title: Fluctuations at a low mean temperature accelerate dengue virus transmission by Aedes aegypti.
abstract: BACKGROUND
  Environmental factors such as temperature can alter mosquito vector competence for arboviruses. Results from recent studies indicate that daily fluctuations around an intermediate mean temperature (26°C) reduce vector competence of Aedes aeygpti for dengue viruses (DENV). Theoretical predictions suggest that the mean temperature in combination with the magnitude of the diurnal temperature range (DTR) mediate the direction of these effects.
  
  
  RESULTS
  We tested the effect of temperature fluctuations on Ae. aegypti vector competence for DENV serotype-1 at high and low mean temperatures, and confirmed this theoretical prediction. A small DTR had no effect on vector competence around a high (30°C) mean, but a large DTR at low temperature (20°C) increased the proportion of infected mosquitoes with a disseminated infection by 60% at 21 and 28 days post-exposure compared to a constant 20°C. This effect resulted from a marked shortening of DENV extrinsic incubation period (EIP) in its mosquito vector; i.e., a decrease from 29.6 to 18.9 days under the fluctuating vs. constant temperature treatment.
  
  
  CONCLUSIONS
  Our results indicate that Ae. aegypti exposed to large fluctuations at low temperatures have a significantly shorter virus EIP than under constant temperature conditions at the same mean, leading to a considerably greater potential for DENV transmission. These results emphasize the value of accounting for daily temperature variation in an effort to more accurately understand and predict the risk of mosquito-borne pathogen transmission, provide a mechanism for sustained DENV transmission in endemic areas during cooler times of the year, and indicate that DENV transmission could be more efficient in temperate regions than previously anticipated.
authors: Department of Entomology, University of California Davis, Davis, California, USA. lbcarrington@gmail.com
authors: Lauren B
authors: LB
authors: Carrington
authors: M Veronica
authors: MV
authors: Armijos
authors: Louis
authors: L
authors: Lambrechts
authors: Thomas W
authors: TW
authors: Scott
mesh_terms: D000330:Aedes / Q000502:physiology* / Q000821:virology*; D000818:Animals; D003080:Cold Temperature; D003716:Dengue Virus / Q000502:physiology*
references: J Med Entomol. 2001 Sep;38(5):646-56
references: 11580037
references: Sci Total Environ. 2010 Oct 15;408(22):5521-8
references: 20817262
references: Can J Microbiol. 1974 Feb;20(2):255-62
references: 4132612
references: J Med Entomol. 2001 Jul;38(4):548-56
references: 11476335
references: Southeast Asian J Trop Med Public Health. 2009 Sep;40(5):942-50
references: 19842378
references: Bull World Health Organ. 1970;43(2):319-25
references: 5312528
references: Vector Borne Zoonotic Dis. 2010 Apr;10(3):259-66
references: 19725769
references: J Med Entomol. 2013 Jan;50(1):43-51
references: 23427651
references: J Med Entomol. 1990 Jul;27(4):607-14
references: 2167374
references: PLoS Negl Trop Dis. 2010 Jun 08;4(6):e706
references: 20544013
references: BMC Ecol. 2011 Oct 05;11:23
references: 21975028
references: Proc Natl Acad Sci U S A. 2011 May 3;108(18):7460-5
references: 21502510
references: Am J Trop Med Hyg. 2013 Apr;88(4):689-97
references: 23438766
references: Trans R Soc Trop Med Hyg. 1971;65(5):661-7
references: 5159140
references: J Med Entomol. 2009 Jan;46(1):33-41
references: 19198515
references: Am J Trop Med Hyg. 1987 Jan;36(1):143-52
references: 3812879
references: Annu Rev Entomol. 2008;53:273-91
references: 17803458
references: J Med Entomol. 2011 Jul;48(4):914-23
references: 21845954
references: Australas Ann Med. 1958 May;7(2):102-7
references: 13546107
references: Am J Trop Med Hyg. 2002 Jul;67(1):85-92
references: 12363070
references: PLoS Pathog. 2008 Jun 27;4(6):e1000092
references: 18584026
references: J Virol Methods. 2006 Jun;134(1-2):183-9
references: 16510196
references: Bull World Health Organ. 1981;59(4):623-30
references: 6976230
references: Adv Virus Res. 2003;60:187-232
references: 14689695
references: PLoS One. 2013;8(3):e58824
references: 23520534
references: Am J Trop Med Hyg. 1981 Sep;30(5):1094-9
references: 7283006
references: J Med Entomol. 2007 Mar;44(2):205-10
references: 17427687
references: Annu Rev Entomol. 1991;36:459-84
references: 2006869
references: PLoS Negl Trop Dis. 2010 May 25;4(5):e646
references: 20520794
references: Trans R Soc Trop Med Hyg. 2011 Aug;105(8):452-8
references: 21700303
references: Med Vet Entomol. 2012 Jun;26(2):210-7
references: 21781139
references: Med Vet Entomol. 2000 Mar;14(1):31-7
references: 10759309
references: Proc Natl Acad Sci U S A. 2010 Aug 24;107(34):15135-9
references: 20696913
references: PLoS Negl Trop Dis. 2009;3(2):e382
references: 19221592
references: Am J Trop Med Hyg. 1976 Mar;25(2):318-25
references: 1259091
references: Med Vet Entomol. 2010 Mar;24(1):66-73
references: 20377733
references: Am J Trop Med Hyg. 1990 Nov;43(5):543-50
references: 2173434