scholarly journals Assessment of mosquito insecticidal activity of bacterial extracts produced by Colombian strains

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Manuela Agudelo-Restrepo ◽  
Martha Lucia Hernández‐Quesada ◽  
Edinson Yonny Sanabria-Duran ◽  
Sandra Inés Uribe-Soto ◽  
Adriana Ortiz-Reyes ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Serratia Marcescens ◽  
Aedes Albopictus ◽  
Insecticidal Activity ◽  
Mosquito Control ◽  
World Health ◽  
Identification System ◽  
Control Disease ◽  
Health Organization ◽  
Emergence Of Resistance

Aedes aegypti and Aedes albopictus are the major vectors for the transmission of more than 30 disease-causing viruses as dengue fever, dengue hemorragic fever, zika, yellow fever and chikungunya. Vector control is one of the important strategies used in order to fight these diseases in tropical and subtropical countries. However, mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. The aim of this study was to identify larvicidal and adulticidal activity of secondary metabolites in extracts produced by bacteria isolated from different sources in Colombia. A total of 105 extracts produced from the same number of bacteria were evaluated for their activity against fourth instar larvae and adults of A. aegypti and A. albopictus using standard protocols defined for the WHO (World Health Organization) and CDC (Control Disease Centre, USA). Six extracts showed relevant activity (more than 50% of mosquito larvae were killed after 48 hours), two of them showed to be actives against larvae of Aedes aegypti and four against larvae of Aedes albopictus. None of the extracts showed activity against the mosquitoes in adult stage. The bacteria producing active extracts were identified using the biolog ® identification system as Serratia marcescens ss marcescens, Escherichia hermannii, Serratia marcescens ss marcescens, Bacillus marisflavi, Bacillus atropheus/subtilis and Pseudomonas chlororaphis subsp. aurantiaca. In conclusion, bacterial extracts are a good source for the search of new strategies in the control of mosquitoes. Further studies to determine the compound responsible for the insecticidal activity are in progress.

scholarly journals Pyrethroid Resistance Status of Aedes (Stegomyia) Aegypti (Linneaus) from Dengue Endemic Areas in Peninsular Malaysia

2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Rosilawati R ◽  
Lee HL ◽  
Nazni WA ◽  
Nurulhusna AH ◽  
Roziah A ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Laboratory Strain ◽  
Control Agent ◽  
Peninsular Malaysia ◽  
World Health ◽  
Resistance Level ◽  
Health Organization

Vector control is still the principal method to control dengue and chemical insecticides, especially the pyrethroids such as permethrin are the forerunners of mosquito control agent. Intensive and extensive use of pyrethroids often result in resistance, thereby hampering control efforts. The present study was conducted to evaluate the susceptible status of Aedes aegypti, the primary vector of dengue against permethrin. A nationwide mosquito sampling via ovitrapping was conducted in 12 dengue hotspots across 5 states in Peninsular Malaysia. Field collected Aedes eggs were hatched and reared until L3 larval and further identified it species. Adult F0 Aedes aegypti were reared until F1 progeny and the female were used in adult assay, performed according to World Health Organization (WHO) protocol as to determine the resistance level. The laboratory strain maintained for more than 1000 generations that were susceptible to permethrin served as the control strain. Evaluation of resistance ratio was assessed by comparing the knockdown rate with laboratory susceptible strain. In this present study, 70% ofAe. aegypti population from dengue hotspots was highly resistance to permethrin. The study clearly demonstrated that widespread of permethrin resistant Ae. aegypti in Malaysian mosquito’s population, indicating the need of implementing an efficient pyrethroid resistance management.

scholarly journals Patterns of Ecological Adaptation of Aedes aegypti and Aedes albopictus and Stegomyia Indices Highlight the Potential Risk of Arbovirus Transmission in Yaoundé, the Capital City of Cameroon

