Avian influenza, also known as bird flu, has been wreaking havoc on the global wildlife population, particularly seals and sea lions. The virus, which first emerged in 2020, has caused the deaths of millions of domesticated birds and has spread to wildlife across the world. While it is not considered a significant threat to humans, its rapid spread in both farming operations and wild ecosystems has led to dire economic and environmental consequences.
Scientists have discovered that seals and sea lions are especially vulnerable to the disease. Outbreaks of avian influenza have been detected in these marine mammals in various regions, from Maine in the United States to Chile in South America. In the United States alone, more than 300 seals have died in New England and a few more in Washington’s Puget Sound. The situation is even worse in South America, where over 20,000 sea lions and thousands of elephant seals have fallen victim to the virus.
The virus can be controlled in domesticated animals, but it spreads rapidly and uncontrollably in wildlife and marine mammals that have not had prior exposure to it. Marcela Uhart, director of the Latin America program at the Karen C. Drayer Wildlife Health Center, explains that once the virus enters wildlife populations, it spreads rapidly through the movement of animals to new areas.
Scientists are still unraveling the precise means by which seals contract the bird flu, but it is believed to occur through contact with infected seabirds. The virus has decimated bird populations in Peru and Chile, with hundreds of thousands of birds dying as a result. The severity of the outbreak has led to concerns about the virus spreading to more endangered species. Bird flu is suspected to have played a role in the deaths of hundreds of endangered Caspian seals in Russia.
The loss of seals and sea lions due to the bird flu outbreak has significant ramifications for ecosystems. These marine mammals play a crucial role as top predators, helping maintain balance in the ocean by preventing the overpopulation of fish species they feed on. The deaths of these animals could lead to the collapse of wildlife populations, generating an ecological crisis, as warned by the World Organisation for Animal Health.
In 2022, an outbreak of bird flu ravaged harbor and gray seals along the North Atlantic coast in New England. The virus, originally thought to be less severe, caused the deaths of over 330 seals. Scientists from Tufts University’s Cummings School of Veterinary Medicine traced the source of the outbreak to gulls, suggesting that seals may have come into contact with infected gulls’ excrement or preyed on infected birds.
Experts have raised concerns about the potential connection between these outbreaks and climate change. Warmer sea temperatures off northern Chile, for example, can reduce the population of forage fish. Consequently, sea lions become weaker and more susceptible to disease. Climate change and warming oceans may be contributing factors to the increase in bird flu outbreaks among marine mammals.
Vaccinating poultry could help mitigate the spread of the disease, according to scientists and environmental advocates. Additionally, the general public is urged to avoid contact with potentially infected wildlife. Authorities have issued warnings about the disease and strongly advised against approaching seabirds or marine mammals displaying symptoms or found dead along coastal areas.
Even seals in aquariums are not completely safe from bird flu. The New England Aquarium, for example, has implemented strict sanitation measures to prevent the transmission of the virus to its animals. These precautions include prohibiting staff from bringing backyard poultry products into the aquarium and erecting an awning to protect seals from birds that could carry the virus.
The deaths of marine mammals due to bird flu have raised concerns about mutations of the avian virus. A study published in the journal Nature Communications highlighted the need for active local surveillance to manage outbreaks and limit spillover into other species, including humans. Another study in the journal Emerging Infectious Diseases discovered nearly identical samples of the virus in dead sea lions, a dead seal, and a dead seabird, suggesting a multispecies outbreak that can affect both marine mammals and birds.
It is imperative to recognize the potential future trends related to these outbreaks and their implications for the industry. Climate change, coupled with the increasing global wildlife trade, poses a significant challenge. As animal habitats continue to be disrupted, the chances of zoonotic diseases spreading to humans also increase. The emergence of new strains, along with the potential for mutation and adaptation of existing strains, necessitates continuous monitoring and proactive measures.
With the current COVID-19 pandemic serving as a sobering reminder of the devastating impact zoonotic diseases can have on human health and global economies, it is crucial to prioritize wildlife and ecosystem conservation. Governments, international organizations, and local communities must collaborate to address the root causes of these outbreaks, including climate change, wildlife trafficking, and habitat destruction.