scholarly journals Efficacy of a Mosaic Long-Lasting Insecticide Net, PermaNet 3.0, against Wild Populations of Culex quinquefasciatus in Experimental Huts in Togo

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Dominic B. Dery ◽  
Guillaume K. Ketoh ◽  
Joseph Chabi ◽  
George Apetogbo ◽  
Isabelle A. Glitho ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Good Control ◽  
Blood Feeding ◽  
Interspecific Difference ◽  
Wild Populations ◽  
Vector Behaviour ◽  
Insecticidal Effect ◽  
Experimental Huts ◽  
The Difference ◽  
Permanet 3.0

PermaNet 3.0 was evaluated against Culex quinquefasciatus in experimental huts in Lomé. Endpoints were deterrence, exophily, blood feeding inhibition, and mortality. Insecticide susceptibility of Culex quinquefasciatus was assessed with permethrin (1%), DDT (4%), bendiocarb (0.1%), deltamethrin (0.5%, 0.05%), carbosulfan (0.4%), and chlorpyrifos methyl (0.4%). Total of 1,223 Cx. quinquefasciatus females were collected. PermaNet 3.0 unwashed deterred 16.84% Culex mosquitoes. After 20 washes, it deterred 5.79% mosquitoes compared to 6.84% deterrence by unwashed PermaNet 2.0. PermaNet 3.0 induced mosquitoes to exit huts 50.48% and inhibited blood feeding 70.97% in unwashed state. After 20 washes, the net induced 42.91% mosquitoes to exit and inhibited 67.06% mosquitoes from blood feeding. PermaNet 3.0 gave 76% personal protection at zero wash and 69% protection after 20 washes. The net retained 7.1% insecticidal effect in the unwashed state and after 20 washes 6.5%. Cx. quinquefasciatus was resistant to tested insecticides (6%–50% mortality). PermaNet 3.0 is a good control tool against mosquitoes. However, Cx. quinquefasciatus is less affected by PermaNet 3.0. The evaluation depicts the success of vector control innovations using pyrethroids and nonpyrethroids in combination on nets. Additional studies with Culex species are recommended to know whether the difference in blood feeding is interspecific (difference in vector behaviour) and not due to intertrial variability.

Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire

2003 ◽  
Vol 93 (6) ◽  
pp. 491-498 ◽  
Author(s):  
J.-M. Hougard ◽  
V. Corbel ◽  
R. N'Guessan ◽  
F. Darriet ◽  
F. Chandre ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Culex Quinquefasciatus ◽  
Resistance Management ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Mosquito Net ◽  
Pyrethroid Insecticides ◽  
Mosquito Nets ◽  
Experimental Huts ◽  
Insecticide Mixtures

AbstractOnly pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m−2 bifenthrin, 300 mg m−2 carbosulfan, a mosaic of 300 mg m−2 carbosulfan on the ceiling and 50 mg m−2 bifenthrin on the sides, and a mixture of 6.25 mg m−2 carbosulfan and 25 mg m−2 bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.

scholarly journals Treatment of Severe Cancer Pain by Transdermal Fentanyl

2010 ◽  
Vol 10 (2) ◽  
pp. 156-164
Author(s):  
Dženita Ljuca ◽  
Samir Husić
Keyword(s):  
Bone Metastasis ◽  
Breakthrough Pain ◽  
Initial Dosage ◽  
Good Control ◽  
Optimal Dosage ◽  
Transdermal Fentanyl ◽  
Time Period ◽  
The Difference ◽  
A Prospective Study ◽  
Opiate Analgesic

The goal of research was to determine the frequency, intensity, time of occurrence, duration and causes of breakthrough pain (BTP) in patients whose carcinoma pain was treated by transdermal fentanyl. (TDF). A prospective study was conducted in a hospice for recumbent patients of the Centre for Palliative Care (hospice) University Clinical Centre Tuzla from October 2009 to December 2010. 33 patients in terminal stage of carcinoma, who had been treated by transdermal fentanyl due to their excruciating pain (7-10 mark on numerica! scale) with initial dosage of 25 μg as a strong opiate analgesic, were monitored within the time period of 10 days. In the statistics we used the even T - test, the Wilcox test and Mann -Whitney test. The difference was seen to be significant at p < 0,05. Treatment by transdermal fentanyl significantly reduces the intensity of strong carcinoma pain (p < 0.0001), with a frequent requirement for dose increase with bone metastasis. The intensity of BTP is higher compared to the pain experienced upon reception. The frequency and intensity of BTP are significantly reduced already in the second day of treatment by transdermal fentanyl (p = 0,0024). The BTP is most intense in patients with neck and head tumours (9,26 ± 0,66), and most frequent with abdomen and pelvic tumour. The biggest number of BTP (68.3 %) occurs within first three days of treatment. BTP most frequently occurs in the evening or at night (between 18:00 and 06:00 h in 62,2 % of the cases), with the duration of usually less than 15 minutes (65,2% of the cases). In 61,6 % cases the occurrence of BTP is related to physical activities or psychosocial incidents, while the cause is undetermined in 38,4 % of examinees.BTP is most frequent within first three days of treatment by TDF. Using the optimal dosage a good control of carcinoma pain is enabled, regardless of the occurrence of bone metastasis, while it also helps reduce the frequency and intensity of BTP.

