NRI lectures Flashcards
When sampling, why is info on age and sex distribution important?
For medically important species often longevity is the most important factor for vectorial capacity and often only females are vectors (blood feed).
What is teneral vs non teneral?
Teneral = have never fed
Non- teneral= have fed many times.
An arthropod stage where it is pale and soft bodied immediately after moulting (will have taken a blood meal prior to this).
What are the factors that differ that affect the behaviour of day active vs night active species (e.g. tsetse vs anopheles)?
- Host motility/ quiescence- active vs passive seeking
- Risk of predators e.g. birds etc
- How much CO2 background there is
- Visual cues
- Wind speed- changes odour directionality
- Desiccation risk
Descrive how baited warthog traps were used to see what tsetses were attracted to
Dead stuffed warthog had fewer flies landing
Live warthog had loads, visual cues suggested to be more important as opposed to visual cues here
Why are tsetses though to be attracted to blue at a long range?
Fur thought to reflect blue light- separates hosts from rocks and trees.
Describe cow experiements that suggested odour is more important than visual cues?
Cow with an incomplete ring around it and an electrified fence to see how many flies were coming from upwind vs downwind- expect more from the downwind side if odour is more important than visuals.
Cow in an underground pit with a fan blowing odour up. Lots of flies caught in the trap by the fan- odour very attractive even when they do not see the cow.
What can be used as a synthetic mix for host odour for tsetses?
Octenol, acetone, co2, phenols.
Why may human landing catches underestimate numbers?
Human decoy trap (human in tent with odour coming out far away next to a trap) caught 2000 mosquitos per night, humans cannot catch all of these themselves.
Why are anopheles gambiae the perfect vectors for malaria?
- Very anthrophilic
- Oviposition sites near humans- manmade containers and hoofprints
- Rest near humans- endophilic
What is a factor that has one of the biggest effects on vectorial capacity?
Whether the vector consistently goes back to the same kind of animal- parasites and arboviruses often more species-specific so having a strong host preference means disease is more likely to spread between blood meals.
What are the main ways in which members of the anopheles gambiae complex differ from one another?
- Host preference-cattle vs human feeding etc
- Endo or exophagic and philic
Tsetses are sympatric with which mosquito species and where are they found?
Anopheles arabiensis- in the tsetse belt because they are associated with the same environments.
What is the feeding preference of An arabiensis?
Is anthropophilic but prefers to bite outdoors so if there are peridomestic hosts outdoors like cows they will preferentially bite these.
How can rats cause different kinds of plague?
Bubonic and pneumonic from fleas. Pharyngeal plague endemic in Mozambique because rats are eaten.
How does the lifecycle of rats mean they can reach very high numbers quickly?
Can nurse a littler while being pregnantwith another- keep churning them out.
They reproduce on a monthly cycle with 6-12 babies per litter.