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 491
Author(s):  
Armel N. Tedjou ◽  
Basile Kamgang ◽  
Aurélie P. Yougang ◽  
Theodel A. Wilson-Bahun ◽  
Flobert Njiokou ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Potential Risk ◽  
Central Africa ◽  
Capital City ◽  
World Health ◽  
Large Cities ◽  
Health Organization ◽  
Almost All ◽  
Prevalent Species

The dynamic of arbovirus vectors such as Aedes aegypti and Ae. albopictus remains poorly understood in large cities in central Africa. Here, we compared the larval ecology, geographical distribution and degree of infestation of Ae. aegypti and Ae. albopictus in Yaoundé, the capital city of Cameroon, and estimated their Stegomyia indices revealing a significant potential risk of arbovirus transmission. An entomological survey was conducted in April–May 2018 in a cluster of houses randomly selected. Each selected house was inspected, the number of inhabitants was recorded, and potential and positive containers for Aedes were characterized. Stegomyia and pupae-based indices were estimated. Overall, 447 houses and 954 containers were inspected comprising 10,801 immature stages of Aedes with 84.95% of Ae. albopictus and 15.05% of Ae. aegypti. Both species bred mainly in discarded tanks and used tyres, associated with turbid water and the presence of plant debris inside containers. Aedes albopictus was the most prevalent species in almost all neighbourhoods. The house index, Breteau index, and container index were higher for Ae. albopictus (38.26%, 71.81%, and 29.61%) compared to those of Ae. aegypti (25.73%, 40.93%, and 16.88%). These indices are high compared to the thresholds established by Pan American Health Organization and World Health Organization, which suggests a high potential risk of arbovirus transmission.

scholarly journals Larvicidal Effectiveness of Azolla pinnata against Aedes aegypti (Diptera: Culicidae) with Its Effects on Larval Morphology and Visualization of Behavioural Response

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Nor Shaida Husna Zulkrnin ◽  
Nurul Nadiah Rozhan ◽  
Nur Amanina Zulkfili ◽  
Nik Raihan Nik Yusoff ◽  
Mohd Sukhairi Mat Rasat ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Larval Mortality ◽  
Control Program ◽  
Test Method ◽  
World Health ◽  
Azolla Pinnata ◽  
Agricultural Field ◽  
Aquatic Fern ◽  
Significant Difference

Dengue is vector-borne diseases with 390 million infections per year extending over 120 countries of the world. Aedes aegypti (L.) (Diptera: Culicidae) is a primary vector for dengue viral infections for humans. Current focus on application of natural product against mosquito vectors has been the main priority for research due to its eco-safety. The extensive use of chemical insecticides has led to severe health problems, environmental pollution, toxic hazards to human and nontarget species, and development of insecticide resistance on mosquitoes. Azolla pinnata is an aquatic fern and predominantly used as feed in poultry industry and as fertilizer in agricultural field for enhancing the fertility of rice paddy soil. The present study was conducted to explore the larvicidal efficacy of A. pinnata using fresh and powdered form against late third-stage larvae (6 days, 5 mm in larvae body length) of Ae. aegypti (L.) (Diptera: Culicidae). The larvicidal bioassays were performed using World Health Organization standard larval susceptibility test method for different concentration for powdered and fresh A. pinnata. Powdered A. pinnata concentration used during larvicidal bioassay ranges from 500ppm to 2000ppm; meanwhile, fresh A. pinnata ranges from 500ppm to 9,000,000 ppm. The highest mortality was at 1853 ppm for powdered A. pinnata compared with fresh A. pinnata at 2,521,535 ppm, while the LC50 for both powdered and fresh A. pinnata recorded at 1262 ppm and 1853 ppm, respectively. Finally, the analysis of variance (ANOVA) showed significant difference on Ae. aegypti larval mortality (F=30.439, df=1, p≤0.001) and concentration (F=20.002, df=1, p≤0.001) compared to powdered and fresh A. pinnata at 24-hour bioassay test. In conclusion, the powdered A. pinnata serves as a good larvicidal agent against Ae. aegypti (L.) (Diptera: Culicidae) and this study provided information on the lethal concentration that may have potential for a more eco-friendly Aedes mosquito control program.

