Use Of Insecticide-treated Nets Research Articles

Insecticide-treated net (ITN) use, factors associated with non-use of ITNs, and occurrence of sand flies in three communities with reported cases of cutaneous leishmaniasis in Ghana.

The insecticide treated bed net (ITN) has been proven for malaria control. Evidence from systematic review also suggests benefits of ITN roll out in reducing the incidence of cutaneous leishmaniasis (CL) and other vector borne diseases. Using a community-based cross-sectional study design, ITN use, factors associated with non-use of ITNs, and occurrence of sand flies were investigated in three communities with reported cases of CL in the Oti region of Ghana. A total of 587 households comprising 189 (32.2%), 200 (34.1%), and 198 (33.7%) households from Ashiabre, Keri, and Sibi Hilltop communities with de facto population of 3639 participated in this study. The proportion of households that owned at least one ITN was 97.1%. The number of households having at least one ITN for every two members was 386 (65.8%) and 3159 (86.8%) household population had access to ITN. The household population that slept in ITN the night before this survey was 2370 (65.1%). Lack of household access to ITN (AOR = 1.80; CI: 1.31, 2.47), having a family size of more than 10 members (AOR = 2.53; CI: 1.20, 4.24), having more than 10 rooms for sleeping in a household (AOR = 10.18; CI: 1.28, 81.00), having 2-4 screened windows (AOR = 1.49; CI: 1.00, 2.20), and having 8-10 screened windows (AOR = 3.57; CI: 1.25, 10.17) were significantly associated with increased odds of not sleeping in ITN the night before the survey. A total of 193 female sand flies were trapped from various locations within the study communities. Factors associated with ITN non-use such as lack of household access to ITN should be incorporated into future efforts to improve ITN use. Species of sand flies and their potential vectorial role in the study communities should also be investigated.

Low Malaria Transmission in Rosso, an Irrigated Rice-Growing Area in Mauritania

The construction of dams along the Senegal River resulted in an increase in irrigated land areas and changes in the epidemiology and transmission of water-related diseases. The objective of this study was to update epidemiological data on malaria in Rosso, one of the major Mauritanian cities along the Senegal River. Febrile patients (n = 318) were screened for malaria using a rapid diagnostic test (RDT) for malaria and microscopic examination of blood smears. Diagnosis was later confirmed by polymerase chain reaction (PCR). The mean age of 318 febrile patients was 25.1 (range 1–80 years). Only 7 (2.2%) and 2 (0.6%) had a positive RDT and thick smear, respectively. PCR confirmed the diagnosis in two Plasmodium vivax-infected patients. Most participants (198/318, 62.3%) had no recent travel history outside Rosso. The majority of the febrile patients (90%, 284/311) owned at least one insecticide-treated net (ITN). The frequency of the use of ITNs was not significantly associated with season (rainy vs. dry seasons; p = 0.9) or with the number of ITNs per household (rs = 0.07; n = 285; p = 0.19). Of 285 individuals with ITNs, only two (0.7%) with no travel history were PCR-positive for malaria. Despite the presence of mosquito breeding sites related to rice irrigation, malaria transmission in Rosso remained very low, possibly due to the high coverage and frequent use of bed nets. Regular entomological surveillance for possible changes in the prevalence of Anopheles mosquito species and their behavioural aspects should be implemented.

Sub-lethal insecticide exposure affects host biting efficiency of Kdr-resistant Anopheles gambiae

The massive use of insecticide-treated nets (ITNs) has drastically changed the environment for malaria vector mosquitoes, challenging their host-seeking behaviour and biting success. Here, we investigated the effect of a brief exposure to an ITN on the biting behaviour of Anopheles gambiae mosquitoes and the interaction between such behaviour and the kdr mutation that confers resistance to pyrethroids. To this aim, we developed a video assay to study the biting behaviour of mosquitoes with similar genetic background, but different kdr locus genotypes (SS i.e. homozygous susceptible, RS i.e. heterozygous and RR i.e. homozygous resistant), after a brief exposure to either control untreated nets or one of two types of pyrethroid-treated nets (deltamethrin or permethrin). In presence of untreated nets, the kdr mutation did not influence mosquito blood feeding success but caused differences in feeding and prediuresis durations and blood meal size. Exposure to deltamethrin ITN decreased the blood feeding success rate of RR and RS mosquitoes, whereas in presence of permethrin ITN, the kdr mutation increased the blood-feeding success of mosquitoes. Exposure to the two types of pyrethroid-treated nets reduced feeding duration, prediuresis duration and blood meal size of all three genotypes. Our study demonstrates a complex interaction between insecticide exposure and the kdr mutation on the biting behavior of mosquitoes, which may substantially impact malaria vector fitness and disease transmission.

