Insecticide Resistance Management Flashcards
What percentage of reduction in malaria transmission can be attributed to vector control?
80%
Where does all insecticides begin (in Africa)?
Begins in west Africa, independently later in east Africa
How can we quantify the strength of resistance change over time?
Experiment by changing exposure in a bioassay - diagnostic dose bioassay. Measure time and concentration quantitative bioassay. Compare lab and field mosquitoes
Examples tube/cone/cage
Where are some vector insecticides developed from?
Agricultural controls
What could account for an increase in pyrethroid resistance?
Improved case monitoring
WHO Global Malaria Programme - what is it?
Strategies for dealing with resistance.
IRS and pyrethroids?
WHO don’t recommend use of pyrethoids, double resistance with use of LLINs
What needs to be considered when selecting an insecticide for an IRS programme?
MoA and duration of efficacy, Ethical/community acceptance, Types of vector, Malaria seasonality, Cost, Resistance (physiology or behavioural), Practicalities (logistics, regulations, environmental conditions)
How can epidemiological impact of resistance be measured?
Vector species compassion, levels of resistance, detecting/treatment, lifelong impact of resistance on mosquitoes, vector behaviours
How does insecticide resistance affect the effectiveness of LLINs?
LLIN mass distribution in areas of high resistance everts 40% fewer episodes than susceptible pop (Briet et al 2013)
Factors affecting efficacy of insecticide based control.
Resistance, washing of ITNs/walls, walk surface, spray equipment, insecticide storage, refusal, insect behaviour
What is Piperonyl but oxide (PBO)?
A chemical compound synergist, not insecticidal alone but increases pyrethroid toxicity. Bednets
Benefit of permethrin and pyriproxyfen bed net?
Insecticidal, may reduce adult longevity and larval production
How could diagnostic dose assays mask the strength of resistance?
If there is a fixed exposure rate of insecticide changes in mortality rate may not be observed. With a varied exposure time or conc, increases in strength of resistance could be observed. (Toe et al 2014)
Why is collection of resistance data needed?
- For selection of the most appropriate insecticide to use
- To identify areas where current insecticide underperforming
- Monitor efficacy of resistance management strategies.
