Lasting Insecticidal Nets Research Articles

Replacement Campaign of Long Lasting Insecticide Treated Nets in Ondo State, Southwest Nigeria, Heartland of Africas Most Efficient Vector Species

Background: Ondo State in Southwest Nigeria, heartland of Africa’s most efficient malaria vector, conducted a Long- Lasting Insecticidal Nets (LLINs) replacement campaign at the last quarter of 2017 with the aim of achieving the recommended coverage of one LLIN per two persons, in line with the National Malaria Elimination Program (NMEP) strategy. The LLIN replacement campaign planned to reach 4,757,725 populations to achieve universal coverage, a proven intervention aimed at reducing malaria morbidity by increasing access to, as well as ownership and utilization of LLINs. The processes to achieve this goal are described in this paper. Methodology: This paper describes the modalities and scheme for LLIN distribution in one of the states in Southern Nigeria. The campaign took place in all the 18 Local Government Areas (LGAs) of the state between September 17 and November 15, 2017. Implementation trainings were held and advocacies were conducted at state level and to traditional and religious leaders followed by community mobilization in all the Local Government Authorities. Intense logistic activities included transportation and positioning of LLINs. The Implementation was endorsed by LLIN Ambassadors. End process evaluation and reverse logistics were carried out. The LLIN replacement was carried out at a time of high malaria transmission during the second rainy season of the year. Excel spreadsheet was used in data analysis. Outcome: The LLIN replacement campaign involved the training of 11,695 personnel in different cadres including teams, supervisors and monitors at state and at LGA levels, independent monitors, ward monitors and town announcers. Distribution point supervisors, health educators and crowd controllers as well as store keepers were also trained. In all 2,734,500 net cards were issued to LGAs of which 2,674,172 (98.0%) net cards were issued to beneficiaries to collect LLINs. In all, 2,444,036 (91.4%) LLINs were redeemed. Reasons for non-use of LLIN ranged from adverse reaction (11.0%) to “no mosquitoes” (1.0%). Majority (82.0%) of people heard about the LLIN campaign from town announcers and none was unaware of the campaign. Hanging rate was low at 55.0% while utilization by under-fives and by pregnant women was 67.0% and 76.0%, respectively. Conclusion: Despite the fact that replacement of LLINs in Ondo state of southwest Nigeria took place on a large scale, its utilization, especially among the at-risk groups, was still low. Aggressive follow-up campaigns to increase utilization should include more purposeful social and health advocacies to community and religious leaders. Use of local drama groups for behavioral change could be an advantage. Distribution of LLINs to school children should also be considered.

Insecticide use pattern and phenotypic susceptibility of Anopheles gambiae sensu lato to commonly used insecticides in Lower Moshi, northern Tanzania

BackgroundEvidence of insecticide resistance has been documented in different malaria endemic areas. Surveillance studies to allow prompt investigation of associated factors to enable effective insecticide resistance management are needed. The objective of this study was to assess insecticide use pattern and phenotypic susceptibility level of Anopheles gambiae sensu lato to insecticides commonly used in malaria control in Moshi, northern Tanzania.MethodsA cross-sectional survey was conducted to assess insecticide usage pattern. Data was collected was through closed and open ended questionnaires The WHO diagnostic standard kit with doses of 0.1% bendiocarb, 0.05% deltamethrin, 0.75% permethrin and 4% DDT were used to detect knockdown time, mortality and resistance ratio of wild A. gambiae sensu lato. The questionnaire survey data was analyzed using descriptive statistics and one-way analysis of variance while susceptibility data was analysed by logistic regression with probit analysis using SPSS program. The WHO criteria was used to evaluate the resistance status of the tested mosquito populations.ResultsA large proportion of respondents (80.8%) reported to have used insecticide mainly for farming purposes (77.3%). Moreover, 93.3% of household reported usage of long lasting insecticidal nets. The frequently used class of insecticide was organophosphate with chloropyrifos as the main active ingredients and dursban was the brand constantly reported. Very few respondents (24.1%) applied integrated vector control approaches of and this significantly associated with level of knowledge of insecticide use (P < 0.001). Overall knockdown time for A. gambiae s.l was highest in DDT, followed by Pyrethroids (Permethrin and deltamethrin) and lowest in bendiocarb. Anopheles gambiae s.l showed susceptibility to bendiocarb, increased tolerance to permethrin and resistant to deltamethrin. The most effective insecticide against the population from tested was bendiocarb, with a resistance ratio ranging between 0.93–2.81.ConclusionEducation on integrated vector management should be instituted and a policy change on insecticide of choice for malaria vector control from pyrethroids to carbamates (bendiocarb) is recommended. Furthermore, studies to detect cross resistance between pyrethroids and organophosphates should be carried out.

