story of bed nets, insecticides and malaria control, and asks whether the nets must always have insecticides.

METHODS

Key attributes of untreated or pyrethroid-treated nets are examined alongside observations of their entomological and epidemiological impacts. Arguments for and against adding insecticides to nets are analysed in contexts of pyrethroid resistance, personal-versus-communal protection, outdoor-biting, need for local production and global health policies.

FINDINGS

Widespread resistance in African malaria vectors has greatly weakened the historical mass mosquitocidal effects of insecticide-treated nets (ITNs), which previously contributed communal benefits to users and non-users. Yet ITNs still achieve substantial epidemiological impact, suggesting that physical integrity, consistent use and population-level coverage are increasingly more important than mosquitocidal properties. Pyrethroid-treatment remains desirable where vectors are sufficiently susceptible, but is no longer universally necessary and should be re-examined alongside other attributes, e.g. durability, coverage, acceptability and access. New ITNs with multiple actives or synergists could provide temporary relief in some settings, but their performance, higher costs, and drawn-out innovation timelines do not justify singular emphasis on insecticides. Similarly, sub-lethal insecticides may remain marginally-impactful by reducing survival of older mosquitoes and disrupting parasite development inside the mosquitoes, but such effects vanish under strong resistance.

CONCLUSIONS

The public health value of nets is increasingly driven by bite prevention, and decreasingly by lethality to mosquitoes. For context-appropriate solutions, it is necessary to acknowledge and evaluate the potential and cost-effectiveness of durable untreated nets across different settings. Though ~ 90% of malaria burden occurs in Africa, most World Health Organization-prequalified nets are manufactured outside Africa, since many local manufacturers lack capacity to produce the recommended insecticidal nets at competitive scale and pricing. By relaxing conditions for insecticides on nets, it is conceivable that non-insecticidal but durable, and possibly bio-degradable nets, could be readily manufactured locally. This essay aims not to discredit ITNs, but to illustrate how singular focus on insecticides can hinder innovation and sustainability.

Rapid shifts in the age-specific burden of malaria following successful control interventions in four regions of Uganda

Background

Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear.

Methods

Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites.

Results

Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively.

Conclusions

These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.

The importance of vector control for the control and elimination of vector-borne diseases

Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished history. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of many VBDs. Here, we describe the history of vector control programmes worldwide from the late 1800s to date. Pre 1940, vector control relied on a thorough understanding of vector ecology and epidemiology, and implementation of environmental management tailored to the ecology and behaviour of local vector species. This complex understanding was replaced by a simplified dependency on a handful of insecticide-based tools, particularly for malaria control, without an adequate understanding of entomology and epidemiology and without proper monitoring and evaluation. With the rising threat from insecticide-resistant vectors, global environmental change, and the need to incorporate more vector control interventions to eliminate these diseases, we advocate for continued investment in evidence-based vector control. There is a need to return to vector control approaches based on a thorough knowledge of the determinants of pathogen transmission, which utilise a range of insecticide and non-insecticide-based approaches in a locally tailored manner for more effective and sustainable vector control.

[Next-generation vector control]

Vector control is a cornerstone of vector-borne infectious disease control, a group of emerging and re-emerging diseases of major public health concern at a global scale. The history and evolution of mosquito disease vectors control, mainly based on the use of chemical insecticides, is emblematic of the successes, failures, lessons learned and experiences gained in setting-up and implementing vector control, and of the challenges that pave the way to sustainable disease vector management. This paper provides a non-exhaustive and non-exclusive overview of some of the most promising cutting-edge technical and strategic innovations that are committed to this endeavour, assessing the strength of scientific evidences for proof of concept, perspectives for scaling-up, and expected impact and outcomes in a rapidly changing world.

LLIN Evaluation in Uganda Project (LLINEUP): factors associated with ownership and use of long-lasting insecticidal nets in Uganda: a cross-sectional survey of 48 districts

BACKGROUND

Long-lasting insecticidal nets (LLINs) are a key malaria control intervention. To investigate factors associated with ownership and use of LLINs in Uganda, a cross-sectional community survey was conducted in March-June 2017, approximately 3 years after a national Universal Coverage Campaign (UCC).

METHODS

Households from 104 clusters (health sub-districts) in 48 districts were randomly selected using two-staged cluster sampling; 50 households were enrolled per cluster. Outcomes were household ownership of LLINs (at least one LLIN), adequate LLIN coverage (at least one LLIN per 2 residents), and use of LLINs (resident slept under a LLIN the previous night). Associations between variables of interest and outcomes were made using multivariate logistic regression.

RESULTS

In total, 5196 households, with 29,627 residents and 6980 bed-nets, were included in the analysis. Overall, 65.0% of households owned at least one LLIN (down from 94% in 2014). In the adjusted analysis, factors most strongly associated with LLIN ownership were living in a wealthier household (highest tercile vs lowest; adjusted odds ratio [aOR] 1.94, 95% CI 1.66-2.28, p < 0.001) and time since the last UCC (29-37 vs 42-53 months; aOR 1.91, 95% CI 1.60-2.28, p < 0.001). Only 17.9% of households had adequate LLIN coverage (down from 65% in 2014). Factors most strongly associated with adequate coverage were fewer residents (2-4 vs ≥ 7; aOR 6.52, 95% CI 5.13-8.29, p < 0.001), living in a wealthier household (highest tercile vs lowest; aOR: 2,32, 95% CI 1.88-2.85, p < 0.001) and time since the last UCC (29-37 vs 42-53 months; aOR 2.13, 95% CI 1.61-2.81, p < 0.001). Only 39.5% of residents used a LLIN the previous night. Age was strongly associated with LLIN use, as were household wealth and time since the last UCC. Children < 5 years (44.7%) and residents > 15 years (44.1%) were more likely to use nets than children aged 5-15 years (30.7%; < 5 years: aOR 1.71, 95% CI 1.62-1.81, p < 0.001; > 15 years: aOR 1.37, 95% CI 1.29-1.45, p < 0.001).

CONCLUSIONS

Long-lasting insecticidal net ownership and coverage have reduced markedly in Uganda since the last net distribution campaign in 2013/14. Houses with many residents, poorer households, and school-aged children should be targeted to improve LLIN coverage and use. Trial registration This study is registered with ISRCTN (17516395).

Insecticide-treated nets mass distribution campaign: benefits and lessons in Zambia

BACKGROUND

Zambia was an early adopter of insecticide-treated nets strategy in 2001, and policy for mass distribution with long-lasting insecticidal nets (LLINs) in 2005. Since then, the country has implemented mass distribution supplemented with routine delivery through antenatal care and under five clinics in health facilities. The national targets of universal (100%) coverage and 80% utilization of LLINs have not been attained. Free mass LLIN distribution campaign in Zambia offers important lessons to inform future campaigns in the African region.

METHODS

This study reviewed LLIN free mass distribution campaign information derived from Zambia's national and World Health Organization Global Malaria Programme annual reports and strategic plans published between 2001 and 2016.

RESULTS

In 2014, a nationwide mass distribution campaign in Zambia delivered all the 6.0 million LLINs in 6 out of 10 provinces in 4 months between June and September before the onset of the rainy season. Compared with 235,800 LLINs and 2.9 million LLINs distributed on a rolling basis in 2008 and 2013, respectively, the 2014 mass campaign, which distributed 6 million LLINs represented the largest one-time-nationwide LLIN distribution in Zambia. The province (Luapula) with highest malaria transmission, mostly with rural settings recorded 98-100% sleeping spaces in homes covered with LLINs. The percentage of households owning at least 1 LLIN increased from 50.9% in 2006 to 77.7% in 2015. The 2014 mass campaign involved a coordinated response with substantial investments into macro (central) and micro (district) level planning, capacity building, tracking and logistics management supported by a new non-health sector partnership landscape. Coordination of LLIN distribution and logistics benefited from the mobile phone technology to transmit "real time" data on commodity tracking that facilitated timely delivery to districts.

CONCLUSION

Free mass distribution of LLINs policy was adopted in 2005 in Zambia. Consistently implemented, has not only contributed to increased coverage of LLINs, but has also produced the added value and lessons of strengthening joint planning, strategic coordination, partnerships with non-health sector institutions and community engagement with traditional leaders at community. Furthermore, the mass distribution, through improving coverage has indirect added (spin-off) value or impact on other arthropod-borne diseases, in addition to malaria.

