scholarly journals Modeling consensus and distance to delivering indoor residual spray (IRS) implementation strategies to control malaria transmission

2020 ◽  
Author(s):  
Sadie Ryan ◽  
Anne C. Martin ◽  
Bhavneet Walia ◽  
Anna Winters ◽  
David A Larsen
Keyword(s):  
Indoor Residual Spraying ◽  
Implementation Strategies ◽  
Network Models ◽  
Malaria Vector Control ◽  
Human Community ◽  
Control Programs ◽  
Malaria Burden ◽  
Risk Prioritization ◽  
Mosquito Nets ◽  
Vector Control Intervention

AbstractBackgroundIndoor residual spraying (IRS) is an effective method to control malaria-transmitting Anopheles mosquitoes and often complements insecticide-treated mosquito nets, the predominant malaria vector control intervention. With insufficient funds to cover every household, malaria control programs must balance the malaria risk to a particular human community against the financial cost of spraying that community. This study creates a framework for modeling the distance to households for targeting IRS implementation, and applies it to potential risk prioritization strategies in four provinces (Luapula, Muchinga, Eastern, and Northern) in Zambia.MethodsWe used optimal network models to assess the travel distance of routes between operations bases and human communities identified through remote sensing. We compared network travel distances to Euclidean distances, to demonstrate the importance of accounting for road route costs. We then compared the distance to reaching communities for different risk prioritization strategies assuming sufficient funds to spray 50% of households, using four underlying malarial risk maps: a) predicted Plasmodium falciparum parasite rate in 2-10 year olds (PfPR), or b) predicted probability of the presence of each of three main malaria transmitting anopheline vectors (An. arabiensis, An. funestus, An. gambiae)ResultsThe estimated one-way network route distance to reach communities to deliver IRS ranged from 0.05 – 115.69 Km. Euclidean distance over and under-estimated these routes by −101.21 – 41.79 Km per trip, as compared to the network route method. There was little overlap between risk map prioritization strategies, both at a district-by-district scale, and across all four provinces. At both scales, agreement for inclusion or exclusion from IRS across all four prioritization strategies occurred in less than 10% of houses. The distances to reaching prioritized communities were either lower, or not statistically different from non-prioritized communities, at both scales of strategy.ConclusionVariation in distance to targeted communities differed depending on risk prioritization strategy used, and higher risk prioritization did not necessarily translate into greater distances in reaching a human community. These findings from Zambia suggest that areas with higher malaria burden may not necessarily be more remote than areas with lower malaria burden.

The impact of stopping and starting indoor residual spraying on malaria burden in 14 districts of Uganda

2020 ◽  
Author(s):  
Jane Namuganga ◽  
Adrienne Epstein ◽  
Joaniter Nankabirwa ◽  
Arthur Mpimbaza ◽  
Moses Kiggundu ◽  
...  
Keyword(s):  
Malaria Incidence ◽  
Critical Role ◽  
Scale Up ◽  
Indoor Residual Spraying ◽  
Fold Increase ◽  
Bed Nets ◽  
Malaria Burden ◽  
Vector Control Intervention ◽  
Using Data ◽  
The Impact

Abstract The scale-up of malaria control efforts has led to marked reductions in malaria burden over the past twenty years, but progress has slowed. Implementation of indoor residual spraying (IRS) of insecticide, a proven vector control intervention, has been limited and difficult to sustain partly because questions remain on its added impact over widely accepted interventions such as bed nets. Using data from 14 enhanced surveillance health facilities in Uganda, a country with high bet net coverage yet high malaria burden, we estimate the impact of starting and stopping IRS. We show that stopping IRS resulted in a 5-fold increase in malaria incidence within 10 months, but reinstating IRS led to an over 5-fold decrease within 8 months. In areas where IRS was initiated and sustained, malaria incidence dropped by 85% after year 4. IRS could play a critical role in achieving global malaria targets, particularly in areas where progress has stalled.

scholarly journals The impact of stopping and starting indoor residual spraying on malaria burden in Uganda

