title: Spatial and temporal association of outbreaks of H5N1 influenza virus infection in wild birds with the 0 degrees C isotherm.
abstract: Wild bird movements and aggregations following spells of cold weather may have resulted in the spread of highly pathogenic avian influenza virus (HPAIV) H5N1 in Europe during the winter of 2005-2006. Waterbirds are constrained in winter to areas where bodies of water remain unfrozen in order to feed. On the one hand, waterbirds may choose to winter as close as possible to their breeding grounds in order to conserve energy for subsequent reproduction, and may be displaced by cold fronts. On the other hand, waterbirds may choose to winter in regions where adverse weather conditions are rare, and may be slowed by cold fronts upon their journey back to the breeding grounds, which typically starts before the end of winter. Waterbirds will thus tend to aggregate along cold fronts close to the 0 degrees C isotherm during winter, creating conditions that favour HPAIV H5N1 transmission and spread. We determined that the occurrence of outbreaks of HPAIV H5N1 infection in waterbirds in Europe during the winter of 2005-2006 was associated with temperatures close to 0 degrees C. The analysis suggests a significant spatial and temporal association of outbreaks caused by HPAIV H5N1 in wild birds with maximum surface air temperatures of 0 degrees C-2 degrees C on the day of the outbreaks and the two preceding days. At locations where waterbird census data have been collected since 1990, maximum mallard counts occurred when average and maximum surface air temperatures were 0 degrees C and 3 degrees C, respectively. Overall, the abundance of mallards (Anas platyrhynchos) and common pochards (Aythya ferina) was highest when surface air temperatures were lower than the mean temperatures of the region investigated. The analysis implies that waterbird movements associated with cold weather, and congregation of waterbirds along the 0 degrees C isotherm likely contributed to the spread and geographical distribution of outbreaks of HPAIV H5N1 infection in wild birds in Europe during the winter of 2005-2006.
authors.affiliation: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Reperant
authors.forename: Neven S
authors.initials: NS
authors.lastname: Fuckar
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Dobson
authors.forename: Thijs
authors.initials: T
authors.lastname: Kuiken
mesh_terms: D025041:Animal Migration; D000818:Animals; D000835:Animals, Wild / Q000821:virology; D046090:Anseriformes / Q000821:virology*; D002980:Climate; D004196:Disease Outbreaks / Q000662:veterinary; D005060:Europe / Q000453:epidemiology; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000453:epidemiology*; D013696:Temperature
references.citation: Avian Dis. 2007 Mar;51(1 Suppl):285-9
references.pmid: 17494568
references.citation: Emerg Infect Dis. 2008 Aug;14(8):1267-70
references.pmid: 18680652
references.citation: Vet Microbiol. 2009 Apr 14;136(1-2):20-6
references.pmid: 19081209
references.citation: Proc Biol Sci. 2009 Mar 22;276(1659):1029-36
references.pmid: 19129127
references.citation: Emerg Infect Dis. 2006 Nov;12(11):1650-6
references.pmid: 17283613
references.citation: Emerg Infect Dis. 2007 Aug;13(8):1139-43
references.pmid: 17953082
references.citation: J Clin Microbiol. 2009 Mar;47(3):666-73
references.pmid: 19109483
references.citation: PLoS One. 2007 Jan 31;2(1):e184
references.pmid: 17264886
references.citation: PLoS Comput Biol. 2009 Apr;5(4):e1000346
references.pmid: 19360126
references.citation: Rev Sci Tech. 2009 Apr;28(1):59-67
references.pmid: 19618619
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 23;106(25):10365-9
references.pmid: 19497868
references.citation: Infect Genet Evol. 2009 Sep;9(5):800-5
references.pmid: 19379841
references.citation: Emerg Infect Dis. 2008 Apr;14(4):600-7
references.pmid: 18394278
references.citation: J Wildl Dis. 2008 Oct;44(4):811-23
references.pmid: 18957637
references.citation: Emerg Infect Dis. 2008 Jan;14(1):136-42
references.pmid: 18258093
references.citation: PLoS One. 2009 Oct 05;4(10):e7289
references.pmid: 19802387
references.citation: J Virol. 2006 Dec;80(24):12229-35
references.pmid: 17035314
references.citation: Transbound Emerg Dis. 2009 Apr;56(3):57-72
references.pmid: 19267878
references.citation: Proc Natl Acad Sci U S A. 2006 Dec 19;103(51):19368-73
references.pmid: 17158217