Analysis of the potential for a malaria vaccine to reduce gaps in malaria intervention coverage

BackgroundThe RTS,S/AS01 malaria vaccine is currently being evaluated in a cluster-randomized pilot implementation programme in three African countries. This study seeks to identify whether vaccination could reach additional children who are at risk from malaria but do not currently have access to, or use, core malaria interventions.MethodsUsing data from household surveys, the overlap between malaria intervention coverage and childhood vaccination (diphtheria-tetanus-pertussis dose 3, DTP3) uptake in 20 African countries with at least one first administrative level unit with Plasmodium falciparum parasite prevalence greater than 10% was calculated. Multilevel logistic regression was used to explore patterns of overlap by demographic and socioeconomic variables. The public health impact of delivering RTS,S/AS01 to those children who do not use an insecticide-treated net (ITN), but who received the DTP3 vaccine, was also estimated.ResultsUptake of DTP3 was higher than malaria intervention coverage in most countries. Overall, 34% of children did not use ITNs and received DTP3, while 35% of children used ITNs and received DTP3, although this breakdown varied by country. It was estimated that there are 33 million children in these 20 countries who do not use an ITN. Of these, 23 million (70%) received the DTP3 vaccine. Vaccinating those 23 million children who receive DTP3 but do not use an ITN could avert up to an estimated 9.7 million (range 8.5–10.8 million) clinical malaria cases each year, assuming all children who receive DTP3 are administered all four RTS,S doses. An additional 10.8 million (9.5–12.0 million) cases could be averted by vaccinating those 24 million children who receive the DTP3 vaccine and use an ITN. Children who had access to or used an ITN were 9–13% more likely to reside in rural areas compared to those who had neither intervention regardless of vaccination status. Mothers’ education status was a strong predictor of intervention uptake and was positively associated with use of ITNs and vaccination uptake and negatively associated with having access to an ITN but not using it. Wealth was also a strong predictor of intervention coverage.ConclusionsChildhood vaccination to prevent malaria has the potential to reduce inequity in access to existing malaria interventions and could substantially reduce the childhood malaria burden in sub-Saharan Africa, even in regions with lower existing DTP3 coverage.

Ownership and use of insecticide-treated nets under Ghana's National Malaria Control Program: What are the correlates?

Ghana's National Malaria Control Program distributes free insecticide-treated nets (ITNs) as a malaria control measure. Some households with the ITN do not use it, however. This paper explores the socioeconomic and demographic determinants of ITN ownership and use among Ghanaian families. Data on 5741households were obtained from the 2019 Ghana Malaria Indicator Survey. The survey is a nationally representative survey that obtains data on malaria-related issues. Negative binomial and Tobit regressions were applied to achieve the study's objectives. Residence (rural-urban), wealth, and administrative region emerged as the most important predictors of ITN ownership and usage in Ghana. The results favoured rural and non-Greater Accra residents. However, wealth had a contrasting association with ITN ownership and use. Whereas affluent households owned more ITNs than the extremely poor, the latter used them more. Also, age and household size were significant for ITN ownership. Both variables had a nonlinear (inverted U-shaped) relationship with ITN ownership. In contrast, the proportion of household members under 5 and the bed net-to-household size ratio were positive and statistically significant determinants of ITN use. The study highlights the need to effectively target the poor, especially in rural areas, for ITNs under the NMCP instead of universal distribution.

Malaria knowledge, prevention practices, and insecticide-treated net ownership and use among foreign migrants: A survey in four malaria transmission districts of Yala Province, Southern Thailand

Malaria knowledge, prevention practices, and insecticide-treated net ownership and use among foreign migrants: A survey in four malaria transmission districts of Yala Province, Southern Thailand

Seasonal prevalence of Plasmodium falciparum infection and use of insecticide-treated nets among children in three agroecosystems in Aboisso, Côte d'Ivoire.

