Lasting Insecticide Research Articles

Universal Access to Malaria Prevention, Diagnosis and Treatment as a Strategy toward Disease Control and Elimination: A Critical Look at Northeastern Nigeria

Background: As early as 2008 there was a call by the United Nations Secretary General to halt malaria death by ensuring universal coverage of malaria interventions to be attained by 2010. This was echoed by the World Health Assem-bly in 2015 by adopting the Global Technical Strategy or malaria 2016-2030 with universal access to malaria prevention, diagnosis and treatment as one of its three pillars. This study had a critical look at the supply and distribution of Artemisin-based Combination Therapy, Rapid Diagnostic Tests and Long Lasting Insecticide Treated Nets in 2017 with a view to critique the universal coverage of these commodities in Adamawa, Bauchi, Borno, Gombe, Taraba and Yobe States in the northeastern geopolitical region of Nigeria. Method: This is a quantitative cross-sectional study using secondary data. The research analyzed the data of malaria intervention commodities received by state malaria elimination programmes from six states across the northeast zone between January and December 2017. Results: The study result showed that RDTs were received and distributed in four of the six states and one state did not receive or distribute any. Commodities for treatment (ACTs) received and distributed showed that only one state had a significant supply and distribution of the commodity, two states had minimal supply and distribution while the other three states had insignificant quantities that did not match the RDT supply and the state that had the highest supply/distribution was the only state supported by the global fund in the northeast zone in 2017. Only one state had a significant quantity of LLINs distributed in 2017. Conclusion: The government of Nigeria and collaborating partners have made concerted efforts to improve access to ACTs, RDTs and LLINs with improvement in levels of intervention across the country. This study however clearly demonstrates the need to intensify efforts in making universal access possible in northeastern Nigeria so that the objectives of the National Malaria Strategic Plan 2014-2020 can be achieved. This comes at a time when donor funding is at cross-roads.

Active Case Search of Kala-azar in an Endemic Area of Bangladesh:

Visceral Leishmaniasis which is also known as kala-azar is one of the most alarming vector borne Disease in Bangladesh. Kala-azar elimination program was launched in Bangladesh in the year 2008. The primary goal of this program is to decrease the burden of Visceral Leishmaniasis as much as possible. Active case search method are currently using for detection of Visceral Leishmaniasis patient in the community. The successful active case search activity or method lies in preventing and reducing Visceral Leishmaniasis in Bangladesh. The purpose of this study was to assess the Active Case Search activity of Visceral Leishmaniasis Elimination Program in selective endemic area in Bangladesh. This cross-sectional study was conducted within the time frame of 1st January 2016 to 31st December 2016 at different unions of Fulbaria upazila in Mymensingh district using purposive sampling technique according to availability of the respondents and data was collected with pre-tested semi-structured questionnaire by face to face interview. A total number of 111 respondents were enrolled in this study as per selection criteria. Among 111 respondent’s male were 71(64%) and female were 40(36%) and 36 (32.4%) were farmer, 29 (26.1%) were students of different classes, 20 (18%) women were housewife, 11 (9.9%) respondents were in service, 6 (5.4%) were day Laborer and 7 (6.3%) had other profession. Regarding housing status most of them {81(72.98%)} had the kacha housing and only a few respondents {3 (2.7%)} had pakka housing. According to the distance of cowshed or cattle house of the majority of the respondents 95(85.6%) were in the nearest location from living room (Less than 12 feet). Among 111 respondents most of them {78(70.3%)} suffered from kala-azar and 33(29.7%) not suffered from kala- azar in the study area and among these 78 respondents 62(77.5%) found Post kala-azar Dermal Leishmaniasis (PKDL) spot on the body. Most of them 80(72.1%) stated that there was no regular routine visit of the health worker. 90 (81.1%) respondents mentioned that the frequency of Indoor Residual Spray (IRS) was once in a year and 21(18.9%) mentioned 2 times in a year. Among 111 respondents 78(70.27%) mentioned that last supply of Long Lasting Insecticide Net (LLIN) was more than 1 year ago,18(16.22%) mentioned before 6 month and 15(13.51%) before 1 year. This study permits to conclude that Active Case Search Activity of Visceral Leishmaniasis program in Bangladesh facing challenges due to lack of monitoring and supervision. Without strengthening of active case search activity, it is impossible to reach the goal.TAJ 2015; 28(2): 26-39

