Polar bears now face a higher risk of contracting pathogens than 30 years ago. A new study led by Karyn Rode and Caroline Van Hemert of the U.S. Geological Survey reveals these findings.
The warming of the Arctic is changing how viruses, bacteria, and parasites spread. Polar bears, being top predators, are at greater risk. They cover large areas and encounter various environments, increasing their exposure.
The study analyzed blood samples from polar bears in the Chukchi Sea. The samples were taken during two periods: 1987-1994 and 2008-2017. Researchers looked for antibodies to six pathogens.
Results showed that five pathogens had become more common over time. These included parasites that cause toxoplasmosis and neosporosis. They also found increases in bacteria that cause rabbit fever and brucellosis. The presence of the canine distemper virus also grew. This marked one of the most rapid increases in pathogen exposure ever reported in these animals.
PATHOGEN RISK AND DIET IMPACT POLAR BEARS’ HEALTH
The study also explored the factors that increased polar bears’ risk of exposure. Diet played a significant role. Researchers found that females had a higher risk than males. This could be because pregnant females den on land to raise cubs, increasing their exposure to pathogens.
WARMING ARCTIC POSES NEW THREATS TO POLAR BEARS
The Arctic is warming almost four times faster than the global average. Polar bears are losing their sea ice habitat at an alarming rate. This environmental shift is creating new opportunities for pathogens to spread. In turn, it poses a growing concern for both wildlife managers and Arctic communities.
PATHOGENS POSE A THREAT TO BOTH POLAR BEARS AND HUMANS
The pathogens found in polar bears are not just a threat to them. Some can be transmitted to humans. Arctic communities that hunt these animals for subsistence food face added risks. The researchers urge further investigation to screen polar bear populations for signs of disease.
The study’s authors note that polar bears’ exposure to pathogens has significantly increased. “For some pathogens, the count of polar bears positive for serum antibodies has more than doubled. This indicates pathogen exposure,” they said. The results suggest that the ways pathogens are transmitted in the Arctic have changed.
ROLE OF CLIMATE CHANGE IN POLAR BEARS’ PATHOGEN EXPOSURE
Climate change is having a profound impact on the Arctic ecosystem. Rising temperatures are altering the distribution of pathogens. These changes are affecting the wildlife that lives there, including polar bears.
Researchers believe that as sea ice melts, polar bears may spend more time on land. This exposes them to new pathogens carried by other animals. Warmer temperatures also allow parasites and bacteria to thrive in environments where they were once rare.
TOXOPLASMOSIS AND NEOSPOROSIS: PARASITES ON THE RISE
Two of the most worrying pathogens in the study are toxoplasmosis and neosporosis. Both are caused by parasites. Toxoplasmosis is a well-known parasite that can infect many animals, including humans. Neosporosis primarily affects animals but poses a serious risk to wildlife.
The study found that these parasites had become more prevalent in these animals over the last three decades. This is likely due to changes in the bears’ environment and diet as their sea ice habitat disappears.
BACTERIAL INFECTIONS BECOMING MORE COMMON
Bacterial infections are also on the rise in polar bears. The study found an increase in exposure to the bacteria that cause rabbit fever and brucellosis. Rabbit fever, also known as tularemia, is a highly infectious disease. It can spread from animals to humans through contaminated water, food, or direct contact with infected animals.
Brucellosis is another bacterial disease that primarily affects animals. But, it can also be transmitted to humans. It causes severe flu-like symptoms and can lead to long-term health problems if left untreated.
CANINE DISTEMPER VIRUS SPREADING
The canine distemper virus is typically linked to domestic dogs. Nevertheless, the virus can infect a wide range of carnivores, including polar bears. The study found that polar bears had become more exposed to this virus over time.
Canine distemper weakens the immune system, making animals more susceptible to other infections. In some cases, it can be fatal. The spread of this virus among polar bears is another worrying sign of how global warming is impacting Arctic wildlife.
WHAT’S NEXT? THE FUTURE HEALTH
Polar bears face multiple stressors related to climate change. The rapid loss of sea ice is affecting their ability to hunt and survive. At the same time, they are becoming more exposed to pathogens.
The researchers call for more work to be done to monitor their health. Regular screening for pathogens is essential to understanding the full impact of climate change on these animals. It is also critical for the health of Arctic communities that rely on these animals for food.
POLAR BEARS AND SUBSISTENCE HUNTING: A RISK TO HUMAN HEALTH
Polar bears are a vital source of food for many Arctic communities. Yet, the pathogens found in polar bears pose a potential risk to humans. Some of the diseases identified in the study, like brucellosis and toxoplasmosis, can be transmitted to people.
these animals are becoming more exposed to these pathogens. This increases the likelihood of humans contracting these diseases through hunting and consumption. This is an important public health concern for people living in the Arctic.
CLIMATE CHANGE A THREAT The findings of this study highlight the interconnectedness of wildlife health and human health. As the Arctic continues to warm, the risk of disease transmission between animals and humans is likely to increase.
Communities in the Arctic must adapt to these changing conditions. This includes taking measures to protect both wildlife and human health. Public health initiatives that screen for zoonotic diseases (those that can spread between animals and humans) will become increasingly important.