scholarly journals Larvicidal potency of Dioscorea sansibarensis leaf extract against vector mosquitoes: Anopheles gambiae s.s. and Culex quinquefasciatus

2021 ◽  
Vol 47 (2) ◽  
pp. 655-663
Author(s):  
Anitha Philbert

Mosquitoes are responsible for transmission of illnesses of public health importance including malaria, lymphatic filariasis, dengue, chikungunya, and many other diseases caused by viruses. Vector control using synthetic insecticides has been the cornerstone for management of vector-borne diseases. However, the chemical based interventions have not been sustainable due to emergency of resistance against insecticides among disease vectors. Plant based mosquitocidal products can be potential alternative tools in vector control. Therefore, the present study aimed at exploring the larvicidal properties of Dioscorea sansibarensis leaf extract against malaria and lymphatic filariasis vectors; Anopheles gambiae s.s. and Culex quinquefasciatus. The larvicidal activities of Dioscorea sansibarensis were assessed following WHO test procedures. Ethanol leaf extract of Dioscorea sansibarensis was evaluated against all the four instar larvae stages of An. gambiae s.s and Cx. quinquefasciatus susceptible laboratory colonies. The highest larvicidal potency was shown against the 4th instar stages of both species with the LC50 values of 60.915 ppm and 80.700 ppm for Cx. quinquefasciatus and An. gambiae s.s., respectively. The respective LC95 values for Cx. quinquefasciatus and An. gambiae s.s. were 168.898 ppm and 249.295 ppm. This implies that the extract can be applied as mosquito larvicide should its impact on non-targeted species be established. Keywords: Dioscorea sansibarensis; vectors, mosquitoes, Zanzibar yams, Dar es Salaam, Tanzania

2019 ◽  
Author(s):  
Walter Fabricio Silva Martins ◽  
Craig Stephen Wilding ◽  
Alison Taylor Isaacs ◽  
Emily Joy Rippon ◽  
Karine Megy ◽  
...  

ABSTRACTCulex quinquefasciatusplays an important role in transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF), as well as many arboviral diseases. Currently, efforts to tackleC. quinquefasciatusvectored diseases are based on either mass drug administration (MDA) for LF, or insecticide-based interventions. Widespread and intensive insecticide usage has resulted in increased resistance in mosquito vectors, includingC. quinquefasciatus. Herein, the transcriptome profile of Ugandan bendiocarb-resistantC. quinquefasciatuswas explored to identify candidate genes associated with insecticide resistance. Resistance to bendiocarb in exposed mosquitoes was marked, with 2.04% mortality following 1h exposure and 58.02% after 4h. Genotyping of the G119SAce-1target site mutation detected a highly significant association (p<0.0001; OR=25) between resistance andAce1-119S. However, synergist assays using the P450 inhibitor PBO or the esterase inhibitor TPP resulted in markedly increased mortality (to ≈80%), suggesting a role of metabolic resistance in the resistance phenotype. Using a novel, custom 60K whole-transcriptome microarray 16 genes significantly overexpressed in resistant mosquitoes were detected, with the P450Cyp6z18showing the highest differential gene expression (>8-fold increase vs unexposed controls). These results provide evidence that bendiocarb-resistance in UgandanC. quinquefasciatusis mediated by both target-site mechanisms and over-expression of detoxification enzymes.


PLoS ONE ◽  
2010 ◽  
Vol 5 (3) ◽  
pp. e9927 ◽  
Author(s):  
Dziedzom de Souza ◽  
Louise Kelly-Hope ◽  
Bernard Lawson ◽  
Michael Wilson ◽  
Daniel Boakye

2016 ◽  
Vol 8 ◽  
pp. IJIS.S37188 ◽  
Author(s):  
Lame Younoussa ◽  
Elias Nchiwan Nukenine ◽  
Charles Okechukwu Esimone