Free mass distribution of long lasting insecticidal nets lead to high levels of LLIN access and use in Madagascar, 2010: A cross-sectional observational study.

BackgroundMadagascar conducted the first two phases of a national free mass distribution campaign of long-lasting insecticidal nets (LLINs) during a political crisis in 2009 aiming to achieve coverage of two LLINs per household as part of the National Malaria Control Strategy. The campaign targeted households in 19 out of 91 total health districts.MethodsA community-based cross-sectional household survey using a three-stage cluster sample design was conducted four months post campaign to assess LLIN ownership, access and use. Multivariable logistic regression analysis was used to identify factors associated with household LLIN access and individual LLIN use.ResultsA total of 2211 households were surveyed representing 8867 people. At least one LLIN was present in 93.5% (95% confidence interval [CI], 91.6–95.5%) of households and 74.8% (95% CI, 71.0–78.6%) owned at least two LLINs. Access measured as the proportion of the population that could potentially be covered by household-owned LLINs was 77.2% (77.2% (95% CI, 72.9–81.3%) and LLIN use by all individuals was 84.2% (95% CI, 81.2–87.2%). LLIN use was associated with knowledge of insecticide treated net use to prevent malaria (OR = 3.58, 95% CI, 1.85–6.94), household ownership of more LLINs (OR 2.82, 95% CI 1.85–4.3), presence of children under five (OR = 2.05, 95% CI, 1.67–2.51), having traveled to the distribution point and receiving information about hanging a bednet (OR = 1.56, 95% CI, 1.41–1.74), and having received a post-campaign visit by a community mobilizer (OR = 1.75, 95% CI, 1.26–2.43). Lower LLIN use was associated with increasing household size (OR = 0.81 95% CI 0.77–0.85) and number of sleeping spaces (OR = 0.55, 95% CI, 0.44–0.68).ConclusionsA large scale free mass LLIN distribution campaign was feasible and effective at achieving high LLIN access and use in Madagascar. Campaign process indicators highlighted potential areas for strengthening implementation to optimize access and equity.

Influence of pyrethroïd-treated bed net on host seeking behavior of Anopheles gambiae s.s. carrying the kdr allele.

The use of long lasting insecticide nets (LLINs) treated with pyrethroïd is known for its major contribution in malaria control. However, LLINs are suspected to induce behavioral changes in malaria vectors, which may in turn drastically affect their efficacy against Plasmodium sp. transmission. In sub Saharan Africa, where malaria imposes the heaviest burden, the main malaria vectors are widely resistant to pyrethroïds, the insecticide family used on LLINs, which also threatens LLIN efficiency. There is therefore a crucial need for deciphering how insecticide-impregnated materials might affect the host-seeking behavior of malaria vectors in regards to insecticide resistance. In this study, we explored the impact of permethrin-impregnated net on the host attractiveness for Anopheles gambiae mosquitoes, either susceptible to insecticides, or carrying the insecticide resistance conferring allele kdr. Groups of female mosquitoes were released in a dual-choice olfactometer and their movements towards an attractive odor source (a rabbit) protected by insecticide-treated (ITN) or untreated nets (UTN) were monitored. Kdr homozygous mosquitoes, resistant to insecticides, were more attracted by a host behind an ITN than an UTN, while the presence of insecticide on the net did not affect the choice of susceptible mosquitoes. These results suggest that permethrin-impregnated net is detectable by malaria vectors and that the kdr mutation impacts their response to a LLIN protected host. We discuss the implication of these results for malaria vector control.

