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Volume 14, Number 5—May 2008

Increase in West Nile Neuroinvasive Disease after Hurricane Katrina

Kevin A. Caillouët*Comments to Author , Sarah R. Michaels*, Xu Xiong*, Ivo Foppa*, and Dawn M. Wesson*
Author affiliations: *Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA;

Main Article

Table 2

Incidence rate ratios of West Nile neuroinvasive disease (WNND) in 2002–2005 and 2006 in Louisiana parishes and Mississippi counties*

State, area West Nile neuroinvasive disease incidence rate†
Incidence rate ratio (95% CI)
2002‡ 2003‡ 2004‡ 2005‡ 2002–2005§ 2006¶
Affected 5.6 1.3 0.2 1.4 2.1 4.4 2.09 (1.48–2.94)
0.47 (0.35–0.64)
Affected 6.1 2.1 0.8 1.5 2.6 6.5 2.45 (1.77–3.47)
Unaffected 5.5 1.7 1.2 1.3 2.4 1.7 0.71 (0.55–1.03)

*WNND incidence rates increased 2-fold in the hurricane-affected regions of both states. The unaffected regions showed a decrease in WNND incidence rates (Louisiana) and no change in incidence (Mississippi). CI, confidence interval.
†No. cases/100,000.
‡Population estimate based on 2000 US Census (8).
§Cumulative WNND incidence = (no. WNND cases 2002 + 2003 + 2004 + 2005) / cumulative population (Census 2000 [8] × 100,000).
¶Population estimate based on 2006 US Census estimate (7).

Main Article

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  3. Knabb  RD, Rhome  JR, Brown  DP. Tropical cyclone report: Hurricane Katrina, August 23–30, 2005 [cited 2008 Feb 19]. Available from
  4. Final evacuation of New Orleans completed. Reuters [International Herald Tribune]. 2005 Sep 4.
  5. Hayes  EB, Komar  N, Nasci  RS, Montgomery  SP, O’Leary  DR, Campbell  GL. Epidemiology and transmission dynamics of West Nile virus disease. Emerg Infect Dis. 2005;11:116773.PubMedGoogle Scholar
  6. US Census Bureau. Special population estimates for impacted counties in the Gulf Coast area. 2007 [cited 2008 Feb 19]. Available from
  7. US Census Bureau. US census 2000 [cited 2008 Feb 19]. Available from
  8. Breidenbach  M, Haagsma  K, Olson  S, Teig  D, Spears  B, McHugh  C, Air Force aerial spray operations to control adult mosquitoes following Hurricanes Katrina and Rita. Wing Beats. 2006;Summer:7–15.

Main Article

Page created: July 08, 2010
Page updated: July 08, 2010
Page reviewed: July 08, 2010
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