Tsetse control Flashcards
Key part of life cycle targeted for vector control
Emerging adult, only vulnerable stage. Have a slow reproductive stragety so only have to kill a few to eliminate the population.
Difficulties of control
Reinvasion, fly long distances seeking host
Four methods of control
Aerial spraying, ground spraying, traps and targets, insecticide treated cattle
Ground spraying
DDT and dieldrin sprayed or fogged directly onto tsetse resting areas. Effective for sufficient period to allow tsetse to emerge.
Pros and cons of ground spraying
Pros: Effective at vastly reducing vector populations.
Cons: logistics, labour intensive, ineffective against reinvasion
Sequential aerosol technique
Timing of spray based on larval and pupal periods - first cycle kills adults, afterwards application targeted at young flies before deposit first larvae.
Insecticide (endosulfan, deltamethrin) prayed from atomiser creating 30-40 micron droplets. Night application above tree canopy, inversion conditions occur. 4 air crafts for overlapping swathes
Sequential aerosol technique pros and cons
Pros: rapid, effective, doesn’t require large labour force or ground support
Cons: expensive, technically demanding, re-invasion susceptibility, can’t use in broken terrain
What host odours attract tsetse?
Carbon dioxide, Acetone, 1-octen-3-ol, 4-methylphenol, 3-n-propylphenol
Targeting tsetse
Rifa triangle
Odour bated targets, population reduced >99% in areas >5 km from invasion front
Tsetse attraction preference
Palpalis - visual. Mortisans - odour
How to attract tsetse not landing on target (many).
ITN panels attached to target, invisible to tsetse so collide
Features of tiny target
Small (25x25 cm), square, blue, flanking net, some baited with attractants
Evidence of target success
Lake Victoria - tsetse population on mainland and an island where no targets have been deployed have remained steady for 2 years.
West Nile region, Uganda
> 90% control across intervention area, >99% where invasion prevented