Enhanced Adhesion of Mosquitoes to Rough Surfaces.

Insects and small animals capable of adhering reversibly to a variety of surfaces employ the unique design of the distal part of their legs. In the case of mosquitoes, their feet are composed of thousands of micro- and nanoscale protruding structures, which impart superhydrophobic properties. Previous research has shown that the superhydrophobic nature of the feet allows mosquitoes to land on water, which is necessary for their reproduction cycle. Here, we show that van der Waals interactions are the main adhesion mechanism employed by mosquitoes to adhere to various surfaces. We further demonstrate that the judicious creation of surface roughness on an opposing surface can increase the adhesion strength because of the increased number of surface elements interacting with the setae through multiple contact points. Although van der Waals forces are shown to be the predominant mechanism by which mosquitoes adhere to surfaces, capillary forces can also contribute to the total adhesion force when the opposing surface is hydrophilic and under humid conditions. These fundamental properties can potentially be applied in the development of superior Long Lasting Insecticidal Nets (LLINs), which represent one of the most effective methods to mitigate mosquito-transmitted infectious diseases such as Malaria, Filaria, Zika, and Dengue.

Genome-Wide Transcription and Functional Analyses Reveal Heterogeneous Molecular Mechanisms Driving Pyrethroids Resistance in the Major Malaria Vector Anopheles funestus Across Africa.

Pyrethroid resistance in malaria vector, An. funestus is increasingly reported across Africa, threatening the sustainability of pyrethroid-based control interventions, including long lasting insecticidal nets (LLINs). Managing this problem requires understanding of the molecular basis of the resistance from different regions of the continent, to establish whether it is being driven by a single or independent selective events. Here, using a genome-wide transcription profiling of pyrethroid resistant populations from southern (Malawi), East (Uganda), and West Africa (Benin), we investigated the molecular basis of resistance, revealing strong differences between the different African regions. The duplicated cytochrome P450 genes (CYP6P9a and CYP6P9b) which were highly overexpressed in southern Africa are not the most upregulated in other regions, where other genes are more overexpressed, including GSTe2 in West (Benin) and CYP9K1 in East (Uganda). The lack of directional selection on both CYP6P9a and CYP6P9b in Uganda in contrast to southern Africa further supports the limited role of these genes outside southern Africa. However, other genes such as the P450 CYP9J11 are commonly overexpressed in all countries across Africa. Here, CYP9J11 is functionally characterized and shown to confer resistance to pyrethroids and moderate cross-resistance to carbamates (bendiocarb). The consistent overexpression of GSTe2 in Benin is coupled with a role of allelic variation at this gene as GAL4-UAS transgenic expression in Drosophila flies showed that the resistant 119F allele is highly efficient in conferring both DDT and permethrin resistance than the L119. The heterogeneity in the molecular basis of resistance and cross-resistance to insecticides in An. funestus populations throughout sub-Saharan African should be taken into account in designing resistance management strategies.

SPATIAL-TEMPORAL DYNAMICS IN HETEROGENEITY OF MALARIA INFECTION IN A SETTING WITH SEASONAL TRANSMISSION: A LONGITUDINAL STUDY IN THE GAMBIA

BackgroundThe reduction in the malaria burden previously reported in The Gambia is largely due to the successful scaling up of control interventions. Understanding the current dynamics of malaria transmission in...

