US - Overwintering population of Aedes Aegypti mosquito found in Washington DC

[Gert van der Hoek]

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  Notre Dame prof finds Zika-related mosquito far from tropics
  
  Jan 31, 2016

SOUTH BEND ? It was by chance. Researcher Andrew Lima noticed a mosquito that seemed odd for Washington, D.C., where he lives. It turned out to be the same species that transmits the Zika virus that is now causing alarm for pregnant women in the tropics.
?They shouldn?t be there,? says Dave Severson, a University of Notre Dame biology professor who?s traveled the world to collect and study the culprit: the Aedes aegypti mosquito.
The nation?s capital is ?considerably north? of habitat where this mosquito normally survives, says Severson, whom the D.C. researcher reached out to for help. A winter?s freeze would kill them. And yet, several hundred of the insects thrived in a small neighborhood within a block of the U.S. Supreme Court building.
?These mosquitoes could fly to the Capitol building,? Severson quipped.
No, the mosquitoes weren?t carrying the virus. But their discovery in D.C., Severson said, begs a question about their ability to adapt: ?Where else are they??

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[Gert van der Hoek]

[h=1]Am J Trop Med Hyg. 2016 Jan 6;94(1):231-5. doi: 10.4269/ajtmh.15-0351. Epub 2015 Nov 2.


Evidence for an Overwintering Population of Aedes aegypti in Capitol Hill Neighborhood, Washington, DC.[/h] [h=3]Abstract[/h]
Aedes aegypti is an invasive, highly anthropophilic mosquito and a major vector for dengue and chikungunya. Population persistence in the continental United States is reportedly limited to southward of the average 10?C winter isotherm, which in the east, bisects Alabama, Mississippi, Georgia, and South Carolina. We report on summer collections and genotypic analyses of Ae. aegypti collected in the Capitol Hill neighborhood in Washington, DC (WDC). Analysis of a 441-bp fragment of the mitochondrial cytochrome oxidase I gene sequence identified the same two haplotype sequences during 2011-2014, and placed these within two di

screte groups known to be derived from lineages resident in the Americas. Analysis of 10 microsatellite loci for specimens collected during 2011-2014 revealed no evidence for introgression of new alleles across years.

Overall, our data support a conclusion that this represents a resident WDC population, likely maintained during winter months in a subterranean habitat that facilitates year-round survival.

 

[Gert van der Hoek]

Map of occurrence points for Ae. aegypti.