Serosurveillance for Japanese encephalitis virus in wild birds captured in Korea

Climate change induced by recent global warming may have a significant impact on vector-borne and zoonotic diseases. For example, the distribution of Japanese encephalitis virus (JEV) has expanded into new regions. We surveyed the levels of hemagglutination-inhibition (HI) antibodies against JEV (Family Flaviviridae, genus Flavivirus) in wild birds captured in Korea. Blood samples were collected from 1,316 wild birds including the following migratory birds: Oceanodroma castro (n = 4), Anas formosa (n = 7), Anas penelope (n = 20), Fulica atra (n = 30), Anas acuta (n = 89), Anas crecca (n = 154), Anas platyrhynchos (n = 214), Aix galericulata (n = 310), and Anas poecilorhyncha (n = 488). All were captured in 16 locations in several Korea provinces between April 2007 and December 2009. Out of the 1,316 serum samples tested, 1,141 (86.7%) were positive for JEV. Wild birds captured in 2009 had a higher seroprevalence of ant-JEV antibodies than those captured in 2007. Wild birds with an HI antibody titer of 1 : 1,280 or higher accounted for 21.2% (280/1,316) of the animals tested. These findings indicated that wild birds from the region examined in our study have been exposed to JEV and may pose a high risk for introducing a new JEV genotype into Korea

Spring migration of mallards (Anas platyrhynchos) tracked with wild-trackers in East Asia

Mallard is a dominant waterfowl species wintered in Korea. We researched the mallard spring migration route, stopover sites, and breeding sites. We used cannon nets in Central Korea to catch and attach 10 wild trackers (WT-200). The mallards’ spring departure dates were from the end of March to early April. The spring migration route varied by individual mallards, with most moving through the North Korean east coast. Breeding sites were distributed among the interior of Northeastern China. The average distance to the breeding areas was 1,265 km [standard deviation (SD)=491 km] and the average days spent from wintering site to breeding site was 25.3 days (SD=19.2 days). The mallards used several stopover sites when on the spring migration route (average 3.3±2.1, range 2–9). The time spent at the stopover sites was a minimum of 1 day to a maximum of 16 days. Wintering mallards in Korea showed various individual trends regarding spring migration timing, migration route, stopover sites, and usage days

Stochastic simulations reveal few green wave surfing populations among spring migrating herbivorous waterfowl

Tracking seasonally changing resources is regarded as a widespread proximate mechanism underpinning animal migration. Migrating herbivores, for example, are hypothesized to track seasonal foliage dynamics over large spatial scales. Previous investigations of this green wave hypothesis involved few species and limited geographical extent, and used conventional correlation that cannot disentangle alternative correlated effects. Here, we introduce stochastic simulations to test this hypothesis using 222 individual spring migration episodes of 14 populations of ten species of geese, swans and dabbling ducks throughout Europe, East Asia, and North America. We find that the green wave cannot be considered a ubiquitous driver of herbivorous waterfowl spring migration, as it explains observed migration patterns of only a few grazing populations in specific regions. We suggest that ecological barriers and particularly human disturbance likely constrain the capacity of herbivorous waterfowl to track the green wave in some regions, highlighting key challenges in conserving migratory birds.publishe

Home range differences by habitat type of raccoon dogs Nyctereutes procyonoides (Carnivora: Canidae)

From July 2013 to November 2014, this research was conducted to secure baseline data to find long-term preventive measures against epidemics from the analysis of home range and movement characteristics of raccoon dogs, which are known as carriers of zoonosis. Researchers conducted a follow-up study with 12 raccoon dogs, each attached with a Global Positioning System mobile transmitter. Analysis of home range used the minimum convex polygon (MCP) method and kernel density estimation (KDE) with accumulating data of time-based locations. Except for three animals that showed unique behavior, the researchers analyzed nine animals and calculated their average home range. As a result, average home range was 0.48±0.35 km2 (MCP method), and KDE result analysis was verified as 0.65±0.66 km2 (95%), 0.31±0.35 km2 (75%), and 0.23±0.28 km2 (50%). Based on the MCP method, acted in range of minimum 0.07 km2 and maximum 1.08 km2, and the core habitat, KDE 50% level showed activity range in 0.02 km2 to 0.37 km2. Three individuals of unique behavior were classified into two types. Two individuals moved 10–20 km and settled at a place different from the existing habitat, and one individual kept moving without a regular sphere of influence. Generally, raccoon dogs are not considered to move if they secure their area of influence; animals in urban areas have a wider area of influence than those living in areas with a rich source of food such as forest and agricultural land