Agroecosystems have been associated with risk of malaria. The aim of this study was to determine the relationship between three agroecosystems: (i) rubber plantation (RP); (ii) oil palm plantation (OPP); (iii) no cash crop plantation (NCCP) and the prevalence of Plasmodium falciparum infection among children living in the Aboisso region. In the three villages within (Ehania-V5) or close (N'zikro) or far from (Ayébo) to each agroecosystem (RP, OPP, and NCCP), two cross-sectional parasitological surveys were carried out during the dry and the peak of the long wet seasons. A total of 586 children aged 1-14years were recruited in the three villages to determine the prevalence of malaria using conventional microscopy. Plasmodium falciparum was the dominant species with an overall infection prevalence of 40.8%. There was a significant difference in prevalence between agroecosystems, during both the dry (p = 0.002) and wet seasons (p < 0.001), which was higher in agricultural settings compared with the NCCP environment, whatever the season. The prevalence of P. falciparum infection increased from the dry to the wet season in agricultural settings (RP and OPP), whereas no difference was noted for NCCP. Less than 18% of children use insecticide-treated nets (ITNs) in the three villages, ranging from 6 (in RP) to 30% (in OPP). Multivariate analysis indicated that age (1-4; 5-9; and 10-14years) was not associated with malaria risk, but the season and living in agricultural villages were associated with a greater risk of malaria infection. Risk of malaria exposure was fourfold higher in children from agricultural villages than their counterpart from the non-agricultural area. Our findings highlight significant variations in the prevalence of P. falciparum according to agroecosystem and season. The findings will be useful in designing and implementing malaria control interventions by the National Malaria Control Program.

Decentralized facility financing versus performance-based payments in primary health care: a large-scale randomized controlled trial in Nigeria

BackgroundHealth system financing presents a challenge in many developing countries. We assessed two reform packages, performance-based financing (PBF) and direct facility financing (DFF), against each other and business-as-usual for maternal and child healthcare (MCH) provision in Nigeria.MethodsWe sampled 571 facilities (269 in PBF; 302 in DFF) in 52 districts randomly assigned to PBF or DFF, and 215 facilities in 25 observable-matched control districts. PBF facilities received $2 ($1 for operating grants plus $1 for bonuses) for every $1 received by DFF facilities (operating grants alone). Both received autonomy, supervision, and enhanced community engagement, isolating the impact of additional performance-linked facility and health worker payments. Facilities and households with recent pregnancies in facility catchments were surveyed at baseline (2014) and endline (2017). Outcomes were Penta3 immunization, institutional deliveries, modern contraceptive prevalence rate (mCPR), four-plus antenatal care (ANC) visits, insecticide-treated mosquito net (ITN) use by under-fives, and directly observed quality of care (QOC). We estimated difference-in-differences with state fixed effects and clustered standard errors.ResultsPBF increased institutional deliveries by 10% points over DFF and 7% over business-as-usual (p<0.01). PBF and DFF were more effective than business-as-usual for Penta3 (p<0.05 and p<0.01, respectively); PBF also for mCPR (p<0.05). Twenty-one of 26 QOC indicators improved in both PBF and DFF relative to business-as-usual (p<0.05). However, except for deliveries, PBF was as or less effective than DFF: Penta3 immunization and ITN use were each 6% less than DFF (p<0.1 for both) and QOC gains were also comparable. Utilization gains come from the middle of the rural wealth distribution (p<0.05).ConclusionsOur findings show that both PBF and DFF represent significant improvements over business-as-usual for service provision and quality of care. However, except for institutional delivery, PBF and DFF do not differ from each other despite PBF disbursing $2 for every dollar disbursed by DFF. These findings highlight the importance of direct facility financing and decentralization in improving PHC and suggest potential complementarities between the two approaches in strengthening MCH service delivery.Trial registrationClinicalTrials.gov NCT03890653; May 8, 2017. Retrospectively registered.