The effect of price on demand for and use of bednets: evidence from a randomized experiment in Madagascar

There is an on-going debate about whether health products, such as insecticide-treated bednets (ITNs) for protection against malaria, should be distributed for free or at a positive price to maximize ownership and use. One argument in favour of free distribution is related to positive externalities. Like vaccines, individual use of ITNs provides a community-wide protective effect against malaria even for non-users. In addition, price may act as a barrier to ownership particularly among those most at-risk who are frequently poor. Alternatively, charging a positive price may reduce donor dependence, more efficiently allocate nets to those most at risk of malaria, and encourage use through a hypothesized sunk cost effect, where individuals are more likely to use goods they pay for. Using a randomized experiment in Madagascar, we evaluate the impact of price on demand for and use of ITNs. We find that price negatively affects both demand and use of ITNs. When price increases by $0.55, demand falls by 23.1% points (CI 19.6–26.6; P < 0.01) and effective coverage falls by 23.1% points (CI 19.6–26.6; P < 0.01). We fail to find evidence of a screening effect for prices greater than zero, but households eligible for free ITNs are more likely to use them if they have more self-reported fevers in the household at baseline. We also fail to find evidence of a sunk cost effect, meaning that households are not more likely to use nets that they pay for. Our results suggest that: (1) only partially subsidizing ITNs significantly limits ownership and (2) distributing ITNs for free or at a small nominal price will maximize demand and effective coverage. Alternative sources of financing should be identified to completely (or almost completely) subsidize the cost of ITNs in order to maximize coverage of ITNs among poor populations at risk of malaria.

Monitoring of long-lasting insecticidal nets (LLINs) coverage versus utilization: a community-based survey in malaria endemic villages of Central India

Background

Despite the known effectiveness of long-lasting insecticidal nets (LLINs) in providing protection against malaria, high level of ownership and use are very difficult to achieve and maintain. Nearly 40,000 LLINs were distributed in 2014 as an intervention tool against malaria transmission in 80 villages of Keshkal sub-district in Chhattisgarh, India. This study assessed LLIN coverage, access, utilization pattern, and key determinants for the net use 1 year after mass distribution.

Methods

In 2015, a cross-sectional household survey was carried out in 80 study clusters (whole village or part of village). From each cluster, 40 households were randomly selected and interviewed using a structured questionnaire adapted from the malaria indicator survey of Roll Back Malaria guidelines. Information on demographic characteristics, LLIN ownership, and its use on the night before the survey, and physical condition of LLINs were recorded.

Results

2970 households were interviewed with a total of 15,003 individuals present in the households during the night before the survey. Nearly 98% of households had at least one LLIN and 59.4% of the surveyed population reportedly used an LLIN the previous night. LLIN use varied from 41 to 94% between the study clusters. Nearly 89% of the LLINs were found in good physical condition (without holes). However, proportion of household with at least one LLIN per two persons was only 39%.

Conclusion

Universal coverage of LLINs was inadequate in the study clusters making it difficult for all household members to use an LLIN. LLIN use varied between clusters and was highest in children under 5 years of age. Health education campaigns and creating awareness about the benefit of sleeping under the LLINs in providing protection against malaria is required not only to high risk groups of pregnant women and children below 5 years of age but all the members of the family to have an epidemiological impact of this intervention at the community level. Relatively high net use despite poor access to LLINs indicates an overall desire to use nets when they are available. The main barrier to increased use of nets is the low coverage at household level.

The paradigm of eave tubes: scaling up house improvement and optimizing insecticide delivery against disease-transmitting mosquitoes

Control of mosquito-borne diseases is greatly compromised by spread of insecticide resistance, high implementation costs and sub-optimal compliance among users. Improved housing has potential to reduce malaria transmission nearly as much as long-lasting insecticide-treated nets (LLINs), while also preventing other arthropod-borne diseases and improving overall well-being. Yet, it is hardly promoted as mainstream intervention, partly because of high costs, minimal communal benefits to people in non-improved houses, and low scalability. By exploiting biological observations of mosquito behaviours around dwellings, scientists have developed a new approach that integrates effective vector control into housing developments. The technique involves blocking eave spaces in local houses, leaving a few cylindrical holes into which plastic tubes with insecticide-laden electrostatic nettings are inserted. Where houses already have blocked eaves, these cylindrical holes are drilled and the tubes inserted. The eave tube technology, as it is called, is an innovative new approach for implementing housing improvements, by creating a new scalable product that can be integrated in houses during or after construction. It takes away insecticides from proximity of users, and instead puts them where mosquitoes are most likely to enter houses, thereby reducing insecticidal exposure among household occupants, while maximizing exposure of mosquitoes. This way, lower quantities of insecticides are used, better house ventilation achieved, intervention costs reduced, and mass communal benefits achieved even were vectors are resistant to similar insecticides when delivered conventionally. There are however still some critical pieces missing, notably epidemiological, social and economic evidence that the above assertions are true and sustainable. Besides, there also some technical limitations to be considered, namely: (1) need for extensive house modifications before eave tubes are inserted, (2) ineligibility of poorest and highest-risk households living in housing structures not amenable to eave tubes, and (3) poor synergies when eave tubes are combined with LLINs or IRS in same households. Overall, this paradigm significantly improves delivery of insecticides against disease-transmitting mosquitoes, and provides opportunities for scaling-up the long-neglected concept of house improvement as a malaria intervention.

The effectiveness of a nationwide universal coverage campaign of insecticide-treated bed nets on childhood malaria in Malawi

Background

Although the universal coverage campaign of insecticide-treated mosquito bed nets (ITNs) has been associated with improved malaria outcomes, recent reports indicate that the campaign is losing its sparkle in some countries. In Malawi, the universal coverage campaign was implemented in 2012, but its impacts are yet to be ascertained. Thus, this study examined the effects of the campaign on malaria morbidity among children in Malawi.

Methods

This is a repeated cross-sectional study. The study used nationally-representative malaria indicator survey (MIS) data collected in 2012 and 2014. In total, the analysis included 4193 children between the ages of 6 and 59 months (2171 from 2012 MIS and 2022 from 2014 MIS). ITNs coverage and malaria morbidity before (2012 = pre-test/control) and after (2014 = post-test/treated) the universal coverage campaign of ITNs were compared. The treated and control samples were matched on measured relevant covariates using propensity scores.

Results

The mean number of ITNs per household improved significantly from 1.1 (SD 1.0) in 2012 to 1.4 (SD 1.1) in 2014 (p < 0.001). Nonetheless, the prevalence of malaria among children increased considerably from 27.7 % (2012) to 32.0 % (2014) (p = 0.002). The risk of malaria was also significantly higher in 2014 compared to 2012 (RR = 1.14; 95 % CI 1.01–1.29). Besides, the use of bed nets was not significantly associated with malaria morbidity in 2014 (RR = 0.92; 95 % CI 0.76–1.12), but it was in 2012 (RR = 0.83; 95 % CI 0.70–1.00).

Conclusions

The universal coverage campaign of ITNs was not associated with a reduced burden of malaria among children in Malawi. This was likely due to increased insecticide resistance, inconsistent use of bed nets and under-utilization of other methods of malaria control. This calls for a multifaceted approach in the fight against malaria instead of simple dependence on ITNs. In particular, local or community level malaria interventions should go hand in hand with the universal coverage campaign.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-016-1550-9) contains supplementary material, which is available to authorized users.

Use of long-lasting insecticide-treated bed nets in a population with universal coverage following a mass distribution campaign in Uganda

Background

Uganda conducted an LLIN mass distribution campaign in 2013 with the goal of achieving universal coverage. Using data from the 2014 malaria indicator survey, this analysis estimated the proportion of the population with access to an LLIN that slept under one the night before the survey and factors associated with not using an LLIN in households that had achieved universal coverage.

Methods

This was a secondary data analysis using the 2014 malaria indicator survey dataset. The outcome was use of an LLIN among households that achieved universal coverage, while independent variables include age, gender, number of household members, residence, number of sleeping rooms, spraying of rooms with insecticide, number of children under 5 years of age, number of women of child-bearing age, relationship structure and community distribution of ant-malarial medicine.

Results

Overall, 3361 (62 %) households of the 5345 achieved universal coverage and were included in the analysis giving a total population of 14,450 individuals. Of these, 11,884 (80.10 %) reported to have slept under an LLIN the night before the survey. Children between 6 and 14 years were significantly less likely to use an LLIN when compared to those under 5 years (75.26 vs 83.12 %), [adjusted OR, 1.29 (1.11–1.49), p = 0.001]. The odds of not using an LLIN, significantly increased from households with five members when compared to those that had one member (79.53 vs 84.88 %), [adjusted OR, 2.16 (1.38–3.38), p = 0.001] and rising even further in households with six or more members (78.04 vs 84.88 %), [OR, 2.27 (1.36–3.71), p = 0.003].

Conclusions

This analysis has showed that 80 % of the population used an LLIN among households that achieved universal coverage following the 2013 mass distribution campaign, especially among children under 5 years, an operational success in this category. However, children between 6 and 14 years and individuals from households with five or more numbers are less likely to use the LLINs. In order to improve usage in these categories, it may require re-focusing the behaviour change communication message to be all-inclusive, especially in era of universal coverage, and to increase the number of LLINs distributed in households with more than four members during future mass distribution campaigns, respectively.