Bio-efficacy, physical integrity, community usage and washing practices of mosquito nets treated with ICON MAXX long-lasting insecticidal treatment in India

BACKGROUND New brands of potential long lasting insecticide nets (LLINs) and LLIN treatment kits require field evaluation before they are used in a vector control programme.OBJECTIVES The aim of this study was to evaluate the bio-efficacy, usage, washing practice and physical integrity of nets treated with LLIN treatment kit, ICON MAXX in a phase III field trial in Odisha state, India.METHODS A total of 300 polyester nets treated with ICON MAXX and 140 polyester nets treated conventionally with lambda-cyhalothrin CS 2.5% ITNs were distributed. The bio-efficacy was evaluated with WHO cone bioassay. The chemical analysis of netting pieces was done at the beginning, after 12 and 36 months of the trial.FINDINGS After one year of distribution of nets, the bioassay showed 100% mortality on both ITNs and ICON MAXX treated nets. At 36 months, the overall pass rate was 58.8% and the mean lambda-cyhalothrin content of LLINs was 34.5 mg ai/m2, showing a loss of 44.4% of the original concentration.CONCLUSION ICON MAXX treated LLIN was found to retain bio-efficacy causing 97% knockdown of Anopheles stephensi up to 30 months and met the WHOPES criteria. However, the desired bio-efficacy was not sustained up to 36 months.

Zooprophylaxis: A Strategy for Effective Delivery of Endectocides for Vector Control

A new strategy is needed for an effective management of residual malaria transmission attained after a wide use of Indoor residual spray and long lasting insecticidal nets. However, insecticides resistance has been a drawback factor for the attained success. The costs for changing insecticides for vector control annual still a challenges to be met by malaria transmission prone areas. The alternative strategy has to be in place for creating a dead end point for vectors than relying on insecticides for IRS and LLINs. The incorporation of zooprophylaxis strategy to deliver endectocides to blood feeding mosquitoes will kill even resistant populations of zoophilic mosquitoes and substantially reduce and eliminate residual malaria transmission.

Placental Malaria in Newly Delivered Women in the Maternity Hospital of Chud Borgou in 2015

Introduction: Malaria remains a major public health issue in sub-Saharan Africa with high mortality in pregnant women and newborn infants. In the latter, malaria is the consequence of placental transmission of plasmodium. This study aims at identifying the factors associated with placental malaria in CHUD/B in 2015. Patients and Method: It was a prospective, descriptive and cross-sectional study with an analytical purpose in the CHUD/Borgou Gynecology and Obstetrics department in Parakou. The study population consisted of pregnant women admitted in the Gynecology and Obstetrics department. It was an exhaustive census of all pregnant women admitted in the CHUD/B Gynecology and Obstetrics department. Results: Placental malaria was diagnosed in 57 pregnant women that is to say a prevalence of 20.28%. The average age of the mothers was 26 ± 6.02 years with extremes of 16 and 51 years. They were housewives in 27% of cases and 33.1% among them were not educated. The factors associated with the occurrence of the infection were the non-use of LLIN (Long Lasting Insecticidal Nets) and fever in the 3rd quarter of pregnancy with respectively p-value of 0.0490 and 0.0388. Conclusion: Placental malaria, an intermediate step in neonatal infection is common in Parakou and LLIN remains the most effective means of prevention in our context.

High malaria transmission in a forested malaria focus in French Guiana: How can exophagic Anopheles darlingi thwart vector control and prevention measures?

In French Guiana, malaria vector control and prevention relies on indoor residual spraying and distribution of long lasting insecticidal nets. These measures are based on solid epidemiological evidence but reveal a poor understanding of the vector. The current study investigated the behaviour of both vectors and humans in relation to the ongoing prevention strategies. In 2012 and 2013, Anopheles mosquitoes were sampled outdoors at different seasons and in various time slots. The collected mosquitoes were identified and screened for Plasmodium infection. Data on human behaviour and malaria episodes were obtained from an interview. A total of 3,135 Anopheles mosquitoes were collected, of which Anopheles darlingi was the predominant species (96.2%). For the December 2012-February 2013 period, the Plasmodium vivax infection rate for An. darlingi was 7.8%, and the entomological inoculation rate was 35.7 infective bites per person per three-month span. In spite of high bednet usage (95.7%) in 2012 and 2013, 52.2% and 37.0% of the participants, respectively, had at least one malaria episode. An. darlingi displayed heterogeneous biting behaviour that peaked between 20:30 and 22:30; however, 27.6% of the inhabitants were not yet protected by bednets by 21:30. The use of additional individual and collective protective measures is required to limit exposure to infective mosquito bites and reduce vector densities.