Primary school students\u2019 poetic malaria messages from Jimma zone, Oromia, Ethiopia: a qualitative content analysis

BackgroundThe engagement of schools in malaria control is an emerging strategy. Little is known about the involvement of students in the development of malaria messages. This study evaluated the message content of primary school students’ malaria poems.MethodsA qualitative content analysis was conducted to explore malaria messages conveyed in poems produced by students. Twenty poems were purposively selected from twenty schools across rural villages in five districts of the Jimma Zone. Data were analyzed using Atlas.ti version 7.1.4 software. The message contents were quantified in terms of frequency, and including metaphors, presented using central themes, categories, and supportive quotations.ResultsA total of 602 malarial contents were generated, and organized into 21 categories under five central themes. 1) Malaria-related knowledge (causation and modes of transmission, mosquito breeding and biting behavior, signs and symptoms, care for insecticide-treated nets (ITNs), and prevention methods), 2) Perceived threats from malaria, 3)The effectiveness of prevention methods (i.e., related to the adaption of ITNs, environmental cleaning, indoor residual spray (IRS), treatment for fever, and drug adherence practices), 4) Misconceptions, beliefs, and malpractices regarding the cause of malaria and drug use) and 5) Direct calls to the adopt ITN, IRS, clean surroundings, treatment, and drug use. The most commonly conveyed message contents were about the severity of malaria, distinguishable signs and symptoms, calls for community participation for malaria elimination, knowledge of preventive methods, and effectiveness of ITN use. Metaphoric expressions (war and death) were used to convey messages about the severity and the need to manage the prognosis of malaria through the active ITN use, which itself was metaphorically represented as ‘a trap’ to mosquitoes.ConclusionsThe poetic analysis indicated that the students developed and disseminated rich malarial messages, especially on malarial knowledge, and perceptions, beliefs, norms and practices of the local community to prevent and control malaria. Therefore, primary school students can be a source of information and would effectively communicate knowledge, perceptions, and promote malaria related practices, particularly in rural settings.

Risk factors for Plasmodium falciparum infection in pregnant women in Burkina Faso: a community-based cross-sectional survey

BackgroundMalaria in pregnancy remains a public health problem in sub-Saharan Africa. Identifying risk factors for malaria in pregnancy could assist in developing interventions to reduce the risk of malaria in Burkina Faso and other countries in the region.MethodsTwo cross-sectional surveys were carried out to measure Plasmodium falciparum infection using microscopy in pregnant women in Saponé Health District, central Burkina Faso. Data were collected on individual, household and environmental variables and their association with P. falciparum infection assessed using multivariable analysis.ResultsA total of 356 pregnant women were enrolled in the surveys, 174 during the dry season and 182 during the wet season. The mean number of doses of sulfadoxine–pyrimethamine for Intermittent Preventive Treatment in pregnancy (IPTp-SP) was 0.4 doses during the first trimester, 1.1 doses at the second and 2.3 doses at the third. Overall prevalence of P. falciparum infection by microscopy was 15.7%; 17.8% in the dry season and 13.7% in the wet season. 88.2% of pregnant women reported sleeping under an insecticide-treated net (ITN) on the previous night. The odds of P. falciparum infection was 65% lower in women who reported using an ITN compared to those that did not use an ITN (Odds ratio, OR = 0.35, 95% CI 0.14–0.86, p = 0.02). IPTp-SP was also associated with reduced P. falciparum infection, with each additional dose of IPTp-SP reducing the odds of infection by 44% (OR = 0.56, 95% CI 0.39–0.79, p = 0.001). Literate women had a 2.54 times higher odds of P. falciparum infection compared to illiterate women (95% CI 1.31–4.91, p = 0.006).ConclusionsThe prevalence of P. falciparum infection among pregnant women remains high in Burkina Faso, although use of IPTp-SP and ITNs were found to reduce the odds of infection. Despite this, compliance with IPTp-SP remains far from that recommended by the National Malaria Control Programme and World Health Organization. Behaviour change communication should be strengthened to encourage compliance with protective malaria control tools during pregnancy.

Are Malaria Risk Factors Based on Gender? A Mixed-Methods Survey in an Urban Setting in Ghana.

Malaria still represents one of the most debilitating and deadly diseases in the world. It has been suggested that malaria has different impacts on women and men due to both social and biological factors. A gender perspective is therefore important to understand how to eliminate malaria. This study aimed to investigate malaria from a gender perspective in a non-for-profit private health facility, HopeXchange Medical Centre, based in Kumasi (Ghana). A sequential mixed-methods design, comprising quantitative and qualitative methods, was used. This study found low ownership (40%) and use (19%) of insecticide-treated nets (ITNs). Most malaria cases were women (62%), who were less educated and had more external risk factors associated with infection. Our study reported a trend of preferring malaria self-medication at home, which was practiced mostly by men (43%). Our data suggest that women are more likely to be exposed to malaria infections than men, especially due to their prolonged exposure to mosquito bites during the most dangerous hours. Our study highlighted the need for future malaria control policies to be more focused on social and behavioral aspects and from a gender perspective.

