title: Surveillance should be strengthened to improve epidemiological understandings of mosquito-borne Barmah Forest virus infection.
abstract: BACKGROUND
  Barmah Forest virus (BFV) is a mosquito-borne virus causing epidemic polyarthritis in Australia. This study used case follow-up of cases from the surveillance system to demonstrate that routinely collected BFV notification data were an unreliable indicator of the true location of exposure.
  
  
  METHODS
  BFV notifications from June 2001 to May 2011 were extracted from the New South Wales (NSW) Notifiable Conditions Information Management System to study case distribution. Disease cluster analysis was performed using spatial scan statistics. Exposure history data were collected from cases notified in 2010 and 2011 to accurately determine travel to high-risk areas.
  
  
  RESULTS
  Cluster analysis using address data identified an area of increased BFV disease incidence in the mid-north coast of NSW contiguous with estuarine wetlands. When travel to this area was investigated, 96.7% (29/30) cases reported having visited coastal regions within four weeks of developing symptoms.
  
  
  CONCLUSIONS
  Along the central NSW coastline, extensive wetlands occur in close proximity to populated areas. These wetlands provide ideal breeding habitats for a range of mosquito species implicated in the transmission of BFV. This is the first study to fully assess case exposure with findings suggesting that sporadic cases of BFV in people living further away from the coast do not reflect alternative exposure sites but are likely to result from travel to coastal regions. Spatial analysis by case address alone may lead to inaccurate understandings of the true distribution of arboviral diseases. Subsequently, this information has important implications for the collection of mosquito-borne disease surveillance information and public health response strategies.
authors.affiliation: Hunter New England Population Health, Newcastle, Australia .
authors.forename: Lutz
authors.initials: L
authors.lastname: Ehlkes
authors.forename: Keith
authors.initials: K
authors.lastname: Eastwood
authors.forename: Cameron
authors.initials: C
authors.lastname: Webb
authors.forename: David
authors.initials: D
authors.lastname: Durrheim
references.citation: Travel Med Infect Dis. 2011 May;9(3):113-25
references.pmid: 21679887
references.citation: J Virol. 2001 Nov;75(21):10118-31
references.pmid: 11581380
references.citation: Commun Dis Intell Q Rep. 2008 Jun;32(2):263-6
references.pmid: 18767428
references.citation: PLoS One. 2011;6(10):e25688
references.pmid: 22022430
references.citation: J Med Entomol. 1999 Nov;36(6):856-60
references.pmid: 10593091
references.citation: Am J Trop Med Hyg. 2007 Mar;76(3):417-23
references.pmid: 17360861
references.citation: Commun Dis Intell Q Rep. 2002;26(4):600-4
references.pmid: 12549534
references.citation: Med J Aust. 1998 Aug 3;169(3):159-63
references.pmid: 9734514
references.citation: Aust J Exp Biol Med Sci. 1986 Jun;64 ( Pt 3):307-9
references.pmid: 3767767
references.citation: J Med Entomol. 1999 Nov;36(6):861-8
references.pmid: 10593092
references.citation: Am J Trop Med Hyg. 1997 Aug;57(2):230-4
references.pmid: 9288821
references.citation: Aust J Exp Biol Med Sci. 1982 Oct;60 (Pt 5):457-70
references.pmid: 6299258
references.citation: Am J Trop Med Hyg. 2001 Dec;65(6):777-82
references.pmid: 11791974
references.citation: N S W Public Health Bull. 2004 Nov-Dec;15(11-12):199-204
references.pmid: 15711614