The Effect of Long Lasting Insecticide Bed Net Use on Malaria Prevalence in the Tombel Health District, South West Region-Cameroon.

Malaria remains a major public health problem in Africa, and its prevalence in Cameroon stands at 29%. Long Lasting Insecticide Nets (LLINs) were distributed in 2011 to reduce malaria mortality and morbidity; however, assessment of this intervention is scanty. The present study in the Tombel health district (THD) investigated the impact of this distribution on malaria prevalence. A total of 31,657 hospital records from 3 health facilities in 3 health areas for 2010–2013 were examined. Records for 2010 and 2011 provided predistribution baseline data, while those of 2012 and 2013 represented postdistribution data. 8,679 (27.4%) patients were positive for malaria. Children below 5 years had the highest prevalence (40.7%). The number of confirmed cases was highest from June to August (peak rainy season). Malaria prevalence was higher in males (25.3%) than in females (23.2%). Malaria prevalence increased in THD from 26.7% in 2010 to 30.7% in 2011 but dropped to 22.7% in 2012 and then increased in 2013 to 29.5%. There was an overall drop in the total number of confirmed malaria cases in 2012; this decrease was significant in Ebonji (p < 0.001) and Nyasoso (p < 0.015) health areas. The distribution of LLINs led to a short lived reduction in malaria prevalence in THD. LLIN distribution and other control activities should be reinforced to keep malaria prevalence low especially among the 0–5-year group.

A Longitudinal Analysis of Mosquito Net Ownership and Use in an Indigenous Batwa Population after a Targeted Distribution

Major efforts for malaria prevention programs have gone into scaling up ownership and use of insecticidal mosquito nets, particularly in sub-Saharan Africa where the malaria burden is high. Socioeconomic inequities in access to long lasting insecticidal nets (LLINs) are reduced with free distributions of nets. However, the relationship between social factors and retention of nets after a free distribution has been less studied, particularly using a longitudinal approach. Our research aimed to estimate the ownership and use of LLINs, and examine the determinants of LLIN retention, within an Indigenous Batwa population after a free LLIN distribution. Two LLINs were given free of charge to each Batwa household in Kanungu District, Uganda in November 2012. Surveyors collected data on LLIN ownership and use through six cross-sectional surveys pre- and post-distribution. Household retention, within household access, and individual use of LLINs were assessed over an 18-month period. Socioeconomic determinants of household retention of LLINs post-distribution were modelled longitudinally using logistic regression with random effects. Direct house-to-house distribution of free LLINs did not result in sustainable increases in the ownership and use of LLINs. Three months post-distribution, only 73% of households owned at least one LLIN and this period also saw the greatest reduction in ownership compared to other study periods. Eighteen-months post distribution, only a third of households still owned a LLIN. Self-reported age-specific use of LLINs was generally higher for children under five, declined for children aged 6–12, and was highest for older adults aged over 35. In the model, household wealth was a significant predictor of LLIN retention, controlling for time and other variables. This research highlights on-going socioeconomic inequities in access to malaria prevention measures among the Batwa in southwestern Uganda, even after free distribution of LLINs, and provides critical information to inform local malaria programs on possible intervention entry-points to increase access and use among this marginalized population.