Novel Reassortant Influenza A(H5N8) Viruses among Inoculated Domestic and Wild Ducks, South Korea, 2014

An outbreak of highly pathogenic avian influenza, caused by a novel reassortant influenza A (H5N8) virus, occurred among poultry and wild birds in South Korea in 2014. The aim of this study was to evaluate the pathogenesis in and mode of transmission of this virus among domestic and wild ducks. Three of the viruses had similar pathogenicity among infected domestic ducks: the H5N8 viruses were moderately pathogenic (0%–20% mortality rate); in wild mallard ducks, the H5N8 and H5N1 viruses did not cause severe illness or death; viral replication and shedding were greater in H5N8-infected mallards than in H5N1-infected mallards. Identification of H5N8 viruses in birds exposed to infected domestic ducks and mallards indicated that the viruses could spread by contact. We propose active surveillance to support prevention of the spread of this virus among wild birds and poultry, especially domestic ducks

Stochastic simulations reveal few green wave surfing populations among spring migrating herbivorous waterfowl

Tracking seasonally changing resources is regarded as a widespread proximate mechanism underpinning animal migration. Migrating herbivores, for example, are hypothesized to track seasonal foliage dynamics over large spatial scales. Previous investigations of this green wave hypothesis involved few species and limited geographical extent, and used conventional correlation that cannot disentangle alternative correlated effects. Here, we introduce stochastic simulations to test this hypothesis using 222 individual spring migration episodes of 14 populations of ten species of geese, swans and dabbling ducks throughout Europe, East Asia, and North America. We find that the green wave cannot be considered a ubiquitous driver of herbivorous waterfowl spring migration, as it explains observed migration patterns of only\ua0a few grazing populations in specific regions. We suggest that ecological barriers and particularly human disturbance likely constrain the capacity of herbivorous waterfowl to track the green wave in some regions, highlighting key challenges in conserving migratory birds

Two distinct flyways with different population trends of Bewick's Swan Cygnus columbianus bewickii in East Asia

Two of the most fundamental ecological questions about any species relate to where they occur and in what abundance. Here, we combine GPS telemetry data, survey data and expert knowledge for the first time to define two distinct flyways (the East Asian Continental and West Pacific flyways), migration routes and abundance for the Eastern population of Bewick’s Swan Cygnus columbianus bewickii. The Eastern population is the largest flyway population, supporting c. 77% of Bewick’s Swan numbers globally. GPS telemetry data showed that birds breeding in the Russian arctic from the Yamal Peninsula to c. 140°E (including the Lena and Yana Deltas), winter in the middle and lower reaches of the Yangtze River in China (which we label the “East Asian Continental flyway”). Bewick’s Swans breeding from the Indigirka River east to the Koluchin Bay winter in Japan, mostly in Niigata, Yamagata and Ishikawa Prefectures (the “West Pacific flyway”). There was no overlap in migration routes used by tagged individuals from the two flyways. Counts of Bewick’s Swans in the East Asian Continental flyway during the 21st century have shown wide between-year variations, reflecting incomplete coverage in earlier years. Bewick’s Swans in this flyway currently numbers c. 65,000 birds based on extensive wintering survey coverage, compared to c. 81,000 in the early 2000s, based on less complete coverage. Chinese-wintering swans now concentrate mainly (c. 80%) at Poyang Lake in Jiangxi Province and Hubei Lakes (mostly in Longgan Lake), compared to a more widespread distribution both within Poyang and throughout the Auhui Lakes in 2004 and 2005. In contrast, Bewick’s Swans of the West Pacific flyway now numbers c. 40,000, compared to just 542 in 1970. This population has shown no significant overall change since 2004, when it numbered c. 45,000 birds. Small numbers within this population probably also winter in South Korea. These results provide our first basic understanding of the winter distribution of Chinese- and Japanese-wintering Bewick’s Swans in relation to their breeding areas, confirming the need to coordinate future research and monitoring in the two flyways, as well as the need for more information on swans wintering in South Korea