Effectiveness of repellent delivered through village health volunteers on malaria incidence in villages in South-East Myanmar: a stepped-wedge cluster-randomised controlled trial protocol

BackgroundTo combat emerging drug resistance in the Greater Mekong Sub-region (GMS) the World Health Organization and GMS countries have committed to eliminating malaria in the region by 2030. The overall approach includes providing universal access to diagnosis and treatment of malaria, and sustainable preventive measures, including vector control. Topical repellents are an intervention that can be used to target residual malaria transmission not covered by long lasting insecticide nets and indoor residual spraying. Although there is strong evidence that topical repellents protect against mosquito bites, evidence is not well established for the effectiveness of repellents distributed as part of malaria control activities in protecting against episodes of malaria. A common approach to deliver malaria services is to assign Village Health Volunteers (VHVs) to villages, particularly where limited or no services exist. The proposed trial aims to provide evidence for the effectiveness of repellent distributed through VHVs in reducing malaria.MethodsThe study is an open stepped-wedge cluster-randomised controlled trial randomised at the village level. Using this approach, repellent (N,N-diethyl-benzamide – 12% w/w, cream) is distributed by VHVs in villages sequentially throughout the malaria transmission season. Villages will be grouped into blocks, with blocks transitioned monthly from control (no repellent) to intervention states (to receive repellent) across 14 monthly intervals in random order). This follows a 4-week baseline period where all villages do not receive repellent. The primary endpoint is defined as the number of individuals positive for Plasmodium falciparum and Plasmodium vivax infections diagnosed by a rapid diagnostic test. Secondary endpoints include symptomatic malaria, Polymerase Chain Reaction (PCR)-detectable Plasmodium spp. infections, molecular markers of drug resistance and antibodies specific for Plasmodium spp. parasites.DiscussionThis study has been approved by relevant institutional ethics committees in Myanmar and Australia. Results will be disseminated through workshops, conferences and peer-reviewed publications. Findings will contribute to a better understanding of the optimal distribution mechanisms of repellent, context specific effectiveness and inform policy makers and implementers of malaria elimination programs in the GMS.Trial registrationAustralian and New Zealand Clinical Trials Registry (ACTRN12616001434482). Retrospectively registered 14th October 2016.

Assessment of net lending strategy to better reach mobile and migrant populations in malaria endemic areas of Cambodia

BackgroundIn Cambodia, internal migration involves migrants moving from non-malaria endemic areas to malaria endemic areas and vice versa. The majority of them work in farms or forests with various malaria transmission levels. In Cambodia, as one of the national approaches to ensure LLIN accessibility and use among mobile and migrant populations (MMPs), a lending scheme of long lasting insecticide treated nets (LLINs) was initiated among farm workers. Through this net lending program, LLINs and long-lasting insecticide treated hammock nets (LLIHNs) will be distributed annually at workplace (e.g. longstanding farms, plantations, industrial sites, as identified by operational district and health center staff) on a ratio of one LLIN per one worker. The main objective of this study is to assess MMPs’ accessibility to LLINs through a lending scheme with plantation owners in remote malaria endemic areas of Cambodia.MethodsThe study used a cross-sectional survey among MMPs using two-stage cluster sampling method. The sampling frame is the list of farms in the four provinces of Banteay Meanchey, Battambang, Pailin, and Pursat in western and northwestern Cambodia bordering with Thailand where the LLIN lending scheme was implemented and where an estimated 100 000 MMPs worked annually. The assessment was carried out from January to February 2013 in these four provinces. It was estimated that 768 workers would be required.ResultsA total of 702 MMPs were interviewed. The ratio of male: female is 1:1. The age group of 21–60 was the largest accounting for 77.6%. About 91% of the MMPs stayed on the farm for less than 6 months. 93.2% of them owned either untreated or insecticide treated nets. LLINs and LLIHNs accounted for 89.5%; and 46.6% of them borrowed the nets from a lending scheme. Among those workers who have LLINs/LLIHNs, 99% slept under LLINs/LLIHNs the night before. However, only 87.4% knew that sleeping under LLINs/LLIHNs protects against malaria.ConclusionsLLIN lending scheme provides an important delivery channel for a substantial percentage of net accessibility (46.6%) to the Cambodian national free-net distribution campaign in remote malaria endemic areas.

