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why are malarial parasites specific for anopheles mosquito. why do they need only anopheles, they just need lower temperature to complete their life cycle. all mosquitoes are cold blooded, so they can get a suitable environment in any of them, why only anopheles?

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closed as off-topic by anongoodnurse, March Ho, James, Chris Jun 30 '16 at 6:02

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework questions are off-topic on Biology unless you have shown your attempt at an answer. For more information see our homework policy." – anongoodnurse, March Ho, James, Chris
If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ Did you look this up - research it - in any way? Can you provide some of the information you found? People (myself included) are happy to answer if the poster shows the research they've done. Thanks. $\endgroup$ – anongoodnurse Jun 29 '16 at 19:47
  • $\begingroup$ I looked this up but didn't get any satisfactory answer. I just want to know why their is specific relationship for their sexual cycle to complete. All they need is lower temperature because when they are inside human body the temperature is not suitable for the syngamy to occur that's the reason they go into anopheles' body but every other mosquito is cold blooded and is capable of providing the atmosphere for the process to occur $\endgroup$ – Kritika Waghmare Jun 29 '16 at 19:57
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    $\begingroup$ One major factor to consider: not all mosquitoes feed on humans. The malaria-carrying mosquitoes must. That's only one factor. There are many more. Saying you researched it and showing your research are two different things. $\endgroup$ – anongoodnurse Jun 29 '16 at 23:37
  • $\begingroup$ @anongoodnurse The Plasmodium falsciparium carrying mosquitoes must feed on humans, but there are other forms of (rodent) malaria. They still are carried by anopheles. $\endgroup$ – skymningen Jun 30 '16 at 7:24
  • $\begingroup$ This isn't actually a bad question, although I agree it needs to show some effort. Short answer, though: they aren't. Avian malaria (Plasmodium relictum) is transmitted by Culex mosquitoes (and possibly by Culicoides biting midges, although there are some issues with that study). The reverse question is also interesting; why do arboviruses seem to be almost-exclusively transmitted by everything else? The only arbovirus transmitted by Anopheles is O N'yong N'yong virus (ONNV). Alain Kohl's group published a nice paper on this recently (ncbi.nlm.nih.gov/pubmed/25548172). $\endgroup$ – arboviral Jun 30 '16 at 7:42
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The host/parasite relationship is normally very specific: because there are a lot of molecules that have to bind each other for the parasite to complete its cycle, a parasite is not capable of invading any given organism; the same way, a host is not invaded by any given parasite.

That being said, you have to keep in mind that mosquitoes are also hosts (despite of, in the case of malaria, having less symptoms when compared to the human host). In fact, regarding malaria, some parasitology books classify the mosquitoes as the "definitive hosts", while humans are "intermediate hosts" (because the sexual reproduction of Plasmodium happens in the mosquito, not in the human being). So, there are a lot of molecules that have to be present for the parasite finding its way through the mosquito's organism. A plasmodium cannot survive inside a Lutzomyia mosquito, the same way a Leishmania cannot survive inside a Anopheles mosquito. There is specificity.

Actually, not all Anopheles are the same (just as not all human beings are the same). They have differences regarding the susceptibility to the parasite:

Some Anopheles species are poor vectors of malaria, as the parasites do not develop well (or at all) within them. There is also variation within species. In the laboratory, it has been possible to select for strains of An. gambiae that are refractory to infection by malaria parasites. These refractory strains have an immune response that encapsulates and kills the parasites after they have invaded the mosquito's stomach wall.

(source: https://www.cdc.gov/malaria/about/biology/mosquitoes/)

Please note that other mosquito species are not resistant to the plasmodium, because we call "resistant" a host that's capable to fight the parasite. The other species are not even hosts!

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