scholarly journals An Experimental Hut Evaluation of PBO-Based and Pyrethroid-Only Nets against the Malaria Vector Anopheles funestus Reveals a Loss of Bed Nets Efficacy Associated with GSTe2 Metabolic Resistance

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 143 ◽  
Author(s):  
Benjamin D. Menze ◽  
Mersimine F. Kouamo ◽  
Murielle J. Wondji ◽  
Williams Tchapga ◽  
Micareme Tchoupo ◽  
...  
Keyword(s):  
Anopheles Funestus ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Bed Nets ◽  
Glutathione S Transferase ◽  
Metabolic Resistance ◽  
Experimental Hut ◽  
The Impact ◽  
Long Lasting Insecticidal Nets ◽  
Permanet 3.0

Growing insecticide resistance in malaria vectors is threatening the effectiveness of insecticide-based interventions, including Long Lasting Insecticidal Nets (LLINs). However, the impact of metabolic resistance on the effectiveness of these tools remains poorly characterized. Using experimental hut trials and genotyping of a glutathione S-transferase resistance marker (L119F-GSTe2), we established that GST-mediated resistance is reducing the efficacy of LLINs against Anopheles funestus. Hut trials performed in Cameroon revealed that Piperonyl butoxide (PBO)-based nets induced a significantly higher mortality against pyrethroid resistant An. funestus than pyrethroid-only nets. Blood feeding rate and deterrence were significantly higher in all LLINs than control. Genotyping the L119F-GSTe2 mutation revealed that, for permethrin-based nets, 119F-GSTe2 resistant mosquitoes have a greater ability to blood feed than susceptible while the opposite effect is observed for deltamethrin-based nets. For Olyset Plus, a significant association with exophily was observed in resistant mosquitoes (OR = 11.7; p < 0.01). Furthermore, GSTe2-resistant mosquitoes (cone assays) significantly survived with PermaNet 2.0 (OR = 2.1; p < 0.01) and PermaNet 3.0 (side) (OR = 30.1; p < 0.001) but not for Olyset Plus. This study shows that the efficacy of PBO-based nets (e.g., blood feeding inhibition) against pyrethroid resistant malaria vectors could be impacted by other mechanisms including GST-mediated metabolic resistance not affected by the synergistic action of PBO. Mosaic LLINs incorporating a GST inhibitor (diethyl maleate) could help improve their efficacy in areas of GST-mediated resistance.

scholarly journals Beat the heat: Culex quinquefasciatus regulates its body temperature during blood-feeding

2020 ◽  
Author(s):  
Joanna M. Reinhold ◽  
Ryan Shaw ◽  
Chloé Lahondère
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Culex Quinquefasciatus ◽  
Evaporative Cooling ◽  
Blood Feeding ◽  
The Body ◽  
List Type ◽  
Physiological Level ◽  
Wide Range ◽  
Warm Blood

AbstractMosquitoes are regarded as one of the most dangerous animals on earth. As they are responsible for the spread of a wide range of both human and animal diseases, research of the underlying mechanisms of their feeding behavior and physiology is critical. Among disease vector mosquitoes, Culex quinquefasciatus, which is a known carrier of West Nile virus and Western Equine Encephalitis, remains relatively understudied. As blood sucking insects, adaptations (either at the molecular or physiological level) while feeding on warm blood is crucial to their survival, as overheating can result in death due to heat stress. Our research aims to study how Cx. quinquefasciatus copes with heat associated with the ingestion of a warm blood-meal and to possibly uncover the adaptations this species uses to avoid thermal stress. Through the use of thermographic imaging, we analyzed the body temperature of Cx. quinquefasciatus while blood feeding. Infrared thermography has allowed us to identify a cooling strategy, evaporative cooling via the production of fluid droplets, and an overall low body temperature in comparison to the blood temperature during feeding. Understanding Cx. quinquefasciatus’ adaptations and various strategies that they employ to reduce their body temperature while blood-feeding constitutes the first step towards the discovery of potential targets of opportunity for their control.HighlightsMosquitoes have evolved to cope with heat stress associated with warm blood ingestionCulex quinquefasciatus displays heterothermy while blood-feedingThe abdominal temperature decreases due to evaporative cooling using urine dropletsOverall, the mosquito body temperature is much cooler than the ingested blood

