Use Of LLINs Research Articles

Assessing LLIN distribution implementation using evidence-informed intervention core elements: a qualitative study in a resource-constrained setting

BackgroundThe National Malaria Elimination Programme implements the mass LLIN Distribution Campaigns in Ghana. Implementation science promotes the systematic study of social contexts, individual experiences, real-world environments, partnerships, and stakeholder consultations regarding the implementation of evidence-informed interventions. In this paper, we assess the core elements of the mass LLIN distribution campaign in a resource constrained setting to learn best implementation practices. Three core domains were assessed through the application of Galbraith’s taxonomy (i.e., implementation, content, and pedagogy) for evidence-informed intervention implementation.MethodsSix districts in two regions (Eastern and Volta) in Ghana participated in this study. Fourteen Focus Group Discussions (FGDs) were conducted across these communities. Eligible participants were purposively sampled considering age, occupation, gender, and care giving for children under 5 years and household head roles. All audio-recorded FGDs were transcribed verbatim, data was assessed and coded through deductive and inductive processes. NVivo software version 13 was used for the coding process. Themes were refined, legitimized, and the most compelling extracts selected to produce the results.ResultsSixty-nine (69) caregivers of children under 5 years and sixty (60) household heads participated in the FGDs. All caregivers were females (69), whilst household heads included more males (41). Core elements identified under implementation domain of the LLIN distribution campaign in Ghana include the registration and distribution processes, preceded by engagement with traditional authorities and continuous involvement of community health volunteers during implementation. For pedagogy domain, core elements include delivery of intervention through outreaches, illustrations, demonstrations, and the use of multiple communication channels. Core elements realized within the content domain include information on effective malaria prevention, and provision of information to enhance their self-efficacy. Yet, participants noted gaps (e.g., misuse) in the desired behavioural outcome of LLIN use and a heavy campaign focus on women.Conclusion and recommendationsAlthough the implementation of the mass LLIN distribution campaigns exhibit components of core elements of evidence informed interventions (implementation, content and pedagogy), it has not achieved its desired behavioural change intentions (i.e. continuous LLIN use). Future campaigns may consider use of continuous innovative pedagogical approaches at the community level and lessons learnt from this study to strengthen the implementation process of evidence-based health interventions. There is also the need for standardization of core elements to identify the number of core elements required within each domain to achieve efficacy.Ethical approvalEthical clearance was obtained from the Ghana Health Service Ethics Review Committee (GHS-ERC: 002/06/21) before the commencement of all data collection.

Factors associated with the use of long-lasting insecticidal nets in pregnant women and mothers with children under five years of age in Gaza province, Mozambique.

Malaria remains a major public health concern worldwide. Malaria is endemic in Mozambique, with seasonal fluctuations throughout the country. Although the number of malaria cases in Mozambique have dropped by 11% from 2020 to 2021, there are still hotspots in the country with persistent high incidence and low insecticide-treated bed net usage. The aim of this study is to evaluate the factors associated with the use of long-lasting insecticidal nets by pregnant women and women with children under 5 years old in two hotspot districts in the Gaza province, Mozambique. A descriptive, qualitative cross-sectional study was conducted between June 15th and 21st 2022. An in-depth interview process was conducted with pregnant women and mothers with children under five years old, exploring their beliefs, experiences, and perception of messages conveyed by health professionals when long-lasting insecticidal nets were being supplied. A total of 48 women participated (24 pregnant women and 24 women with children under 5 years). Most participants recognized the protective effects of long-lasting insecticidal nets in preventing malaria, and understood that women and children were high risk groups. The nets were reported to cause side effects and difficulty breathing by 100% of pregnant women, while 54.2% of mothers with children under 5 reported no side effects. The majority of women in both groups reported that their health professionals did not educate them about how to use or handle the nets properly. Only 16.7% of mothers with children under 5 received correct handling instructions. Providing clear, culturally sensitive, and practical information on the correct use of LLINs, as well as regular monitoring of their proper use, would be a great step forward for Mozambique's national malaria program.

Host feeding preferences of malaria vectors in an area of low malaria transmission