Comparative effectiveness of malaria preventive measures on pregnancy outcome in Abeokuta, Ogun State, Nigeria

The burden of malaria and its associated problems in pregnancy can be reduced by the use of different malaria preventive measures. This study was conducted to determine the comparative effectiveness of three different malaria preventive measures on populations of parturient in Abeokuta, Ogun State, Nigeria. Blood samples from maternal placenta were collected from 211 parturient. Blood films were prepared, stained with 10% giemsa and observed for malaria parasites under the microscope. Relevant maternal demographic characteristics were obtained from the parturient and chi-square test was conducted to measure relationships using SPSS version 16.0. A low prevalence of maternal and placental malaria infections were recorded among parturient that used either Long Lasting Insecticidal Nets (LLIN) or Intermittent Preventive Treatment (IPT) during pregnancy (p&lt;0.05), compared with those who did not. Only maternal peripheral blood malaria parasite infection showed a significant relationship (p&lt;0.05) with dosage of IPT taken. Malaria parasite infection of the maternal peripheral, placenta and cord blood were significantly high with increase in gestational age at which IPT was first administered. High proportion of parturient who employed only one preventive measure during pregnancy significantly had maternal, placenta and cord malaria parasite infections (p&lt;0.05) compared with mothers who combined two or more preventive measures. Parturient that received IPT during pregnancy recorded a significantly low (p&lt;0.05) occurrence of poor pregnancy outcome, compared to those that did not. IPT and LLIN proved to be very useful tools in combating malaria infections if used early in pregnancy.Keywords: prevention, malaria, placenta, cord, gestation, parturient

Evaluation of different mesh sizes of long lasting insecticidal nets against Phlebotomus argentipes Annandale and Brunetti (Diptera: Psychodidae), in Bihar state of India

The study present result of long lasting insecticidal nets (LLINs) of different mesh sizes viz. PermaNet(R) 156mesh/inch2, PermaNet(R) 196mesh/inch2, PermaNet(R) 196mesh/inch2+75cm border of fine cloth in reducing Phlebotomus argentipes population along with community acceptance in three intervention villages. Entire experimental period of treatments maximum reduction 93.67% was observed in PermaNet(R) 196mesh/inch2+75cm border followed by PermaNet(R) 196mesh/inch2 91.90 and 74.29% in PermaNet(R)156mesh/inch2, when compared to control all the LLINs were showed significant reduction of P. argentipes population while compare to between them there was no significant difference. The significant reduction in gravid P. argentipes, was recorded as 71.87, 87.92 and 91.27%, in PermaNet(R) 156mesh/inch2, PermaNet(R) 196mesh/inch2 and PermaNet(R) 196mesh/inch2+75cm, respectively. The preference was high for PermaNet(R) 156mesh/inch2 without any side effect of LLINs.

When intensity of deltamethrin resistance in Anopheles gambiae s.l. leads to loss of Long Lasting Insecticidal Nets bio-efficacy: a case study in north Cameroon.

BackgroundIn Cameroon, insecticide resistance in Anopheles (An.) gambiae s.l. has been reported in several foci, prompting further investigations on associated patterns of Long-Lasting Insecticidal Nets (LLINs) bio-efficacy. The current study, conducted from June to August 2011, explored the intensity of deltamethrin resistance in An. gambiae s.l. from Pitoa and its impact on the residual bio-efficacy of LifeNet, a LLIN with deltamethrin incorporated into polypropylene nets (PND).MethodsTwo-four days old females An. gambiae s.l. reared from larval collections in Pitoa were tested for susceptibility to DDT, permethrin and deltamethrin, using standard World Health Organization (WHO) tube assays. Intensity of deltamethrin resistance was explored using WHO tube assays, but across six working concentrations from 0.001 % to 0.5 %. Bio-efficacy of unwashed and washed PND was assessed using WHO cone test. Species identification and kdr 1014 genotyping were performed on mosquito samples that were not exposed to insecticides, using PCR-RFLP and HOLA methods respectively. The Kisumu reference susceptible strain of An. gambiae s.s. was used for comparisons.ResultsA total of 1895 An. gambiae s.l. specimens from Pitoa were used for resistance and PND bio-efficacy testing. This mosquito population was resistant to DDT, permethrin and deltamethrin, with 18–40 min knockdown times for 50 % of tested mosquitoes and 59–77 % mortality. Deltamethrin Resistance Ratio compared with the Kisumu strain was estimated at ≥500 fold. LifeNets were effective against the susceptible Kisumu (100 % knockdown (KD60min) and mortality) and the resistant Pitoa samples (95 % KD60min, 83–95 % mortality). However, the bio-efficacy gradually dropped against the Pitoa samples when nets were washed (X2 = 35.887, df = 8, p < 0.001), and fell under the WHO efficacy threshold (80 % mortality and/or 95 % KD60min) between 10 and 15 washes. The Pitoa samples were composed of three sibling species: An. arabiensis (132/154, 86 %), An. coluzzii (19/154, 12 %) and An. gambiae s.s. (3/154, 2 %). The kdr L1014F allele was found only in An. coluzzii (Npositive = 13/19), at 34 % frequency and heterozygote stage. No specimen carried the kdr L1014S allele.ConclusionsThe current study showed that LifeNet might still offer some protection against the resistant An. gambiae s.l. population from Pitoa, provided appropriate dose of insecticide is available on the nets.

