As tropical disease spread under the influence of clime change and increase global apparent movement , the residents of one vulnerable city have receive strange defender in the form of northern cardinal ( Cardinalis cardinalis ) .
West Nile Virus ( WNV ) is a mosquito - borne disease that has infect an estimated 780,000 North Americans since 1999 . In austere cases , consequences include brain infection that have taken 1,700 lives in the United States alone .
With 3.3 infection per 100,000 the great unwashed , Georgia has proven surprisingly immune equate to other US cities , conceive that one - third of Atlanta - area birds tested for the virus have been taint .
Emory University’sDr Rebecca Levinewas struck by the fact that Chicago has five times as many human WNV infections per head as Atlanta , even though birds in the expanse are less likely to be infected than those around Atlanta .
In theAmerican Journal of Tropical Medicine and Hygiene , Levine assign the deviation to the type of wench in the region , and in particular the way that redbird constitute a protective cuticle for Atlantans . The entire US southeast looks like benefit to some degree .
WNV is called a “ spillover ” disease because the virus circulates mostly among animals , sometimes spilling into nearby human populations . American robins are particularly combat-ready facilitator of the disease , earning the tag “ superspreaders ” . They harbor the computer virus at high grade in their blood , giving it back to Culex mosquitoes that burn them , which then carry it on to world .
" What we establish is that , for some strange ground , around the middle of July , mosquitoes in Atlanta seem to decide that they have had their filling of Turdus migratorius and they exchange to give on cardinals , " Levine sound out in astatement . " But cardinals , even though they can be taint with West Nile virus , are much less likely to have enough virus circulating in their profligate to convey the disease back to feeding mosquitoes . That is why we bid them ' supersuppressors ' . "
The timing of the switch could n’t be better , pass off as mosquito populations approach their yearly summit .
These wench really are guardian angel . Phil Lowe / Shutterstock
The cardinals are probably not bearing the burden alone . mocker , gray catbirds and brown thrasher also appear to have a crush effect , showing why it really is a sinfulness to shoot down a mockingbird .
The big question is what can be done to boost WNV suppression . Promoting suppressive species is one obvious option , but more information about why the mosquito change diet would probably serve . Levine noted that WNV transmission seems to be miserable from birds populate old growth forests than those in other habitats . “ So , we might find oneself that keeping older growth woodland entire , even in urban area , can provide more than just an interesting piece of history , " shesaid . Atlanta has an remarkably declamatory amount of urban tree diagram hide for a major American city , almost four meter Chicago ’s .
An even more important query is whether there are metal money that act as suppressors for more dangerous mosquito - borne diseases . If so , these could become the New equivalents of thegeese that save Rome .
