scholarly journals Patterns of human exposure to malaria vectors in Zanzibar and implications for malaria elimination efforts

2020 ◽  
Author(s):  
April Monroe ◽  
Dickson Msaky ◽  
Samson Kiware ◽  
Brian B. Tarimo ◽  
Sarah Moore ◽  
...  
Keyword(s):  
Malaria Elimination ◽  
Malaria Prevention ◽  
Outdoor Exposure ◽  
Malaria Prevalence ◽  
Malaria Vectors ◽  
Insecticide Treated Nets ◽  
Weighted Estimates ◽  
Anopheles Mosquitoes ◽  
Increased Risk ◽  
Itn Use

Abstract Background Zanzibar provides a good case study for malaria elimination. The islands have experienced a dramatic reduction in malaria burden since the introduction of effective vector control interventions and case management. Malaria prevalence has now been maintained below 1% for the past decade and the islands can feasibly aim for elimination. Methods To better understand factors that may contribute to remaining low-level malaria transmission in Zanzibar, layered human behavioural and entomological research was conducted between December 2016 and December 2017 in 135 randomly selected households across six administrative wards. The study included: 1) household surveys, 2) structured household observations of nighttime activity and sleeping patterns, and 3) paired indoor and outdoor mosquito collections. Entomological and human behavioural data were integrated to provide weighted estimates of exposure to vector bites, accounting for proportions of people indoors or outdoors, and protected by insecticide-treated nets (ITNs) each hour of the night. Results Overall, 92% of female Anopheles mosquitoes were caught in the rainy season compared to 8% in the dry season and 72% were caught outdoors compared to 28% indoors. For individual ITN users, ITNs prevented an estimated two-thirds (66%) of exposure to vector bites and nearly three quarters (73%) of residual exposure was estimated to occur outdoors. Based on observed levels of ITN use in the study sites, the population-wide mean personal protection provided by ITNs was 42%. Discussion/Conclusions This study identified gaps in malaria prevention in Zanzibar with results directly applicable for improving ongoing programme activities. While overall biting risk was low, the most notable finding was that current levels of ITN use are estimated to prevent less than half of exposure to malaria vector bites. Variation in ITN use across sites and seasons suggests that additional gains could be made through targeted social and behaviour change interventions. However, even for ITN users, gaps in protection remain, with a majority of exposure to vector bites occurring outdoors before going to sleep. Supplemental interventions targeting outdoor exposure to malaria vectors, and groups that may be at increased risk of exposure to malaria vectors, should be explored.

scholarly journals Patterns of human exposure to malaria vectors in Zanzibar and implications for malaria elimination efforts

2019 ◽  
Author(s):  
April Monroe ◽  
Dickson Msaky ◽  
Samson Kiware ◽  
Brian Tarimo ◽  
Sarah Moore ◽  
...  
Keyword(s):  
Malaria Elimination ◽  
Rainy Season ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Insecticide Treated Nets ◽  
Weighted Estimates ◽  
Behavior Change Interventions ◽  
Increased Risk ◽  
Itn Use ◽  
Indoor And Outdoor

Abstract Background: Zanzibar provides a good case study for malaria elimination. The islands have experienced a dramatic reduction in malaria burden since the introduction of effective vector control interventions and case management. Malaria prevalence has now been maintained below 1% for the past decade and the islands can feasibly aim for elimination. Methods: To better understand factors that may contribute to remaining low-level malaria transmission in Zanzibar, layered human behavioral and entomological research was conducted between December 2016 and December 2017 in 135 randomly selected households across six administrative wards selected based on high annual parasite incidence and receipt of indoor residual spraying (IRS). The study included: 1) household surveys, 2) structured household observations of nighttime activity and sleeping patterns, and 3) paired indoor and outdoor mosquito collections. Entomological and human behavioral data were integrated to provide weighted estimates of exposure to vector bites, accounting for proportions of people indoors or outdoors, and protected by insecticide-treated nets (ITNs) each hour of the night. Results: The percentage of study participants outdoors and away from home peaked in the early evening with a higher percentage of males observed away throughout the night compared to females. Overall, 92% of female Anopheles mosquitoes were caught in the rainy season compared to 8% in the dry season and 72% were caught outdoors compared to 28% indoors. Observed levels of ITN use were estimated to prevent an average of 42% of exposure to vector bites of all exposure that would otherwise occur. For ITN users, use of an ITN while asleep prevented an estimated two-thirds (66%) of exposure to vector bites and nearly three quarters (73%) of remaining exposure was estimated to occur outdoors. Discussion/Conclusions: This study identified gaps in malaria prevention in Zanzibar with results directly applicable for improving ongoing program activities. While overall biting risk was low, the most notable finding was that current levels of ITN use are estimated to prevent less than half of exposure to malaria vector bites. Variation in ITN use across sites suggests that additional gains could be made through targeted social and behavior change interventions in sites with low levels of ITN use, with additional focus on increasing net use in the rainy season when biting risk is higher. However, even for ITN users, gaps in protection remain, with a majority of exposure to vector bites occurring outdoors before going to sleep. Supplemental interventions targeting outdoor exposure to malaria vectors, and groups that may be at increased risk of exposure to malaria vectors, should be explored. Interventions such as larval source management, which can reduce both indoor and outdoor-biting vector populations, could also be considered.