Studying the behaviour and trophic preferences of mosquitoes is an important step in understanding the exposure of vertebrate hosts to vector-borne diseases. In the case of human malaria, transmission increases when mosquitoes feed more on humans than on other animals. Therefore, understanding the spatio-temporal dynamics of vectors and their feeding preferences is essential for improving vector control measures. In this study, we investigated the feeding behaviour of Anopheles mosquitoes at two sites in the Sudanian areas of Senegal where transmission is low following the implementation of vector control measures. Blood-fed mosquitoes were collected monthly from July to November 2022 by pyrethrum spray catches in sleeping rooms of almost all houses in Dielmo and Ndiop villages, and blood meals were identified as from human, bovine, ovine, equine and chicken by ELISA. Species from the An. gambiae complex were identified by PCR. The types and numbers of potential domestic animal hosts were recorded in each village. The Human Blood Index (HBI) and the Manly Selection Ratio (MSR) were calculated to determine whether hosts were selected in proportion to their abundance. Spatio-temporal variation in HBI was examined using the Moran’s index. A total of 1251 endophilic Anopheles females were collected in 115 bedrooms, including 864 blood fed females of 6 species. An. arabiensis and An. funestus were predominant in Dielmo and Ndiop, respectively. Of the 864 blood meals tested, 853 gave a single host positive result mainly on bovine, equine, human, ovine and chicken in decreasing order in both villages. Overall, these hosts were not selected in proportion to their abundance. The human host was under-selected, highlighting a marked zoophily for the vectors. Over time and space, the HBI were low with no obvious trend, with higher and lower values observed in each of the five months at different points in each village. These results highlight the zoophilic and exophagic behaviour of malaria vectors. This behaviour is likely to be a consequence of the distribution and use of LLINs in both villages and may increase risk of residual outdoor transmission. This underlines the need to study the feeding host profile of outdoor resting populations and how domestic animals may influence malaria epidemiology in order to tailor effective malaria vector control strategies in the two villages.

Anopheles funestus sensu stricto Giles (Diptera:Culicidae) bites after sunrise at two rural villages in northern Malawi and its implications for malaria vector control.

Malawi has scaled up distribution and use of LLINs but their effectiveness depends on vector behaviour. This study reports information on where and when peak biting takes place by Anopheles vectors at two study sites in northern Malawi. The study was carried out at a single village each in Nkhata Bay and Karonga districts, northern Malawi. Monthly, three teams of four people each sampled mosquitoes using Human Landing Collections (HLCs) from 6.00 pm to 6.00 am. Mosquitoes were counted and identified by PCR. Plasmodium falciparum sporozoites were detected by ELISA and an entomological inoculation rate was estimated. A total of 4,668 and 2,079 mosquitoes were sampled in Nkhata Bay and Karonga districts respectively. An. funestus s.s was common (91.3%; n = 2,611) in Nkhata Bay while An. arabiensis was common (96.9%; n = 706) in Karonga. Pf sporozoite rates varied from 0.8% (4/484) to 3.3% (51/1558). Individuals in Nkhata Bay received more bites (approx. 200 bites/ person/ night) compared to Karonga (approx. 50 bites/ person/ night). An. funestus was more likely to bite indoors (p=0.002) while An. arabiensis was (p=0.05) more likely to bite outdoors. Furthermore, An. funestus peak biting was in the early morning hours from 4:00 am (approx. 331 and 177 bites/ person/ night indoors and outdoors respectively) and remained high till 6:00 am. An. arabiensis peak biting (approx. 63 and 62 bites/ person/ night indoors and outdoors respectively) was around mid-night (12:00). An EIR of 108.4 infective bites/ person/ year was estimated for Nkhata Bay compared to 9.1 infective bites/ person/ year for Karonga. An. funestus s.s. had a considerable Pf sporozite infection rate and EIR. The shift in biting behaviour shown by this species poses a challenge to malaria control. Further studies are required to understand the biting behaviour of Anopheles vectors in Malawi.

Effect of a fifth round of seasonal malaria chemoprevention in children aged 5–14 years in Dangassa, an area of long transmission in Mali

Despite a significant reduction in the burden of malaria in children under five years-old, the efficient implementation of seasonal malaria chemoprevention (SMC) at large scale remains a major concern in areas with long malaria transmission. Low coverage rate in the unattainable areas during the rainy season, a shift in the risk of malaria to older children and the rebound in malaria incidence after stopping drug administration are mainly reported in these areas. These gaps represent a major challenge in the efficient implementation of SMC measures. An open randomized study was conducted to assess the effect of a fifth additional round to current regime of SMC in older children living in Dangassa, a rural malaria endemic area. Poisson regression Model was used to estimate the reduction in malaria incidence in the intervention group compared to the control group including age groups (5–9 and 10–14 years) and the use of long-lasting insecticidal nets (LLINs; Yes or No) with a threshold at 5%. Overall, a downward trend in participation rate was observed from August (94.3%) to November (87.2%). In November (round 4), the risk of malaria incidence was similar in both groups (IRR = 0.66, 95%CI [0.35–1.22]). In December (round 5), a decrease of 51% in malaria incidence was observed in intervention group compared to control group adjusted for age groups and the use of LLINs (IRR = 0.49, 95%CI [0.26–0.94]), of which 17% of reduction is attributable to the 5th round in the intervention group. An additional fifth round of SMC resulted in a significant reduction of malaria incidence in the intervention group. The number of SMC rounds could be adapted to the local condition of malaria transmission.