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jane F. Namuganga ◽  
Adrienne Epstein ◽  
Joaniter I. Nankabirwa ◽  
Arthur Mpimbaza ◽  
Moses Kiggundu ◽  
...  
Keyword(s):  
Malaria Incidence ◽  
Critical Role ◽  
Scale Up ◽  
Indoor Residual Spraying ◽  
Fold Increase ◽  
Bed Nets ◽  
Malaria Burden ◽  
Vector Control Intervention ◽  
Using Data ◽  
The Impact

AbstractThe scale-up of malaria control efforts has led to marked reductions in malaria burden over the past twenty years, but progress has slowed. Implementation of indoor residual spraying (IRS) of insecticide, a proven vector control intervention, has been limited and difficult to sustain partly because questions remain on its added impact over widely accepted interventions such as bed nets. Using data from 14 enhanced surveillance health facilities in Uganda, a country with high bed net coverage yet high malaria burden, we estimate the impact of starting and stopping IRS on changes in malaria incidence. We show that stopping IRS was associated with a 5-fold increase in malaria incidence within 10 months, but reinstating IRS was associated with an over 5-fold decrease within 8 months. In areas where IRS was initiated and sustained, malaria incidence dropped by 85% after year 4. IRS could play a critical role in achieving global malaria targets, particularly in areas where progress has stalled.

scholarly journals Resistance of Anopheles gambiae to the new insecticide clothianidin associated with unrestricted use of agricultural neonicotinoids in Yaoundé, Cameroon

2020 ◽  
Author(s):  
Caroline Fouet ◽  
Ayukarah F. Ashu ◽  
Marilene M. Ambadiang ◽  
Williams Tchapga ◽  
Charles S. Wondji ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Agricultural Sector ◽  
Indoor Residual Spraying ◽  
Urban Ecosystems ◽  
Malaria Vector Control ◽  
Cytochrome P450 Enzymes ◽  
Control Programs ◽  
Rural And Urban ◽  
Integral Role ◽  
Small Clusters

AbstractBackgroundNew active ingredients, mostly repurposed from the agricultural sector, are gradually being introduced into malaria vector control programs. Prior to scaling up novel insecticides, it is vital to assess if their use in agriculture has already selected mosquito populations with reduced susceptibility in some areas. The aim of the present study was to determine if the use of neonicotinoids in agricultural pest management could drive resistance to clothianidin—a neonicotinoid recently prequalified by WHO for indoor residual spraying.MethodsWe carried out intensive sampling of Anopheles gambiae, An. coluzzii and Culex sp. larvae from a large suburban farm and from 4 surrounding locations belonging to the rural and urban ecosystems of Yaoundé, Cameroon. Using WHO tube tests and CDC bottle bioassays, we tested the recommended diagnostic doses of clothianidin against field-collected populations using two laboratory strains as susceptible controls. We exposed adult mosquitoes to the insecticide for 1 h and monitored mortality rates for seven consecutive days.ResultsAn. coluzzii and Culex sp. mosquitoes were fully susceptible to clothianidin reaching 100% mortality by day 3. By contrast, An. gambiae populations revealed heterogeneous profiles ranging from susceptibility to strong resistance. Populations from the suburban farm, where neonicotinoids are routinely used, displayed the lowest mortality rate (46.5 % ± 5.65) and were capable of surviving 5X and 10X the diagnostic dose of clothianidin. When clothianidin was tested in combination with the synergist piperonyl butoxide, mortality of resistant populations increased from 46.5 % to 92.7 % implying that Cytochrome P450 enzymes play an integral role in the genetic mechanism underlying clothianidin resistance in An. gambiae.ConclusionsThese findings show that small clusters of resistance to clothianidin may exist around farmlands where agricultural neonicotinoids are being used. Patches of intensive agriculture should be particularly monitored in indoor residual spraying target areas.

scholarly journals Impact of seasonality and malaria control interventions on Anopheles density and species composition from three areas of Uganda with differing malaria endemicity

