West Nile (WN) virus was found throughout New York State in 2000, with the
epicenter in New York City and surrounding counties. We tested 3,403 dead b
irds and 9,954 mosquito pools for WN virus during the transmission season.
Sixty-three avian species, representing 30 families and 14 orders, tested p
ositive for WN virus. The highest proportion of dead birds that tested posi
tive for WN virus was in American Crows in the epicenter (67% positive, n=9
07). Eight mosquito species, representing four genera, were positive for WN
virus. The minimum infection rate per 1,000 mosquitoes (MIR) was highest f
or Culex pipiens in the epicenter: 3.53 for the entire season and 7.49 for
the peak week of August 13. Staten Island had the highest MIR (11.42 for Cx
. pipiens), which was associated with the highest proportion of dead Americ
an Crows that tested positive for WN virus (92%, n=48) and the highest numb
er of human cases (n=10).