Evidence of Insecticide Resistance to Pyrethroids and Bendiocarb in Anopheles funestus from Tsararano, Marovoay District, Madagascar.

Introduction In Madagascar, malaria control relies on the countrywide use of long lasting insecticide treated bed nets (LLINs) and on indoor residual spraying (IRS) in the central highland area as well as a small area on the eastern coast. We tested insecticide resistance mechanisms of Anopheles funestus from Tsararano, a malaria endemic village in the coastal health district of Marovoay. Methods Insecticide susceptibility bioassays were done in July 2017 on first-generation Anopheles funestus (F1) to assess (i) the susceptibility to permethrin (0.05%), deltamethrin (0.05%), DDT (4%), malathion (5%), fenitrothion (1%), and bendiocarb (0.1%); (ii) the effect of preexposure to the piperonyl butoxide (PBO) synergist; and (iii) the enzymatic activities of cytochrome P450, esterases, and glutathione S-transferases (GST). Results Our results demonstrated that An. funestus was phenotypically resistant to pyrethroids and bendiocarb, with a mortality rate (MR) of 33.6% (95%CI: 24.5-43.7%) and 86% (95%CI: 77.6-92.1%), respectively. In contrast, An. funestus were 100% susceptible to DDT and organophosphates (malathion and fenitrothion). Preexposure of An. funestus to PBO synergist significantly restored the susceptibility to bendiocarb (MR=100%) and increased the MR in the pyrethroid group, from 96% (95%CI: 90.0-98.9%) to 100% for deltamethrin and permethrin, respectively (χ2 = 43, df = 3, P< 0.0001). Enzymatic activities of cytochrome P450 and α-esterases were significantly elevated among An. funestus compared with the IPM reference strain (Mann-Whitney U= 30, P<0.0001; U = 145.5, P <0.0001, respectively). No significant differences of β-esterases activities compared to the IPM reference strain were observed (Mann-Whitney U = 392.5, P = 0.08). Conclusion In Tsararano, despite the absence of an IRS programme, there is evidence of high levels of insecticide resistance to pyrethroids and bendiocarb in An.

Efficacy of a Pheromone Trap with Insecticide-treated Long-lasting Screen Against Fall Armyworm (faw), Spodoptera Frugiperda (lepidoptera: Noctuidae)

Food Security is an issue that will impact everyone by 2050 and it is projected there will be a global crisis unless action is taken. Currently the fall army worm (FAW), Spodoptera frugiperda, is a new pest to the Sub-Saharan region and the outbreaks over the past two years have been devastating. A promising novel technology is the combination of a pheromone lure from ChemTica Internacional S.A. and yellow long-lasting insecticide treated ZeroFly Screen from Vestergaard SA. To test this technology, we compared the attraction and mortality of traps made of old soda bottles in five different sites of Zambia with maize and wheat crops. Besides the attraction of the pheromone-baited traps we also compared the effect of the colour of the insecticidal net, between black and yellow screens. Our results showed that in all sites there were significant differences in trap catches between lure baited and non-baited traps. A total of 1129 FAW adults were trapped, of which 51.20% were from baited traps with the yellow long-lasting insecticide treated screen, 41.45% from traps baited and the black long-lasting insecticide treated screen and 7.35% from trap without lure or the insecticide treated screen. The trap with yellow insecticide treated screen was able to trap 110 more FAW than the black treated screen and the control. Significant differences were also observed in number of moths caught from each location and district. The highest catches were recorded from wheat crops at Zambia National Service (ZNS) Farm in Chongwe and Chaloshi farm in Chisamba districts, respectively, whilst the lowest catch was recorded in a maize field at Tugama farm in Chilanga district. It was also noticed that the pheromone used is specific to FAW as no other insects were recorded in all the sites. Therefore, the pheromone lure from ChemTica and the yellow long lasting insecticide treated screen from Vestergaard SA can be used in the integrated pest management of FAW in Zambia in both, maize and wheat, these complimentary methods include but are not limited to; the use of Biopesticides – fungal, viral or bacteria based products such as Metarhizium anisopliae or bacteria-based Bacillus thuringiensis that have proven effective against fall armyworm and have been used to control it in the US and Brazil.

