BIOL 322
Adult Control: Insecticide Treated Nets - answer Requires long lasting, low toxicity, fast
acting chemicals e.g. pyrethroids (permethrin)
Endophilic/ Endophilism - answerAn endophilic mosquito is a mosquito that tends to
inhabit/rest indoors. Endophilism facilitates the blocking of malaria transmission through
application of residual insecticides to walls.
Vector, Insecticide and Major applications – answer Anopheles, Culex mosquitoes:
DDT = Residual House Spraying, pyrethroids = Impregnated bed nets
Aedes + Culex: OPs, pyrethroids = Larviciding, misting, fogging
Glossina tsetse flies:
pyrethroids = Traps and targets, DDT, dieldrin and endosulfan = Aerial application and
ground spraying
Simulium blackflies: temephos = larvicides (OCP)
Triatoma bugs: deltamethrin = Residual House
Spraying (SCI)
Mechanisms of insecticide resistance - answerGenetic: alterations in the target site,
reducing insecticide binding e.g. knock down resistance (KDR)
Metabolic: increases in rate of insecticide breakdown through amplification or
modification of enzymes e.g. esterases, cytochrome P450s
Biological control: Biocides - answerBti Bacillus thuringensis serotype israelensis
'Bio-insecticide' - bacteria produce Cry and Cyt pore-forming toxins (from a plasmid)
that lyse larval midgut epithelial cells
Kill larvae of mosquitoes, gnats, blackflies - more specific than chemical insecticides
Under investigation for Aedes aegypti / dengue control, e.g. in Queensland Australia
Efficacy declines steadily over a few months - frequent applications needed, logistically
more difficult
Liquid or granular formulations
, Less suitable for epidemic control
Resistance can be selected in lab
Biological control: predators - answerUse of predacious copepods of the genus
MesocyclopsU
Fish - Guppies (Gambusia 'mosquitofish') and Poecilia used in storage tanks, e.g. in
India
Predacious Mosquitoes - Toxorhynchites larvae - Ae. albopictus vulnerable
Entomopathogenic Fungi - answerMany species - e.g. Beauveria bassiana
Inhibits malaria parasite development to infectious stage
Mosquitoes infected with B. bassiana had 30% less contact with human blood feeding
volunteers
Also inhibited dengue replication in the midgut
Wolbachia - answerThe release of male and female Aedes aegypti mosquitoes with
Wolbachia over a number of weeks.
These mosquitoes then breed with the wild mosquito population. Over time, the
percentage of mosquitoes carrying Wolbachia grows until it remains high without the
need for further releases.
Mosquitoes with Wolbachia are less able to transmit viruses to people, decreasing the
risk of Zika, dengue and chikungunya outbreaks.
Wolbachia contd - answerWolbachia bacteria can be used in several ways, including to
suppress mosquito populations. Other research may involve the release of only male
mosquitoes with Wolbachia. When these mosquitoes mate with wild female mosquitoes
without Wolbachia, they are unable to reproduce.
This technique requires the release of a large number of male mosquitoes to reduce the
overall mosquito population. As with insecticides, this technique would need to be
reapplied over time as the population of mosquitoes gradually returns.
Wolbachia and cytoplasmic incompatibility (CI) - answerHigh density wMel strain &
closely related wMelPop transferred into Aedes aegypti and Ae. albopictus from
Drosophila by embryo microinjection
wMel has lower fitness costs; thus much easier to introduce into populations (lower
threshold for spread)
Adult Control: Insecticide Treated Nets - answer Requires long lasting, low toxicity, fast
acting chemicals e.g. pyrethroids (permethrin)
Endophilic/ Endophilism - answerAn endophilic mosquito is a mosquito that tends to
inhabit/rest indoors. Endophilism facilitates the blocking of malaria transmission through
application of residual insecticides to walls.
Vector, Insecticide and Major applications – answer Anopheles, Culex mosquitoes:
DDT = Residual House Spraying, pyrethroids = Impregnated bed nets
Aedes + Culex: OPs, pyrethroids = Larviciding, misting, fogging
Glossina tsetse flies:
pyrethroids = Traps and targets, DDT, dieldrin and endosulfan = Aerial application and
ground spraying
Simulium blackflies: temephos = larvicides (OCP)
Triatoma bugs: deltamethrin = Residual House
Spraying (SCI)
Mechanisms of insecticide resistance - answerGenetic: alterations in the target site,
reducing insecticide binding e.g. knock down resistance (KDR)
Metabolic: increases in rate of insecticide breakdown through amplification or
modification of enzymes e.g. esterases, cytochrome P450s
Biological control: Biocides - answerBti Bacillus thuringensis serotype israelensis
'Bio-insecticide' - bacteria produce Cry and Cyt pore-forming toxins (from a plasmid)
that lyse larval midgut epithelial cells
Kill larvae of mosquitoes, gnats, blackflies - more specific than chemical insecticides
Under investigation for Aedes aegypti / dengue control, e.g. in Queensland Australia
Efficacy declines steadily over a few months - frequent applications needed, logistically
more difficult
Liquid or granular formulations
, Less suitable for epidemic control
Resistance can be selected in lab
Biological control: predators - answerUse of predacious copepods of the genus
MesocyclopsU
Fish - Guppies (Gambusia 'mosquitofish') and Poecilia used in storage tanks, e.g. in
India
Predacious Mosquitoes - Toxorhynchites larvae - Ae. albopictus vulnerable
Entomopathogenic Fungi - answerMany species - e.g. Beauveria bassiana
Inhibits malaria parasite development to infectious stage
Mosquitoes infected with B. bassiana had 30% less contact with human blood feeding
volunteers
Also inhibited dengue replication in the midgut
Wolbachia - answerThe release of male and female Aedes aegypti mosquitoes with
Wolbachia over a number of weeks.
These mosquitoes then breed with the wild mosquito population. Over time, the
percentage of mosquitoes carrying Wolbachia grows until it remains high without the
need for further releases.
Mosquitoes with Wolbachia are less able to transmit viruses to people, decreasing the
risk of Zika, dengue and chikungunya outbreaks.
Wolbachia contd - answerWolbachia bacteria can be used in several ways, including to
suppress mosquito populations. Other research may involve the release of only male
mosquitoes with Wolbachia. When these mosquitoes mate with wild female mosquitoes
without Wolbachia, they are unable to reproduce.
This technique requires the release of a large number of male mosquitoes to reduce the
overall mosquito population. As with insecticides, this technique would need to be
reapplied over time as the population of mosquitoes gradually returns.
Wolbachia and cytoplasmic incompatibility (CI) - answerHigh density wMel strain &
closely related wMelPop transferred into Aedes aegypti and Ae. albopictus from
Drosophila by embryo microinjection
wMel has lower fitness costs; thus much easier to introduce into populations (lower
threshold for spread)
