Volume 9, Number 3—March 2003
Research
Experimental Infection of North American Birds with the New York 1999 Strain of West Nile Virus
Table 4
Illness observed in eight species of birds exposed to West Nile virus (WNV) by mosquito bitea
Species | No. exposed | No. unexposedb | No. fatal infections (% exposed) | Days postinoculation that death occurred | Mean no. days to death (range) |
---|---|---|---|---|---|
Ring-billed gull |
2 |
0 |
2 (100) |
5, 13c |
9.0 (5–13) |
Blue Jay |
4 |
0 |
3 (75) |
4, 5, 5 |
4.7 (4–5) |
Black-billed Magpie |
3 |
0 |
3 (100) |
6, 6, 6 |
6.0 (6–6) |
American Crow |
8 |
8 |
8 (100) |
4, 4, 5, 5, 5, 6, 6, 6 |
5.1 (4–6) |
Fish Crow |
9 |
0 |
5 (55) |
6, 9, 10, 10,c 13 |
9.6 (6–13) |
Common Grackle |
6 |
6 |
2 (33) |
4, 5 |
4.5 (4–5) |
House Finch |
2 |
3 |
2 (100) |
6, 8 |
7.0 (6–8) |
House Sparrow | 6 | 5 | 3 (50) | 3, 5, 6 | 4.7 (3–6) |
aPreliminary mortality rates were highest in the Passerines, especially the corvids. No signs of clinical illness were observed among species of the following orders: Anseriformes, Ciconiiformes, Galliformes, Gruiformes, Columbiformes, Psittaciformes, Strigiformes, and Piciformes. No obvious differences in mortality rates were observed among birds exposed to WNV by means other than mosquito bite (orally exposed and contact-exposed groups; data not shown).
bUnexposed controls were blood sampled daily for the same period as the exposed birds, with no resulting illness.
cEuthanized.