scholarly journals Determinants of Uptake of Malaria Preventive Interventions among Pregnant Women in Eastern Uganda

2020 ◽  
Author(s):  
Solomon Tsebeni Wafula ◽  
Hilbert Mendoza ◽  
Aisha Nalugya ◽  
David Musoke ◽  
Peter Waiswa
Keyword(s):  
Intermittent Preventive Treatment ◽  
Preventive Treatment ◽  
Cost Effective ◽  
Wealth Quintile ◽  
Malaria Prevention ◽  
Sub Saharan Africa ◽  
Insecticide Treated Nets ◽  
Cross Sectional ◽  
Itn Use ◽  
Eastern Uganda

Abstract Background Consistent use of insecticide-treated nets (ITNs) and intermittent preventive treatment in pregnancy (IPTp) have been recommended as cost-effective interventions for malaria prevention during pregnancy in endemic areas. However, the coverage of these interventions during pregnancy in sub-Saharan Africa is still suboptimal. In this study, we investigated the uptake of IPTp and ITNs, and associated factors among women during their recent pregnancy in Eastern Uganda. Methods This was a cross-sectional study conducted among 2,062 women who had delivered within the last 12 months in three districts in Eastern Uganda. The primary outcomes were consistent ITN use and optimal uptake (at least 3 doses) of IPTp. A modified Poisson regression was used to examine the association between consistent ITN use and the uptake of optimal doses of IPTp with independent variables. Data were analyzed using Stata 14 software. Results The level of uptake of IPTp3 (at least three doses) was 14.7 %, while IPTp2 (at least two doses) was 60.0%. The majority (86.4%) of mothers reported regularly sleeping under mosquito nets for the full duration of pregnancy. Uptake of IPTp3 was associated with engaging in farming (adjusted PR = 1.71, 95% CI [1.28 – 2.28]) or business (adjusted PR = 1.60, 95% CI [1.05 – 2.44]), and attending at least 4 antenatal care (ANC) visits (adjusted PR = 1.72, 95%CI [1.34 – 2.22]). On the other hand, consistent ITN use was associated with belonging to the fourth wealth quintile (adjusted PR = 1.08, 95% CI [1.02 – 1.14]) or fifth wealth quintile (adjusted PR = 1.08, 95% CI [1.02- 1.15]), and attending at least 4 ANC visits (adjusted PR = 1.07, 95% CI [1.03- 1.11]). Conclusion Uptake of IPTp3 and consistent ITN use during pregnancy were lower than recommended guidelines, thus threatening the progress so far made towards malaria elimination. Our findings highlight the need for more efforts to enhance utilisation of ANC services, which is likely to increase the uptake of these two key malaria preventive measures during pregnancy.

scholarly journals Variation in the effectiveness of insecticide treated nets against malaria and outdoor biting by vectors in Kilifi, Kenya

2018 ◽  
Vol 2 ◽  
pp. 22 ◽  
Author(s):  
Alice Kamau ◽  
Joseph M. Mwangangi ◽  
Martin K. Rono ◽  
Polycarp Mogeni ◽  
Irene Omedo ◽  
...  
Keyword(s):  
Geographical Area ◽  
Healthcare Facility ◽  
Insecticide Treated Nets ◽  
Spatial Scan Statistic ◽  
Scan Statistic ◽  
Anopheles Mosquitoes ◽  
Outdoor Biting ◽  
Itn Use ◽  
Clinical Surveillance ◽  
Spatial Scan