Prevalence of Malaria and Associated Factors Among Children Under 5 Years Following Mass Net Campaign and Indoor Residual Spraying in Amolatar District

Background: Mass LLINs distribution campaign and Indoor Residual Spraying (IRS) have been identified by the WHO as effective approaches for malaria prevention and control. Despite the scale up of interventions towards control and elimination of malaria, it’s still endemic in 91 countries worldwide with 3.3 billion people at risk of developing. In 2015, 212 million malaria cases occurred globally resulting into 429,000 deaths, 92% were in Africa. In 2019, 409,000 people died of malaria, mostly vulnerable children in sub-Saharan Africa. Methods: A community based, cross-sectional research design using quantitative data collection method was used. Semi-structured questionnaire were employed. Bivariate and multivariate logistic regression analysis were done to identify factors associated to the prevalence of malaria among <5yrs. Results: The intended respondents (238) were interviewed and up to 44.1% (105/238) children tested positive for malaria. At multivariate analysis, Children living with married caretakers (AOR=2.54, 95% CI=1.23-5.25) had statistically significant association with malaria prevalence, Children of caretakers with poor perception towards LLIN use had 68% increased odds of getting malaria. Whereas, children who stay far away from water bodies (AOR=0.07, 95% CI=0.01-0.56) had reduced odds of getting malaria. Conclusions and recommendations: Malaria remains the major public health problems among children under 5 years in Amolatar district. Children living with married caretakers, Caretakers with poor perception towards LLIN use and living near water bodies were the risk factors to malaria. DHTs to strengthen malaria prevention and control strategies among children <5 years, health information dissemination about eliminating stagnating water bodies, and addressing poor perception of mothers of children <5years.

An Investment Case for the Scale-up and Use of Insecticide-Treated Nets Halfway into the SDG Targets

AbstractThis article examines a policy of scaling up LLINs by 10 percentage points from 2020 levels with a 90% cap in the 29 highest-burden countries in Africa along with social and behavioral change (SBC) and information education and communication (IEC) campaigns to increase the use and effectiveness of LLINs. The incremental cost of this scenario compared to a baseline of maintaining malaria interventions at 2020 levels has a present-day (2023) value of 5.7 billion US$ 2021 discounted at 8% over the period 2023–2030 (undiscounted starting at US$ 416 million in 2023 increasing to US$ 1.4 billion in 2030). This investment will prevent 1.07 billion clinical cases and save 1,337,069 lives. With standardized Copenhagen Consensus Center assumptions, the mortality benefit translates to a present value of US$ 225.9 billion. The direct economic gain is also substantial: the incremental scenarios lead to US$ 7.7 billion in reduced health system expenditure from the reduced treatment of cases, a reduction in the cost of delivering malaria control activities, and reduced household out-of-pocket expenses for malaria treatment. The productivity gains from averted employee and caretaker absenteeism and presenteeism add benefits with a present value of US$ 41.7 billion. Each dollar spent on the incremental scenario delivers US$ 48 in social and economic benefits.

Mediation of behavioural and socioeconomic risk factors associated with malaria in children in Ghana

Abstract Background and objectives Malaria remains a major global public health concern and a leading cause of morbidity and mortality especially among children <5 years in Ghana. While an association between poverty and malaria has long been recognised, evidence on the causal pathways between socioeconomic position (SEP) and malaria is scarce. Our study contributes to addressing this gap by investigating the association whilst taking mediation through potential behavioural and socioeconomic factors into account. This can help to identify more specific targets for interventions on a structural level. Methods Using data of 3,004 children from the Malaria Indicator Survey of the Demographic and Health Surveys Program conducted in Ghana in 2019, a household wealth index (quintiles) was derived using principal component analysis based on household assets. Causal multiple mediation analyses investigated mediating effects of treatment-seeking, bed net (LLIN) use, educational attainment, and housing conditions on the association between socioeconomic position and children's malaria fever events. Results Higher maternal educational attainment and housing conditions jointly mediate 18% of the association between socioeconomic position and malaria fever events (OR = 0.98; 95%CI = 0.96-0.99). Maternal educational attainment and seeking formal prenatal health care jointly mediate 20% of the total effect (OR = 0.98; 95%CI = 0.95-1.00), in presence of a lower socioeconomic position. No strong mediation was found for educational attainment jointly with the use of LLINs between malaria and socioeconomic position in this study (OR = 0.99; 95%CI = 0.97-1.01). Conclusions As shown by the proportions mediated between malaria and socioeconomic position, findings suggest that current malaria control efforts could be strengthened by investments at the structural levels, such as increased (female) education, targeted improvements in housing, and stronger integration of informal health care. Key messages

