Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vecto...Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vectors in Africa. For vector control, insecticides are on the front line, unfortunately, reported resistance jeopardizes the effectiveness of this strategy. The objective of this review was to determine the geographical distribution and insecticide resistance mechanisms of Ae. aegypti and Ae. Albopictus in Africa. Methods: A systematic review of the literature in scientific databases (PubMed, Google Scholar, ScienceDirect, Hinari) allowed us to identify relevant articles on the geographical distribution of Aedes aegypti, Aedes albopictus and arboviral diseases. On the other hand, studies related to insecticides used in vector control against Aedes, associated resistances and their molecular and metabolic mechanisms. Results: A total of 94 studies met the inclusion criteria for this search. Aedes aegypti is reported in most of Africa, and Aedes albopictus in part. There is a re-emergence and outbreak of Arbovirus epidemics in West and Central Africa. The insecticides used were organochlorines, carbamates, organophosphates and pyrethroids. In Aedes, target site insensitivity and metabolic resistance would be the 2 main mechanisms of resistance to these insecticides. Interpretation & Conclusion: Resistance has been recorded in all four major classes of insecticides recommended by WHO for vector control and eradication. New vector control methods such as the use of plant extracts with larvicidal and adulticidal activities, advanced modern biotechnology techniques, and nanobiotechnology need to be developed.展开更多
<b><span>Context:</span></b><span> The vector control is essential in malaria prevention strategies in several endemic countries in Africa including Burkina Faso. The high transmission of...<b><span>Context:</span></b><span> The vector control is essential in malaria prevention strategies in several endemic countries in Africa including Burkina Faso. The high transmission of malaria occurs during the period of high vector abundance (August to October) in Burkina Faso. Therefore, a vector control strategy based on the use of indoor residual spraying targeting this period should provide effective protection against malaria. This study aimed to evaluate the effect of bendiocarb applied in indoor residual spraying on entomological parameters of malaria transmission in a pyrethroid resistance area in southwestern, Burkina Faso.</span><span> </span><b><span>Methods:</span></b><span> CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in entomological parameter within malaria vector in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding pattern, biting and sporozoites rates as well as the malaria transmission risk estimated by entomological inoculation rate. </span><b><span>Results:</span></b><span> A total of 26,276 mosquitoes (13,555 anopheline and 12</span><span>,</span><span>721 other culicines) were collected using both CDC light trap (9158 mosquitoes) and PSC collection methods (17,118 mosquitoes) from June to December 2012. </span><i><span>An. gambiae</span></i><span> complex was the predominant species collected. </span><i><span>An. gambiae</span></i><span> was the predominant species collected (P = 0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n = 4303) compared with unsprayed villages (n = 12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of </span><i><span>An. gambiae</span></i><span> s.l. and </span><i><span>An. funestus </span></i><span>s.l. were significantly lower in sprayed areas compared to unsprayed areas (P < 0.05). Overall, malaria vector transmission risk was significant four-fold lower in villages which received IRS (P = 0.0001) whatever the malaria vectors species</span><span> </span><span> (</span><i><span>An. gambiae</span></i><span> s</span><span>.</span><span>l</span><span>.</span><span> and </span><i><span>An. An. funestus </span></i><span>s.l.). </span><b><span>Conclusions:</span></b><span> The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within </span><i><span>An. funestus</span></i><span> s.l. which became more zoophagic following IRS. The indoor residual spraying could be promoted as a control tool in areas where malaria transmission occurs during a given period of year.</span>展开更多
文摘Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vectors in Africa. For vector control, insecticides are on the front line, unfortunately, reported resistance jeopardizes the effectiveness of this strategy. The objective of this review was to determine the geographical distribution and insecticide resistance mechanisms of Ae. aegypti and Ae. Albopictus in Africa. Methods: A systematic review of the literature in scientific databases (PubMed, Google Scholar, ScienceDirect, Hinari) allowed us to identify relevant articles on the geographical distribution of Aedes aegypti, Aedes albopictus and arboviral diseases. On the other hand, studies related to insecticides used in vector control against Aedes, associated resistances and their molecular and metabolic mechanisms. Results: A total of 94 studies met the inclusion criteria for this search. Aedes aegypti is reported in most of Africa, and Aedes albopictus in part. There is a re-emergence and outbreak of Arbovirus epidemics in West and Central Africa. The insecticides used were organochlorines, carbamates, organophosphates and pyrethroids. In Aedes, target site insensitivity and metabolic resistance would be the 2 main mechanisms of resistance to these insecticides. Interpretation & Conclusion: Resistance has been recorded in all four major classes of insecticides recommended by WHO for vector control and eradication. New vector control methods such as the use of plant extracts with larvicidal and adulticidal activities, advanced modern biotechnology techniques, and nanobiotechnology need to be developed.
文摘<b><span>Context:</span></b><span> The vector control is essential in malaria prevention strategies in several endemic countries in Africa including Burkina Faso. The high transmission of malaria occurs during the period of high vector abundance (August to October) in Burkina Faso. Therefore, a vector control strategy based on the use of indoor residual spraying targeting this period should provide effective protection against malaria. This study aimed to evaluate the effect of bendiocarb applied in indoor residual spraying on entomological parameters of malaria transmission in a pyrethroid resistance area in southwestern, Burkina Faso.</span><span> </span><b><span>Methods:</span></b><span> CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in entomological parameter within malaria vector in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding pattern, biting and sporozoites rates as well as the malaria transmission risk estimated by entomological inoculation rate. </span><b><span>Results:</span></b><span> A total of 26,276 mosquitoes (13,555 anopheline and 12</span><span>,</span><span>721 other culicines) were collected using both CDC light trap (9158 mosquitoes) and PSC collection methods (17,118 mosquitoes) from June to December 2012. </span><i><span>An. gambiae</span></i><span> complex was the predominant species collected. </span><i><span>An. gambiae</span></i><span> was the predominant species collected (P = 0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n = 4303) compared with unsprayed villages (n = 12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of </span><i><span>An. gambiae</span></i><span> s.l. and </span><i><span>An. funestus </span></i><span>s.l. were significantly lower in sprayed areas compared to unsprayed areas (P < 0.05). Overall, malaria vector transmission risk was significant four-fold lower in villages which received IRS (P = 0.0001) whatever the malaria vectors species</span><span> </span><span> (</span><i><span>An. gambiae</span></i><span> s</span><span>.</span><span>l</span><span>.</span><span> and </span><i><span>An. An. funestus </span></i><span>s.l.). </span><b><span>Conclusions:</span></b><span> The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within </span><i><span>An. funestus</span></i><span> s.l. which became more zoophagic following IRS. The indoor residual spraying could be promoted as a control tool in areas where malaria transmission occurs during a given period of year.</span>