Mosquitoes are vectors of several human pathogens, and great attention has recently been placed on insecticides from plant-derived products, in search for mosquito control agents. This study, thus, investigated the potency of Boswellia dalzielii methanol leaf extract and its four fractions as mosquito ovicide, larvicide, and pupicide against Anopheles gambiae and Culex quinquefasciatus. The plant products were tested at the following concentrations: 125, 250, 500, 1000, and 2000 ppm on eggs and 312.5, 625, 1250, and 2500 ppm on the larvae and pupae of the mosquitoes. For results, hatchability of A. gambiae eggs was reduced to 5% with n-hexane fraction at 2000 ppm. Among the plant products tested, n-hexane fraction was most toxic against A. gambiae (LC50 = 385.9 ppm) and C. quinquefasciatus (LC50 = 3394.9 ppm). The n-hexane fraction of B. dalzielii might be used as a mosquitocidal agent in the breeding sites of A. gambiae and C. quinquefasciatus.


2012 ◽  
Vol 5 (1) ◽  
Author(s):  
Eliningaya J Kweka ◽  
Goufa Zhou ◽  
Leila B Beilhe ◽  
Amruta Dixit ◽  
Yaw Afrane ◽  
...  

Parasite ◽  
2018 ◽  
Vol 25 ◽  
pp. 42 ◽  
Author(s):  
Soromane Camara ◽  
Ludovic Phamien Ahoua Alou ◽  
Alphonsine Amanan Koffi ◽  
Yao Cyntia Muriel Clegban ◽  
Jean-Paul Kabran ◽  
...  

Background: The widespread insecticide resistance in malaria vector populations is a serious threat to the efficacy of vector control tools. As a result, the World Health Organization (WHO) supports the development of alternative tools that combine several insecticides with the aim of improving vector control and the management of insecticide resistance. In the present study, a long-lasting insecticidal net treated with a mixture of chlorfenapyr and alphacypermethrin was evaluated against wild pyrethroid-resistant Anopheles gambiae s.s in M’bé, Côte d’Ivoire. Centers for Disease Control and Prevention (CDC) bottle tests were carried out with resistant An. gambiae s.s. of M’bé and the susceptible strain, to assess the resistance level to chlorfenapyr and alphacypermethrin. Results: CDC bottle bioassays revealed a high level of resistance of An. gambiae s.s. population from M’bé to alphacypermethrin, whereas they revealed low resistance to chlorfenapyr. In experimental huts, Interceptor® G2 that was unwashed or washed 20 times killed 87% and 82% of An. gambiae s.s., respectively, whereas Interceptor® LN that was either unwashed or washed 20 times killed only about 10% of the mosquitoes. The blood-feeding inhibition induced by Interceptor® was not significantly different compared to untreated nets, whereas Interceptor® G2 that was unwashed or washed 20 times induced 42% and 34% inhibition of blood-feeding, respectively. Conclusion: Interceptor® G2 met the WHOPES criteria to undergo a phase III study. Investigation of its efficacy at a community level and the conduct of randomized controlled trials dealing with epidemiological outputs are warranted in order to study the potential of Interceptor® G2 to better protect communities.


2019 ◽  
Vol 3 (1) ◽  
pp. 138-144
Author(s):  
Adedapo O. Adeogun ◽  
Kehinde O.K. Popoola ◽  
Abiodun K. Olakiigbe ◽  
Samson T. Awolola