A systematic review of knowledge, attitudes and beliefs about malaria among the South Asian population

BACKGROUND

Malaria is one of the deadliest mosquito-borne diseases in the world. More than 80% of the total populations are at risk of malaria in the 22 countries in Asia and the Pacific. South Asia alone is home to an estimated 1.4 billion people at risk of contracting malaria. Despite the remarkable progress in reducing the burden of malaria, evidence of the disease based on knowledge of the social and cultural contexts from a South Asian perspective is limited. Our objective was to understand the knowledge, attitudes and beliefs about malaria in South Asian communities.

METHODOLOGY

We conducted a systematic literature review, searching six databases, between 1990 and 2015, focusing on knowledge, attitudes and beliefs about malaria in South Asia. Databases were searched using both 'free terms' and 'index terms' funnelled using Boolean operators and truncations. Inclusion and exclusion criteria were set, and included papers were scrutinised, employing a critical appraisal tool to find the best available evidences to support the study purpose.

RESULTS AND DISCUSSION

Evidence from 32 articles (26 quantitative, four qualitative and two mixed methods). General knowledge and awareness of the disease, its transmission, and control and preventative measures were generally found to be lacking amongst both the general public and healthcare professionals. In addition, the study shows that poor socio-economic factors - including limited access to services due to poor/limited availability - and issues of affordability are considered as major risk factors.

CONCLUSION

This review suggests the importance of increasing health awareness, mobilising the local or community healthcare professionals, for prevention as well as early detection and effective treatment of malaria among people who are at risk. Malaria is also a disease associated with poverty and socio-cultural factors; therefore, strong political will, wider partnerships between health and non-health sectors, and strengthening health systems' technical and managerial capabilities at all level of primary healthcare systems, is inevitable.

The risk of incomplete personal protection coverage in vector-borne disease

Personal protection (PP) techniques, such as insecticide-treated nets, repellents and medications, include some of the most important and commonest ways used today to protect individuals from vector-borne infectious diseases. In this study, we explore the possibility that a PP intervention with partial coverage may have the counterintuitive effect of increasing disease burden at the population level, by increasing the biting intensity on the unprotected portion of the population. To this end, we have developed a dynamic model which incorporates parameters that describe the potential effects of PP on vector searching and biting behaviour and calculated its basic reproductive rate, R0. R0 is a well-established threshold of disease risk; the higher R0 is above unity, the stronger the disease onset intensity. When R0 is below unity, the disease is typically unable to persist. The model analysis revealed that partial coverage with popular PP techniques can realistically lead to a substantial increase in the reproductive number. An increase in R0 implies an increase in disease burden and difficulties in eradication efforts within certain parameter regimes. Our findings therefore stress the importance of studying vector behavioural patterns in response to PP interventions for future mitigation of vector-borne diseases.

Long-lasting insecticidal net source, ownership and use in the context of universal coverage: a household survey in eastern Rwanda

Background

Universal long-lasting insecticidal net (LLIN) coverage (ULC) has reduced malaria morbidity and mortality across Africa. Although information is available on bed net use in specific groups, such as pregnant women and children under 5 years, there is paucity of data on their use among the general population. Bed net source, ownership and determinants of use among individuals from households in an eastern Rwanda community 8 months after a ULC were characterized.

Methods

Using household-based, interviewer-administered questionnaires and interviewer-direct observations, data on bed net source, ownership and key determinants of net use, including demographics, socio-economic status indicators, house structure characteristics, as well as of bed net quantity, type and integrity, were collected from 1400 randomly selected households. Univariate and mixed effects logistic regression modelling was done to assess for determinants of bed net use.

Results

A total of 1410 households and 6598 individuals were included in the study. Overall, the proportion of households with at least one net was 92 % while bed net usage was reported among 72 % of household members. Of the households surveyed, a total ownership of 2768 nets was reported, of which about 96 % were reportedly LLINs received from the ULC. By interviewer-physical observation, 88 % of the nets owned were of the LLIN type with the remaining 12 % did not carry any mark to enable type recognition. The odds of bed net use were significantly lower among males and individuals: from households of low socio-economic status, from households with <two bed nets, from households reporting use of ≥two sleeping spaces, and those reporting to have not slept on a bed.

Conclusion

In this study, despite high a bed net coverage, over 25 % of members reported not to have slept under a bed net the night before the survey. Males were particularly less likely to use bed nets even where nets were available. Household socio-economic status, number of bed nets and type and number of sleeping spaces were key determinants of bed net use. To maximize impact of ULC, strategies that target males as well as those that ensure ITN coverage for all, address barriers to feasible and convenient bed net use including covering over all sleeping space types, and provide net hanging supports, are needed.

Evaluation of a universal coverage bed net distribution campaign in four districts in Sofala Province, Mozambique

BACKGROUND

Malaria is the leading cause of death in Mozambique in children under five years old. In 2009, Mozambique developed a novel bed net distribution model to increase coverage, based on assumptions about sleeping patterns. The coverage and impact of a bed net distribution campaign using this model in four districts in Sofala Province, Mozambique was evaluated.

METHODS

Paired household, cross-sectional surveys were conducted one month after the 2010 distribution of 140,000 bed nets and again 14 months after the campaign in 2011. During household visits, malaria blood smears were performed and haemoglobin levels were assessed on children under five and data on bed net ownership, access and use were collected; these indicators were analysed at individual, household and community levels. Logistic regression was used to evaluate predictors of malaria infection and anaemia.

RESULTS

The campaign reached 98% (95% CI: 97-99%) of households registered during the precampaign listing, with 81% (95% CI: 77-85%) of sleeping spaces covered by campaign bed nets and 85% (95% CI: 81-88%) of the population sleeping in a sleeping space with a campaign bed net designated for the sleeping space. One year after the campaign, 65% (95% CI: 57-72%) of sleeping spaces were observed to have hanging bed nets. The proportion of sleeping spaces for which bed nets were reported used four or more times per week was 65% (95% CI: 56-74%) in the wet season and 60% (95% CI: 52-68%) in the dry season. Malaria parasitaemia prevalence in children under five years old was 47% (95% CI: 40-54%) in 2010 and 36% (95% CI: 27-45%) in 2011. Individual-level malaria infection and anaemia were significantly associated with community-level use of bed nets.

CONCLUSIONS

The campaign using the novel distribution model achieved high coverage, although usage was not uniformly high. A significant decrease in malaria parasitaemia prevalence a year after the campaign was not observed, but community-level use of bed nets was significantly associated with a reduced risk for malaria infection and anaemia in children under five.

Individual and household factors associated with use of insecticide treated nets in southern Ethiopia

BACKGROUND

Although mass distribution has been considered as the best method to rapidly scale up the coverage of long-lasting insecticidal nets (LLINs) for malaria prevention, little information is available on determinants associated with net utilization at local settings. We studied individual and household factors associated with LLIN use in Halaba district in southern Ethiopia.

METHODS

This is a population-based survey conducted in October 2008 in 16 randomly selected villages. Data on individual and household characteristics, LLIN ownership and use were collected through house-to-house visits. Univariate and multiple logistic regression models were used to examine the effect of each independent variable on LLIN use by respondents.

RESULTS

A total of 1235 households participated in the study, and 755/1235 (61.1%) had owned at least one LLIN. Among LLIN-owning households, 419/629 (66.6%) children under the age of five years and 33/55 (60.0%) pregnant women slept under an LLIN the night before the survey. The number of LLINs hung in the household (adjusted OR [aOR] 13.2, 95% CI: 3.7-47.5) and knowledge about malaria (aOR 2.3, 95% CI: 1.2-4.5) were the two important predictors associated with LLINs use.

CONCLUSIONS

A substantial gap between net ownership and use was identified. Hanging nets and knowledge of malaria predict higher odds of sleeping under an LLIN the previous night. More intensive research on factors that contribute to low LLIN usage is needed.

Long-lasting insecticide-treated bed net ownership and use among children under five years of age following a targeted distribution in central Uganda

Background

Universal coverage of long-lasting insecticide-treated bed nets (LLINs) for prevention of malaria was adopted by the Uganda National Malaria Control Programme in 2007. The first mass distribution of LLINs was implemented in 2010. Initially, a campaign targeted to households with pregnant women and children aged <five years was carried out, prior to a planned fill-in campaign to achieve universal LLIN coverage. This survey was conducted after the targeted distribution in central Uganda to assess progress in LLIN ownership and usage among children <five years.

Methods

A two-stage, cluster-sample, cross-sectional household survey was carried out in early 2011 in Central region districts surveyed during the 2009 Malaria Indicator Survey (MIS). In the first sampling stage, 30 enumeration areas (EAs) were selected and all households were enumerated. Within each sampled EA, 20 households were randomly selected for interview using two questionnaires: a household questionnaire and a woman’s questionnaire for all women aged 15-49 years, both modified from the MIS.

