A retrospective evaluation reveals that H5 avian flu surfaced in Oregon wastewater weeks earlier than the state’s first outbreak in poultry and wild birds and a pair of years earlier than the primary outbreak in US cattle.
A group led by Oregon State College researchers evaluated 551 influenza A virus–constructive wastewater samples from 20 websites from September 2021 to July 2024.
In January 2022, H5N1 clade 2.3.4.4b virus was first recognized in wild birds in america. In Oregon, the clade was first detected in wild birds and poultry in Might 2022.
“Interpretation of avian influenza A(H5) subtype detections in wastewater requires an understanding of human and animal contributors to the sewershed as a result of present testing doesn’t distinguish between human and animal sources,” the authors wrote. “Potential animal contributors embody wild birds, farms with poultry or dairy cattle outbreaks, and dairy processing amenities.”
The outcomes have been printed in Morbidity and Mortality Weekly Report.
Wild birds the possible offender
Of the 551 influenza A–constructive samples, 21 (3.8%) examined constructive for H5 in 12 communities 6 weeks earlier than Oregon’s first outbreak in home poultry, 7 weeks earlier than the primary detection in wild birds, and a pair of years earlier than the primary outbreak in US dairy cattle (the virus hasn’t been present in cattle or milk in Oregon).
Wastewater surveillance, with consideration of all animal contributors and together with different surveillance metrics, has the potential to strengthen ongoing avian influenza surveillance efforts.
“No affiliation was discovered between detection of avian influenza A(H5) in a neighborhood’s wastewater and historical past of an HPAI A(H5) outbreak amongst poultry within the county or presence of dairy processing amenities or dairy farms inside the sewershed,” the researchers wrote.
Avian flu was discovered most frequently in two communities with necessary wild hen habitats, which the authors mentioned implicates wild birds as a big contributor to wastewater H5 contamination.
“Oregon is positioned alongside the Pacific Flyway, a significant north-south route for migratory birds within the Americas that extends from Alaska to Patagonia,” the authors wrote. “Wastewater surveillance, with consideration of all animal contributors and together with different surveillance metrics, has the potential to strengthen ongoing avian influenza surveillance efforts.”