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Henry Ddumba Mawejje ◽  
Maxwell Kilama ◽  
Simon P. Kigozi ◽  
Alex K. Musiime ◽  
Moses Kamya ◽  
...  
Keyword(s):  
Species Composition ◽  
Vector Control ◽  
Malaria Control ◽  
Mosquito Species ◽  
Density Ratio ◽  
Indoor Residual Spraying ◽  
Sub Saharan Africa ◽  
Malaria Vector Control ◽  
Vector Density ◽  
Llin Distribution

Abstract Background Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the malaria control interventions primarily responsible for reductions in transmission intensity across sub-Saharan Africa. These interventions, however, may have differential impact on Anopheles species composition and density. This study examined the changing pattern of Anopheles species in three areas of Uganda with markedly different transmission intensities and different levels of vector control. Methods From October 2011 to June 2016 mosquitoes were collected monthly using CDC light traps from 100 randomly selected households in three areas: Walukuba (low transmission), Kihihi (moderate transmission) and Nagongera (high transmission). LLINs were distributed in November 2013 in Walukuba and Nagongera and in June 2014 in Kihihi. IRS was implemented only in Nagongera, with three rounds of bendiocarb delivered between December 2014 and June 2015. Mosquito species were identified morphologically and by PCR (Polymerase Chain Reaction). Results In Walukuba, LLIN distribution was associated with a decline in Anopheles funestus vector density (0.07 vs 0.02 mosquitoes per house per night, density ratio [DR] 0.34, 95% CI: 0.18–0.65, p = 0.001), but not Anopheles gambiae sensu stricto (s.s.) nor Anopheles arabiensis. In Kihihi, over 98% of mosquitoes were An. gambiae s.s. and LLIN distribution was associated with a decline in An. gambiae s.s. vector density (4.00 vs 2.46, DR 0.68, 95% CI: 0.49–0.94, p = 0.02). In Nagongera, the combination of LLINs and multiple rounds of IRS was associated with almost complete elimination of An. gambiae s.s. (28.0 vs 0.17, DR 0.004, 95% CI: 0.002–0.009, p < 0.001), and An. funestus sensu lato (s.l.) (3.90 vs 0.006, DR 0.001, 95% CI: 0.0005–0.004, p < 0.001), with a less pronounced decline in An. arabiensis (9.18 vs 2.00, DR 0.15 95% CI: 0.07–0.33, p < 0.001). Conclusions LLIN distribution was associated with reductions in An. funestus s.l. in the lowest transmission site and An. gambiae s.s. in the moderate transmission site. In the highest transmission site, a combination of LLINs and multiple rounds of IRS was associated with the near collapse of An. gambiae s.s. and An. funestus s.l. Following IRS, An. arabiensis, a behaviourally resilient vector, became the predominant species, which may have implications for malaria vector control activities. Development of interventions targeted at outdoor biting remains a priority.

scholarly journals Addressing key gaps in implementation of mosquito larviciding to accelerate malaria vector control in southern Tanzania: results of a stakeholder engagement process in local district councils

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Salum A. Mapua ◽  
Marceline F. Finda ◽  
Ismail H. Nambunga ◽  
Betwel J. Msugupakulya ◽  
Kusirye Ukio ◽  
...  
Keyword(s):  
Malaria Control ◽  
Public Engagement ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Production Plant ◽  
Community Members ◽  
Key Informants ◽  
Larval Source Management ◽  
Source Management