Background: Insecticide treated nets (ITNs) protect humans against bites from the Anopheles mosquito vectors that transmit malaria, thereby reducing malaria morbidity and mortality. It has been noted that ITN use leads to a switch from indoor to outdoor feeding among these vectors. It might be expected that outdoor feeding would undermine the effectiveness of ITNs that target indoors vectors, but data are limited. Methods: We linked homestead level geospatial data to clinical surveillance data at a primary healthcare facility in Kilifi County in order to map geographical heterogeneity in ITN effectiveness and observed vector feeding behaviour using landing catches and CDC light traps in six selected areas of varying ITN effectiveness. We quantified the interaction between mosquitoes and humans to evaluate whether outdoor vector biting is a potential explanation for the variation in ITN effectiveness. Results: We observed 37% and 46% visits associated with positive malaria slides among ITN users and non-ITN-users, respectively; ITN use was associated with 32% protection from malaria (crude OR = 0.68, 95% CI: 0.64, 0.73). We obtained significant modification of ITN effectiveness by geographical area (p=0.016), and identified significant hotspots using the spatial scan statistic. Majority of mosquitoes were caught outdoor (60%) and were of the An. funestus group (75%). The overall propensity to feed at times when most people are indoor was high; the vast majority of the Anopheles mosquitoes were caught at times when most people are indoor. Estimates for the proportion of human-mosquito contact between the first and last hour when most humans were indoor was consistently high, ranging from 0.83 to 1.00. Conclusion: Our data therefore do not support the hypothesis that outdoor biting limits the effectiveness of ITNs in our study area.

scholarly journals Net age, but not integrity, may be associated with decreased protection against Plasmodium falciparum infection in southern Malawi

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Liana R. Andronescu ◽  
Andrea G. Buchwald ◽  
Jenna E. Coalson ◽  
Lauren Cohee ◽  
Andy Bauleni ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Protective Efficacy ◽  
Malaria Prevalence ◽  
Community Level ◽  
Infection Prevalence ◽  
Insecticide Treated Nets ◽  
Contributing Factors ◽  
Cross Sectional ◽  
Blood Samples ◽  
Itn Use

Abstract Background Distribution campaigns for insecticide-treated nets (ITN) have increased the use of ITNs in Malawi, but malaria prevalence remains high even among those using the nets. Previous studies have addressed ITN ownership, insecticide resistance, and frequency of ITN use as possible contributing factors to the high prevalence of malaria infection despite high ITN coverage, but have rarely considered whether the condition of the ITN, or how many people use it, impacts efficacy. This study assessed how ITN integrity, ITN age, and the number of persons sharing a net might mitigate or reduce protective efficacy among self-identified ITN users in Malawi. Methods From 2012 to 2014, six cross-sectional surveys were conducted in both the rainy and dry seasons in southern Malawi. Data were collected on ITN use, integrity (number and size of holes), and age. Blood samples for detecting Plasmodium falciparum infection were obtained from reported ITN users over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. The final model controlled for gender, household eaves, and community-level infection prevalence during the rainy season. Results There were 9646 ITN users with blood samples across six surveys, 15% of whom tested positive for P. falciparum infection. Among children under 5 years old, there was a 50% increased odds of P. falciparum infection among those sleeping under an ITN older than two years, compared to those using an ITN less than 2 years old (OR = 1.50; 95% CI 1.07–2.08). ITN integrity and number of individuals sharing an ITN were not associated with P. falciparum infection. Conclusions Older ITNs were associated with higher rates of P. falciparum in young children, which may indicate that insecticide concentrations play a larger role in infection prevention than the physical barrier of an ITN. ITN use was self-reported and the integrity measures lacked the precision of newer methods, suggesting a need for objective measures of ITN use and more precise assessment of ITN integrity.

scholarly journals Determinants of uptake of malaria preventive interventions among pregnant women in eastern Uganda

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Solomon Tsebeni Wafula ◽  
Hilbert Mendoza ◽  
Aisha Nalugya ◽  
David Musoke ◽  
Peter Waiswa
Keyword(s):  
Intermittent Preventive Treatment ◽  
Preventive Treatment ◽  
Cost Effective ◽  
Wealth Quintile ◽  
Malaria Prevention ◽  
Sub Saharan Africa ◽  
Insecticide Treated Nets ◽  
Cross Sectional ◽  
Itn Use ◽  
Eastern Uganda