Results

When compared to 2009 MIS results, household ownership of at least one LLIN increased by 47%, from 22 to 69% after the targeted campaign. LLIN use among children <five years increased by 40%, from 11 to 51%. Households with a child <six years old at the time of the survey, a proxy for those targeted, were significantly more likely to have received a campaign bed net (80.7 vs 35.2%, p < 0.001). LLIN ownership and use was equitable after the targeted campaign, with no significant differences by household wealth status.

However, the proportion of households with at least one LLIN per two people was still low after the first campaign phase, increasing from 8.5 to 25.9%.

Conclusions

The first phase of the campaign led to substantial increases in both LLIN ownership and equitable use among children <five years in the Central region. However, access to an LLIN within the household was still low after the first phase of the campaign, indicating the need for the universal fill-in campaign.

Transmission of malaria in relation to distribution and coverage of long-lasting insecticidal nets in central Côte d'Ivoire

Background

The use of long-lasting insecticidal nets (LLINs) is an effective malaria control strategy. However, there are challenges to achieve high coverage, such as distribution sustainability, and coverage keep-up. This study assessed the effect of LLINs coverage and contextual factors on entomological indicators of malaria in rural Côte d’Ivoire.

Methods

The study was carried out between July 2009 and May 2012 in three villages (Bozi, N’Dakonankro and Yoho) of central Côte d’Ivoire. In Bozi and Yoho, LLINs were distributed free of charge by the national malaria control programme in 2008. In Bozi, an additional distribution was carried out in May 2011. No specific interventions were done in N’Dakonankro. Entomological surveys were conducted in July 2009 and July 2010 (baseline), and in August and November 2011 and in February 2012. Frequency of circumsporozoite protein was determined using an enzyme-linked immunosorbent assay. Regression models were employed to assess the impact of LLINs and changing patterns of irrigated rice farming on entomological parameters, and to determine associations with LLINs coverage and other contextual factors.

Results

In Bozi, high proportion of LLIN usage was observed (95-100%). After six months, 95% of LLINs were washed at least once and 79% were washed up to three times within one year. Anopheles gambiae was the predominant malaria vector (66.6% of all mosquitoes caught). From 2009 to 2012, in N’Dakonankro, the mean annual entomological inoculation rate (EIR) increased significantly from 116.8 infectious bites/human/year (ib/h/y) to 408.8 ib/h/y, while in the intervention villages, the EIR decreased significantly from 514.6 ib/h/y to 62.0 ib/h/y (Bozi) and from 83.9 ib/h/y to 25.5 ib/h/y (Yoho). The risk of an infectious bite over the three-year period was significantly lower in the intervention villages compared to the control village (p <0.001).

Conclusion

High coverage and sensitization of households to use LLINs through regular visits (particularly in Bozi) and abandoning irrigated rice farming (in Yoho) resulted in highly significant reductions of EIR. The national malaria control programme should consider household sensitization and education campaigns and other contextual factors to maximize the benefit of LLINs.

Impact of long-lasting, insecticidal nets on anaemia and prevalence of Plasmodium falciparum among children under five years in areas with highly resistant malaria vectors

Background

The widespread use of insecticide-treated nets (LLINs) leads to the development of vector resistance to insecticide. This resistance can reduce the effectiveness of LLIN-based interventions and perhaps reverse progress in reducing malaria morbidity. To prevent such difficulty, it is important to know the real impact of resistance in the effectiveness of mosquito nets. Therefore, an assessment of LLIN efficacy was conducted in malaria prevention among children in high and low resistance areas.

Methods

The study was conducted in four rural districts and included 32 villages categorized as low or high resistance areas in Plateau Department, south-western Benin. Larvae collection was conducted to measure vector susceptibility to deltamethrin and knockdown resistance (kdr) frequency. In each resistance area, around 500 children were selected to measure the prevalence of malaria infection as well as the prevalence of anaemia associated with the use of LLINs.

Results

Observed mortalities of Anopheles gambiae s.s population exposed to deltamethrin ranged from 19 to 96%. Knockdown resistance frequency was between 38 and 84%. The prevalence of malaria infection in children under five years was 22.4% (19.9-25.1). This prevalence was 17.3% (14.2-20.9) in areas of high resistance and 27.1% (23.5-31.1) in areas of low resistance (p = 0.04). Eight on ten children that were aged six - 30 months against seven on ten of those aged 31–59 months were anaemic. The anaemia observed in the six to 30-month old children was significantly higher than in the 31–59 month old children (p = 0.00) but no difference associated with resistance areas was observed (p = 0.35). The net use rate was 71%. The risk of having malaria was significantly reduced (p < 0.05) with LLIN use in both low and high resistance areas. The preventive effect of LLINs in high resistance areas was 60% (95% CI: 40–70), and was significantly higher than that observed in low resistance areas (p < 0.05).

Conclusion

The results of this study showed that the resistance of malaria vectors seems to date not have affected the impact of LLINs and the use of LLINs was highly associated with reduced malaria prevalence irrespective of resistance.

Proposed use of spatial mortality assessments as part of the pesticide evaluation scheme for vector control

Background

The WHO Pesticide Evaluation Scheme to evaluate the efficacy of insecticides does not include the testing of a lethal effect at a distance. A tool was developed to evaluate the spatial mortality of an insecticide product against adult mosquitoes at a distance under laboratory and field conditions. Operational implications are discussed.

Methods

Insecticide paint, Inesfly 5A IGR™, containing two organophosphates (OPs): chlorpyrifos and diazinon, and one insect growth regulator (IGR): pyriproxyfen, was the product tested. Laboratory tests were performed using “distance boxes” with surfaces treated with one layer of control or insecticide paint at a dose of 1 kg/6 sq m. Field tests were conducted up to 12 months in six experimental huts randomly allocated to control or one or two layers of insecticide paint at 1 kg/6 sq m. All distance tests were performed using reference-susceptible strains of Anopheles gambiae and Culex quinquefasciatus left overnight at a distance of 1 m from control or treated surfaces.

Results

After an overnight exposition at distances of 1 m, field and laboratory evaluations at 0 months after treatment (T0) yielded 100% mortality rates on surfaces treated with one layer at 1 kg/6 sq m against susceptible strains of An. gambiae and Cx. quinquefasciatus. Testing for long-term efficacy in the field gave mortality rates of 96-100% after an overnight exposition at a distance of 1 m for up to 12 months in huts where a larger volume was treated (walls and ceilings) with one or two layers of insecticide paint.

Conclusion

A comprehensive evaluation of the full profile of insecticide products, both upon contact and spatially, may help rationalize vector control efforts more efficiently. Treating a large enough volume may extend a product’s mortality efficacy in the long-term, which contact tests would fail to assess. It is hereby proposed to explore the development of cost effective methods to assess spatial mortality and to include them as one additional measurement of insecticide efficacy against mosquitoes and other arthropod vectors in WHOPES Phase I and Phase II studies.

Evaluation of the coverage and effective use rate of long-lasting insecticidal nets after nation-wide scale up of their distribution in Benin

Background

In Benin, around four million Long-Lasting Insecticide-treated Nets were freely distributed to household to prevent malaria in 2011. In contrast to a previous campaign that targeted only children under 5 years and pregnant women, this distribution campaign was conducted in order to achieve universal coverage. This study presents the results of LLIN coverage and utilization after the distribution campaign.

Methods

The study was a cross-sectional household survey which utilized a stratified two-stage cluster sampling design. The strata represented the twelve departments covered by the national distribution campaign in 2011 and included a total of 4,800 households randomly selected in the country. A questionnaire adapted from the standard Malaria Indicator Survey (MIS) Household Questionnaire was used. Data were entered using QPS software and analyzed with R 2.14.1.

Results

LLIN ownership was 86.4% (74 – 94). On average, each household received 3 LLINs (2–4). The proportion of households that met the ratio one net for two persons was 77%.

The proportions of individuals sleeping under LLINs were high (84.8%). LLIN use among urban residents was 10% lower than in effective users from rural areas (P = 0.00224).

Conclusions

The universal distribution campaign conducted in Benin has increased LLIN ownership and use in the community. But additional efforts are need to improve and maintain LLIN coverage.

Exploring the impact of targeted distribution of free bed nets on households bed net ownership, socio-economic disparities and childhood malaria infection rates: analysis of national malaria survey data from three sub-Saharan Africa countries

Background

The last decade has witnessed increased funding for malaria control. Malaria experts have used the opportunity to advocate for rollout of such interventions as free bed nets. A free bed net distribution strategy is seen as the quickest way to improve coverage of effective malaria control tools especially among poorest communities. Evidence to support this claim is however, sparse. This study explored the effectiveness of targeted free bed net distribution strategy in achieving equity in terms of ownership and use of bed nets and also reduction of malaria prevalence among children under-five years of age.