scholarly journals Assessment of the susceptibility status of Aedes aegypti (Diptera: Culicidae) populations to pyriproxyfen and malathion in a nation-wide monitoring of insecticide resistance performed in Brazil from 2017 to 2018

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Kauara Brito Campos ◽  
Ademir Jesus Martins ◽  
Cynara de Melo Rodovalho ◽  
Diogo Fernandes Bellinato ◽  
Luciana dos Santos Dias ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Mosquito Control ◽  
Natural Populations ◽  
Adult Emergence ◽  
World Health ◽  
Two Generations ◽  
Wide Scale ◽  
Susceptibility Tests ◽  
The One ◽  
Health Organization

Abstract Background Chemical mosquito control using malathion has been applied in Brazil since 1985. To obtain chemical control effectiveness, vector susceptibility insecticide monitoring is required. This study aimed to describe bioassay standardizations and determine the susceptibility profile of Ae. aegypti populations to malathion and pyriproxyfen, used on a national scale in Brazil between 2017 and 2018, and discuss the observed impacts in arbovirus control. Methods The diagnostic-doses (DD) of pyriproxyfen and malathion were determined as the double of adult emergence inhibition (EI) and lethal doses for 99% of the Rockefeller reference strain, respectively. To monitor natural populations, sampling was performed in 132 Brazilian cities, using egg traps. Colonies were raised in the laboratory for one or two generations (F1 or F2) and submitted to susceptibility tests, where larvae were exposed to the pyriproxyfen DD (0.03 µg/l) and adults, to the malathion DD determined in the present study (20 µg), in addition to the one established by the World Health Organization (WHO) DD (50 µg) in a bottle assay. Dose-response (DR) bioassays with pyriproxyfen were performed on populations that did not achieve 98% EI in the DD assays. Results Susceptibility alterations to pyriproxyfen were recorded in six (4.5%) Ae. aegypti populations from the states of Bahia and Ceará, with Resistance Ratios (RR95) ranging from 1.51 to 3.58. Concerning malathion, 73 (55.3%) populations distributed throughout the country were resistant when exposed to the local DD 20 µg/bottle. On the other hand, no population was resistant, and only 10 (7.6%) populations in eight states were considered as exhibiting decreased susceptibility (mortality ratios between 90 and 98%) when exposed to the WHO DD (50 µg/bottle). Conclusions The feasibility of conducting an insecticide resistance monitoring action on a nation-wide scale was confirmed herein, employing standardized and strongly coordinated sampling methods and laboratory bioassays. Brazilian Ae. aegypti populations exhibiting decreased susceptibility to pyriproxyfen were identified. The local DD for malathion was more sensitive than the WHO DD for early decreased susceptibility detection.

scholarly journals Study and analysis the effect of chemical composition of spring water of dhofar region against turbidity

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Ahmmed Saadi Ibrahim ◽  
◽  
Tafoul Abdullah Al Kathiri ◽  
Tariq Omar Hassan Al Rashidi Al Rashidi ◽  
Salim Ahmed Salim Al Shanfari Al Shanfari ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Properties ◽  
Solid Particles ◽  
World Health ◽  
Identification System ◽  
Physiochemical Parameters ◽  
Percentage Difference ◽  
Quality Water ◽  
The Difference ◽  
Health Organization

The aim of this study is to calculate the physical properties of eight springs of the water of the Dhofar region in Oman using physiochemical parameters like pH, total dissolved solids (TDS), conductivity, turbidity, and dissolved oxygen (DO). The chemical properties estimated the concentrations of the metals in springs of water and specified the best healthy spring of water depending on the percentage difference between the actual and normal range set by the World Health Organization (WHO). Eight samples for each test were collected from eight springs of water, namely, Ain Hamran, Ain Deribat, Ain Tobruk, Ain Al-Nabi Ayoub, Ain Atom, Ain Jarziz, Ain Sahlnot, and Ain Razat using an atomic absorption spectrophotometer (AAS) to study the chemical composition of the samples. Ain Jarziz represented high quality water because the percentage difference between actual and WHO was 78.78% compared to Ain Al-Nabi Ayoub, where the difference percentage was 105.95 %. Quantity of dissolved solid particles has a big effect on TDS and conductivity compared to the turbidity. Identification system was used to evaluate the effect of the quality of the chemical composition on the turbidity for Ions of Cl-1, So4 -2, Ca+2, Na+1, Mg+2, and K+1 to be equal to 99.52%, 75.4%, 92.548%, 95.346%, 98.011%, and 97.33 %, respectively. However, more studies are required to conform with the outcomes of this research employing this energetic technique.