"Tazomoka Is Not a Problem". Local Perspectives on Malaria, Fever Case Management and Bed Net Use in Madagascar.

BackgroundAlthough its incidence has been decreasing during the last decade, malaria is still a major public health issue in Madagascar. The use of Long Lasting Insecticidal Nets (LLIN) remains a key malaria control intervention strategy in Madagascar, however, it encounters some obstacles. The present study aimed to explore the local terminology related to malaria, information channels about malaria, attitude towards bed nets, and health care seeking practices in case of fever. This article presents novel qualitative findings about malaria. Until now, no such data has been published for Madagascar.MethodsA comparative qualitative study was carried out at four sites in Madagascar, each differing by malaria epidemiology and socio-cultural background of the populations. Seventy-one semi-structured interviews were conducted with biomedical and traditional caregivers, and members of the local population. In addition, observations of the living conditions and the uses of bed net were conducted.ResultsDue to the differences between local and biomedical perspectives on malaria, official messages did not have the expected impact on population in terms of prevention and care seeking behaviors. Rather, most information retained about malaria was spread through informal information circulation channels. Most interviewees perceived malaria as a disease that is simple to treat. Tazomoka (“mosquito fever”), the Malagasy biomedical word for malaria, was not used by populations. Tazo (“fever”) and tazomahery (“strong fever”) were the terms more commonly used by members of the local population to refer to malaria related symptoms. According to local perceptions in all areas, tazo and tazomahery were not caused by mosquitos. Each of these symptoms required specific health recourse. The usual fever management strategies consisted of self-medication or recourse to traditional and biomedical caregivers. Usage of bed nets was intermittent and was not directly linked to protection against malaria in the eyes of most Malagasy people.ConclusionsThis article highlights the conflicting understanding of malaria between local perceptions and the biomedical establishment in Madagascar. Local perceptions of malaria present a holistic vision of the disease that includes various social and cultural dimensions, rather than reflecting one universal understanding, as in the biomedical image. The consideration of this “holistic vision” and other socio-cultural aspects surrounding the understanding of malaria is essential in implementing successful control intervention strategies.

Adherence to Malaria Preventive Measures and Associated Factors in Badewacho District, Southern Ethiopia