Malaria vector dynamics and utilization of insecticide-treated nets in low-transmission setting in Southwest Ethiopia: implications for residual transmission

BackgroundUnderstanding the behaviour of local malaria vectors is essential as effectiveness of the commonly used vector-targeted malaria control tools heavily relies on behaviour of the major malaria vectors. This study was conducted to determine species composition, biting behaviour, host preference and infectivity of anopheline mosquitoes, and assess utilization of insecticide-treated nets (ITNs) in a low transmission setting in Southwest Ethiopia.MethodsAdult anopheline mosquitoes were collected using human landing catches (HLCs), Centers for Disease Control and Prevention (CDC) light traps (LTs) and Pyrethrum Spray Catches (PSCs) from June 2016 to May 2018 in Kishe, Jimma Zone, Southwest Ethiopia. The anopheline mosquitoes were morphologically identified. Moreover, sub-sample of An. gambiae s.l. was identified to species using polymerase chain reaction (PCR). Circum-sporozoite proteins (CSPs) and blood meal sources of the anopheline mosquitoes were tested using enzyme-linked immunosorbent assay (ELISA). In addition, a cross-sectional survey was conducted to assess ITN utilization by the inhabitants.ResultsA total of 3659 anopheline mosquitoes comprising An. coustani complex (84.4%), An. gambiae s.l. (11.3%), and An. pharoensis and An. squamosus comprising less than 5% were collected. The anopheline mosquitoes showed marked outdoor (67%) and early evening (63%) biting behaviour. An. coustani complex and An. gambiae s.l. were predominantly zoophilic and anthropophilic, respectively. None of the sampled anopheline were CSP-positive. Most of the households (97.8%) owned at least one ITN, with modest usage by the inhabitants (73.4%). ITN usage was significantly higher among under-five children (AOR = 7.9, 95% CI: 4.41–14.03), household heads and spouses (AOR = 4.8, 95% CI: 3.0–7.59), those with sufficient access to ITNs (AOR = 1.8, 95% CI: 1.39–2.35), and who were not utilizing alternative mosquito repellents (AOR = 2.2, 95% CI: 1.58–2.99).ConclusionThe anopheline mosquito species exhibited predominantly outdoor and early evening biting activity. Household ITN coverage was high with slight gap in usage. Vector control interventions should target outdoor and early biting vectors to further suppress the local mosquito population. Moreover, sensitization of the community on consistent use of ITNs is required.

Effects of Door-to-Door Hang-Up Visits on the Use of Long-Lasting Insecticide-Treated Mosquito Nets in the Democratic Republic of the Congo: A Cluster Randomized Controlled Trial.

Malaria accounts for 14% of child deaths in the Democratic Republic of the Congo, and one of the key interventions used to prevent malaria is to distribute insecticide-treated bednets (ITNs), especially long-lasting insecticidal nets (LLINs). The global health community and the Roll Back Malaria initiative have been struggling to achieve universal health coverage using ITNs, and recent studies have reported mixed results about the effects of door-to-door visits and mass distribution campaigns. We aimed to compare LLIN use for those provided by door-to-door hang-up visits and by conventional fixed distribution from distribution centers accompanied by a mass distribution campaign. A cluster randomized control trial was conducted in rural areas of Maniema Province, Democratic Republic of the Congo (DR Congo). Cross-sectional surveys were conducted on 2120 and 2156 households, respectively, with at least one child aged less than five in 76 villages. We assessed the effectiveness of door-to-door hang-up visits on the use of LLINs by exploring the interaction between the “intervention group” and “time” using generalized estimating equation models. Increased LLINs use was observed in all age groups in both arms, but usage differences were not significantly different (relative risk (RR) of LLINs use among children < 5 in the intervention group versus the control group after adjusted for clustering: 1.06, 95% CI: 0.85–1.33). We conclude that the door-to-door hang-up visits are not sufficient to persuade individuals (pregnant woman, children < 5, or all study participants) to use LLINs, although it did appear to be effective for the youngest children in the household.