scholarly journals Kerentanan larva Aedes aegypti di Jawa Timur terhadap Temephos komersial dengan dosis berbeda

2021 ◽  
Vol 25 (2) ◽  
pp. 165
Author(s):  
Firas Khaleyla ◽  
Etik Ainun Rohmah ◽  
Kris Cahyo Mulyatno
Keyword(s):  
Aedes Aegypti ◽  
World Health Organization ◽  
World Health ◽  
Health Organization

Pengendalian populasi nyamuk Ae. Aegypti di Indonesia dilakukan sebagai upaya untuk menekan penularan virus dengue, salah satunya dengan penaburan larvasida temephos. Dosis operasional penggunaan temephos di Indonesia (1 mg/L) lebih tinggi dibandingkan dosis yang disarankan World Health Organization (WHO) (0,012 mg/L). Di Jawa Timur, terdapat temephos yang beredar komersial dengan perbedaan pada dosis penggunaan, yaitu10 gram/100 L air (10 G) dan 8 gram/100 L air (8G). Penelitian ini dilakukan untuk memeriksa kerentanan populasi larva Ae. aegypti yang berasal dari Jember (JEM), Surabaya (SBY), dan koleksi Laboratorium Entomologi Universitas Airlangga (LAB) terhadap temephos10G dan 8G pada dosis pemakaian tinggi (1 mg/L) hingga rendah (0,015625 mg/L). Uji mortalitas pada larva dilakukan sesuai dengan ketentuan WHO dengan replikasi 4 kali. Data dianalisis secara statistik. Hasil menunjukkan bahwa ketiga kelompoklarva Ae. aegypti mengalami >90% mortalitas dengan penambahan temephos pada dosis rendah (0,015625 mg/L) pada ambang waktu 240 menit, baik untuk temephos10 G maupun 8 G. Perbedaan respon mortalitas yang signifikan antara dosis tertinggi (1 mg/L) dan dosisterendah (0,015625 mg/L) ditemukan pada kelompok JEM pada dosis 8 G dan 10 G serta LAB pada dosis 8 G. Kelompok JEM dan SBY memiliki rasio resistensi 95 (RR95) temephos dengan kategori rendah (<5) dibandingkan dengan kelompok LAB. Semua kelompok masih memiliki kerentanan pada temephoskomersial pada dosis rendah (0,015625 mg/L). Dari hasil penelitian ini, kami menyarankan untuk menurunkan dosis operasional larvasida temephos yang digunakan untuk pengendalian populasi larva Ae. aegypti di Jawa Timur.

scholarly journals Transgenic expression of Nix converts genetic females into males and allows automated sex sorting in Aedes albopictus

2021 ◽  
Author(s):  
Célia Lutrat ◽  
Roenick Proveti Olmo ◽  
Thierry Baldet ◽  
Jérémy Bouyer ◽  
Eric Marois
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Mosquito Control ◽  
Flight Performance ◽  
Genetic Sexing ◽  
Transgenic Expression ◽  
Fluorescence Marker ◽  
Transgenic Lines ◽  
Genetic Sexing Strains ◽  
Primary Gene