Malaria remains a major public health problem in Ethiopia threatening the lives of 68% of the population. At present, long lasting insecticidal nets and indoor residual spraying are the major malaria prevention and control methods in the country.This study was undertaken to assess adherence to currently available malaria preventive methods its associated factors inBadewacho District, Southern Ethiopia.A community based cross-sectional study was conducted between February and March, 2013. Systematic random sampling method was used to collect data on preventive measures from 138 households through semi-structured questionnaires administered to interviewees during home to home visit. The data was computed using a statistical soft ware SPSS version 16.0. A P-value &lt;0.05 and 95% CI excluding 1 were considered statistically significant.The coverage and the proportion of households with one or more of their members utilizing mosquito nets in the district were 73.2% and 44.2% respectively. Net utilization of households with under-five year children was 32.1%. Dirtiness of the nets, lack of appropriate area for hanging, wearing out, and adherence to other preventive measures were mentioned as reasons for not using the nets. Only 63(45.7%) of the respondents knew that mosquitoes transmit malaria and most households sought treatment in public health facilities.Utilization of mosquito net was significantly associated with previous treatment for malaria in government health institutions and knowledge about malaria prevention methods.Coverage and utilization of the major malaria preventive measures was low in theBadewacho District, Southern Ethiopia. This indicates the necessity of health education to increase the community awareness in utilization of available malaria preventive measures to reduce the disease burden.

Determinants of Impregnated Net Ownership and Utilization in Rural Community on the Thai-Myanmar Border in Prachuab Khiri Khan, Thailand

Efficacy of Insecticide-treated Nets (ITNs), Long Lasting Insecticidal Nets (LLINs) and Indoor Residual Spraying (IRS) in reducing malaria transmission are strongly presented in various countries. ITNs, LLINs and IRS free-of-charge have been used to control among Thai vulnerable populations since 2008. Studies found that the utilization of impreganted net among vulnerable Thai was low. This study investigated factors associated with impregnated net ownership and utilization among population living in rural community. Random samples of 1,673 respondents living in 678 households on the Thai-Myanmar border in Prachuab Khiri Khan province were interviewed from October 2010 to May 2011. The prevalence of impregnated nets ownership was 41%, and 70% of their own utilized them. In multivariate analysis, Thaipladthin ethnicity (adjusted Odds ratio (aOR) 2.1; 95% CI: 1.2-3.6) and access to IRS (aOR 2.3; 95% CI: 1.6-3.1) were associated with impregnated net ownership. Malaria infection (aOR 4.2; 95% CI: 1.8-9.4), and irregularly use of electric fan (aOR 2.0; 95% CI: 1.3-3.1) were positively associated with net utilization. Whereas, high level of barrier to ITN/LLIN utilization (aOR 0.6; 95% CI: 0.4-0.9) was associated with net utilization. Our findings reflect an existing gap between net ownership and utilization. To scale-up the adoption of impregnated net utilization, enforcing ownership through sustainable strategies that involved social marketing should be addressed.

Seasonal Dynamics, Longevity, and Biting Activity of Anopheline Mosquitoes in Southwestern Ethiopia

Continuous monitoring of vector species composition, abundance, dynamics, feeding pattern, and host finding strategy is the base to determine when, what, and how control should be implemented. Thus, this study was conducted to assess entomological parameters of anopheline mosquitoes in nine villages in Seka district, southwestern Ethiopia, from June to December 2012. Mosquito collection was carried out from selected households in each of the nine study villages using light trap catches from June to December 2012. Differences in mean mosquito density, parity rates before, and after indoor residual spraying (IRS) operation were compared. In total, 1,136 adult female anopheline mosquitoes were collected during the study period. All anopheline mosquitoes collected belong to three species. Anopheles gambiae senso lato Giles was the most predominant (69.7%) followed by Anopheles coustani s.l. Laveran (22.7%) and Anopheles pharoensis Theobald (7.6%). There was significant variation in mean mosquito density among An. gambiae s.l., An. coustani s.l., and An. pharoensis. Parity rate of An. gambiae s.l. before spray operation was significantly higher than after spray operation. The highest peak biting activity of An. gambiae s.l. was between 1800 and 2100 hours. The longevity of An. gambiae s.l. ranged from 3.4 to 12.5 d. The highest vector abundance and parity rate were recorded in July and August. In conclusion, the behavioral plasticity and early biting activity of An. gambiae s.l. could affect current vector control tools (IRS and long lasting insecticidal nets). Hence, it is imperative to explore intervention tools for outdoor malaria vector control in addition to the existing IRS and long-lasting insecticidal nets.