Individual, community and societal correlates of insecticide treated net use among pregnant women in sub-Saharan Africa: a multi-level analysis

BackgroundMalaria in pregnancy is a crucial public health concern due to the enormous risk it poses to maternal and newborn health. The World Health Organisation therefore recommends insecticide-treated net (ITN) for pregnant women. The world over, sub-Saharan Africa bears the highest prevalence of malaria and its associated complications. This study investigated the individual, community and society level factors associated with ITN use among pregnant women in sub-Saharan Africa.MethodsThe study was conducted with Demographic and Health Survey data of 21 sub-Saharan African countries. A total of 17,731 pregnant women who possessed ITN participated in the study. Descriptive computation of ITN use by survey country and socio-demographic characteristics was conducted. Further, five multi-level binary logistic regression models were fitted with MLwiN 3.05 package in STATA. The Markov Chain Monte Carlo (MCMC) estimation procedure was used in estimating the parameters whilst the Bayesian Deviance Information Criterion was used for the model fitness test.ResultsOn average, 74.2% pregnant women in SSA used ITN. The highest prevalence of ITN use occurred in Mali (83.7%) whilst the least usage occurred in Namibia (7%). Women aged 30–34 were more likely to use ITN compared with those aged 45–49 [aOR = 1.14; Crl = 1.07–1.50]. Poorest women were less probable to use ITN relative to richest women [aOR = 0.79; Crl = 0.70–0.89]. Compared to women who did not want their pregnancies at all, women who wanted their pregnancies [aOR = 1.06; Crl = 1.04–1.19] were more probable to use ITN. Women in male-headed households had higher likelihood of ITN use compared to those from female-headed households [aOR = 1.28; Crl = 1.19–1.39]. On the whole, 38.1% variation in ITN use was attributable to societal level factors whilst 20.9% variation was attributable to community level factors.ConclusionThe study has revealed that in addition to individual level factors, community and society level factors affect ITN use in SSA. In as much as the study points towards the need to incorporate community and societal variations in ITN interventions, active involvement of men can yield better outcome for ITN utilisation interventions in SSA.

Examining the incentives and disincentives in the maintenance of Insecticide-Treated Nets among householders in Ghana.

This study explored the factors that affect the incentive to care for Insecticide-Treated Nets (ITNs) among householders in the Shai-Osudoku District of Ghana. The study employed a descriptive qualitative design. Four in-depth interviews (IDIs) and four focus group discussions (FGDs) were conducted to gather the data from 38 participants. A thematic technique was used to analyse the data. Householders were aware of the importance and use of ITNs. The factors underlying the motivation of householders to care for ITNs included their need to stay healthy; inadequate funds to acquire new ITNs and pay for healthcare cost; and their knowledge of the use and efficacy of ITNs. It was also found that obtaining the nets at no cost; limited time available to mend the ITNs; and limited knowledge on how to mend the ITNs disincentivised householders from effectively caring for the nets. There is a need to rethink current ITN intervention programmes in ways that will improve the contents of public education messages and strengthen monitoring frameworks to ensure that householders take optimum care of their nets.

Factors Affecting Uptake and Utilization of Insecticide Treated Net Among Women of Reproductive Age (15 – 49 years) Group Attending Antenatal Clinics in Nasarawa State Nigeria

Background: Vector control is the main path to preventing and reducing malaria transmission. The ownership and use of Insecticide-Treated Nets (ITNs) is the core vector control method and a proven intervention for the control and elimination of malaria in several malaria-endemic countries. This study determined the factors affecting the uptake and utilization of ITN by women in their reproductive age group in Nasarawa State Nigeria. Methods : A descriptive cross sectional study among women of reproductive age group (15 – 49 years) attending Ante Natal Clinic at the Dalhatu Araf Specialist Hospital Lafia, General Hospital Akwanga and Medical Centre Mararaba Gurku in Nasarawa State Nigeria. An interviewer administered questionnaire was used after obtaining an informed consent. Ethical approval was gotten from the state research ethics committee. Data analysis was done using SPSS version 23.0. Results: The mean age of this study population was 27.9 ± 10.6 years. Of the total number of 772 participants in this study, a larger chunk of 707 (91.6%) have heard of insecticide treated net. In addition, most 538 (69.7%) participants said healthcare workers emphasizes the use of insecticide treated net during their antenatal care visits. More than half of the participants, 432 (56.0%) owned an ITN at home. Utilization of insecticide treated nets showed that, 451 (58.4%) sleeps under an insecticide treated net, with 334 (74.1%) of these sleeping under it daily. Reasons for not using ITN for some were; due to heat 137 (30.4%), due to smell 83 (18.3%) and others for no good reason 86 (19.1%) respectively. Beliefs about usefulness of ITN showed 320 (71.0%) felt it is very good and useful in preventing malaria. Conclusions: Most participants are aware of ITN. More than half owned (56%) and sleeps (58.4%) under the ITN. About 71% believed ITN is useful in preventing mosquito bites and malaria. Reasons for declining using ITN among some were due to the ITN’s heat and smell. While more than two-third felt ITN is useful in preventing mosquito bites and malaria. Keywords: Factors, Insecticide Treated Nets, Uptake, Utilization. DOI: 10.7176/JHMN/92-06 Publication date: August 31 st 2021

