Environmental Surveillance and Detection of Infectious Highly Pathogenic Avian Influenza Virus in Iowa Wetlands

Avian influenza viruses
(AIVs) infect both wild birds
and domestic
poultry, resulting in economically costly outbreaks that have the
potential to impact public health. Currently, a knowledge gap exists
regarding the detection of infectious AIVs in the aquatic environment.
In response to the 2021–2022 Eurasian strain highly pathogenic
avian influenza (HPAI) A/goose/Guangdong/1/1996 clade 2.3.4.4 lineage
H5 outbreak, an AIV environmental outbreak response study was conducted
using a One Health approach. An optimized method was used to temporally
sample (April and May 2022) and analyze (culture and molecular methods)
surface water from five water bodies (four wetlands and one lake used
as a comparison location) in areas near confirmed HPAI detections
in wild bird or poultry operations. Avian influenza viruses were isolated
from water samples collected in April from all four wetlands (not
from the comparison lake sample); HPAI H5N1 was isolated from one
wetland. No virus was isolated from the May samples. Several factors,
including increased water temperatures, precipitation, biotic and
abiotic factors, and absence of AIV-contaminated fecal material due
to fewer waterfowl present, may have contributed to the lack of virus
isolation from May samples. Results demonstrate surface water as a
plausible medium for transmission of AIVs, including the HPAI virus.