Modelling the effect of bednet coverage on malaria transmission in South Sudan.

A campaign for malaria control, using Long Lasting Insecticide Nets (LLINs) was launched in South Sudan in 2009. The success of such a campaign often depends upon adequate available resources and reliable surveillance data which help officials understand existing infections. An optimal allocation of resources for malaria control at a sub-national scale is therefore paramount to the success of efforts to reduce malaria prevalence. In this paper, we extend an existing SIR mathematical model to capture the effect of LLINs on malaria transmission. Available data on malaria is utilized to determine realistic parameter values of this model using a Bayesian approach via Markov Chain Monte Carlo (MCMC) methods. Then, we explore the parasite prevalence on a continued rollout of LLINs in three different settings in order to create a sub-national projection of malaria. Further, we calculate the model’s basic reproductive number and study its sensitivity to LLINs’ coverage and its efficacy. From the numerical simulation results, we notice a basic reproduction number, , confirming a substantial increase of incidence cases if no form of intervention takes place in the community. This work indicates that an effective use of LLINs may reduce and hence malaria transmission. We hope that this study will provide a basis for recommending a scaling-up of the entry point of LLINs’ distribution that targets households in areas at risk of malaria.

Community health priorities: Lessons for malaria prevention from Balaka district, Malawi.

Communication to address priority health challenges typically draws on epidemiological research in conjunction with referencing global and country strategies. While community-level perspectives on health challenges typically align with national priorities, nuances and barriers that constrain health response may be less well known. To deepen understanding of the relation between situational aspects of health and ways of making meaning, community insights into health priorities were explored. Action Media, an established participatory research methodology for informing health communication design and strategy, was undertaken with parents of children under 5 in Balaka District, Malawi. Participants identified malaria as a priority concern in their community. While it was reported that there was strong commitment to consistent use of long lasting insecticide treated nets, there was frustration that malaria incidence remained high. It was observed that risk of exposure to mosquito bites was increased as a result of chores and other activities that extended into the early evenings prior to retiring to bed under a bed net. Bed bug infestations were said to be a common and ongoing concern. Some community members alleviated discomfort by abandoning their beds and sleeping outside without adequate protection while others boiled their bed nets to remove bed bugs. Accessing distant health facilities when ill with malaria was difficult for adults and children. Participants identified the need for effective strategies to address these concerns including accessing mosquito repellant, eradicating bed bugs, treating malaria locally and collaborating in malaria control activities. Meeting targets for malaria prevention requires consideration of contextual factors that undermine effective malaria prevention in affected communities. Such factors are not immediately apparent through epidemiological data. Regularly assessing contextual challenges in high malaria incidence areas provides opportunities to understand gaps, to refine intervention strategies and to inform communication programming.

Efficacy of Long Lasting Insecticide Nets in Killing Halyomorpha Halys in Pear Orchards

Efficacy of Long Lasting Insecticide Nets in Killing<i> Halyomorpha Halys</i> in Pear Orchards

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.