"Use of Insecticide-Treated Nets (ITN) Against Diseases Vectors and Sucking Blood Arthropods"

Mosquitoes (Culicidae), Sand flies (Psychodidae), Black flies (Simuliidae), Biting Midges (Ceratopogonidae), Tabanids (Tabanidae), Stable fly (Muscidae), Tsetse fly (Glossinidae), Kissing bug (Reduviidae), Bedbug (Cimicidae), Flea (Pulicidae), Head and body louse (Pediculicidae), Crab (Phthiridae), Mite (Trombiculidae), Hard Ticks (Ixodidae), Soft ticks (Argasidae)...

Determination of the discriminating concentration of chlorfenapyr (pyrrole) and Anopheles gambiae sensu lato susceptibility testing in preparation for distribution of Interceptor\xae G2 insecticide-treated nets

BackgroundFollowing agricultural use and large-scale distribution of insecticide-treated nets (ITNs), malaria vector resistance to pyrethroids is widespread in sub-Saharan Africa. Interceptor® G2 is a new dual active ingredient (AI) ITN treated with alpha-cypermethrin and chlorfenapyr for the control of pyrethroid-resistant malaria vectors. In anticipation of these new nets being more widely distributed, testing was conducted to develop a chlorfenapyr susceptibility bioassay protocol and gather susceptibility information.MethodsBottle bioassay tests were conducted using five concentrations of chlorfenapyr at 12.5, 25, 50, 100, and 200 µg AI/bottle in 10 countries in sub-Saharan Africa using 13,639 wild-collected Anopheles gambiae sensu lato (s.l.) (56 vector populations per dose) and 4,494 pyrethroid-susceptible insectary mosquitoes from 8 colonized strains. In parallel, susceptibility tests were conducted using a provisional discriminating concentration of 100 µg AI/bottle in 16 countries using 23,422 wild-collected, pyrethroid-resistant An. gambiae s.l. (259 vector populations). Exposure time was 60 min, with mortality recorded at 24, 48 and 72 h after exposure.ResultsMedian mortality rates (up to 72 h after exposure) of insectary colony mosquitoes was 100% at all five concentrations tested, but the lowest dose to kill all mosquitoes tested was 50 µg AI/bottle. The median 72-h mortality of wild An. gambiae s.l. in 10 countries was 71.5, 90.5, 96.5, 100, and 100% at concentrations of 12.5, 25, 50, 100, and 200 µg AI/bottle, respectively. Log-probit analysis of the five concentrations tested determined that the LC95 of wild An. gambiae s.l. was 67.9 µg AI/bottle (95% CI: 48.8–119.5). The discriminating concentration of 203.8 µg AI/bottle (95% CI: 146–359) was calculated by multiplying the LC95 by three. However, the difference in mortality between 100 and 200 µg AI/bottle was minimal and large-scale testing using 100 µg AI/bottle with wild An. gambiae s.l. in 16 countries showed that this concentration was generally suitable, with a median mortality rate of 100% at 72 h.ConclusionsThis study determined that 100 or 200 µg AI/bottle chlorfenapyr in bottle bioassays are suitable discriminating concentrations for monitoring susceptibility of wild An. gambiae s.l., using mortality recorded up to 72 h. Testing in 16 countries in sub-Saharan Africa demonstrated vector susceptibility to chlorfenapyr, including mosquitoes with multiple resistance mechanisms to pyrethroids.

Malaria risk factors in northern Namibia: The importance of occupation, age and mobility in characterizing high-risk populations.