Abstract Background Consistent use of insecticide-treated nets (ITNs) and intermittent preventive treatment in pregnancy (IPTp) have been recommended as cost-effective interventions for malaria prevention during pregnancy in endemic areas. However, the coverage and utilization of these interventions during pregnancy in sub-Saharan Africa is still suboptimal. This study aimed to determine the uptake of IPTp and ITNs and associated factors among women during their recent pregnancy in Eastern Uganda. Methods This was a cross-sectional study conducted among 2062 women who had delivered within the last 12 months prior to the start of the study in three districts of Eastern Uganda. The primary outcomes were consistent ITN use and optimal uptake (at least 3 doses) of IPTp. A modified Poisson regression was used to examine the association between consistent ITN use and the uptake of optimal doses of IPTp with independent variables. Data were analysed using Stata 14 software. Results The level of uptake of IPTp3 (at least three doses) was 14.7%, while IPTp2 (at least two doses) was 60.0%. The majority (86.4%) of mothers reported regularly sleeping under mosquito nets for the full duration of pregnancy. Uptake of IPTp3 was associated with engaging in farming (adjusted PR = 1.71, 95% CI [1.28–2.28]) or business (adjusted PR = 1.60, 95% CI [1.05–2.44]), and attending at least 4 antenatal care (ANC) visits (adjusted PR = 1.72, 95% CI [1.34–2.22]). On the other hand, consistent ITN use was associated with belonging to the fourth wealth quintile (adjusted PR = 1.08, 95% CI [1.02–1.14]) or fifth wealth quintile (adjusted PR = 1.08, 95% CI [1.02–1.15]), and attending at least 4 ANC visits (adjusted PR = 1.07, 95% CI [1.03–1.11]). Conclusion Uptake of IPTp3 and consistent ITN use during pregnancy were lower and higher than the current Ugandan national targets, respectively. Study findings highlight the need for more efforts to enhance utilization of ANC services, which is likely to increase the uptake of these two key malaria preventive measures during pregnancy.

scholarly journals Understanding the gap between access and use: a qualitative study on barriers and facilitators to insecticide-treated net use in Ghana

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Collins Stephen Ahorlu ◽  
Philip Adongo ◽  
Hannah Koenker ◽  
Sixte Zigirumugabe ◽  
Solomon Sika-Bright ◽  
...  
Keyword(s):  
Focus Group ◽  
Skin Irritation ◽  
Continuous Distribution ◽  
Malaria Prevention ◽  
Insecticide Treated Nets ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Study Results ◽  
Itn Use

Abstract Background Mass and continuous distribution channels have significantly increased access to insecticide-treated nets (ITNs) in Ghana since 2000. Despite these gains, a large gap remains between ITN access and use. Methods A qualitative research study was carried out to explore the individual and contextual factors influencing ITN use among those with access in three sites in Ghana. Eighteen focus group discussions, and free listing and ranking activities were carried out with 174 participants; seven of those participants were selected for in-depth case study. Focus group discussions and case study interviews were audio-recorded, transcribed verbatim, and analysed thematically. Results ITN use, as described by study participants, was not binary; it varied throughout the night, across seasons, and over time. Heat was the most commonly cited barrier to consistent ITN use and contributed to low reported ITN use during the dry season. Barriers to ITN use throughout the year included skin irritation; lack of airflow in the sleeping space; and, in some cases, a lack of information on the connection between the use of ITNs and malaria prevention. Falling ill or losing a loved one to malaria was the most powerful motivator for consistent ITN use. Participants also discussed developing a habit of ITN use and the economic benefit of prevention over treatment as facilitating factors. Participants reported gender differences in ITN use, noting that men were more likely than women and children to stay outdoors late at night and more likely to sleep outdoors without an ITN. Conclusion The study results suggest the greatest gains in ITN use among those with access could be made by promoting consistent use throughout the year among occasional and seasonal users. Opportunities for improving communication messages, such as increasing the time ITNs are aired before first use, as well as structural approaches to enhance the usability of ITNs in challenging contexts, such as promoting solutions for outdoor ITN use, were identified from this work. The information from this study can be used to inform social and behaviour change messaging and innovative approaches to closing the ITN use gap in Ghana.

scholarly journals Variation in the effectiveness of insecticide treated nets against malaria and outdoor biting by vectors in Kilifi, Kenya