International Health Care Topics: Malaria Prevention Analyses, Nursing Perspective, and Patient Perspectives

The issue for May 2018 issue covered three main areas including two articles about Malaria treatment in Nigeria, two articles about healthcare workers, one from Saudi Arabia the other from Australia, and one article about patients satisfaction from the United States (US). There were 216 million Malaria cases in worldwide in 2016. The majority of Malaria cases and deaths occur in Africa. Malaria is a main public issue in Nigeria. The number of Malaria cases and deaths in Nigeria is greater than that in the rest of the world. Articles entitled “Replacement Campaign of Long Lasting Insecticide Treated Nets in Ondo State, Southwest Nigeria, Heartland of Africa’s Most Efficient Vector Species” and “Performance of Microscopy Method and Rapid Diagnostic Tests in Malaria Diagnosis amongst Pregnant Women in Lagos, Southwest Nigeria” contribute to improving prevention and treatment efforts for Malaria in Nigeria.

Factors Affecting Use of Insecticide Treated Nets by Children Under Five Years of Age in Kenya

Malaria is a major cause of morbidity and mortality worldwide and mostly affects pregnant women and children under five years of age. It is among the leading cause of deaths in under five years of age with an approximate of 20 percent of all deaths in Kenya. The World Health Organization recommends the use of Long Lasting Insecticide Treated Nets (LLINs) and Insecticide Treated Nets (ITNs) for prevention of malaria infection. Although several studies have analysed the accessibility, availability, ownership and utilization of ITNs by children less than five years of age, information on intra-household factors that influence utilization of ITNs by children less than five years of age is very limited. This study investigated the factors that influence use of ITNs and LLINs by children under five years across the country using the random utility model because of the nature of the outcomes which are discrete in nature. The regression results showed that age of household head, household size, gender of child and the head of the household, presence of fever, treatment of net since acquisition significantly affected use of ITNs. The study concludes that these factors hinder use of ITNs by children under five years and therefore presence of an ITN in a household may not guarantee utilisation. The study recommends that efforts be made to increase awareness on the importance of ensuring children under five years sleep under an ITN if reduction in morbidity and mortality in this age group is to be realised.

Long Lasting Insecticide Treated Net and Factors Limiting Effective Utilization in a High Malaria Incidence County of Wulu, South Sudan

Long Lasting Insecticide Treated Net and Factors Limiting Effective Utilization in a High Malaria Incidence County of Wulu, South Sudan

Malaria control in a tribal area of central India using existing tools

Malaria is difficult to control in central India because of geographical terrain, efficient vectors, and perennial transmission of Plasmodium falciparum and socio-cultural practices of ethnic tribes. The objective was to develop a model to prevent and control malaria in hard to reach areas using existing tools. Baigachak (Tribe population 31,900) situated in Dindori district was undertaken for this study. Intervention measures used are indoor residual spray (IRS), long lasting insecticide treated bed nets (LLINs), prompt diagnosis and treatment along with intensive Information, Education and Communication (IEC) involving school children as agent of change. Door to door rapid fever surveys were carried out in the study area from 2009 to 14 and finger prick blood smears were made from all fever cases and examined under microscope. Mosquitoes were assayed for the presence of sporozoites by enzyme-linked immunosorbent assay (ELISA) technique and sibling species by polymerase chain reaction (PCR). There are two highly efficient vectors i.e. Anopheles culicifacies and An. fluviatilis. In monsoon season of 2009, the man hour density for An. culicifacies was 36.2 which declined to 10.9 during monsoon season of 2010-14 (t = 6.52; p < 0.0001). Epidemiological results revealed that malaria positivity was declined from 27% in 2009–3% in 2014 (Trend chi2 = 57.21; p < 0.0001) and P. falciparum declined from 23.6 to 2.4% (Trend chi2 = 48.33; p < 0.0001). Spleen rate was declined from 47% in 2009–5% in 2014 (χ2 for trend = 6.1; p = 0.0135). Baigachak has achieved a remarkable 89% reduction in malaria. This study confirms that the control strategies undertaken in this study are useful and should be extended at multiple sites for further validation.

