Table 2. Demographic data and results of immunohistochemistry and molecular testing performed in seals infected by HPAI A(H5N1) during the 2022 outbreak in the St. Lawrence Estuary, Quebec, Canada*.
| Case no. | Date found |
Species† | Age group/sex | AIV IHC | Initial PCR at MAPAQ |
Confirmatory PCR at NCFAD |
Sample type‡ | Lineage | IAV histologic lesions | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Matrix | H5 | Matrix | H5 | |||||||||
| 217719 | May 30 | Harbor seal | Adult/F | + | + | + | + | + | Swab | EU/NA | Yes | |
| 216969 | June 7 | Harbor seal | <1 y | + | + | + | + | + | Swab | EU | Yes | |
| 216970 | June 7 | Harbor seal | Adult/F | + | + | + | + | + | Swab | EU | Yes | |
| 216971 | June 8 | Harbor seal | Adult/F | - | +/− | + | + | + | Swab | EU | Yes | |
| 216947 | June 10 | Harbor seal | Adult/F | + | + | + | + | + | Brain | EU/NA | Yes | |
| 216983 | June 11 | Harbor seal | Adult/F | NP | + | + | + | + | Swab | EU/NA | NP§ | |
| 216985 | June 13 | Harbor seal | <1 y/F | NP | + | + | + | + | Swab | NP | NP§ | |
| 216972 | June 14 | Harbor seal | <1 y/F | + | + | + | + | + | Swab | EU | Yes | |
| 217671 | June 14 | Harbor seal | Adult/F | + | + | + | + | + | Swab | EU | Yes | |
| 216987 | June 19 | Harbor seal | Adult/F | NP | + | + | + | + | Swab | EU/NA | NP§ | |
| 216988 | June 20 | Harbor seal | <1 y/F | + | + | + | + | + | Swab | EU/NA | Yes | |
| 216989 | June 20 | Harbor seal | Adult/F | NP | + | + | + | + | Swab | NP | NP§ | |
| 217670 | June 20 | Harbor seal | <1 y/F | + | + | + | + | + | Swab | EU/NA | Yes | |
| 216973 | June 22 | Harbor seal | Adult/F | NP | + | +/− | + | + | Brain | NP | Yes | |
| 216974 | June 22 | Harbor seal | <1 y/F | + | +/− | + | + | + | Brain | EU/NA | Yes | |
| 217794 | June 24 | Gray seal | Adult/F | + | + | + | + | + | Swab | EU/NA | Yes | |
| 217642 | June 26 | Harbor seal | <1 y/F | + | + | + | + | + | Swab | EU/NA | Yes | |
| 217665 | June 26 | Harbor seal | <1 y/F | + | +/− | + | + | + | Swab | EU/NA | Yes | |
| 217667 | June 26 | Harbor seal | <1 y/F | NP | + | + | + | - | Lung | NP | Yes | |
| 217611 | July 7 | Harbor seal | <1 y/F | NP | + | + | + | + | Swab | EU/NA | NP§ | |
| 217612 | July 8 | Harbor seal | <1 y/ND | NP | +/− | +/− | + | + | Swab | NP | NP§ | |
*EU, fully Eurasian lineage; EU/NA, reassortment between Eurasian and North American lineages; HPAI, highly pathogenic avian influenza; IAV, influenza virus; IHC, immunohistochemistry; MAPAQ, Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec; NCFAD, National Center for Foreign Animal Disease; ND, not determined; NP, not performed. –, negative; +, positive; +/−, suspicious. †Harbor seal, Phoca vitulina; gray seal, Halichoerus grypus. ‡Swab indicates combined nasal and rectal swab samples. Frozen lung or brain were submitted when swab testing results were negative. §Cases for which only swabs collected in the fields were available; no necropsy performed.