Aedes albopictus is a major vector of arboviruses. Better understanding of its sex determination is crucial for developing mosquito control tools, especially genetic sexing strains. In Aedes aegypti, Nix is the primary gene responsible for masculinization and Nix-expressing genetic females develop into fertile, albeit flightless, males. In Ae. albopictus, Nix has also been implicated in masculinization but its role remains to be further characterized. In this work, we established Ae. albopictus transgenic lines ectopically expressing Nix. Several were composed exclusively of genetic females, with transgenic individuals being phenotypic and functional males due to the expression of the Nix transgene. Their reproductive fitness was marginally impaired, while their flight performance was similar to controls. Overall, our results show that Nix is sufficient for full masculinization in Ae. albopictus. Moreover, the transgene construct contains a fluorescence marker allowing efficient automated sex sorting. Consequently, such strains constitute valuable sexing strains for genetic control.

scholarly journals Insecticide resistance in dengue vectors from hotspots in Selangor, Malaysia

2021 ◽  
Vol 15 (3) ◽  
pp. e0009205
Author(s):  
Rosilawati Rasli ◽  
Yoon Ling Cheong ◽  
M. Khairuddin Che Ibrahim ◽  
Siti Futri Farahininajua Fikri ◽  
Rusydi Najmuddin Norzali ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Aedes Albopictus ◽  
World Health ◽  
Dengue Vector ◽  
Organophosphate Insecticide ◽  
Potential Threat ◽  
Pyrethroid Insecticides ◽  
Dengue Vector Control

Background In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance. Method and results The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species. Conclusion The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

scholarly journals Chemical composition and insecticidal activity of Anacyclus pyrethrum essential oil from the Bensliman area against Culex pipiens

2020 ◽  
Vol 10 (1) ◽  
pp. 13-21
Author(s):  
Kawtar El Mokhtari ◽  
M'hammed EL Kouali ◽  
Mohammed Talbi ◽  
Latifa Hajji ◽  
Abdelhak El Brouzi
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Insecticidal Activity ◽  
Culex Pipiens ◽  
Larval Mortality ◽  
World Health ◽  
Herbaceous Plant ◽  
Health Organization ◽  
Asteraceae Family ◽  
Lc50 And Lc90

Anacyclus pyrethrum is a herbaceous plant that belongs to the Asteraceae family. The focus of the present study is to extract the essential oil from this plant, to determine its chemical composition and to evaluate its insecticidal activity against the larvae of the mosquito Culex pipiens. The essential oil from A. pyrethrum collected from the region of Bensliman in Morocco was extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry were studied. Essential oil yield obtained by hydrodistillation was 0.09%. The major aroma constituents were Spathulenol (20.47%), Germacrene D (16.48%), Caryophyllene oxide (13.20%), 4(14)-Salviale-1-one (8.27%) and Caryophyllene 4(14),8(15)-dien-5α-ol (7.30%). The larvicidal test carried out according to a methodology based on the standard protocol of the World Health Organization was studied on 4th instar larvae of C. pipiens and showed that A. pyrethrum essential oil possesses remarkable insecticidal properties.  After 24 hours of exposition, larvicidal assays revealed a 100% mortality of C. pipiens larvae. The dose of 40 μL/mL was toxic enough to cause 100% larval mortality of C. pipiens. The lethal concentrations LC50 and LC90 calculated for the essential oil studied were of the order of 14.79 μL/mL and 19.95 μL/mL, respectively. To control mosquitoes, this essential oil extracted from A. pyrethrum might be used as a natural insecticide and therefore could be an alternative to synthetic insecticides already present on the market.

Spinosyns Delivered in Sugar Meals to Aedes aegypti and Aedes albopictus (Diptera: Culicidae): Acute Toxicity and Subacute Effects on Survival, Fecundity, and Fertility

2022 ◽  
Author(s):  
Abdullah A Alomar ◽  
Barry W Alto ◽  
Edward D Walker
Keyword(s):  
Acute Toxicity ◽  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Nutritive Value ◽  
Mosquito Control ◽  
Environmental Safety ◽  
Adult Mosquito ◽  
Hatch Rate ◽  
Median Lethal Concentrations ◽  
Males And Females

Abstract Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits. This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC50 concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

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