The impact of mass distribution of long lasting insecticide-treated bed-nets on the malaria parasite burden in the Buea Health District in South-West Cameroon: a hospital based chart review of patient\u2019s laboratory records

BackgroundMalaria remains a leading cause of illness and deaths in Cameroon. The use of long lasting insecticide treated bed nets (LLITN) is the most effective method to reduce the burden of malaria. The aim of this study was to determine the impact of the mass distribution of LLITN on the hospital prevalence of malaria (prevalence of malaria in patients with a presumptive diagnosis of malaria), in the Buea Health District in the South-West Region of Cameroon.MethodsA hospital-based chart review of records of malaria confirmatory test results in health facilities of the Buea Health District from January 2011 through December 2013. Data were extracted with the help of a grid, then analyzed with EPIinfo version 6 and Microsoft Excel 2010. Chi square test was used to compare prevalence and ANOVA was used to compare mean parasitaemia.ResultsA total of 17,268 records were reviewed, 3545[20.5% (19.9–21.1)] confirmed malaria positive with mean trophozoite count of 2735.3 ± 23,323.5 trophozoite/µl of blood. Prevalence was higher in males 1497 [23.5% (22.4–24.5)] than females 2047 [18.8% (18.1–19.6)], p < 0.01. Significant evidence of a reduction in the prevalence of malaria was found in under-fives in 2012 (p = 0.03).ConclusionsUniversal coverage with LLITN failed to guarantee effective control of malaria in the Buea Health District, as expected. Continuous and appropriate use of LLITN is indispensable, in addition to periodic sensitization, booster campaigns of LLITN distribution and evaluation research for effective prevention and control of malaria.

Caretakers\u2019 understanding of malaria, use of insecticide treated net and care seeking-behavior for febrile illness of their children in Ethiopia

BackgroundLocal understandings of malaria and use of preventive measures-are critical factors in sustained control of malaria. This study assessed caretakers’ knowledge on malaria, use of Long Lasting Insecticide Treated Nets (LLINs) and care-seeking behavior for their children’s illness in different malaria transmission settings of Ethiopia.MethodsData were collected from 709 caretakers of children of 2–9 years of age during in 2016. A standard questionnaire was used to assess caretakers’ perceptions of malaria, use of LLIN and care seeking behavior for febrile illness of children aged 2–9 years.ResultsThe caretakers recognized malaria mostly by chills (70.4%, 499/709), fever (45.7%, 324/709) and headache (39.8%, 282/709). Overall, only 66.4% (471) of the caretakers knew that mosquito bite caused malaria and that it was quite heterogeneous by localities (ranging from 26.1% to 89.4%) and altitude (p < 0.05). Majority, 72.2% (512), of the caretakers knew that sleeping under LLIN could prevent malaria. Overall knowledge on malaria (mean = 51.2%) was very low with significant variations by localities, altitude and levels of malaria transmission, being low in high altitude and low in transmission areas (p < 0.05). Four hundred ninety-one (69.3%, 491/709) of the children slept under LLIN in the previous night. Of malaria related knowledge items, only knowledge of LLIN was associated with net use; non-use of LLN was higher among caretakers who did not know the role of LLIN (AOR = 0.47, 95%CI: 0.28–0.77, p = 0.003). Of course, attributing causation of malaria to stagnant water discouraged use of net (p = 0.021). Of febrile children (n = 122), only 50 (41.0%) sought care with only 17 (34.0%) seeking the care promptly. There was no significant link between knowledge of malaria and care seeking behavior (p > 0.05). However, knowledge of malaria had some level of influence on treatment source preference where caretakers with greater knowledge preferred pharmacy as source of care.ConclusionsThe findings demonstrated that caretakers’ understanding of malaria was unsatisfactory with marked heterogeneity by localities. The present evidence suggests that knowledge is not sufficient enough to drive LLIN use and care seeking. Yet, context-specific health education interventions are important besides ensuring access to necessary preventive tools.

Wash resistance and bio-efficacy of Olyset® Plus, a long-lasting insecticide-treated mosquito net with synergist against malaria vector, Anopheles stephensi.