In areas of low and unstable transmission, malaria cases occur in populations with lower access to malaria services and interventions, and in groups with specific malaria risk exposures often away from the household. In support of the Namibian National Vector Borne Disease Program’s drive to better target interventions based upon risk, we implemented a health facility-based case control study aimed to identify risk factors for symptomatic malaria in Zambezi Region, northern Namibia. A total of 770 febrile individuals reporting to 6 health facilities and testing positive by rapid diagnostic test (RDT) between February 2015 and April 2016 were recruited as cases; 641 febrile individuals testing negative by RDT at the same health facilities through June 2016 were recruited as controls. Data on socio-demographics, housing construction, overnight travel, use of malaria prevention and outdoor behaviors at night were collected through interview and recorded on a tablet-based questionnaire. Remotely-sensed environmental data were extracted for geo-located village residence locations. Multivariable logistic regression was conducted to identify risk factors and latent class analyses (LCA) used to identify and characterize high-risk subgroups. The majority of participants (87% of cases and 69% of controls) were recruited during the 2016 transmission season, an outbreak year in Southern Africa. After adjustment, cases were more likely to be cattle herders (Adjusted Odds Ratio (aOR): 4.46 95%CI 1.05–18.96), members of the police or other security personnel (aOR: 4.60 95%CI: 1.16–18.16), and pensioners/unemployed persons (aOR: 2.25 95%CI 1.24–4.08), compared to agricultural workers (most common category). Children (aOR 2.28 95%CI 1.13–4.59) and self-identified students were at higher risk of malaria (aOR: 4.32 95%CI 2.31–8.10). Other actionable risk factors for malaria included housing and behavioral characteristics, including traditional home construction and sleeping in an open structure (versus modern structure: aOR: 2.01 95%CI 1.45–2.79 and aOR: 4.76 95%CI: 2.14–10.57); cross border travel in the prior 30 days (aOR: 10.55 95%CI 2.94–37.84); and outdoor agricultural work at night (aOR: 2.09 95%CI 1.12–3.87). Malaria preventive activities were all protective and included personal use of an insecticide treated net (ITN) (aOR: 0.61 95%CI 0.42–0.87), adequate household ITN coverage (aOR: 0.63 95%CI 0.42–0.94), and household indoor residual spraying (IRS) in the past year (versus never sprayed: (aOR: 0.63 95%CI 0.44–0.90). A number of environmental factors were associated with increased risk of malaria, including lower temperatures, higher rainfall and increased vegetation for the 30 days prior to diagnosis and residing more than 5 minutes from a health facility. LCA identified six classes of cases, with class membership strongly correlated with occupation, age and select behavioral risk factors. Use of ITNs and IRS coverage was similarly low across classes. For malaria elimination these high-risk groups will need targeted and tailored intervention strategies, for example, by implementing alternative delivery methods of interventions through schools and worksites, as well as the use of specific interventions that address outdoor transmission.

Association between biological sex and insecticide-treated net use among household members in ethnic minority and internally displaced populations in eastern Myanmar.

Malaria prevalence in Myanmar is highest among remote and ethnic minority populations living near forest fringes along the country's international borders. Insecticide-treated nets (ITNs) are a key intervention used to prevent malaria transmission, but insufficient ITN availability and low use can hinder effectiveness. This study assessed age and sex disparities in ITN possession, access, and use among household members of ethnic minority and internally displaced populations in eastern Myanmar. Cross-sectional data from the 2013 Eastern Burma Retrospective Mortality Survey were used to describe prevalence of ITN possession, access, and use. The association between a household member's biological sex and their ITN use was assessed using multilevel log binomial regression. Age and household ITN supply were tested as potential effect modifiers. Of 37927 household members, 89.8% (95% CI: 89.5, 90.1) of people lived in households with at least one ITN. Approximately half belonged to households with sufficient ITN supply and used an ITN. Pregnant women and children under five had the highest proportion of ITN use regardless of sufficient household ITN status. Female adults aged 15 to 49 years old (Risk ratio or RR: 1.4, 95% CI: 1.29, 1.52) were more likely to use ITNs. This relationship did not differ by sufficient household ITN status. The findings suggest that among ethnic minority populations in areas where ITN use is indicated, many households do not have adequate ITN supply, and many individuals are not using ITNs. Children under five and pregnant women appear to be prioritized for ITN use and overall, women are slightly more likely to use ITNs than men. This study's findings can support efforts ensuring that all household members belonging to ethnic minority and displaced populations in Eastern Myanmar benefit from sufficient ITN access and use for malaria prevention.