Malaria and Associated Risk Factors among Pregnant Women attending Antenatal Care in Awka, Anambra State, Nigeria

Malaria in pregnancy is a major public health problem in endemic areas of sub-Saharan Africa. It is a major contributor to adverse maternal and perinatal outcome. This work was carried out to determine the prevalence and associated risk factors of malaria among pregnant women attending antenatal clinics in Awka. Microscopy was used to determine the prevalence of malaria among the pregnant women, while structure questionnaire was used to determine the knowledge and use of IPTp and LLINs among thepregnant women. Out of the 300 pregnant women screened for malaria, 184 (61.3%) were positive for malaria parasite.of 184 positive for malaria, 130(47.1%) had mild malaria, 49(27.0%) moderate infection, while 5(2.7%) had severe malaria. Of the 184 pregnant women positive for malaria parasite, those less than 20 years (70.0%) were more infected with malaria parasite, followed by 21-30 years (65.4%), while 41 years and above (20.0%) years were the least infected. Those in their first trimester had the highest prevalence of malaria (76.2%). Primigravidae (64.5%) were more infected than multigravidae (56.1%) Pregnant women with non formal education were most infected (95.0%), followed by primary education (27.3%), while secondary education showed the lowest rate of malaria in pregnancy (92.9%). Farmers reported the highest cases(86.3%) of malaria in pregnancy, while civil servants reported the least (27.3%). Married women showed the highest cases of malaria in pregnancy (65.1%), while single reported the least (51.0%).the knowledge and compliance of IPTp among the pregnant women studied were 84.7% and 52.7% respectively, while knowledge of LLINs was 51.7%. intensified health education is needed to reducethe burden of malaria among pregnant womenin Awka.

Prevalence and risk factors of malaria and anaemia and the impact of preventive methods among pregnant women: A case study at the Akatsi South District in Ghana.

AimThis study aimed to ascertain the prevalence and risk factors of malaria and anaemia as well as the impact of preventive methods among pregnant women at the Akatsi South District Hospital of Ghana.Subjects and methodsA hospital based cross-sectional study using simple random sampling technique was conducted among 200 pregnant women receiving antenatal care and laboratory services at the Akatsi District Hospital from May 2016 to July 2016. A semi-structured questionnaire was administered to obtain participants’ malaria preventive methods in addition to demographic and gestational details. Participants’ hemoglobin and malaria status were assessed using one milliliter (1 ml) whole blood collected from each participant following standard procedures. Factors that produced a p-value of ≤0.2 from the univariate model were included in the final model. Association between potential covariates and the outcomes was assessed using multivariate logistic regression. The Clopper-Pearson test statistic was used to determine the 95% confidence intervals of the outcome variables of interest. We also estimated the population attributable fraction (PAF) of anaemia due to malaria by substituting the adjusted relative risk estimates (RRi) (using the adjrr command in STATA) of anaemia due to malaria into the category-specific attributable formula. P-values of <0.05 were considered statistically significant.ResultsPrevalence of anaemia in pregnancy (AiP), malaria in pregnancy (MiP) and AiP/MiP comorbidity was 63.5% (95% CI:56.4–70.2), 11.0% (96% CI:7.0–16.2) and 10.5% (95% CI:6.6–15.6) respectively. Prevalence rates of AiP (66.7%) and MiP (18.5%) predominated among pregnant women aged < 20 years. PAF of AiP due to MiP was 34.5% (95% CI:23.8–43.6). High use of IPTp-SP, 64.0% (95% CI:56.9–70.6) and LLIN, 90.0% (95% CI:85.0–93.8) was observed in this study. Only 42.0% (95% CI:35.1–49.2) used repellent. Not being on the IPTp-SP program posed a 11.70 times risk of MiP (95% CI:2.32–58.96; p = 0.003) compared to pregnant women on the IPTp-SP program. Similarly, not sleeping under LLIN posed an 8.07 times risk of MiP (95% CI:1.98–32.2; p = 0.004) compared to pregnant women who slept under LLIN. Meanwhile, being positive for MiP posed a 12.10 times risk (95% CI:1.35–85.06; p = 0.025) of AiP compared to those negative for malaria whereas failure to attend ANC as scheduled posed 6.34 times risk (95% CI:1.81–22.19; p = 0.004) of AiP among the pregnant women studied.ConclusionThe prevalence of MiP and AiP among pregnant women in the Akatsi South District remains a great concern. High utilization of IPTp-SP and LLIN was observed with a resultant positive effect on malaria prevalence among pregnant women. Improved access to IPTp-SP and LLIN is hence encouraged to help further diminish the risk of malaria infection amongst pregnant women in the District.

