Field Efficacy of VectoMax FG and VectoLex CG Biological Larvicides for Malaria Vector Control in Northwestern Brazil

2019 ◽  
Vol 57 (3) ◽  
pp. 942-946 ◽  
Author(s):  
Pablo S Fontoura ◽  
Anderson S da Costa ◽  
Francismar S Ribeiro ◽  
Marcílio S Ferreira ◽  
Marcia C Castro ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Amazon Basin ◽  
Larval Density ◽  
Indoor Residual Spraying ◽  
Residual Effect ◽  
Fish Farming ◽  
Malaria Vector Control ◽  
Fish Ponds ◽  
Anopheles Darlingi ◽  
Larval Habitats

Abstract Despite historical and contemporary evidence of its effectiveness, larval source management with insecticides remains little used by most malaria control programs worldwide. Here we show that environmentally safe biological larvicides under field conditions can significantly reduce anopheline larval density in fish farming ponds that have became major larval habitats across the Amazon Basin. Importantly, the primary local malaria vector, Anopheles darlingi Root (Diptera: Culicidae), feeds and rests predominantly outdoors, being little affected by interventions such as long-lasting insecticidal bed net distribution and indoor residual spraying. We found >95% reduction in late-instar density up to 7 d after the first application of VectoMax FG or VectoLex CG (both from Valent BioSciences), and up to 21 d after larvicide reapplication in fish ponds (n = 20) situated in the main residual malaria pocket of Brazil, irrespective of the formulation or dosage (10 or 20 kg/ha) used. These results are consistent with a substantial residual effect upon retreatment and support the use of biological larvicides to reduce the density of anopheline larvae in this and similar settings across the Amazon where larval habitats are readily identified and accessible.

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 Quantifying and characterizing hourly human exposure to malaria vectors bites in rural southwest Burkina Faso

2019 ◽  
Author(s):  
D.D Soma ◽  
B Zogo ◽  
P Taconet ◽  
A Somé ◽  
S Coulibaly ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Vector Control ◽  
Rural Area ◽  
Malaria Vector ◽  
Human Exposure ◽  
Protective Efficacy ◽  
Indoor Residual Spraying ◽  
World Health ◽  
Malaria Vectors ◽  
Malaria Vector Control

AbstractBackgroundTo sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommends the combination of effective tools. Before designing and implementing additional strategies in any setting, it is critical to monitor or predict when and where transmission occurs. However, to date, very few studies have quantified the behavioural interactions between humans and Anopheles vectors. Here, we characterized residual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used.MethodsWe analysed data on both human and malaria vectors behaviours from 27 villages to measure hourly human exposure to vector bites in dry and rainy seasons using mathematical models. We estimated the protective efficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users were exposed to vector bites.ResultsThe percentage of the population who declared sleeping under a LLIN the previous night was very high regardless of the season, with an average LLIN use ranging from 92.43% to 99.89%. The use of LLIN provided > 80% protection against exposure to vector bites. The proportion of exposure for LLIN users was 29-57% after 05:00 and 0.05-12 % before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90% for children under five years old in the dry cold season.ConclusionsThis study supports the current use of LLIN as a primary malaria vector control tool. It also emphasises the need to complement LLIN with indoor-implemented measures such as indoor residual spraying (IRS) and/or house improvement to effectively combat malaria in the rural area of Diébougou. Furthermore, malaria elimination programmes would also require strategies that target outdoor biting vectors to be successful in the area.

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

2020 ◽  
Author(s):  
Corine Ngufor ◽  
Renaud Govoetchan ◽  
Augustin Fongnikin ◽  
Estelle Vigninou ◽  
Thomas Syme ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Cross Resistance ◽  
Malaria Vector Control ◽  
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. A more diversified portfolio of IRS insecticides is required; insecticides with new chemistries which can provide improved and prolonged control of insecticide-resistant vector populations are urgently needed. Broflanilide is a newly discovered insecticide being considered for malaria vector control. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON™ T500) for IRS on mud and cement wall substrates in WHO 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, mortality of susceptible and pyrethroid-resistant A. gambiae s.l. with broflanilide WP treated substrates was >80% for 6-14 months. At application rates of 100mg/m2 and 150 mg/m2, mortality of wild pyrethroid-resistant A. gambiae s.l. entering treated experimental huts in Covè, Benin was 57%-66% with broflanilide WP and did not differ significantly from pirimiphos-methyl CS (57-66% vs. 56%, P>0.05). Mosquito mortality did not differ between the two application rates and local wall substrate-types tested (P>0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on broflanilide WP treated hut walls remained >80% for both susceptible and resistant strains of A. gambiae s.l.. Broflanilide shows potential to significantly improve the control of malaria transmitted by pyrethroid-resistant mosquito vectors and would thus be a crucial addition to the current portfolio of IRS insecticides.One Sentence SummaryVECTRON™ T500, a new wettable powder formulation of broflanilide developed for indoor residual spraying, showed high and prolonged activity against wild pyrethroid-resistant malaria vectors, on local wall substrates, in laboratory bioassays and experimental household settings in Benin.