2018 ◽  
Vol 2 ◽  
pp. 22
Author(s):  
Alice Kamau ◽  
Joseph M. Mwangangi ◽  
Martin K. Rono ◽  
Polycarp Mogeni ◽  
Irene Omedo ◽  
...  
Keyword(s):  
Geographical Area ◽  
Healthcare Facility ◽  
Insecticide Treated Nets ◽  
Spatial Scan Statistic ◽  
Scan Statistic ◽  
Anopheles Mosquitoes ◽  
Outdoor Biting ◽  
Itn Use ◽  
Clinical Surveillance ◽  
Spatial Scan

Background: Insecticide treated nets (ITNs) protect humans against bites from the Anopheles mosquito vectors that transmit malaria, thereby reducing malaria morbidity and mortality. It has been noted that ITN use leads to a switch from indoor to outdoor feeding among these vectors. It might be expected that outdoor feeding would undermine the effectiveness of ITNs that target indoors vectors, but data are limited. Methods: We linked homestead level geospatial data to clinical surveillance data at a primary healthcare facility in Kilifi County in order to map geographical heterogeneity in ITN effectiveness and observed vector feeding behaviour using landing catches and CDC light traps in six selected areas of varying ITN effectiveness. We quantified the interaction between mosquitoes and humans to evaluate whether outdoor vector biting is a potential explanation for the variation in ITN effectiveness. Results: We observed 37% and 46% visits associated with positive malaria slides among ITN users and non-ITN-users, respectively; ITN use was associated with 32% protection from malaria (crude OR = 0.68, 95% CI: 0.64, 0.73). We obtained significant modification of ITN effectiveness by geographical area (p=0.016), and identified significant hotspots using the spatial scan statistic. Majority of mosquitoes were caught outdoor (60%) and were of the An. funestus group (75%). The overall propensity to feed at times when most people are indoor was high; the vast majority of the Anopheles mosquitoes were caught at times when most people are indoor. Estimates for the proportion of human-mosquito contact between the first and last hour when most humans were indoor was consistently high, ranging from 0.83 to 1.00. Conclusion: Our data do not provide evidence of an epidemiological association between microgeographical variations in ITN effectiveness and variations in the microgeographical distribution of outdoor biting.

scholarly journals Retrospective and cross-sectional study on the prevalence of malaria in selected areas under elimination program in Dembiya district, North-western Ethiopia

2021 ◽  
Author(s):  
Mihretu Tarekegn ◽  
Habte Tekie ◽  
Sisay Dugassa ◽  
Yitbarek Wolde-hawariat
Keyword(s):  
Malaria Transmission ◽  
Malaria Elimination ◽  
Indoor Residual Spraying ◽  
Public Health Problem ◽  
Malaria Prevention ◽  
Cross Sectional Study ◽  
Malaria Prevalence ◽  
Northwest Ethiopia ◽  
Malaria Parasites ◽  
Cross Sectional

Abstract Background: Ethiopia embarked on combating malaria with an aim to eliminate malaria from low transmission districts by 2030. This involves malaria vector interventions by implementing mainly indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) against endophilic and endophagic female Anopheles mosquitoes. Limited published reports are available about the status of malaria in areas under malaria elimination program in Ethiopia. This study intended to assess the prevalence of malaria in selected areas with a long history of implementing malaria prevention and elimination strategies. Methods: A cross-sectional parasitological survey was conducted in two selected malaria endemic areas in Dembiya District, Northwest Ethiopia. Thin and thick blood smears collected from 735 randomly selected individuals were microscopically examined for malaria parasites. Six years retrospective malaria data was also collected from the medical records of the health centres. Structured questionnaires were prepared to collect information about the socio-economic data of the population. The data were analysed using SPSS version 20 and p ≤0.05 were considered statistically significant. Results: The six-year retrospective malaria prevalence trend indicates an overall malaria prevalence of 22.4%, out of which Plasmodium falciparum was the dominant species. From a total of 735 slides examined for the presence of malaria parasites, 3.5% (n=26) were positive for malaria parasites, in which P. falciparum was more prevalent (n=17; 2.3%), P. vivax (n=5; 0.7%), and mixed infections (n=4; 0.5%). Males were 2.6 times more likely to be infected with malaria than females (AOR = 2.6; 95% CI: 1.0, 6.4), and individuals with frequent outdoor activity were 16.4 times more vulnerable than individuals with limited outdoor activities (AOR= 16.4, 95% CI: 1.8, 147.9). Furthermore, awareness about malaria transmission was significantly associated with the prevalence of malaria.Conclusions: Malaria is still a public health problem in Dembiya district irrespective of the past and existing vector control interventions. A malaria elimination plan might not be successful unless other alternative intervention tools targeting outdoor malaria transmission are included. For this, continuous monitoring of vectors’ susceptibility, density, and behaviour is very important in such areas.