Abstract Background Larval source management was historically one of the most effective malaria control methods but is now widely deprioritized in Africa, where insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are preferred. However, in Tanzania, following initial successes in urban Dar-es-Salaam starting early-2000s, the government now encourages larviciding in both rural and urban councils nationwide to complement other efforts; and a biolarvicide production-plant has been established outside the commercial capital. This study investigated key obstacles and opportunities relevant to effective rollout of larviciding for malaria control, with a focus on the meso-endemic region of Morogoro, southern Tanzania. Methods Key-informants were interviewed to assess awareness and perceptions regarding larviciding among designated health officials (malaria focal persons, vector surveillance officers and ward health officers) in nine administrative councils (n = 27). Interviewer-administered questionnaires were used to assess awareness and perceptions of community members in selected areas regarding larviciding (n = 490). Thematic content analysis was done and descriptive statistics used to summarize the findings. Results A majority of malaria control officials had participated in larviciding at least once over the previous three years. A majority of community members had neutral perceptions towards positive aspects of larviciding, but overall support for larviciding was high, although several challenges were expressed, notably: (i) insufficient knowledge for identifying relevant aquatic habitats of malaria vectors and applying larvicides, (ii) inadequate monitoring of programme effectiveness, (iii) limited financing, and (iv) lack of personal protective equipment. Although the key-informants reported sensitizing local communities, most community members were still unaware of larviciding and its potential. Conclusions The larviciding programme was widely supported by both communities and malaria control officials, but there were gaps in technical knowledge, implementation and public engagement. To improve overall impact, it is important to: (i) intensify training efforts, particularly for identifying habitats of important vectors, (ii) adopt standard technical principles for applying larvicides or larval source management, (iii) improve financing for local implementation and (iv) improve public engagement to boost community awareness and participation. These lessons could also be valuable for other malaria endemic areas wishing to deploy larviciding for malaria control or elimination.

scholarly journals Efficacy of broflanilide (VECTRON T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Corine Ngufor ◽  
Renaud Govoetchan ◽  
Augustin Fongnikin ◽  
Estelle Vigninou ◽  
Thomas Syme ◽  
...  
Keyword(s):  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Cross Resistance ◽  
Malaria Vector Control ◽  
Mosquito Vectors ◽  
Experimental Huts ◽  
Application Rates ◽  
Wettable Powder ◽  
Cone Bioassay ◽  
Pirimiphos Methyl

AbstractThe rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. Insecticides with new chemistries are urgently needed. Broflanilide is a newly discovered insecticide under consideration. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON T500) for IRS on mud and cement wall substrates in laboratory and experimental hut studies against pyrethroid-resistant malaria vectors in Benin, in comparison with pirimiphos-methyl CS (Actellic 300CS). There was no evidence of cross-resistance to pyrethroids and broflanilide in CDC bottle bioassays. In laboratory cone bioassays, broflanilide WP-treated substrates killed > 80% of susceptible and pyrethroid-resistant An. gambiae sl for 6–14 months. At application rates of 100 mg/m2 and 150 mg/m2, mortality of wild pyrethroid-resistant An. gambiae sl entering experimental huts in Covè, Benin treated with VECTRON T500 was similar to pirimiphos-methyl CS (57–66% vs. 56%, P > 0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on VECTRON T500 treated hut walls remained > 80%. IRS with broflanilide shows potential to significantly improve the control of malaria transmitted by pyrethroid-resistant mosquito vectors and could thus be a crucial addition to the current portfolio of IRS insecticides.

scholarly journals Residual and Fumigant Effects of Bendiocarb WP80 in a Malarious Areas in Borderline of Iran and Pakistan  

2021 ◽  
Author(s):  
Mohammad Reza Abai ◽  
Hassan Vatandoost ◽  
Hossein Dorzadeh ◽  
Mansoreh Shayeghi ◽  
Ahmad Ali Hanafi-bojd ◽  
...  
Keyword(s):  
Vector Control ◽  
Anopheles Stephensi ◽  
Indoor Residual Spraying ◽  
Residual Effect ◽  
Malaria Vector Control ◽  
Biological Assays ◽  
The Public ◽  
Main Activity ◽  
Contact Bioassay ◽  
Old Females

Abstract Background: Malaria and leishmaniasis are the public health problems in southern Iran. The main activity of vector control is indoor residual spraying using pyrethrpids. The aim of study was to evaluate the biological assays of bendiocarb WP at different surfaces of wall. Materials and Methods: The residual effect of bendicocarb WP80 at 400 mg/m2 was evauated on various local surfaces of rooms such as mud and plaster as well as thatch roofs and wooden. WHO standard cones using contact bioassays were carried out using laboratory reared sugar-fed, 48-72 h old females of Anopheles stephensi . Contact bioassays were carried out on sprayed surfaces for 150 days.Results: Contact bioassay on surfaces treated with bendicocarb WP80 diffferent surfaces was estimated about 2 months. Fumigant tests of bendicocarb WP80 at 400 mg/m2 revealed 50-93.83% mortality with one month persistency.Discussion: The rsults hsowed that carbamte insecticide could be used as rotation with pyrethroids for malaria vector control .

