Volume 10, Number 12—December 2004
Dispatch
Detecting West Nile Virus in Owls and Raptors by an Antigen-capture Assay
Ady Y. Gancz*
, Douglas G. Campbell*, Ian K. Barker*, Robbin Lindsay†, and Bruce Hunter*
, Douglas G. Campbell*, Ian K. Barker*, Robbin Lindsay†, and Bruce Hunter*Table
RT-PCR results and sensitivity of the VecTest assay in 19 species of North American owls and raptors tested for West Nile virusa
| RT-PCR |
VecTest |
|||||||
|---|---|---|---|---|---|---|---|---|
| OP swab |
Cloacal swab |
Combinedb |
||||||
| Species | N | No. positive | N | Sn (%) | N | Sn (%) | N | Sn (%) |
| Great Gray Owl (Strix nebulosa)c | 19 | 17 | 19 | 100.0 | 19 | 100.0 | 19 | 100.0 |
| Northern Hawk Owl (Surnia ulula)c | 16 | 16 | 16 | 100.0 | 15 | 93.3 | 15 | 100.0 |
| Boreal Owl (Aegolius funereus)c | 13 | 10 | 13 | 80.0 | 13 | 90.0 | 13 | 90.0 |
| Northern Saw-whet Owl (Aegolius acadicus)c | 12 | 10 | 12 | 100.0 | 12 | 100.0 | 12 | 100.0 |
| Snowy Owl (Bubo scandiacus)c | 9 | 9 | 9 | 88.9 | 9 | 77.8 | 9 | 88.9 |
| Great Horned Owl (Bubo virginianus) | 10 | 8 | 10 | 62.5 | 4 | 50.0 | 4 | 50.0 |
| Short-eared Owl (Asio flammeus) | 3 | 2 | 3 | 50.0 | 3 | 50.0 | 3 | 50.0 |
| Long-eared Owls (Asio otus) | 3 | 1 | 3 | 100.0 | 3 | 100.0 | 3 | 100.0 |
| Barred Owl (Strix varia) | 2 | 0 | 2 | – | 2 | – | 2 | – |
| Northern Pygmy-Owl (Glaucidium gnoma) | 1 | 1 | 1 | 0.0 | 1 | 0.0 | 1 | 0.0 |
| Flammulated Owl (Otus flammeolus) | 1 | 1 | 1 | 0.0 | 1 | 0.0 | 1 | 0.0 |
| Tawny Owl (Strix aluco) | 1 | 1 | 1 | 0.0 | 1 | 100 | 1 | 100 |
| Eastern Screech-Owl (Megascops asio) | 2 | 0 | 2 | – | 2 | – | 2 | – |
| Spotted Owl (Strix occidentalis) | 1 | 0 | 1 | – | 1 | – | 1 | – |
| American Kestrel (Falco sparverius) | 1 | 0 | 1 | – | 1 | – | 1 | – |
| Red-tailed Hawk (Buteo jamaicensis) | 19 | 11 | 19 | 36.4 | 0 | –- | 0 | – |
| Cooper’s Hawk (Accipiter cooperii) | 2 | 1 | 2 | 0.0 | 0 | – | 0 | – |
| Sharp-shinned Hawk (Accipiter striatus) | 4 | 1 | 4 | 100.0 | 0 | – | 0 | – |
| Osprey (Pandion haliaetus) | 1 | 0 | 1 | – | 0 | – | 0 | – |
| Total | 120 | 89 | 120 | 77.5 | 86 | 88.4 | 86 | 91.4 |
aRT-PCR, real-time reverse transcription–polymerase chain reaction; OP, oropharyngeal; N, sample size; Sn, sensitivity.
bResults of oropharyngeal and cloacal swab testing were considered in parallel (i.e., the bird was considered positive if one of the two tests was positive).
cNorthern owl species.
