When sea otters in Alaska were diagnosed with the docmper phocine virus (PDV) in 2004, scientists were confused. The pathogen in the. T Morbillivirus The genus containing viruses was found only in Europe and on the east coast of North America.
“We didn't understand how a virus came from the Atlantic into these sea otters. It is not a widespread species, ”says Tracey Goldstein, a scientist at the University of California Davis who investigates how pathogens transform through marine ecosystems.
Using 15 years of data from 2001 to 2016, Goldstein and her research team were able to see upticks in PDV corresponding to reductions in Arctic sea ice. This new range for the otters probably allowed infected animals to move backwards, into new territories before which the virus did not appear before. Results of the study, published today in the journal Science Reports, it shows how climate change could open new ways to spread diseases.
From Europe to North America
Phocine's distemper virus was first detected in 1988 in northern Europe, where it received about 18,000 dead seals, most of which were harboring seals. A similar outbreak occurred in 2002. It is unclear where PDV came from. According to some research, it emerged in the Arctic, but distemper varieties are found in many animals. Local vets routinely vaccinate pet dogs against the canine version.
And in seals, together with dogs, the symptoms of the virus include breathing difficulties, loose from the nose and eyes, fever, and in marine mammals, irregular swimming.
It extends by direct contact or if an animal comes into direct contact with an infection.
“It has been shown that the virus is easily spread between marine mammals,” says Shawn Johnson, vice president of veterinary medicine at the Marine Marine Center in Sausalito, California.
The first major outbreak of PDV occurred along the East Coast of the United States in 2006. In the past year, the National Oceanic and Atmospheric Administration has been logging what they report as high numbers of dead seals from Maine to Virginia. The test results indicate that PDV is the main offender.
When and where PDV from northern Europe spread to the north Pacific just off the coast of Alaska, Goldstein and her team searched for records and records of biological samples taken from 2,530 live and 165 dead seals of species that consume part of it. at least on Arctic ice. They then looked at data depicting the arrival of sea ice at a particular time of the year, called the size of the Arctic ice. In the years when sea ice was low, the following years showed an increase in PDV.
2016 was the last year since the data study was adopted. Over the past three years Arctic sea ice has continued to decline.
New pathways for infection
Sea ice opens new routes of migration for marine mammals, allowing them to easily cross the Atlantic through the Arctic Circle. Goldstein says that the added stress of forage longer for food systems can weaken the immune system, making them easier for diseases.
“They are no longer traveling looking for food. This will have an impact on overall health, and become more susceptible to disease, ”she says.
As so many marine species migrate annually in the Arctic, it may act as a location to multiply and spread the disease.
“The Arctic could be a perfect melting pot to transmit the disease,” says Johnson.
The disease was not yet found in California, but Johnson says that he and other scientists are still on the alert. The virus may spread south, he says. Many marine species migrate in California in the north and interact with animals in more northerly regions where the disease is documented.
Some marine mammals can be vaccinated against PDV, but it is difficult to do so on a large scale to prevent the spread of the disease. Hawaiian monk seals are regularly vaccinated against PDV. Only about 1,400 people stay in this species, and while the disease is moving to the south, it is the potential impact on guardians.
Goldstein says that there is still a great deal of uncertainty about the disease and how it will evolve as the Arctic climate continues to decline.
In addition to PDV, Johnson says that they are monitoring other diseases that are increasing as a result of climate change. Leptospirosis, a bacterium that can be spread from animals to humans, is growing, as well as algal blooms, by fish infection with toxin that creates brain damage in marine mammals.
“We need to be vigilant and watch out,” says Johnson. “There may be major changes in the circulating diseases.” T
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