scholarly journals Long-lasting microbial larvicides for controlling insecticide resistant and outdoor transmitting vectors: a cost-effective supplement for malaria interventions

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Guofa Zhou ◽  
Eugenia Lo ◽  
Andrew K. Githeko ◽  
Yaw A. Afrane ◽  
Guiyun Yan
Keyword(s):  
Cost Effectiveness ◽  
Vector Control ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Cost Effective ◽  
Control Measures ◽  
Malaria Vector Control ◽  
Potential Cost ◽  
Outdoor Transmission ◽  
Indoor And Outdoor

AbstractThe issues of pyrethroid resistance and outdoor malaria parasite transmission have prompted the WHO to call for the development and adoption of viable alternative vector control methods. Larval source management is one of the core malaria vector interventions recommended by the Ministry of Health in many African countries, but it is rarely implemented due to concerns on its cost-effectiveness. New long-lasting microbial larvicide can be a promising cost-effective supplement to current vector control and elimination methods because microbial larvicide uses killing mechanisms different from pyrethroids and other chemical insecticides. It has been shown to be effective in reducing the overall vector abundance and thus both indoor and outdoor transmission. In our opinion, the long-lasting formulation can potentially reduce the cost of larvicide field application, and should be evaluated for its cost-effectiveness, resistance development, and impact on non-target organisms when integrating with other malaria vector control measures. In this opinion, we highlight that long-lasting microbial larvicide can be a potential cost-effective product that complements current front-line long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) programs for malaria control and elimination. Microbial larviciding targets immature mosquitoes, reduces both indoor and outdoor transmission and is not affected by vector resistance to synthetic insecticides. This control method is a shift from the conventional LLINs and IRS programs that mainly target indoor-biting and resting adult mosquitoes.

scholarly journals Effect of LongRange™ eprinomectin on Anopheles arabiensis by feeding on calves treated with the drug

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Aklilu Belay ◽  
Beyene Petros ◽  
Teshome Gebre-Michael ◽  
Meshesha Balkew
Keyword(s):  
Anopheles Arabiensis ◽  
Control Method ◽  
Indoor Residual Spraying ◽  
Adult Emergence ◽  
Malaria Vector Control ◽  
Egg Hatchability ◽  
Kaplan Meier ◽  
Recorded Data ◽  
Long Lasting Insecticidal Nets ◽  
Nylon Cloth

Abstract Background Misuse of long-lasting insecticidal nets together with resistance of vectors to most of the insecticides for indoor residual spraying and impregnated nets threaten malaria vector control interventions, requiring search for alternative control methods. Reports have shown that Anopheles mosquitoes die when they feed on endectocidal drugs used to treat humans and animals. A study was designed to investigate the efficacy of LongRange™ (eprinomectin 5%) on laboratory reared Anopheles arabiensis fed on treated calves. Methods Anopheles arabiensis from insectary colony was fed on three calves treated with therapeutic dose of LongRange™ eprinomectin (1 ml/50 kg) and on non-treated three other calves as control arm. For the feeding, mosquitoes were placed in paper cups covered with nylon cloth mesh and then allowed to feed on the necks of calves. Subsequently, mosquito survival, fecundity, egg hatchability, larval development and adult emergence were recorded. Data were entered and analysed by using SPSS version 20. The Kaplan–Meier survival analysis and independent sample t-test were used. Results All mosquitoes that fed on LongRange™ Eprinomectin treated calves died within 7 days following blood ingestion. The drug also slightly affected fecundity and hatchability of An. arabiensis. Conclusion Treating livestock with LongRange™ (eprinomectin 5%) may serve as a supplementary control method for zoophagic An. arabiensis.

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