Heliothis armigera (Hb.) (Noctuidae) in Western Tanganyika. II.—Ecology and natural and chemical control

1965 ◽  
Vol 56 (1) ◽  
pp. 127-140 ◽  
Author(s):  
W. Reed
Keyword(s):  
Host Plants ◽  
Large Scale ◽  
Good Control ◽  
Heliothis Armigera ◽  
Natural Control ◽  
Trap Crops ◽  
Cultural Methods ◽  
Untreated Cotton ◽  
Regular Sampling ◽  
The Difference

In Western Tanganyika, Heliothis armigera (Hb.) occurs as a major pest of cotton from February to April, but also feeds on many other host plants. The dry season (August–October) is spanned usually by diapause pupae, the moths emerging from which oviposit on a species of Gleome, on which the first generation develops, giving rise to adults in November–December. Larvae of the second generation feed mainly on early-sown maize, and it is usually those of the third and fourth generations that attack cotton. Two subsequent generations occur on a variety of host plants, including late cotton, maize and legumes. The increasing severity of the attacks of Heliothis on cotton has accompanied the replacement of sorghum by maize in recent years. Maize is not only an intermediate host on which Heliothis builds up before it attacks cotton but also a source of diapause pupae later in the season.In studies of the natural control of H. armigera, based on regular sampling of eggs and larvae on host plants in the field, the most important parasites were the Tachinids Drino imberbis (Wied.) and Goniophthalmus halli Mesnil, and field observations suggested that a species of Chrysopa (Neuroptera) was the main predator. Increasing use of insecticides may be reducing the effectiveness of natural control. A polyhedral virus was common, mainly found in larvae of Heliothis feeding on maize. The control of Heliothis on cotton by cultural methods was attempted by banning early sowing of maize and by sowing strips of maize in cotton fields as trap crops. Neither method is practicable on a large scale. Early sowing of cotton appears to be the best means of withstanding attack by Heliothis, for the local strains of cotton are able to compensate by later growth even for a very heavy Heliothis attack, provided they are sown early enough to utilise the late rains.In cotton that was subject to a heavy attack by H. armigera, five applications at 2-week intervals of DDT at 1 lb. per acre gave good control of the larvae and increased the yield from about 200 lb. seed cotton per acre to about 500 lb., the difference being mainly in the early pickings. The addition of toxaphene increased the yield, probably by controlling Earias spp., but neither toxaphene alone nor carbaryl appeared to control Heliothis. The numbers of eggs laid were higher on cotton treated with DDT than on untreated cotton.

scholarly journals Assessment of Synthetic Membranes for Artificial Blood Feeding of Culicidae

Insects ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 15
Author(s):  
Luciana S. Dias ◽  
Jonatas C. Caldeira ◽  
Luiz G. S. R. Bauzer ◽  
José B. P. Lima
Keyword(s):  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Public Health Problem ◽  
Blood Feeding ◽  
Pathogen Transmission ◽  
Collagen Membrane ◽  
Major Public Health Problem ◽  
Synthetic Membranes ◽  
Artificial Blood ◽  
Potential Pathogen

Potential pathogen transmission through hematophagy in Culicidae is a major public-health problem, and several studies have been performed to better understand this phenomenon. Research on these insects often requires the maintenance of colonies in the laboratory. Due to the hematophagic habits of these organisms, blood must be provided in order to guarantee the reproduction of individuals that constitute the colonies. Some species of mammals and birds are used as a direct blood source in many laboratories. Due to current bioethical parameters, the direct use of animals has been replaced by artificial blood feeding by using synthetic membranes to simulate animal skin. In this study, the efficiency of collagen and latex in the artificial feeding of mosquitoes of the Aedes aegypti and Culex quinquefasciatus species was evaluated and compared with Parafilm®, a standard membrane that is frequently used for this purpose. Important aspects of the feeding and reproduction of these insects were considered. For both species, latex showed the poorest performance. Collagen membrane performed well in most parameters, but was not as efficient as Parafilm® for fecundity in Aedes aegypti, and for the percentage of engorged females in Culex quinquefasciatus. We concluded that, although collagen is more resistant and easier to handle, Parafilm® was the most efficient among the three evaluated membranes for the artificial blood feeding of mosquitoes.

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