In order that a mosquito female will become a vector of West Nile Virus it has to bite an infected bird first. Infected birds have high West Nile Virus density in their blood, enough to infect the biting mosquito. Biting an infected mammal, like humans or horses for instance, will not infect the mosquito female and it will not become a vector.
Which bird is more likely to infect mosquitoes with West Nile Virus? Scientists often ask themselves that question. A bird that just recently got bitten by a West Nile Virus carrying mosquito has not accumulated enough viruses in its blood to infect the second biting mosquito. On the other hand, a bird that got bitten by such infected mosquito long ago is either over the fever and does not have enough viruses to infect again, or is already dead by now and will not attract any biting mosquito.
Accordingly, only a bird that got bitten by a West Nile Virus carrying mosquito early enough to rich the virus density pick, but not too long ago to be over the pick (immune and getting better or dead) can actually infect another mosquito to become the next WNV vector.
For years crows thought to be one of the leading candidate bird species to carry West Nile Virus. However, researchers now think that at least in North East USA – American Robins, being favorite host for Culexmosquitoes, are the main carrier of this recently spread virus.
Beside the question regarding its immune system, a question regarding the bird attractiveness for mosquito bites should be asked as well when wondering what makes a bird a preferred vector of West Nile Virus. So what makes a bird more attractive to mosquito bites? Mosquitoes are attracted mainly by odors for their blood meal host. Probably Robins got the most attractive odor to the mosquito females.
Behavioral patterns may also be a reason. If the bird can be found in the same location as the mosquitoes, it is more likely to get bitten. For this reason I believe albatrosses, for example, are rarely bitten as they spend much of their time in the middle of the ocean. I also believe that day active birds (like Robins) will get bitten more frequently by night active mosquitoes (like Culex), as they are more likely to get bitten while asleep. Moreover, for a very active bird like the swallow for instance, this should be even truer.
Finally, different studies have demonstrated that infected mosquito females change their behavior – especially biting and flying behavioral modes. Thus, I often wonder if a West Nile virus infected mosquito female is attracted to birds in a similar manner as a healthy mosquito?
Think of a bird species that sleeps up high on particularly high trees. Imagine also that a certain mosquito species is in the habit of biting these birds while they are sleeping. Will a West Nile Virus infected (and probably weak) mosquito female be likely to make the effort to fly so high for a blood meal, or will it change its feeding behavior and search for a biting victim closer to ground?
In summary, numerous factors are joined together to determine whether a certain bird species would be involved with West Nile Virus cycle or not. See herein more details on West Nile Virus :)
Which bird is more likely to infect mosquitoes with West Nile Virus? Scientists often ask themselves that question. A bird that just recently got bitten by a West Nile Virus carrying mosquito has not accumulated enough viruses in its blood to infect the second biting mosquito. On the other hand, a bird that got bitten by such infected mosquito long ago is either over the fever and does not have enough viruses to infect again, or is already dead by now and will not attract any biting mosquito.
Accordingly, only a bird that got bitten by a West Nile Virus carrying mosquito early enough to rich the virus density pick, but not too long ago to be over the pick (immune and getting better or dead) can actually infect another mosquito to become the next WNV vector.
For years crows thought to be one of the leading candidate bird species to carry West Nile Virus. However, researchers now think that at least in North East USA – American Robins, being favorite host for Culexmosquitoes, are the main carrier of this recently spread virus.
Beside the question regarding its immune system, a question regarding the bird attractiveness for mosquito bites should be asked as well when wondering what makes a bird a preferred vector of West Nile Virus. So what makes a bird more attractive to mosquito bites? Mosquitoes are attracted mainly by odors for their blood meal host. Probably Robins got the most attractive odor to the mosquito females.
Behavioral patterns may also be a reason. If the bird can be found in the same location as the mosquitoes, it is more likely to get bitten. For this reason I believe albatrosses, for example, are rarely bitten as they spend much of their time in the middle of the ocean. I also believe that day active birds (like Robins) will get bitten more frequently by night active mosquitoes (like Culex), as they are more likely to get bitten while asleep. Moreover, for a very active bird like the swallow for instance, this should be even truer.
Finally, different studies have demonstrated that infected mosquito females change their behavior – especially biting and flying behavioral modes. Thus, I often wonder if a West Nile virus infected mosquito female is attracted to birds in a similar manner as a healthy mosquito?
Think of a bird species that sleeps up high on particularly high trees. Imagine also that a certain mosquito species is in the habit of biting these birds while they are sleeping. Will a West Nile Virus infected (and probably weak) mosquito female be likely to make the effort to fly so high for a blood meal, or will it change its feeding behavior and search for a biting victim closer to ground?
In summary, numerous factors are joined together to determine whether a certain bird species would be involved with West Nile Virus cycle or not. See herein more details on West Nile Virus :)
WNV and the Right Bird
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murat