essays
yinWest nile virus: spread, epidemiology, ecology
Geog 380, Spring 2011
Objectives
Describe the sequence of events of WNV;
Understand the epidemiology/ecology of WNV;
Analyze the spatial (geographic) spread of WNV
Fit West Nile into the “Factors of Emergence”
framework
The sequence of events (described well in Drexler)
Source: Google Earth, accessed 4/20/10
Source: Google Earth, Accessed 4/20/10
Hospital admissions and initial detection
Series of patients admitted to Flushing Hospital
AUG 12:
60 year old gentleman
History of fever, weakness, nausea x 1 wk.
Hospital course:
Confusion, proximal (near the body) muscle weakness, urinary retention, respiratory insufficiency
Intubated and put on ventilatory support
(cont)
AUG 15- 80 y/o man
1 week history of fever, headache, weakness, diarrhea
Developed flacid paralysis
Died
AUG 18-SEPT 2
4 more patients—encephalitis
2 patients--meningitis
Published in Clinical Infectious Diseases, 2000;30:413-8
“This outbreak emphasizes the important relationship veterinarians, physicians, and the public health structure should have in the surveillance of disease.” Asnis et al, in Clinical Infectious Diseases, 2000;30:413-8
Full epidemiologic investigation
Identify patients
Look for common behaviors/exposures
Map/analyze spatially
Risk factors (case-control)
New syndrome
Reactions
Spraying
Warnings to public
Risk communication
Social amplification of risk
Not newsy any more
Lots of people even think that WNV is gone!
Genome sequenced (RT-PCR)
Lipkin lab: Jia et al, Lancet 1999;354:1971-2
From Kramer et al, Annu Rev Entomol, 2008;53:61-81
West Nile Virus Incidence
Rate by Year
Source: Sugumuran et al,
Int J Health Geographics
2009
West Nile Neuro-
Invasive Incidence
Rate, 2000
Source: MMWR,
July 9, 2009
http://westnilemaps.usgs.gov/us_human.html
Source:
Source: Petersen and Hayes, Med Clin North. Am, 2008,
Migratory
Birds
Source:
Gubler, CID,
2007
Iwamoto et al., New England Journal of Medicine, 2003;348:2196-2203