To determine the wash resistance of Olyset® Plus using World Health Organization Pesticide Evaluation Scheme standard washing procedure and to assess the value of knock down and mortality rates of Anopheles stephensiat different regimens of long lasting insecticide treated nets washings. The study was conducted at the Bioassay Laboratory of Culicidae Insectary, School of Public Health, Tehran University of Medical Sciences, Iran. The net was made of polyester impregnated with permethrin and piperonyl butoxide at a ratio of 2:1. The washing resistance was assessed using Le Chat® soap and a shaker incubator set at a speed of 155 r/min, 30°C for 10min. The cone bioassay test was carried out according to World Health Organization recommended guideline with tolerant field strain of female Anopheles stephensi to pyrethroids. The knockdown and mortality rates of female mosquitoes exposed to Olyset® Plus from un-washed nets to 2 washings were 79.7% and 88.8% respectively. Mortality was dropped to zero while active ingredient estimated 0.532μg/100cm2 to 0.481μg/100cm2 after 15 washings. A positive correlation was seen between residues of permethrin on nets, knockdown rate and mortality rate of female Anopheles stephensi exposed to different regimes of washed Olyset® Plus (r=0.954, P=0.001). It is recommended that a preliminary survey conducted on resistance level of Anopheles vectors before the distribution of Olyset® Plus in malaria endemic communities.

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.

Host-seeking activity of a Tanzanian population of Anopheles arabiensis at an insecticide treated bed net

BackgroundUnderstanding how mosquitoes respond to long lasting insecticide treated nets (LLINs) is fundamental to sustaining the effectiveness of this essential control tool. We report on studies with a tracking system to investigate behaviour of wild anophelines at an LLIN, in an experimental hut at a rural site in Mwanza, Tanzania.MethodsGroups of adult female mosquitoes (n = 10 per replicate) reared from larvae of a local population, identified as predominantly (95%) Anopheles arabiensis, were released in the hut. An infrared video tracking system recorded flight and net contact activity over 1 h as the mosquitoes attempted to reach a supine human volunteer within a bed net (either a deltamethrin-treated LLIN or an untreated control net). A range of activities, including flight path, position in relation to the bed net and duration of net contact, were quantified and compared between treatments.ResultsThe total time that female An. arabiensis spent in flight around LLINs was significantly lower than at untreated nets [F(1,10) = 9.26, p = 0.012], primarily due to a substantial reduction in the time mosquitoes spent in persistent ‘bouncing’ flight [F(1,10) = 18.48, p = 0.002]. Most activity occurred at the net roof but significantly less so with LLINs (56.8% of total) than untreated nets [85.0%; Χ2 (15) = 234.69, p < 0.001]. Activity levels at the bed net directly above the host torso were significantly higher with untreated nets (74.2%) than LLINs [38.4%; Χ2 (15) = 33.54, p = 0.004]. ‘Visiting’ and ‘bouncing’ rates were highest above the volunteer’s chest in untreated nets (39.9 and 50.4%, respectively) and LLINs [29.9 and 42.4%; Χ2 (13) = 89.91, p < 0.001; Χ2 (9) = 45.73, p < 0.001]. Highest resting rates were above the torso in untreated nets [77%; Χ2 (9) = 63.12, p < 0.001], but in LLINs only 33.2% of resting occurred here [Χ2 (9) = 27.59, p = 0.001], with resting times spread between the short vertical side of the net adjacent to the volunteer’s head (21.8%) and feet (16.2%). Duration of net contact by a single mosquito was estimated at 204–290 s on untreated nets and 46–82 s on LLINs. While latency to net contact was similar in both treatments, the reduction in activity over 60 min was significantly more rapid for LLINs [F(1,10) = 6.81, p = 0.026], reiterating an ‘attract and kill’ rather than a repellent mode of action.ConclusionsThe study has demonstrated the potential for detailed investigations of behaviour of wild mosquito populations under field conditions. The results validate the findings of earlier laboratory studies on mosquito activity at LLINs, and reinforce the key role of multiple brief contacts at the net roof as the critical LLIN mode of action.

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.