West Nile virus--an old virus learning new tricks?
West Nile virus (WNV) has spread across the United States causing annual outbreaks since its emergence in 1999. Although severe disease develops only in about 1% of infections, WNV has claimed a total of 564 lives in the 5 years from 1999 to 2003. Observation of flaccid paralysis due to WNV infection at a higher incidence than previously documented and the devastating mortality recorded in infected American bird species triggered concerns about a potentially enhanced virulence of this virus. Here we summarize recent observations made during the American outbreaks regarding host range and transmission modes of WNV, and discuss epidemiological aspects of the emergence of this pathogen in the new habitat.
Briese
Thomas
T
The Jerome L. and Dawn Greene Infectious Disease Laboratory, Mailman School of Public Health, Columbia University, New York 10032, USA.
Bernard
Kristen A
KA
D000820:Animal Diseases / Q000635:transmission / Q000821:virology; D000818:Animals; D001179:Arthropod Vectors / Q000821:virology; D001717:Birds / Q000821:virology; D004196:Disease Outbreaks; D004197:Disease Reservoirs / Q000662:veterinary / Q000821:virology; D018562:Disease Transmission, Infectious; D005260:Female; D006799:Housing, Animal; D006801:Humans; D015994:Incidence; D018445:Infectious Disease Transmission, Vertical; D008895:Milk, Human / Q000821:virology; D009026:Mortality; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000821:virology; D019737:Transplants / Q000009:adverse effects; D014481:United States; D014901:West Nile Fever / Q000453:epidemiology* / Q000635:transmission / Q000662:veterinary; D014902:West Nile virus