Anopheles and control Flashcards
Which is the ONLY vector for human malaria”?
Anopheles mosquitoes.
What is incrimination?
Detecting malaria parasites in a mosquito to show that it is a vector for malaria (must be sporozoites in salivary glands).
How are anopheles eggs laid?
Singly and on the surface of the water due to the presence of floats.
Describe the defining features of Anopheles larvae.
- Has no siphon
- (Hence) lies parallel to water surface
Describe the defining head features of anopheles.
-Males have clubbed palps
-Females have palps as long as proboscis
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Describe anopheles wings.
Wings are veined with blocks of black and white bands along the front edge of the wing.
i.e. TYPICALLY WINGS ARE BANDED
Describe anopheles legs.
Legs are also often banded with speckling close to the body.
What does endo/exophagic and endo/exophilic refer to?
Where mosquitoes prefer to feed and rest respectively.
Why arent all Anopheles mosquitoes vectors?
Internal metabolic and immunological differences means that some are not competent to be vectors.
What is the gonotrophic cycle?
Process of having blood meal and using this to produce eggs.
Describe the sporogonic cycle.
Gametocytes are ingested by a female mosquito. They form gametes and fertilise to become zygotes. Zygotes elongate to form ookinetes and these invade midgut and form oocysts which release sporozoites.
What are secondary vectors in the context of anopheles mosquitos.
Species of anopheles that are not primary vectors, however do have capacity to be. They may not be primary vectors for various reasons such as they do not come into as much contact with humans. Killing or eradicating primary vectors may cause open a niche for secondary vectors to become important vectors.
Why is the age of mosquitoes an important factor to consider when thinking of vectors?
They must be old enough to transmit- usually transmit on their 3rd or 4th blood meal as the parasite takes time to develop to a transmissible stage.
What are combination pyrethrin nets? What is their benefit?
Insecticide-treated bednets that are combined with a synergist. THis often blocks the mosquito receptors and makes them sensitive to pyrethrin again. This is useful in situations where pyrethrin resistance is widespread.
What are the downsides of using pyrethroid treated nets? How (what method) can pyrethroids be used for mosquito control instead? Why should we be careful of using pyrethroids?
Pyrethroids are very non-toxic to humans (very safe) but are toxic to aquatic life. Therefore, pyrethroids should be reserved for indoor residual spraying to minimise damage to aquatic systems that can come about when nets are washed.
We should be careful using pyrethroids as resistance to this insecticide is emerging.
