Highly pathogenic avian influenza (HPAI) outbreaks
engender a severe economic impact on the poultry
industry and public health. Migratory waterfowl are
considered the natural hosts of HPAI virus, and HPAI
viruses are known to be transmitted over long distances
during seasonal bird migration. Bird migration is greatly
affected by the weather. Many studies have shown
the relationship between either autumn or spring bird
migration and climate. However, few studies have shown
the relationship between annual bird migration and annual
weather. This study aimed to establish a model for the
number of migratory waterfowl involved in HPAI virus
transmission based on meteorological data. From 136
species of waterfowl that were observed at Futatsudate
in Miyazaki, Japan, from 2008 to 2016, we selected
potential high-risk species that could introduce the HPAI
virus into Miyazaki and defined them as ‘risky birds’. We
also performed cluster analysis to select meteorological
factors. We then analysed the meteorological data and
the total number of risky birds using a generalised linear
mixed model. We selected 10 species as risky birds:
Mallard (Anas platyrhynchos), Northern pintail (Anas
acuta), Eurasian wigeon (Anas penelope), Eurasian teal
(Anas crecca), Common pochard (Aythya ferina), Eurasian
coot (Fulica atra), Northern shoveler (Anas clypeata),
Common shelduck (Tadorna tadorna), Tufted duck
(Aythya fuligula) and Herring gull (Larus argentatus). We
succeeded in clustering 35 meteorological factors into
four clusters and identified three meteorological factors
associated with their migration: (1) the average daily
maximum temperature; (2) the mean value of global solar
radiation and (3) the maximum daily precipitation. We
thus demonstrated the relationship between the number
of risky birds and meteorological data. The dynamics of
migratory waterfowl was relevant to the risk of an HPAI
outbreak, and our data could contribute to cost and time
savings in strengthening preventive measures against
epidemics. |