The Effectiveness of Installing Long-lasting Insecticidal Nets as Malaria Prevention Efforts: A Systematic Literature Review

Malaria is a parasitic disease that is often the cause of death, especially in tropical and subtropical areas. One way to eradicate malaria is to break the chain of disease transmission in order to control the mosquito vector of malaria. The use of insecticide-treated mosquito nets can be used as an alternative in controlling malaria vectors for people who refuse to use the Indoor Residual Spraying (IRS) method. The review articles were obtained through a search using the Pubmed, Google Scholar, Garuda, and ScienceDirect databases. The keywords used were (LLINs OR "Long Lasting Insecticidal Nets") AND Malaria. 1843 articles were obtained, and extraction was carried out based on the restriction criteria so that 13 articles were obtained. In conclusion, the use of insecticide-treated mosquito nets LLIN is effective in killing mosquito vectors so that it has the potential to prevent malaria.

Effect of Health Education through Community leaders on increased knowledge of Households Regarding malaria control, treatment and prevention in intervention and control villages of New Halfa Locality-Kassala State (2017-2020)

Malaria vector control in Sudan has a long history. The primary vector control interventions are IRS in targeted areas with irrigation schemes, use of LLINs, LSM, and space spraying during an emergency. The present study aimed to assess the effect of Health Education through Community leaders on increased knowledge of Households Regarding malaria control, treatment and prevention in intervention and control villages of New Halfa Locality-Kassala State (2017-2020). Randomized community trials (Controlled intervention study) in New Halfa locality among two communities were randomly assigned to the intervention group which receive health education messages regarding the use of LLINs and control group where there is no health education. A standard Questionnaire was used to collect data from the head of household at each village. The information collected should include the owner and using LLINs, distributed to household. The observation the conditions of LLINs. This Questionnaire was done with committee for integrated vector management - Federal Ministry of Health and WHO. There were association between education level and overall mean knowledge of respondents about mosquito breeding sites, malaria control, uncomplicated malaria symptoms, severe malaria symptoms, and uncomplicated malaria treatment, severe malaria treatment, and fever treatment, p &lt; 0.05. However, the overall mean knowledge was significantly more significant among those who have University education were compared to other level of education, p&lt; 0.05. An increase knowledge scores was observed when pre- and post-test scores on malaria prevention and control were compared. Health education packages.i.e., mass media messages during Bed nets campaigns and the role of community leaders on malaria, was found to have improved knowledge of malaria prevention and control among the studied community.

Effect of Health Education through Community leaders on increased knowledge of Households Regarding malaria control, treatment and prevention in intervention and control villages of New Halfa Locality-Kassala State (2017-2020)

Malaria vector control in Sudan has a long history. The primary vector control interventions are IRS in targeted areas with irrigation schemes, use of LLINs, LSM, and space spraying during an emergency. The present study aimed to assess the effect of Health Education through Community leaders on increased knowledge of Households Regarding malaria control, treatment and prevention in intervention and control villages of New Halfa Locality-Kassala State (2017-2020). Randomized community trials (Controlled intervention study) in New Halfa locality among two communities were randomly assigned to the intervention group which receive health education messages regarding the use of LLINs and control group where there is no health education. A standard Questionnaire was used to collect data from the head of household at each village. The information collected should include the owner and using LLINs, distributed to household. The observation the conditions of LLINs. This Questionnaire was done with committee for integrated vector management - Federal Ministry of Health and WHO. There were association between education level and overall mean knowledge of respondents about mosquito breeding sites, malaria control, uncomplicated malaria symptoms, severe malaria symptoms, and uncomplicated malaria treatment, severe malaria treatment, and fever treatment, p &lt; 0.05. However, the overall mean knowledge was significantly more significant among those who have University education were compared to other level of education, p&lt; 0.05. An increase knowledge scores was observed when pre- and post-test scores on malaria prevention and control were compared. Health education packages.i.e., mass media messages during Bed nets campaigns and the role of community leaders on malaria, was found to have improved knowledge of malaria prevention and control among the studied community.

Reduction in malaria burden following the introduction of indoor residual spraying in areas protected by long-lasting insecticidal nets in Western Kenya, 2016-2018.

Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the main malaria vector control measures deployed in Kenya. Widespread pyrethroid resistance among the primary vectors in Western Kenya has necessitated the re-introduction of IRS using an organophosphate insecticide, pirimiphos-methyl (Actellic® 300CS), as a pyrethroid resistance management strategy. Evaluation of the effectiveness of the combined use of non-pyrethroid IRS and LLINs has yielded varied results. We aimed to evaluate the effect of non-pyrethroid IRS and LLINs on malaria indicators in a high malaria transmission area. We reviewed records and tallied monthly aggregate of outpatient department (OPD) attendance, suspected malaria cases, those tested for malaria and those testing positive for malaria at two health facilities, one from Nyatike, an intervention sub-county, and one from Suba, a comparison sub-county, both located in Western Kenya, from February 1, 2016, through March 31, 2018. The first round of IRS was conducted in February-March 2017 in Nyatike sub-county and the second round one year later in both Nyatike and Suba sub-counties. The mass distribution of LLINs has been conducted in both locations. We performed descriptive analysis and estimated the effect of the interventions and temporal changes of malaria indicators using Poisson regression for a period before and after the first round of IRS. A higher reduction in the intervention area in total OPD, the proportion of OPD visits due to suspected malaria, testing positivity rate and annual malaria incidences were observed except for the total OPD visits among the under 5 children (59% decrease observed in the comparison area vs 33% decrease in the intervention area, net change -27%, P <0.001). The percentage decline in annual malaria incidence observed in the intervention area was more than twice the observed percentage decline in the comparison area across all the age groups. A marked decline in the monthly testing positivity rate (TPR) was noticed in the intervention area, while no major changes were observed in the comparison area. The monthly TPR reduced from 46% in February 2016 to 11% in February 2018, representing a 76% absolute decrease in TPR among all ages (RR = 0.24, 95% CI 0.12-0.46). In the comparison area, TPR was 16% in both February 2016 and February 2018 (RR = 1.0, 95% CI 0.52-2.09). A month-by-month comparison revealed lower TPR in Year 2 compared to Year 1 in the intervention area for most of the one year after the introduction of the IRS. Our findings demonstrated a reduced malaria burden among populations protected by both non-pyrethroid IRS and LLINs implying a possible additional benefit afforded by the combined intervention in the malaria-endemic zone.

Evaluation at the Level of Health Facilities, of the Protective Efficacy of LLINs in Children under 5 Years Old from Localities of Low and High Resistance of Vectors to Pyrethroid Insecticides in Benin in West Africa

Context: The resistance to pyrethroids in malaria vectors continues to grow in Africa and could therefore compromise or reduce substantially the effectiveness of LLINs in preventing malaria. It is therefore of paramount importance to evaluate the protective efficacy of LLINs in children sleeping in areas of vector resistance to insecticides in order to draw lessons for future interventions. This study assesses the effect of the use of LLINs on malaria morbidity in clusters of low and high resistance of vectors to pyrethroids. Methods: This is a cross-sectional case-control study with one control for one case that was conducted in the communes of Kétou, Ifangni, Kétou, and Pobè in the Plateau department of southern Benin. The use of LLINs and malaria morbidity was measured and compared in children from clusters of low and high vector resistance to insecticides. In each commune, 30 cases and 30 controls were recruited for a total of 240 children under 5 years of age from villages with low and high insecticide resistance. Results: According to the localities of origin of the children, of all parents of children surveyed, 169 (70.4%) asserted the children slept under an LLIN the day before they arrived at the health center. This rate represents 70.8% (85 children) among the cases and 70.0% (84 children) among the controls without significant difference (p = 0.8). The use of LLINs the day before the survey, the frequency of their use during the two weeks preceding the day of the survey, their availability at the household level, the use of other tools for protection against mosquito bites are the same in the two groups of children (cases and controls) (p > 0.05) as well in low and high resistance villages. On the other hand, the parasite prevalence, the splenomegaly and the geometric means of the parasite densities, are significantly higher in the cases than in the controls (p < 0.05). Conclusion: The evaluation of epidemiological indicators in children under five years old at the level of health centers did not enable demonstrating the impact of resistance on the operational effectiveness of the LLINs. The information collected within the four health facilities only reflects the situation that should normally be seen in the population under the real conditions of use of LLINs in high and low resistance areas.

Risk factors associated with malaria infection identified through reactive case detection in Zanzibar, 2012\u20132019