Background: Members of the Anopheles gambiae s.l. remain the most efficient vectors of malaria parasite in Africa. However, for timely and effective vector control activities, the distribution of these important vectors in local communities is crucial. We therefore determine the distribution of the members of Anopheles gambiae s.l. in Oyo State, Nigeria Methods: Larval stages of Anopheles mosquitoes were collected from identified mosquito breeding sites in six localities (Oluyole, Eruwa, Oyo, Ojoo, Bodija, and Ogbomoso) in Oyo State and reared to adults. Three to five days old adult emergence were identified morphologically using standard methods. A total of 100 mosquitoes were selected from each of localities for molecular analysis. DNA were extracted and Polymerase Chain Reaction (PCR-ID) followed by restriction endonucleases digestion was used for molecular identification. Results: A total of 58 larval breeding sites were sampled out of which 12 (20.7%) had Anophelines only, 21 (36.2%) contained Culicines only and the remaining 25 (43.1%) had both Anophelines and Culicines. The mosquitoes were mostly found in footprints, followed by tire tracks, pools, puddle and ponds. The habitat type distribution for Anopheline and Culicines were not different (χ2=5.25, DF=5, P>0.01). A total of 1,725 Anophelines emerged from the collection out of which, 823 were females. All the female samples were morphologically identified as members of the Anopheles gambiae s.l.. A total of 600 (72.9%) of the female Anopheline population was subjected to PCR. PCR-ID showed that the mosquito populations contained higher numbers of Anopheles arabiensis (58%) than Anopheles gambiae s.s. (42%). Enzyme digest indicate that samples from Oluyole, Iwo road and Bodija were man-ly the M form (now called An. coluzzii), while both M (An. colizzii) and S (An. gambiae) form occur in sympatry in Oyo town and Eruwa. Conclusion: This study presents information on the distribution of Anopheles arabiensis, Anopheles coluzzii and Anopheles gambiae in Oyo State. This has implication on the vector control activities in the State as members of these Anopheles mosquitoes exhibit varying feeding behaviours, transmission pattern and resistance profiles. Such information is useful in planning vector control activities for the State


2018 ◽  
Vol 5 (10) ◽  
pp. 347-358
Author(s):  
Kayode David Ileke

Anopheles gambiae (Giles, 1902) and Culex quinquefasciatus (Say, 1832) mosquitoes are the main vectors of human malaria and lymphatic filariasis, respectively. This study aims to analyze the larvicidal, pupicidal and adulticidal properties of Monodora myristica (Dunal, 1831) and Conyza sumatrensis (Retzius, 1742-1821) extracts against An. gambiae and Cx. quinquefasciatus. The experiment was conducted in the laboratory at ambient temperature of 28 oC +/- 2 oC and 75% +/- 5% relative humidity. The results showed that M. myristica and C. sumatrensis extracts significantly affect all stages of An. gambiae and Cx. quinquefasciatus tested. The mosquitocidal toxicity of the two plant extracts is dosage dependent. Anti-larval activity of M. myristica at rate 500 mg/L and 1,000 mg/L caused 100% mortality of An. gambiae larvae while it evoked 80% and 100% mortality of Cx. quinquefasciatus larvae. The same trend of results were also obtained on the anti-pupal and adulticidal toxicity of M. myristica and C. sumatrensis extracts. As larvicides, pupicides and adulticides, the LC50s and LC90s, after 24 h varied across plant extracts and mosquito species. C. sumatrensis attained LC50 and LC90 at higher concentration than M. myristica. On An. gambiae larvae, the LC50s after 24 h, varied from 86.95 mg/L (M. myristica) to 131.73 mg/L (C. sumatrensis). Similarly, the LC90s after 24 h on An. gambiae larvae, varied from 278.39 mg/L (M. myristica) to 131.73 mg/L (C. sumatrensis). For Cx. quinquefasciatus larvae, the LC50s after 24 h, varied from 391.41 mg/L (M. myristica) to 898.20 mg/L (C. sumatrensis). The seed extract of M. myristica exerted the best pupicidal activity among the two tested extracts with LC50 and LC90 values of 140.61 mg/L and 520.35 mg/L on An. gambiae, respectively, followed by leaf of C. sumatrensis with LC50 and LC90 values of 157.59 mg/L and 781.86 mg/L on An. gambiae, respectively. More concentrations were require to achieve 50% and 90% death of Cx. quinquefasciatus pupae. On adulticidal activity, seed of M. myristica exerted LC50 and LC90 values of 122.79 mg/L and 502.99 mg/L on An. gambiae, respectively, followed by leaf of C. sumatrensis with LC50 and LC90 values of 215.05 mg/L and 981.25 mg/L on An. gambiae, respectively. More concentrations were require to achieve 50% and 90% death of Cx. quinquefasciatus adults. The two tested plants can be integrated into pest management programmes to combat human malaria and lymphatic filariasis vectors breeding site in Nigeria. I recommend formulation of M. myristica seeds which have the lowest LC50 and LC90 after 24 h of exposure for field evaluation.


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