Health officials in Alaska have identified the first known death linked to a recently discovered virus called Alaskapox.
Since its discovery in 2015, seven Alaskapox infections have been reported, according to the state Department of Health. The most recent case was identified in an elderly man who died last month.
"This is the first case of severe Alaskapox infection resulting in hospitalisation and death," the health department said in a release last week.
The man had a weakened immune system because of cancer treatment, which probably contributed to the severity of his illness, officials noted.
Experts say that the illness is often mild and that infections remain rare in humans, as the virus is primarily found in small mammal populations throughout Alaska.
"Six of the seven cases have been mild and self-limited, so the patient didn't even need to get any supportive care from a health care provider," said Dr Joe McLaughlin, state epidemiologist and chief of the Alaska Section of Epidemiology at the Alaska Department of Health.
Still, there is a lot that isn't known about the virus, McLaughlin said, including how it spreads from animals to humans and how long it has been around.
What is Alaskapox?
Alaskapox was discovered only recently, but McLaughlin says the virus is endemic in small mammal populations in Alaska, regularly infecting red-backed voles and shrews as well as other rodents like red squirrels.
The virus belongs to the orthopoxvirus genus, which also includes better-known viruses such as smallpox and mpox that often infect mammals and cause skin lesions.
McLaughlin notes that Alaskapox is an "old world" virus, typically found in Africa, Asia and Europe.
"It's very possible that this virus has been present in Alaska for hundreds, if not thousands, of years," he said.
However, more Alaskapox cases coming to light does not mean the virus has become more prevalent in the state's small mammal population in recent years.
"What has changed is clinician awareness and the general public's awareness that Alaskapox virus is something that's a possibility," McLaughlin said. "It's possible that cases occurred prior to 2015 and were just subclinical or mildly clinical and just were not diagnosed."
A 'geographically distinct' virus
Although it's unclear how long the virus has been circulating in the state, infections follow contact with animals, according to Dr Julia Rogers, an epidemiologist with the Epidemic Intelligence Service at the US Centers for Disease Control and Prevention assigned to the Alaska Department of Health.
"These individuals have acquired it from some kind of contact with an animal," she said.
The first case of Alaskapox was discovered in July 2015 in a woman living near Fairbanks in central Alaska, according to the state health department. Since then, five additional cases have been reported in the Fairbanks area.
The most recent case - which resulted in the first known death from Alaskapox - is also the first discovered outside of Fairbanks. It was reported about 500 miles south on the Kenai Peninsula, officials say.
This indicates that Alaskapox is more geographically widespread than previously thought.
"We were able to sequence the virus from this patient's case, and it did show that there was a distinction between this case and the clusters of cases that we were able to sequence from Fairbanks," Rogers said.
However, she adds that the recent discovery is probably due to geographic distinctions in the virus and is not a result of the virus being "carried down from the Fairbanks area."
None of the seven people diagnosed with Alaskapox had recently traveled outside the state or the country, and no cases have been identified outside of Alaska, experts say.
Possible spread through domestic animals
More sampling of the affected animal populations is needed to fully understand how the virus spreads from animals to humans, Rogers says, but contact with small mammals and domestic animals that encounter them could play a role.
Health officials say the man who died lived in a heavily wooded area and cared for a stray cat that hunted small mammals.
"The stray cat would come into the house occasionally, and he would play with the cat, and it would frequently scratch him," McLaughlin said.
The Alaska Department of Health says scratches from the cat are a "possible source" of infection in this case.
"That also follows patterns of evidence for other old-world orthopoxviruses," McLaughlin added. "A traumatic event is usually introducing infection from pet to human."
Alaskapox symptoms and treatment
Apart from the latest case, all the Alaskapox patients have had mild illness that resolved on its own after a few weeks, according to the state Department of Health.
Symptoms typically include one or more skin lesions that look at first like a spider bite, McLaughlin says. Swollen lymph nodes, muscle pain and fever can also occur.
"If there's any kind of series or individual symptoms that follow that kind of case definition and you don't have any other known cause or there's no known illness that's contributing to those symptoms, then you should definitely go see your health care provider, and they can do an additional assessment and some testing," Rogers said.
People with weakened immune systems can have more severe symptoms, health officials note. The man who died from Alaskapox had slow wound healing, malnutrition, acute renal failure and respiratory failure.
Antiviral and immune-globulin treatments may be prescribed, McLaughlin says.
Experts note that although some orthopoxviruses can spread between people through direct contact with skin lesions, there is no evidence that a person with Alaskapox can spread it to someone else.
"There's no need for people outside of Alaska to be concerned," McLaughlin said. "Those within Alaska should just be aware that it is an infection that they can acquire."
CNN