BackgroundOver the past two decades, Zanzibar substantially reduced malaria burden. As malaria decreases, sustainable improvements in control interventions may increasingly depend on accurate knowledge of malaria risk factors to further target interventions. This study aimed to investigate the risk factors associated with malaria infection in Zanzibar.MethodsSurveillance data from Zanzibar’s Malaria Case Notification system from August 2012 and December 2019 were analyzed. This system collects data on malaria cases passively detected and reported by all health facilities (index cases), and household-based reactive case detection (RCD) activities linked to those primary cases. All members of households of the index cases were screened for malaria using a malaria rapid diagnostic test (RDT). Individuals with a positive RDT were treated with artemisinin-based combination therapy. Univariate and multivariate logistic regression analyses were done to investigate the association between RDT positivity among the household members and explanatory factors with adjustment for seasonality and clustering at Shehia level.ResultsA total of 30,647 cases were reported of whom household RCD was completed for 21,443 (63%) index case households and 85,318 household members tested for malaria. The findings show that younger age (p-value for trend [Ptrend] < 0.001), history of fever in the last 2 weeks (odds ratio [OR] = 35.7; 95% CI 32.3–39.5), travel outside Zanzibar in the last 30 days (OR = 2.5; 95% CI 2.3–2.8) and living in Unguja (OR = 1.2; 95% CI 1.0–1.5) were independently associated with increased odds of RDT positivity. In contrast, male gender (OR=0.8; 95% CI 0.7–0.9), sleeping under an LLIN the previous night (OR = 0.9; 95% CI 0.7–0.9), having higher household net access (Ptrend < 0.001), and living in a household that received IRS in the last 12 months (OR = 0.8; 95% CI 0.7–0.9) were independently associated with reduced odds of RDT positivity. A significant effect modification of combining IRS and LLIN was also noted (OR = 0.7; 95% CI 0.6–0.8).ConclusionsThe findings suggest that vector control remains an important malaria prevention intervention: they underscore the need to maintain universal access to LLINs, the persistent promotion of LLIN use, and application of IRS. Additionally, enhanced behavioural change and preventive strategies targeting children aged 5–14 years and travellers are needed.

Bioefficacy and durability of Olyset\xae Plus, a permethrin and piperonyl butoxide-treated insecticidal net in a 3-year long trial in Kenya

BackgroundLong-lasting insecticide nets (LLINs) are a core malaria intervention. LLINs should retain efficacy against mosquito vectors for a minimum of three years. Efficacy and durability of Olyset® Plus, a permethrin and piperonyl butoxide (PBO) treated LLIN, was evaluated versus permethrin treated Olyset® Net. In the absence of WHO guidelines of how to evaluate PBO nets, and considering the manufacturer’s product claim, Olyset® Plus was evaluated as a pyrethroid LLIN.MethodsThis was a household randomized controlled trial in a malaria endemic rice cultivation zone of Kirinyaga County, Kenya between 2014 and 2017. Cone bioassays and tunnel tests were done against Anopheles gambiae Kisumu. The chemical content, fabric integrity and LLIN survivorship were monitored. Comparisons between nets were tested for significance using the Chi-square test. Exact binomial distribution with 95% confidence intervals (95% CI) was used for percentages. The WHO efficacy criteria used were ≥ 95% knockdown and/or ≥ 80% mortality rate in cone bioassays and ≥ 80% mortality and/or ≥ 90% blood-feeding inhibition in tunnel tests.ResultsAt 36 months, Olyset® Plus lost 52% permethrin and 87% PBO content; Olyset® Net lost 24% permethrin. Over 80% of Olyset® Plus and Olyset® Net passed the WHO efficacy criteria for LLINs up to 18 and 12 months, respectively. At month 36, 91.2% Olyset® Plus and 86.4% Olyset® Net survived, while 72% and 63% developed at least one hole. The proportionate Hole Index (pHI) values representing nets in good, serviceable and torn condition were 49.6%, 27.1% and 23.2%, respectively for Olyset® Plus, and 44.9%, 32.8% and 22.2%, respectively for Olyset® Net but were not significantly different.ConclusionsOlyset® Plus retained efficacy above or close to the WHO efficacy criteria for about 2 years than Olyset® Net (1–1.5 years). Both nets did not meet the 3-year WHO efficacy criteria, and showed little attrition, comparable physical durability and survivorship, with 50% of Olyset® Plus having good and serviceable condition after 3 years. Better community education on appropriate use and upkeep of LLINs is essential to ensure effectiveness of LLIN based malaria interventions.Graphical

Malaria prevalence and long-lasting insecticidal net use in rural western Uganda: results of a cross-sectional survey conducted in an area of highly variable malaria transmission intensity