scholarly journals Monthly biological larviciding associated with a tenfold decrease in larval density in fish farming ponds and reduced community-wide malaria incidence in northwestern Brazil

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Pablo S. Fontoura ◽  
Marcos F. Silva ◽  
Anderson S. da Costa ◽  
Francismar S. Ribeiro ◽  
Marcílio S. Ferreira ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Malaria Incidence ◽  
Larval Density ◽  
Fish Farming ◽  
Interrupted Time Series ◽  
Fish Ponds ◽  
Interrupted Time Series Analysis ◽  
Incidence Trends ◽  
Series Analysis

Abstract Background Larvicides are typically applied to fixed and findable mosquito breeding sites, such as fish farming ponds used in commercial aquaculture, to kill immature forms and thereby reduce the size of adult malaria vector populations. However, there is little evidence suggesting that larviciding may suppress community-wide malaria transmission outside Africa. Here, we tested whether the biological larvicide VectoMax FG applied at monthly intervals to fish farming ponds can reduce malaria incidence in Amazonian Brazil. Methods This study was carried out in Vila Assis Brasil (VAB; population 1700), a peri-urban malaria hotspot in northwestern Brazil with a baseline annual parasite incidence of 553 malaria cases per 1000 inhabitants. The intervention consisted of monthly treatments with 20 kg/ha of VectoMax FG of all water-filled fish ponds in VAB (n ranging between 167 and 170) with a surface area between 20 and 8000 m2, using knapsack power mistblowers. We used single-group interrupted time-series analysis to compare monthly larval density measurements in fish ponds during a 14-month pre-intervention period (September 2017–October 2018), with measurements made during November 2018–October 2019 and shortly after the 12-month intervention (November 2019). We used interrupted time-series analysis with a comparison group to contrast the malaria incidence trends in VAB and nearby nonintervention localities before and during the intervention. Results Average larval densities decreased tenfold in treated fish farming ponds, from 0.467 (95% confidence interval [CI], 0.444–0.490) anopheline larvae per dip pre-intervention (September 2017–October 2018) to 0.046 (95% CI, 0.041–0.051) larvae per dip during (November 2018–October 2019) and shortly after the intervention (November 2019). Average malaria incidence rates decreased by 0.08 (95% CI, 0.04–0.11) cases per 100 person-months (P < 0.0001) during the intervention in VAB and remained nearly unchanged in comparison localities. We estimate that the intervention averted 24.5 (95% CI, 6.2–42.8) malaria cases in VAB between January and December 2019. Conclusions Regular larviciding is associated with a dramatic decrease in larval density and a modest but significant decrease in community-wide malaria incidence. Larviciding may provide a valuable complementary vector control strategy in commercial aquaculture settings across the Amazon. Graphical abstract

scholarly journals Improved Use of Drone Imagery for Malaria Vector Control through Technology-Assisted Digitizing (TAD)

2022 ◽  
Vol 14 (2) ◽  
pp. 317
Author(s):  
Andy Hardy ◽  
Gregory Oakes ◽  
Juma Hassan ◽  
Yussuf Yussuf
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Supervised Classification ◽  
Region Growing ◽  
Malaria Vector Control ◽  
Larval Habitats ◽  
Classification Approach ◽  
Spatial Intelligence ◽  
Supervised Image Classification ◽  
Complex Features

Drones have the potential to revolutionize malaria vector control initiatives through rapid and accurate mapping of potential malarial mosquito larval habitats to help direct field Larval Source Management (LSM) efforts. However, there are no clear recommendations on how these habitats can be extracted from drone imagery in an operational context. This paper compares the results of two mapping approaches: supervised image classification using machine learning and Technology-Assisted Digitising (TAD) mapping that employs a new region growing tool suitable for non-experts. These approaches were applied concurrently to drone imagery acquired at seven sites in Zanzibar, United Republic of Tanzania. Whilst the two approaches were similar in processing time, the TAD approach significantly outperformed the supervised classification approach at all sites (t = 5.1, p < 0.01). Overall accuracy scores (mean overall accuracy 62%) suggest that a supervised classification approach is unsuitable for mapping potential malarial mosquito larval habitats in Zanzibar, whereas the TAD approach offers a simple and accurate (mean overall accuracy 96%) means of mapping these complex features. We recommend that this approach be used alongside targeted ground-based surveying (i.e., in areas inappropriate for drone surveying) for generating precise and accurate spatial intelligence to support operational LSM programmes.

Monitoring of Larval Habitats and Mosquito Densities in the Sudan Savanna of Mali: Implications for Malaria Vector Control

2007 ◽  
Vol 77 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Nafomon Sogoba ◽  
Thomas Smith ◽  
Sékou F. Traoré ◽  
José M. C. Ribeiro ◽  
Abdoulaye Touré ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Malaria Vector Control ◽  
Larval Habitats ◽  
Sudan Savanna
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