Methods

National malaria indicator survey (MIS) data from Angola, Tanzania and Uganda was used in the analysis. Hierarchical multilevel logistic regression models were used to analyse the relationship between variables of interest. Outcome variables were defined as: childhood test-confirmed malaria infections, household ownership of any mosquito net and children’s use of any mosquito nets. Marginal effects of having free bed net distribution on households with different wealth status were calculated.

Results

Angolan children from wealthier households were 6.4 percentage points less likely to be parasitaemic than those in poorest households, whereas those from Tanzania and Uganda were less likely to test malaria positive by 7 and 11.6 percentage points respectively (p < 0.001). The study estimates and present results on the marginal effects based on the impact of free bed net distribution on children's malaria status given their socio-economic background. Poorest households were less likely to own a net by 21.4% in Tanzania, and 2.8% in Uganda, whereas both poorer and wealthier Angolan households almost achieved parity in bed net ownership (p < 0.001). Wealthier households had a higher margin of using nets than poorest people in both Tanzania and Uganda by 11.4% and 3.9% respectively. However, the poorest household in Angola had a 6.1% net use advantage over children in wealthier households (p < 0.001).

Conclusion

This is the first study to use nationally representative data to explore inequalities in bed net ownership and related consequences on childhood malaria infection rates across different countries. While targeted distribution of free bed nets improved overall bed net ownership, it did not overcome ownership inequalities as measured by household socioeconomic status. Use of bed nets was disproportionately lower among poorest children, except for Angola where bed net use was higher among poorest households when compared to children in wealthier households. The study highlights the need for malaria control world governing bodies and policy makers to continue working on finding appropriate strategies to improve access to effective malaria control tools especially by the poorest who often times bears the brunt of malaria burden than their wealthier counterparts.

High effective coverage of vector control interventions in children after achieving low malaria transmission in Zanzibar, Tanzania

Background

Formerly a high malaria transmission area, Zanzibar is now targeting malaria elimination. A major challenge is to avoid resurgence of malaria, the success of which includes maintaining high effective coverage of vector control interventions such as bed nets and indoor residual spraying (IRS). In this study, caretakers' continued use of preventive measures for their children is evaluated, following a sharp reduction in malaria transmission.

Methods

A cross-sectional community-based survey was conducted in June 2009 in North A and Micheweni districts in Zanzibar. Households were randomly selected using two-stage cluster sampling. Interviews were conducted with 560 caretakers of under-five-year old children, who were asked about perceptions on the malaria situation, vector control, household assets, and intention for continued use of vector control as malaria burden further decreases.

Results

Effective coverage of vector control interventions for under-five children remains high, although most caretakers (65%; 363/560) did not perceive malaria as presently being a major health issue. Seventy percent (447/643) of the under-five children slept under a long-lasting insecticidal net (LLIN) and 94% (607/643) were living in houses targeted with IRS. In total, 98% (628/643) of the children were covered by at least one of the vector control interventions. Seasonal bed-net use for children was reported by 25% (125/508) of caretakers of children who used bed nets. A high proportion of caretakers (95%; 500/524) stated that they intended to continue using preventive measures for their under-five children as malaria burden further reduces. Malaria risk perceptions and different perceptions of vector control were not found to be significantly associated with LLIN effective coverage.

Conclusions

While the majority of caretakers felt that malaria had been reduced in Zanzibar, effective coverage of vector control interventions remained high. Caretakers appreciated the interventions and recognized the value of sustaining their use. Thus, sustaining high effective coverage of vector control interventions, which is crucial for reaching malaria elimination in Zanzibar, can be achieved by maintaining effective delivery of these interventions.

Field evaluation of permethrin long-lasting insecticide treated nets (Olyset(®)) for malaria control in an endemic area, southeast of Iran

Long lasting insecticide treated nets (LLINs) have been advocated as an effective tool for prevention and control of malaria. Olyset net was the first LLINs which became commercially available and obtained WHO approval. According to the national strategic plan on evaluation of Olyset net, a field trial was conducted to determine the efficacy of these nets against malaria vectors in an endemic area in the southeast of Iran. Fourteen villages with similar topographical and epidemiological situations were selected and randomly assigned to two clusters of the study: Olyset net and untreated net. Distribution of nets was carried out to cover 100% of the population in Olyset net and untreated net cluster. Anopheline mosquitoes were collected monthly using different WHO standard methods in both areas to determine their abundance, feeding pattern and resting behaviour. Human blood index was determined using ELISA test. Additionally, Olyset nets were evaluated for their biological activity using WHO cone bioassay test by susceptible colony of Anopheles stephensi (Beech strain) and then for insecticide residues by employing high performance thin layer chromatography. Malaria incidence was measured by passive and active case detection from all study population. In total 2115 adult anopheline mosquitoes were collected and identified using morphological characters. They comprised of seven species: Anopheles dthali (Liston), A. culicifacies (Giles), A. stephensi (Liston), A. superpictus (Grassi), A.fluviatilis (James), A. moghulensis (Christophers) and A. turkhudi (Liston). A. dthali, A. culicifacies and A. stephensi were most prevalent species in both areas. In the Olyset net study area, there was a significant reduction of 41.1%, 54.4%, 59.39% and 64.1% in the indoor-resting density of A. culicifacies, A. stephensi, A. dthali and A. superpictus, respectively, with an overall reduction of 39.3% in total mosquitoes in comparison with untreated net area. A significant reduction was also observed in human blood index of vector species in the Olyset net villages. Bioefficacy test results of Olyset nets showed that the median knockdown time was 1.48 and 3.25min, while the average mortality rate was 100% and 72.3%±7.07 in baseline and after 1 year of intervention, respectively. The average permethrin content reached to 68.31% (683.1mg/m(2)) of the initial insecticide dose of 937±21.69mg/m(2) (nearly 1000mg/m(2)) at the end of intervention. Malaria incidence was reduced by 96.6% and 64.8% in the village with Olyset nets and in the villages with untreated nets, respectively. During intervention period, there was a reduction of 93.2% in malaria incidence in Olyset net area as compared to the untreated area. This study indicated that Olyset nets have a major impact on malaria vectors and disease burden; therefore it could be recommended as an effective personal protection tool for malaria control in malarious areas.

Assessment of Long-Lasting Insecticidal Nets (LLINs) on Vectors and Malaria Transmission in the Commune of Aguegues, Benin

INTRODUCTION

To overcome the problems of periodic re-impregnation of mosquito nets and low rates of treatment, the commune of Aguegues was chosen to evaluate the effects of Olyset(®) nets on malaria transmission and against An. gambiae.

METHODS

87 old Olyset(®) nets installed five years ago were identified in the village 'Akpadon'. 10 untreated nets were installed in 10 structures of type "a bedroom and parlour" in the village 'Akodji'. Four rooms without nets were identified in the village 'Donoukpa'. Entomological and epidemiological evaluations were conducted during the May to October 2011. 24 sessions of capture or 2088 men-nights resulted in the capture of 30,608 mosquitoes.

RESULTS

The entrance of anopheles was significantly reduced in the village with Olyset(®) nets. 45% of mosquitoes captured inside rooms with Olyset(®) nets were found dead after 24 hrs of obser-vation. Overall, parasitemia was very low in the treated village (4.52%). 18 (4.64%) cases of malaria fever were from Akpadon with 7.5% positive blade smear, 29 (10.98%) were from Akodji with 8.37% positive blade smear, and 80 (95.23%) come from Donoukpa with 38.09% positive blade smear. The Olyset(®) nets and untreated net were adjusted hemoglobin levels.

CONCLUSION

Olyset(®) net had a very high knock down effect and is an alternative in malaria control.

Addressing Inequities in Access to Health Products through the Use of Social Marketing, Community Mobilization, and Local Entrepreneurs in Rural Western Kenya

While social marketing can increase uptake of health products in developing countries, providing equitable access is challenging. We conducted a 2-year evaluation of uptake of WaterGuard, insecticide-treated bednets (ITNs), and micronutrient Sprinkles in Western Kenya. Sixty villages were randomly assigned to intervention and comparison groups. Following a baseline survey (BL), a multifaceted intervention comprising social marketing of these products, home visits by product vendors from a local women’s group (Safe Water and AIDS Project, or SWAP), product promotions, and modeling of water treatment and safe storage in was implemented in intervention villages. Comparison villages received only social marketing of WaterGuard and ITNs. We surveyed again at one year (FU1), implemented the intervention in comparison villages, and surveyed again at two years (FU2). At BL, <3% of households had been visited by a SWAP vendor. At FU1, more intervention than comparison households had been visited by a SWAP vendor (39% versus 9%, P<0.0001), and purchased WaterGuard (14% versus 2%, P<0.0001), Sprinkles (36% versus 6%, P<0.0001), or ITNs (3% versus 1%, P<0.04) from that vendor. During FU2, 47% and 41% of original intervention and comparison households, respectively, reported ever receiving a SWAP vendor visit (P=0.16); >90% those reported ever purchasing a product from the vendor. WaterGuard (P=0.02) and ITNs (P=0.005) were purchased less frequently by lower-SES than higher-SES households; Sprinkles, the least expensive product, was purchased equally across all quintiles.

