Absolutely, Positively Last of the Mosquitoes

AnnouncementsSpeaking Today: Sean Allen, Lauren TorbettSpeaking Thursday: Mark Goodman, Charity SelbredeAbout Thursdays Class …

Sampling Adults

• Males – Not interested in them

• Blood questing females – Light/CO2 traps

• Gravid females – Gravid traps

• General – Resting Boxes (Culeseta & Anopheles)

• Non-attraction traps – sample at random

CDC - Light/CO2 Baited Trap• Can use gas, dry ice, or

chemical sachet• Generally overnight• May be used with light• Some differentiate by time

Other Traps for Blood Questers

Mosquito magnet used as a sampling tool Sonic trap mimics the

sound of a dog’s heartbeat

Gravid Traps1. Generally left overnight

2. The type of water affects trap catch

3. Very susceptible to rainfall

4. May also find eggs on/near water

Impact Assessment

• Biting Rate– Human Bait– Animal Bait

• Disease Risk– Prevalence in Mosquito Population– Prevalence in Host Population

Human Landing/Biting Rate1. Fixed time interval2. Sample at same time of day

3. Standardized human

4. Widely restricted

Sentinel Animals

More commonly used as an early warning for disease risk

Landing Rates & Impact

• Human Nuisance – Must know two things:– Number of bites people are willing to tolerate– Bite rate that results in action

• Disease risk – Must know the proportion of bites that result in new infections

Final Thoughts on Mosquito Population Sampling

• All commonly used methods are relative – None give absolute estimates.

• Different species are sampled at different rates for each technique.

• Generally, must pre-define which species in the mosquito complex is the target of a sampling program then select the appropriate technique(s).

Determining Disease Prevalence in Mosquito Populations

Sort into pools

Many diseases have simple strip tests available (tend to be around 70% accurate, but their cheap & easy).

This one costs $60 & does 20 tests

More accurate and sophisticated techniques are available

• Most are based on an amplification procedure.

• Such procedures require facilities with appropriate containment as well as specialized equipment & training.

• Cost prohibitive in many management programs (typically $20 – 25/test).

End of Mosquitoes

Brachycerous Flies

Muscid Flies

• Flies in the family Muscidae• Similar in appearance to house flies (Musca

domestica)• Not typically human disease vector• Main problems for humans:

– Nuisance– Contamination– Exsanguination possible– Can be significant economic problems (esp. on

livestock)

Principal Species in Kentucky

• About twice as many species as mosquitoes world wide

• 5 X as many species in N. America (vs. mosquitoes)

• Only 9 species of med/vet importance (cf. Table 16.1).

• Only 4 of these are important in Kentucky

1. House Flies

• Eggs laid in batches of 75 – 150, 500 in a female’s lifetime

• Immatures are maggots– Vermiform

diperteran larvae without distinct head capsules

• Sexually dimorphic• Life cycle ~ 10d

2. Stable Fly

• Stomoxys calcitrans• Similar life cycle &

appearance to house fly• Blood feeder• Larvae breed in wet

organic matter (esp. straw mixed with manure)

• Primary effect: Reduces livestock performance (economic); nuisance

3. Horn Fly

• Haematobia irritans• Mostly on cattle backs• Essentially only a cattle problem (larval habitat)• Economic pest of cattle

4. Face Fly

• Musca autumnalis• Similar in appearance to

house fly• Main Impacts:

– Transmit eye diseases in livestock (e.g. bacterial conjunctivis [Pink Eye])

– Irritate Livestock (Economic)

– May attempt to overwinter in large numbers in houses (nuisance).