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First detected in Atlantic Canada in December 2021, highly pathogenic avian influenza virus (HPAIV) subtype H5N1 clade 2.3.4.4b, A/Goose/Guangdong/1/96 lineage, has caused massive mortality in wild birds and domestic poultry in North America. Swallows (Hirundinidae), abundant in North American agricultural ecosystems, have been proposed as possible (bridge) species for HPAIV transmission between wild and domestic birds. We aimed to seek evidence of the potential role of swallows in bridging AIV infection between wild bird reservoirs and poultry flocks in eastern Canada. During a wide-scale outbreak of HPAIV in wild birds and poultry farms across eastern Canada, 200 samples were collected from swallow breeding sites in the Canadian provinces of New Brunswick, Nova Scotia, Ontario, and Quebec, June-August 2022. Samples came from Barn Swallow (Hirundo rustica; n=142), Tree Swallow (Tachycineta bicolor; n=56), and Cliff Swallow (Petrochelidon pyrrhonota; n=2) nests. All samples tested negative for AIV, suggesting that HPAIV and low pathogenic AIV (LPAIV) strains were probably not circulating widely in swallows during the 2022 breeding season in eastern Canada; thus swallows may present a low risk of transmitting AIV. Within a management context, these findings suggest that removing nests of Barn Swallows, a species at risk in Canada, from the exterior of biosecure domestic poultry facilities may not significantly reduce risks of HPAI transmission to poultry., (© Wildlife Disease Association 2024.)

Perilymphatic fistula is defined as an abnormal communication between the perilymph-filled space and the middle ear, or cranial spaces. The manifestations include a broad spectrum of neuro-otological symptoms such as hearing loss, vertigo/dizziness, disequilibrium, aural fullness, tinnitus, and cognitive dysfunction. By sealing the fistula, perilymphatic fistula is a surgically correctable disease. Also, appropriate recognition and treatment of perilymphatic fistula can improve a patient's condition and hence the quality of life. However, the difficulty in making a definitive diagnosis due to the lack of an appropriate biomarker to detect perilymph leakage has caused a long-standing debate regarding its management. We have reported a clinical test for the diagnosis of perilymphatic fistula by detecting a perilymph specific protein, Cochlin-tomoprotein, as a diagnostic marker using a western blot. The aim of this study is to establish an ELISA-based human Cochlin-tomoprotein detection test and to evaluate its diagnostic accuracy in clinical subjects. The results of ELISA showed good dilution reproducibility. The mean concentration was 49.7±9.4 of 10 perilymph samples. The ROC curve in differentiating the perilymph leakage condition from the normal middle ear was significant (P < 0.001) with an area under the curve (AUC) of 0.918 (95% CI 0.824-0.100). We defined the diagnostic criteria as follows: CTP<0.4 negative; 0.4≦CTP<0.8 intermediate; 0.8≦CTP(ng/ml) positive in the clinical usage of the hCTP ELISA, and sensitivity and specificity were 86.4% and 100%, respectively. We further tested the expression specificity of the Cochlin-tomoprotein by testing blood and CSF samples. The concentration was below the detection limit (0.2 ng/ml) in 38 of the 40 blood, and 14 of the 19 CSF samples. We report the accuracy of this test for the diagnosis of perilymphatic fistula. Using ELISA, we can improve the throughput of the test. Furthermore, it is useful for a large-scale study to characterize the clinical picture and delineate the management of this medical condition.