BackgroundLong-lasting insecticidal nets (LLINs) remain a cornerstone of malaria control, but strategies to sustain universal coverage and high rates of use are not well-defined. A more complete understanding of context-specific factors, including transmission intensity and access to health facilities, may inform sub-district distribution approaches and tailored messaging campaigns.MethodsA cross-sectional survey of 2190 households was conducted in a single sub-county of western Uganda that experiences highly variable malaria transmission intensity. The survey was carried out approximately 3 years after the most recent mass distribution campaign. At each household, study staff documented reported LLIN use and source among children 2 to 10 years of age and performed a malaria rapid diagnostic test. Elevation and distance to the nearest health facility was estimated for each household. Associations between parasite prevalence and LLIN use were estimated from log binomial regression models with elevation and distance to clinic being the primary variables of interest.ResultsOverall, 6.8% (148 of 2170) of children age 2–10 years of age had a positive RDT result, yielding a weighted estimate of 5.8% (95% confidence interval [CI] 5.4–6.2%). There was substantial variability in the positivity rates among villages, with the highest elevation villages having lower prevalence than lowest-elevation villages (p < .001). Only 64.7% (95% CI 64.0–65.5%) of children were reported to have slept under a LLIN the previous night. Compared to those living < 1 km from a health centre, households at ≥ 2 km were less likely to report the child sleeping under a LLIN (RR 0.86, 95% CI 0.83–0.89, p < .001). Households located farther from a health centre received a higher proportion of LLINs from government distributions compared to households living closer to health centres.ConclusionsLLIN use and sourcing was correlated with household elevation and estimated distance to the nearest health facility. The findings suggest that current facility-based distribution strategies are limited in their reach. More frequent mass distribution campaigns and complementary approaches are likely required to maintain universal LLIN coverage and high rates of use among children in rural Uganda.

The causes of holes and loss of physical integrity in long\u2010lasting insecticidal nets

BackgroundLong-lasting insecticidal nets (LLINs) are expected to last for at least 3 years, but whilst this may be achieved from an insecticidal perspective, physical protection is frequently compromised much earlier because of the rapid accumulation of holes during use. To understand why LLINs are so susceptible to loss of physical integrity, thousands of hole damage sites in LLINs retrieved from the field in Africa and Asia were forensically studied to identify the persistent underlying causes.MethodsA total of 525 LLINs consisting of six different brands from five different countries across Africa and Asia were collected from the field after 1 to 3 years in use. More than 42,000 individual sites of hole damage were analysed based on the morphology and size of each individual hole, aided by optical microscopy (OM) and scanning electron microscopy (SEM). The fracture morphology enabled positive identification of the underlying mechanisms of the damage.ResultsAcross all LLINs and geographical settings, mechanical damage is the primary cause of holes and loss of physical integrity in LLINs (63.14% by frequency and 81.52% by area). Snagging is the single most frequent mechanical damage mechanism, whilst the largest sized holes in LLINs result from seam failure and tearing. Abrasion and hole enlargement are also responsible for a progressive loss in the physical integrity of nets. Collectively, these five modes of mechanical damage can be expected to result from normal use of LLINs by households. Evidence of deliberate cutting, burn holes and rodent damage was observed to a lesser degree, which LLINs are not designed to withstand.ConclusionsLoss of physical integrity in LLINs is an inevitable consequence of using a vector control product that has an inherently low resistance to mechanical damage during normal use. To improve performance, new specifications based on laboratory textile testing is needed, to assess the resistance of LLIN products to the primary causes of mechanical damage when in use, which are snagging, tearing, abrasion and hole enlargement. Seam construction also needs to meet a revised minimum standard to reduce the risk of a rapid loss of physical integrity during use.

Use of malaria preventive measures among pregnant women attending antenatal clinic at Federal Medical Center, Yenagoa

Background: Malaria in pregnancy remains a major contributor to maternal and infant morbidity and mortality despite scale up in interventions. Its prevention is one of the major interventions in reducing maternal and infant morbidity and mortality. This cross-sectional study was conducted with the aim of assessing the use of preventive measures against malaria among pregnant women attending antenatal clinic in FMC Yenagoa. Methods and materials:: A systematic sampling technique was used to select 297 women. A pre-tested structured interviewer-administered questionnaire was used to collect data. Univariate analysis was conducted to compute frequencies and proportions; and bivariate analysis was used to compare associations between the independent variables and the outcome variables. Multivariate logistic regression analysis was also done to determine independent association between variables Epi-Info version 7.3. and Microsoft Excel were used for all the data analysis. Results: The mean age of respondents was 28.8 ± 2.6 years. Most women had tertiary level of education, (59.2%) and were majorly (88.2%) urban dwellers. Two hundred and fifty (84.2%) stated that they had used LLINs, and 196 (78%) used them the night prior to the interview. Also, 286 (96.3%) reported taking at least one dose of sulphadoxine/pyrimethamine in the current pregnancy. Those who were gainfully employed and those who earned above the minimum wage were 3.2 and 2.9 times more likely to have used LLIN respectively [OR = 3.2 (CI: 1.6 - 6.3)] and [OR = 2.9 (CI: 1.5 – 5.7)]. On logistic regression, there was statistically significant association between the use of LLIN and being employed [OR = 2.43 (CI: 1.10-5.38)], as well as income > #18,000 [OR = 2.36 (CI: 1.08-5.16)]. Conclusion: The use of appropriate preventive measures against malaria was generally high among the participants in this study. Predictors of the use of malaria prevention methods in our cohort of subjects were found to be income > #18,000 and being gainfully employed.