Can universal insecticide-treated net campaigns achieve equity in coverage and use? the case of northern Nigeria

Background

Insecticide-treated nets (ITNs) are effective tools for malaria prevention and can significantly reduce severe disease and mortality due to malaria, especially among children under five in endemic areas. However, ITN coverage and use remain low and inequitable among different socio-economic groups in sub-Saharan Africa, particularly in Nigeria. Several strategies have been proposed to increase coverage and use and reduce inequity in Nigeria, including free distribution campaigns recently conducted by the Nigerian federal government. Using data from the first post-campaign survey, the authors investigated the effect of the mass free distribution campaigns in achieving equity in household ownership and use of ITNs.

Methods

A post-campaign survey was undertaken in November 2009 in northern Nigeria to assess the effect of the campaigns in addressing equity across different socio-economic groups. The survey included 987 households randomly selected from 60 clusters in Kano state. Using logistic regression and the Lorenz concentration curve and index, the authors assessed equity in ITN coverage and use.

Results

ITN ownership coverage increased from 10% before the campaigns to 70%-a more than fivefold increase. The campaigns reduced the ownership coverage gap by 75%, effectively reaching parity among wealth quintiles (Concentration index 0.02, 95% CI (-0.02 ; 0.05) versus 0.21 95%CI (0.08 ; 0.34) before the campaigns). ITN use (individuals reporting having slept under an ITN the night before the survey visit) among individuals from households owning at least one ITN, was 53.1% with no statistically significant difference between the lowest, second, third and fourth wealth quintiles and the highest wealth quintile (lowest: odds ratio (OR) 0.87, 95% confidence interval (CI) (0.67 ; 1.13); second: OR 0.85, 95% CI (0.66 ; 1.24); third: OR 1.10 95% CI (0.86 ; 1.4) and fourth OR 0.91 95% CI (0.72 ; 1.15).

Conclusion

The campaign had a significant impact by increasing ITN coverage and reducing inequity in ownership and use. Free ITN distribution campaigns should be sustained to increase equitable coverage. These campaigns should be supplemented with other ITN distribution strategies to cover newborns and replace aging nets.

Free distribution of insecticidal bed nets improves possession and preferential use by households and is equitable: findings from two cross-sectional surveys in thirteen malaria endemic districts of Bangladesh

BACKGROUND

BRAC, an indigenous non-governmental development organization (NGO), has been implementing a programme to prevent and control malaria in the 13 malaria-endemic districts of Bangladesh since 2007. One of the critical preventive interventions is the distribution of insecticidal bed nets (long-lasting insecticide-treated nets, LLINs and insecticide-treated ordinary nets, ITNs) to the community free of cost. This study aimed to assess progress in the possession, preferential use, and knowledge on use of the LLIN/ITNs including the programme's avowed pro-poor inclination one and three and half years after intervention began.

METHODS

A convenient sampling strategy based on malaria endemicity in the districts was adopted. First, thirty upazila (sub-district, with a population around 250,000)s were selected at random, with high prevalent districts contributing more upazilas; second, from each upazila, one (2008) to two (2011) villages (covered by insecticidal bed net distribution programme) were selected. From each village, households that had either one under-five child and/or a pregnant woman were included in the survey, one household being included only once. Data were collected using a pre-tested structured questionnaire.

RESULTS

In all, 3,760 households in 2008 and 7,895 households in 2011 were surveyed for collecting relevant information. Proportion of households with at least one LLIN, and at least one LLIN/ITN increased (22-59 to 62-67% and 22-64% to 74-76% respectively) over time, including increase in the mean number of LLIN/ITNs per household (≤ 1 to 1 +). The programme achieved > 80% coverage in sleeping under an LLIN/ITN in the case of under-five children and pregnant women, especially in the high-endemic districts. Knowledge regarding critical time of hanging the net also increased over time (7-22 to 44-54%), but remained low. The pro-poor inclination of the programme is reflected in the status of relevant indicators according to self-rated poverty status of the households.

CONCLUSIONS

There has been a substantial improvement in possession and usage of insecticidal bed nets especially for the two most vulnerable groups (under-five children and pregnant women), including a reduction of gaps between the high and low endemic districts, and the deficit and non-deficit households during the study period.

Polypropylene-based long-life insecticide-treated mosquito netting

The World Health Organization (WHO) is promoting the use of insecticide treated nets (ITNs) in order to roll back malaria. Long-life netting (LLIN) is preferred and this study investigated the possibility of incorporating the insecticide in the fiber polymer. Multifilament polypropylene (PP) yarn, containing up to 0.76% of pyrethroid insecticide, was successfully produced on a conventional production-scale fiber-spinning machine. The insecticides were incorporated via masterbatches that contained up to 18.8% active with low-density polyethylene (LDPE) as the carrier. Nets knitted from the yarns were tested using bioassays with mosquitoes. Initial efficacy complied with WHO specifications but the performance deteriorated with the number of wash cycles. Crystalline insecticides, featuring a melting point above the wash temperature of 60°C (e.g., β-cyfluthrin), provided better wash resistance than amorphous insecticides (e.g., cyfluthrin).

A cluster-randomized trial of mass drug administration with a gametocytocidal drug combination to interrupt malaria transmission in a low endemic area in Tanzania

BACKGROUND

Effective mass drug administration (MDA) with anti-malarial drugs can clear the human infectious reservoir for malaria and thereby interrupt malaria transmission. The likelihood of success of MDA depends on the intensity and seasonality of malaria transmission, the efficacy of the intervention in rapidly clearing all malaria parasite stages and the degree to which symptomatic and asymptomatic parasite carriers participate in the intervention. The impact of MDA with the gametocytocidal drug combination sulphadoxine-pyrimethamine (SP) plus artesunate (AS) plus primaquine (PQ, single dose 0.75 mg/kg) on malaria transmission was determined in an area of very low and seasonal malaria transmission in northern Tanzania.

METHODS

In a cluster-randomized trial in four villages in Lower Moshi, Tanzania, eight clusters (1,110 individuals; cluster size 47- 209) were randomized to observed treatment with SP+AS+PQ and eight clusters (2,347 individuals, cluster size 55- 737) to treatment with placebo over three days. Intervention and control clusters were 1 km apart; households that were located between clusters were treated as buffer zones where all individuals received SP+AS+PQ but were not selected for the evaluation. Passive case detection was done for the entire cohort and active case detection in 149 children aged 1-10 year from the intervention arm and 143 from the control arm. Four cross-sectional surveys assessed parasite carriage by microscopy and molecular methods during a five-month follow-up period.

RESULTS

The coverage rate in the intervention arm was 93.0% (1,117/1,201). Parasite prevalence by molecular detection methods was 2.2-2.7% prior to the intervention and undetectable during follow-up in both the control and intervention clusters. None of the slides collected during cross-sectional surveys had microscopically detectable parasite densities. Three clinical malaria episodes occurred in the intervention (n = 1) and control clusters (n = 2).

CONCLUSIONS

This study illustrates the possibility to achieve high coverage with a three-day intervention but also the difficulty in defining suitable outcome measures to evaluate interventions in areas of very low malaria transmission intensity. The decline in transmission intensity prior to the intervention made it impossible to assess the impact of MDA in the chosen study setting.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00509015.

Net risk: a risk assessment of long-lasting insecticide bed nets used for malaria management

Despite the demonstrated ability of bed nets that have been factory-impregnated with long-lasting insecticides (LLINs) to protect people from malaria and despite the ambitious plans for their widespread use, the health risks from the LLINs themselves have not been adequately investigated and reported in the peer-reviewed science literature. Here, we use a probabilistic risk assessment approach to estimate the risks to Africans from inhalation, dermal, and oral exposures to the newer LLINs with permethrin, α-cypermethrin, or deltamethrin as the insecticide active ingredient. We estimated exposures to LLINs using 17 age groups to incorporate different body weights and sleeping behaviors. Risk quotients (exposure divided by toxic threshold) at the 50th and 90th percentiles for non-cancer risks were < 1.0 for lifetime adjusted risk and all youth and adult age groups. Risk quotients for infants and toddlers (0-3 years) and child groups from 3 to 10 years were ≥ 1.0 for specific bed nets.

