Volume 19, Number 6—June 2013
Letter
Flaviviruses in Game Birds, Southern Spain, 2011–2012
Table
Results of serologic studies in red-legged partridges and common pheasants, southern Spain, 2011–2012*
| Species, no. | Age | ELISA, WNV | VNT titers† |
Interpretation‡ | ||
|---|---|---|---|---|---|---|
| WNV | BAGV | USUV | ||||
| Partridges (Alectoris rufa), n = 159 | ||||||
| 6 | Juvenile | + | 10–20 | <5 | <5 | WNV |
| 7 | Adult | + | 10–20 | <5 | <5 | WNV |
| 1 | Adult | + | 160 | 20 | 20 | WNV |
| 4 | Not determined | + | 10–80 | <5 | <5 | WNV |
| 1 | Not determined | + | 80 | <5 | 10 | WNV |
| 2 | Juvenile | + | 10 | 40 | <5 | BAGV |
| 1 | Juvenile | + | 20 | 80 | 10 | BAGV |
| 1 | Juvenile | – | <5 | 160 | 10 | BAGV |
| 2 | Adult | + | 20, 40 | 80, 320 | 10 | BAGV |
| 1 | Adult | + | <5 | 20 | <5 | BAGV |
| 1 | Adult | + | <10‡ | 40 | <10‡ | BAGV |
| 1 | Adult | – | <5 | 40 | <5 | BAGV |
| 1 | Adult | + | <5 | <5 | 40 | USUV |
| 2 | Juvenile | + | 10, 20 | 20, 40 | <5 | Flavivirus |
| 3 | Adult | + | <5 | <5 | <5 | Flavivirus |
| 2 | Adult | + | 20, 80 | 80, 160 | 40 | Flavivirus |
| 1 | Adult | + | 20 | <5 | 10 | Flavivirus |
| 1 | Adult | + | 160 | <20‡ | 80 | Flavivirus |
| 1 | Adult | + | 40 | 40 | <10‡ | Flavivirus |
| 1 | Adult | – | <10‡ | 20 | <10‡ | Flavivirus |
| 3 | Not determined | + | <5 | <5 | <5 | Flavivirus |
| 1 |
Not determined |
+ |
<5 |
10 |
<5 |
Flavivirus |
| Pheasants (Phasianus colchicus), n = 13 | ||||||
| 1 | Adult | + | 80 | 20 | 10 | WNV |
| 2 | Not determined | + | 10, 20 | <5 | <5 | WNV |
| 2 | Adult | + | 10, 80 | 80, 640 | 20 | BAGV |
| 1 | Adult | – | <5 | 20 | <5 | BAGV |
| 3 | Adult | + | 20–40 | 20–160 | 40–160 | Flavivirus |
| 1 | Adult | + | 10 | <5 | <5 | Flavivirus |
| 1 | Adult | – | <5 | 10 | <5 | Flavivirus |
| 1 |
Adult |
Not determined |
<20‡ |
<20‡ |
40 |
Flavivirus |
| Positive, no. (%) | ||||||
| Partridges | 40 (25) | 31 (19) | 17 (11) | 11 (7) | ||
| Pheasants | 9 (69) | 9 (69) | 8 (62) | 7 (54) | ||
| Total | 49 (28) | 40 (23) | 25 (15) | 18 (10) | ||
*WNV, West Nile virus; VNT, virus neutralization test; BAGV, Bagaza virus; USUV, Usutu virus; +, positive; –, negative. Boldface indicates VNT-positive serum.
†Serum samples were titrated from 5 to 1,280 dilutions and neutralization titers of >10 were considered positive.
‡Differentiation was based on comparison of VNT titers obtained in parallel against the 3 flaviviruses: the neutralizing immune response observed was considered specific when VNT titer for a given virus was >4-fold higher than titers obtained for the other viruses; samples showing VNT titer differences <4-fold between the viruses examined were considered positive for flavivirus but not conclusive for any specific virus.
‡VNT at the indicated (or lower) dilution(s) could not be determined because of cytotoxic effect caused by the sample.