A recently emerged mosquito-borne disease, the Usutu virus, is posing a significant risk to blackbird populations in the UK. First detected in the country in 2020, the virus has rapidly expanded through southern England, raising alarms among scientists and conservationists. Data indicates that this spread corresponds with a notable decline in blackbird numbers, as concerns regarding the virus's impact on these cherished songbirds mount.
The Usutu virus originates from Africa and has been known to cause severe mortality in various bird species, particularly in blackbirds. Symptoms in affected birds may include lethargy, weakness, and loss of coordination, culminating in seizures and death. As the disease has progressed, a direct correlation between its presence and declining blackbird populations has been observed. This troubling trend has prompted institutions like the British Trust for Ornithology (BTO) to initiate special monitoring projects, encouraging the public to participate in counting and observing blackbirds in their gardens. Their initiative, dubbed the Blackbirds in Gardens project, aims to gather data on how blackbirds use urban green spaces and assess the potential effects of the Usutu virus on their numbers.
The BTO has stated that individuals with gardens and an interest in local wildlife can contribute valuable data by recognising and reporting sightings of blackbirds. This survey is part of the broader Vector-Borne RADAR initiative, collaborating with organizations such as the Animal and Plant Health Agency (APHA), the UK Health Security Agency, and the Zoological Society of London. Dr Arran Folly from the APHA highlighted the unexpected persistence and expanded range of the Usutu virus, indicating that climate change may be facilitating the rise of mosquito populations and the diseases they carry within the UK.
The recent risk assessment published by the UK government outlines a low risk of the Usutu virus to human health, with a strong emphasis on monitoring both bird and mosquito populations. They recommend enhancing public awareness around mosquito bite prevention and continuing surveillance for any human cases. Despite this low risk, the potential impact on wildlife—particularly on susceptible species—remains a pressing concern.
Climate change is increasingly recognized as a key factor in the virus's spread across Europe. Researchers point to rising temperatures and changing precipitation patterns as drivers that might allow mosquito populations, including the primary vector Culex pipiens, to flourish in previously unwelcoming environments. The Royal Horticultural Society has conveyed the need for public involvement in reducing mosquito breeding grounds, which can be achieved by eliminating standing water on private properties.
Public health advice on mosquito bite prevention highlights standard precautions such as using insect repellent and wearing long clothing. However, the focus on protecting wildlife from the Usutu virus requires a community effort, as local observation and reporting can significantly aid ongoing research and monitoring efforts during this critical time for blackbirds in the UK.
As the threat from the Usutu virus becomes clearer, it underscores the intricate connections between climate, wildlife health, and public awareness. Conserving blackbirds not only contributes to biodiversity but also enhances the natural beauty of gardens across the nation, making it a priority for both individuals and conservation organisations alike.
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Source: Noah Wire Services