scholarly journals Evaluation of different deployment strategies for larviciding to control malaria: a simulation study

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Manuela Runge ◽  
Salum Mapua ◽  
Ismail Nambunga ◽  
Thomas A. Smith ◽  
Nakul Chitnis ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Critical Role ◽  
Indoor Residual Spraying ◽  
Malaria Prevalence ◽  
Transmission Model ◽  
Malaria Vectors ◽  
Relative Reduction ◽  
Insecticide Treated Nets ◽  
Host Seeking ◽  
The Impact

Abstract Background Larviciding against malaria vectors in Africa has been limited to indoor residual spraying and insecticide-treated nets, but is increasingly being considered by some countries as a complementary strategy. However, despite progress towards improved larvicides and new tools for mapping or treating mosquito-breeding sites, little is known about the optimal deployment strategies for larviciding in different transmission and seasonality settings. Methods A malaria transmission model, OpenMalaria, was used to simulate varying larviciding strategies and their impact on host-seeking mosquito densities, entomological inoculation rate (EIR) and malaria prevalence. Variations in coverage, duration, frequency, and timing of larviciding were simulated for three transmission intensities and four transmission seasonality profiles. Malaria transmission was assumed to follow rainfall with a lag of one month. Theoretical sub-Saharan African settings with Anopheles gambiae as the dominant vector were chosen to explore impact. Relative reduction compared to no larviciding was predicted for each indicator during the simulated larviciding period. Results Larviciding immediately reduced the predicted host-seeking mosquito densities and EIRs to a maximum that approached or exceeded the simulated coverage. Reduction in prevalence was delayed by approximately one month. The relative reduction in prevalence was up to four times higher at low than high transmission. Reducing larviciding frequency (i.e., from every 5 to 10 days) resulted in substantial loss in effectiveness (54, 45 and 53% loss of impact for host-seeking mosquito densities, EIR and prevalence, respectively). In seasonal settings the most effective timing of larviciding was during or at the beginning of the rainy season and least impactful during the dry season, assuming larviciding deployment for four months. Conclusion The results highlight the critical role of deployment strategies on the impact of larviciding. Overall, larviciding would be more effective in settings with low and seasonal transmission, and at the beginning and during the peak densities of the target species populations. For maximum impact, implementers should consider the practical ranges of coverage, duration, frequency, and timing of larviciding in their respective contexts. More operational data and improved calibration would enable models to become a practical tool to support malaria control programmes in developing larviciding strategies that account for the diversity of contexts.

scholarly journals When they don't bite, we smell money: understanding malaria bednet misuse

Parasitology ◽  
2013 ◽  
Vol 140 (5) ◽  
pp. 580-586 ◽  
Author(s):  
KEITA HONJO ◽  
LUIS FERNANDO CHAVES ◽  
AKIKO SATAKE ◽  
AKIRA KANEKO ◽  
NOBORU MINAKAWA
Keyword(s):  
Mathematical Model ◽  
Malaria Elimination ◽  
Malaria Infection ◽  
Lake Victoria ◽  
Community Effects ◽  
Insecticide Treated Nets ◽  
Emergent Behaviour ◽  
Model Predictions ◽  
Itn Use ◽  
Open Question

SUMMARYInsecticide-treated nets (ITNs) are a major tool to control malaria. Over recent years increased ITN coverage has been associated with decreased malaria transmission. However, ITN ‘misuse’ has been increasingly reported and whether this emergent behaviour poses a threat to successful malaria control and elimination is an open question. Here, we use a game theory mathematical model to understand the possible roles of poverty and malaria infection protection by individual and emerging ‘community effects’ on the ‘misuse’ of malaria bednets. We compare model predictions with data from our studies in Lake Victoria Islands (LVI), Kenya and Aneityum, Vanuatu. Our model shows that alternative ITN use is likely to emerge in impoverished populations and could be exacerbated if ITNs become ineffective or when large ‘community effects’ emerge. Our model predicted patterns of ITN use similar to the observed in LVI, where ‘misuse’ is common and the high ITN use in Aneityum, more than 20 years after malaria elimination in 1990. We think that observed differences in ITN use may be shaped by different degrees of economic and social development, and educational components of the Aneityum elimination, where traditional cooperative attitudes were strengthened with the malaria elimination intervention and post-elimination surveillance.

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