Malaria vector control: from past to future

Malaria is one of the most common vector-borne diseases widespread in the tropical and subtropical regions. Despite considerable success of malaria control programs in the past, malaria still continues as a major public health problem in several countries. Vector control is an essential part for reducing malaria transmission and became less effective in recent years, due to many technical and administrative reasons, including poor or no adoption of alternative tools. Of the different strategies available for vector control, the most successful are indoor residual spraying and insecticide-treated nets (ITNs), including long-lasting ITNs and materials. Earlier DDT spray has shown spectacular success in decimating disease vectors but resulted in development of insecticide resistance, and to control the resistant mosquitoes, organophosphates, carbamates, and synthetic pyrethroids were introduced in indoor residual spraying with needed success but subsequently resulted in the development of widespread multiple insecticide resistance in vectors. Vector control in many countries still use insecticides in the absence of viable alternatives. Few developments for vector control, using ovitraps, space spray, biological control agents, etc., were encouraging when used in limited scale. Likewise, recent introduction of safer vector control agents, such as insect growth regulators, biocontrol agents, and natural plant products have yet to gain the needed scale of utility for vector control. Bacterial pesticides are promising and are effective in many countries. Environmental management has shown sufficient promise for vector control and disease management but still needs advocacy for inter-sectoral coordination and sometimes are very work-intensive. The more recent genetic manipulation and sterile insect techniques are under development and consideration for use in routine vector control and for these, standardized procedures and methods are available but need thorough understanding of biology, ethical considerations, and sufficiently trained manpower for implementation being technically intensive methods. All the methods mentioned in the review that are being implemented or proposed for implementation needs effective inter-sectoral coordination and community participation. The latest strategy is evolution-proof insecticides that include fungal biopesticides, Wolbachia, and Denso virus that essentially manipulate the life cycle of the mosquitoes were found effective but needs more research. However, for effective vector control, integrated vector management methods, involving use of combination of effective tools, is needed and is also suggested by Global Malaria Control Strategy. This review article raises issues associated with the present-day vector control strategies and state opportunities with a focus on ongoing research and recent advances to enable to sustain the gains achieved so far.

Different delivery mechanisms for insecticide-treated nets in rural Burkina Faso: a provider's perspective

BACKGROUND

Insecticide-treated nets (ITNs) have been confirmed to be a very effective tool in malaria control. Two different delivery strategies for roll-out of ITN programmes have been the focus of debate in the last years: free distribution and distribution through commercial marketing systems. They are now seen as complementary rather than opponent. Acceptance of these programmes by the community and involved providers is an important aspect influencing their sustainability. This paper looks at how providers perceived, understood and accepted two interventions involving two different delivery strategies (subsidized sales supported by social marketing and free distribution to pregnant women attending antenatal care services).

METHODS

The interventions took place in one province of north-western Burkina Faso in 2006 in the frame of a large randomized controlled ITN intervention study. For this descriptive qualitative study data were collected through focus group discussions and individual interviews. A total of four focus group discussions and eleven individual interviews have been conducted with the providers of the study interventions.

RESULTS

The free distribution intervention was well accepted and perceived as running well. The health care staff had a positive and beneficial view of the intervention and did not feel overwhelmed by the additional workload. The social marketing intervention was also seen as positive by the rural shopkeepers. However, working in market economy, shopkeepers feared the risk of unsold ITNs, due to the low demand and capacity to pay for the product in the community.

CONCLUSION

The combination of ITN free distribution and social marketing was in general well accepted by the different providers. However, low purchasing power of clients and the resulting financial insecurities of shopkeepers remain a challenge to ITN social marketing in rural SSA.

Rapid increase in ownership and use of long-lasting insecticidal nets and decrease in prevalence of malaria in three regional States of ethiopia (2006-2007)

Following recent large scale-up of malaria control interventions in Ethiopia, this study aimed to compare ownership and use of long-lasting insecticidal nets (LLIN), and the change in malaria prevalence using two population-based household surveys in three regions of the country. Each survey used multistage cluster random sampling with 25 households per cluster. Household net ownership tripled from 19.6% in 2006 to 68.4% in 2007, with mean LLIN per household increasing from 0.3 to 1.2. Net use overall more than doubled from 15.3% to 34.5%, but in households owning LLIN, use declined from 71.7% to 48.3%. Parasitemia declined from 4.1% to 0.4%. Large scale-up of net ownership over a short period of time was possible. However, a large increase in net ownership was not necessarily mirrored directly by increased net use. Better targeting of nets to malaria-risk areas and sustained behavioural change communication are needed to increase and maintain net use.

Possession and usage of insecticidal bed nets among the people of Uganda: is BRAC Uganda Health Programme pursuing a pro-poor path?

Background

The use of insecticidal bed nets is found to be an effective public health tool for control of malaria, especially for under-five children and pregnant women. BRAC, an indigenous Bangladeshi non-governmental development organization, started working in the East African state of Uganda in June 2006. As part of its efforts to improve the health and well-being of its participants, BRAC Uganda has been distributing long lasting insecticide-treated bed nets (LLIN) at a subsidized price through health volunteers since February 2008. This study was conducted in March-April 2009 to examine how equitable the programme had been in consistence with BRAC Uganda's pro-poor policy.

Methodology/Principal Findings

Information on possession of LLINs and relevant knowledge on its proper use and maintenance was collected from households either with an under-five child and/or a pregnant woman. The sample included three villages from each of the 10 branch offices where BRAC Uganda's community-based health programme was operating. Data were collected by trained enumerators through face-to-face interviews using a hand-held personal digital assistant (PDA). Findings reveal that the study population had superficial knowledge on malaria and its transmission, including the use and maintenance of LLINs. The households' rate of possession of bed nets (41–59%), and the proportion of under-five children (17–19%) and pregnant women (25–27%) who reported sleeping under an LLIN were not encouraging. Inequity was observed in the number of LLINs possessed by the households, in the knowledge on its use and maintenance, and between the two programme areas.

Conclusions/Significance

The BRAC Uganda's LLINs distribution at a subsidized price appeared to be inadequate and inequitable, and BRAC's knowledge dissemination is insufficient for initiating preventive actions such as proper use of LLINs to interrupt malaria transmission. Findings contribute to the on-going debate on LLINs distribution in Africa and make a strong case for its free distribution.

Ownership and usage of insecticide-treated bed nets after free distribution via a voucher system in two provinces of Mozambique

Background

Insecticide-treated bed nets (ITNs) are an efficacious intervention for malaria prevention. During a national immunization campaign in Mozambique, vouchers, which were to be redeemed at a later date for free ITNs, were distributed in Manica and Sofala provinces. A survey to evaluate ITN ownership and usage post-campaign was conducted.

Methods

Four districts in each province and four enumeration areas (EAs) in each district were selected using probability proportional to size. Within each EA, 32 households (HHs) were selected using a simple random sample. Interviews to assess ownership and usage were conducted in each of the selected HHs using personal digital assistants.

Results

Valid interviews were completed for 947 (92.5%) (440 in Manica and 507 in Sofala) of the 1,024 selected HHs. Among participating HHs, 65.0% in Manica and 63.1% in Sofala reported that at least one child under five years of age slept in the house the previous night. HH ownership of at least one bed net of any kind was 20.6% (95% confidence interval [CI]: 7.9%-43.6%) and 35.6% (95% CI: 27.8%-44.3%) pre-campaign; and 55.1% (95% CI: 43.6%-66.1%) and 59.6 (95% CI: 42.4%-74.7%) post-campaign in Manica and Sofala, respectively. Post-campaign HH ownership of at least one ITN was 50.2% (95% CI: 41.8%-58.5%) for both provinces combined. In addition, 60.3% (95% CI: 50.6%-69.2%) of children under five years of age slept under an ITN the previous night.

Conclusions

This ITN distribution increased bed net ownership and usage rates. Integration of ITN distribution with immunization campaigns presents an opportunity for reaching malaria control targets and should continue to be considered.

Sleeping arrangement and house structure affect bed net use in villages along Lake Victoria

Background

Although insecticide-treated bed nets are effective tools, use often does not follow ownership. House structure and space arrangements may make the attempt to use bed nets difficult, especially for school age children. The objectives of this study were to explore whether an individual's sleeping arrangements and house structure affect bed net use in villages along Lake Victoria in western Kenya.

Methods

Sleeping arrangements of residents were directly observed for use of a bed net, use of a bed, and location. House size, number and types of rooms, bed availability, and residents' ages were estimated. The family heads and mothers were asked about the reason for not using bed nets. Individual bed net use was examined against age and sleeping arrangement. Net use at the household level was examined against four variables: bed availability, bed net availability, house size, and number of rooms.

Results

Bed net use by children between five and 15 years of age was lower than that among the other age classes. However, age was dropped from the final model, and sleeping arrangement was significantly associated with net use. Net use was significantly associated with bed availability, number of rooms and their interaction.

Conclusion

Net use was affected by sleeping arrangement and availability of suitable locations for hanging nets, in addition to net availability. Most residents had likely not realized that sleeping arrangement was a factor in net use. The ease of hanging a net is particularly important for children.

