First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions
First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions
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DOI：
10.1186/1475-2875-10-24
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发表时间：
2011-02-02
期刊：
影响因子：
3
通讯作者：
Takken, Willem
中科院分区：
文献类型：
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作者：
Howard, Annabel F. V.;N'Guessan, Raphael;Takken, Willem
背景：对杀虫剂具有抗药性的蚊子正在损害现有蚊子控制工具控制疟疾病媒的能力。一种新的蚊子控制方法是使用昆虫病原真菌。在实验室条件下，这些真菌已被证明对易受杀虫剂影响的蚊子和对杀虫剂有抗性的蚊子都是致命的。本研究的目的是，看看是否可以使用昆虫病原真菌感染的抗疟疾载体在现场条件下，并看到是否的毒力和生存能力的真菌分生孢子暴露后降低到周围的非洲现场conditions.Methods：本研究使用的真菌球孢白僵菌感染的抗疟疾载体冈比亚按蚊。s（双翅目：蚊科）VKPER实验室菌落菌株。将真菌分生孢子施加到聚酯网上，并在西非田间条件下保持不同的时间段。在蚊帐施用后1、3和5天，通过暴露An.冈比亚湾S.在野外条件下进行的世卫组织锥形生物测定中的VKPER蚊子。此外，还对B.结果：在田间条件下，接种20 d后，测定球孢菌分生孢子的数量，结果表明：B.白僵菌感染导致死亡率显着增加，与对照蚊子相比，接触真菌的蚊子每天死亡的风险增加了2.5倍。然而，B.随着暴露在田间条件下时间的增加，球孢分生孢子减少，网上处理时间越长，真菌诱导的死亡率越低。这可能是由于气候原因，因为实验室试验在同一试验时间段内没有发现这种下降。分生孢子的活力也随着暴露于净和自然非生物环境条件的增加而下降。经20 d的野外暴露后，分生孢子的存活率为30%，而对照分生孢子的存活率为79%。目前，该系统已在田间试验中证实了球孢霉真菌分生孢子对耐甲氧西林蚊子的作用，但还需要进一步研究环境条件对真菌毒力和生存力的作用，以期最终使真菌分生孢子递送系统更能承受非洲的环境气候。
Background: Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions.Methods: This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s. s (Diptera: Culicidae) VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s. s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions.Results: The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5x for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but the viability of control conidia not exposed to the net or field conditions was 79%.Conclusions: This work shows promise for the use of B. bassiana fungal conidia against insecticide-resistant mosquitoes in the field, but further work is required to examine the role of environmental conditions on fungal virulence and viability with a view to eventually making the fungal conidia delivery system more able to withstand the ambient African climate.