System effectiveness of a targeted free mass distribution of long lasting insecticidal nets in Zanzibar, Tanzania

Background

Insecticide-treated nets (ITN) and long-lasting insecticidal treated nets (LLIN) are important means of malaria prevention. Although there is consensus regarding their importance, there is uncertainty as to which delivery strategies are optimal for dispensing these life saving interventions. A targeted mass distribution of free LLINs to children under five and pregnant women was implemented in Zanzibar between August 2005 and January 2006. The outcomes of this distribution among children under five were evaluated, four to nine months after implementation.

Methods

Two cross-sectional surveys were conducted in May 2006 in two districts of Zanzibar: Micheweni (MI) on Pemba Island and North A (NA) on Unguja Island. Household interviews were conducted with 509 caretakers of under-five children, who were surveyed for socio-economic status, the net distribution process, perceptions and use of bed nets. Each step in the distribution process was assessed in all children one to five years of age for unconditional and conditional proportion of success. System effectiveness (the accumulated proportion of success) and equity effectiveness were calculated, and predictors for LLIN use were identified.

Results

The overall proportion of children under five sleeping under any type of treated net was 83.7% (318/380) in MI and 91.8% (357/389) in NA. The LLIN usage was 56.8% (216/380) in MI and 86.9% (338/389) in NA. Overall system effectiveness was 49% in MI and 87% in NA, and equity was found in the distribution scale-up in NA. In both districts, the predicting factor of a child sleeping under an LLIN was caretakers thinking that LLINs are better than conventional nets (OR = 2.8, p = 0.005 in MI and 2.5, p = 0.041 in NA), in addition to receiving an LLIN (OR = 4.9, p < 0.001 in MI and in OR = 30.1, p = 0.001 in NA).

Conclusions

Targeted free mass distribution of LLINs can result in high and equitable bed net coverage among children under five. However, in order to sustain high effective coverage, there is need for complimentary distribution strategies between mass distribution campaigns. Considering the community's preferences prior to a mass distribution and addressing the communities concerns through information, education and communication, may improve the LLIN usage.

Contribution of integrated campaign distribution of long-lasting insecticidal nets to coverage of target groups and total populations in malaria-endemic areas in Madagascar

In October 2007, Madagascar conducted a nationwide integrated campaign to deliver measles vaccination, mebendazole, and vitamin A to children six months to five years of age. In 59 of the 111 districts, long-lasting insecticidal nets (LLINs) were delivered to children less than five years of age in combination with the other interventions. A community-based, cross-sectional survey assessed LLIN ownership and use six months post-campaign during the rainy season. LLIN ownership was analyzed by wealth quintile to assess equity. In the 59 districts, 76.8% of households possessed at least one LLIN from any source and 56.4% of households possessed a campaign net. Equity of campaign net ownership was evident. Post-campaign, the LLIN use target of > or = 80% by children less than five years of age and a high level of LLIN use (69%) by pregnant women were attained. Targeted LLIN distribution further contributed to total population coverage (60%) through use of campaign nets by all age groups.

Long-lasting insecticide-treated net usage in eastern Sierra Leone - the success of free distribution

OBJECTIVE

Médecins Sans Frontières (MSF) runs a malaria control project in Bo and Pujehun districts (population 158 000) that includes the mass distribution, routine delivery and demonstration of correct use of free, long-lasting insecticide-treated nets (LLINs). In 2006/2007, around 65 000 LLINs were distributed. The aim of this follow-up study was to measure LLIN usage and ownership in the project area.

METHODS

Heads of 900 randomly selected households in 30 clusters were interviewed, using a standardized questionnaire, about household use of LLINs. The condition of any LLIN was physically assessed.

RESULTS

Of the 900 households reported, 83.4% owning at least one LLIN. Of the 16.6% without an LLIN, 91.9% had not participated in the MSF mass distribution. In 94.1% of the households reporting LLINs, the nets were observed hanging correctly over the beds. Of the 1135 hanging LLINs, 75.2% had no holes or 10 or fewer finger-size holes. The most common source of LLINs was MSF (75.2%). Of the 4997 household members, 67.2% reported sleeping under an LLIN the night before the study, including 76.8% of children under 5 years and 73.0% of pregnant women.

CONCLUSION

Our results show that MSF achieved good usage with freely distributed LLINs. It is one of the few areas where results almost achieve the new targets set in 2005 by Roll Back Malaria to have at least 80% of pregnant women and children under 5 years using LLINs by 2010.

Socioeconomic aspects of neglected tropical diseases

Although many examples of highly cost-effective interventions to control neglected tropical diseases exist, our understanding of the full economic effect that these diseases have on individuals, households, and nations needs to be improved to target interventions more effectively and equitably. We review data for the effect of neglected tropical diseases on a population's health and economy. We also present evidence on the costs, cost-effectiveness, and financing of strategies to monitor, control, or reduce morbidity and mortality associated with these diseases. We explore the potential for economies of scale and scope in terms of the costs and benefits of successfully delivering large-scale and integrated interventions. The low cost of neglected tropical disease control is driven by four factors: the commitment of pharmaceutical companies to provide free drugs; the scale of programmes; the opportunities for synergising delivery modes; and the often non-remunerated volunteer contribution of communities and teachers in drug distribution. Finally, we make suggestions for future economic research.

Plasmodium infection and its risk factors in eastern Uganda

BACKGROUND

Malaria is a leading cause of disease burden in Uganda, although surprisingly few contemporary, age-stratified data exist on malaria epidemiology in the country. This report presents results from a total population survey of malaria infection and intervention coverage in a rural area of eastern Uganda, with a specific focus on how risk factors differ between demographic groups in this population.

METHODS

In 2008, a cross-sectional survey was conducted in four contiguous villages in Mulanda, sub-county in Tororo district, eastern Uganda, to investigate the epidemiology and risk factors of Plasmodium species infection. All permanent residents were invited to participate, with blood smears collected from 1,844 individuals aged between six months and 88 years (representing 78% of the population). Demographic, household and socio-economic characteristics were combined with environmental data using a Geographical Information System. Hierarchical models were used to explore patterns of malaria infection and identify individual, household and environmental risk factors.

RESULTS

Overall, 709 individuals were infected with Plasmodium, with prevalence highest among 5-9 year olds (63.5%). Thin films from a random sample of 20% of parasite positive participants showed that 94.0% of infections were Plasmodium falciparum and 6.0% were P. malariae; no other species or mixed infections were seen. In total, 68% of households owned at least one mosquito although only 27% of school-aged children reported sleeping under a net the previous night. In multivariate analysis, infection risk was highest amongst children aged 5-9 years and remained high in older children. Risk of infection was lower for those that reported sleeping under a bed net the previous night and living more than 750 m from a rice-growing area. After accounting for clustering within compounds, there was no evidence for an association between infection prevalence and socio-economic status, and no evidence for spatial clustering.

CONCLUSION

These findings demonstrate that mosquito net usage remains inadequate and is strongly associated with risk of malaria among school-aged children. Infection risk amongst adults is influenced by proximity to potential mosquito breeding grounds. Taken together, these findings emphasize the importance of increasing net coverage, especially among school-aged children.

Determining and addressing obstacles to the effective use of long-lasting insecticide-impregnated nets in rural Tanzania

BACKGROUND

The objective of this project was to achieve high, sustainable levels of net coverage in a village in rural Tanzania by combining free distribution of long-lasting insecticide-impregnated nets (LLINs) with community-tailored education. In Tanzania, malaria is the leading cause of morbidity and mortality. Although malaria bed nets have a well-established role in reducing disease burden, few rural households have access to nets, and effective use depends on personal practices and attitudes.

METHODS

Five practices and attitudes inconsistent with effective LLIN use were identified from household interviews (n = 10). A randomized survey of villagers (n = 132) verified local prevalence of these practices and attitudes. Community leaders held an educational session for two members of every household addressing these practice and attitudes, demonstrating proper LLIN use, and emphasizing behaviour modification. Attendees received one or two LLINs per household. Surveys distributed three weeks (n = 104) and 15 months (n = 104) post-intervention assessed corrected practices and attitudes. Project efficacy was defined by correction of baseline practices and attitudes as well as high rates of reported daily net use, with statistical significance determined by chi-square test.

RESULTS

Baseline interviews and surveys revealed incorrect practices and attitudes regarding 1) use of nets in dry season, 2) need to retreat LLINs, 3) children napping under nets, 4) need to repair nets, and 5) net procurement as a priority, with 53- 88.6% incorrect responses (11.4-47% correct responses). A three-week follow-up demonstrated 83-95% correct responses. Fifteen-month follow-up showed statistically significant (p < 0.01) corrections from baseline in all five practice and attitudes (39.4-93.3% correct answers). 89.4% of respondents reported using their nets every night, and 93.3% affirmed purchase of nets as a financial priority.

CONCLUSIONS

Results suggest that addressing community-specific practices and attitudes prior to LLIN distribution promotes consistent and correct use, and helps change attitudes towards bed nets as a preventative health measure. Future LLIN distributions can learn from the paradigm established in this project.