1st fatal case of Alaskapox may have been tied to stray cat

illustration of blocky, roughly rectangular viral particles with bumps on their surfaces
Orthopoxviruses, like those pictured here, include the viruses that cause cowpox, mpox and the rare Alaskapox. (Image credit: SERGII IAREMENKO/SCIENCE PHOTO LIBRARY via Getty Images)

A man has died in what is thought to be the first fatal case of Alaskapox, a rare infection caused by a virus in the same broad group as smallpox and mpox.

Many viruses in this group, known as orthopoxviruses, infect both animals and humans, including the camelpox, cowpox and mpox viruses. The Alaskapox virus was first discovered in 2015 in a person in Fairbanks, Alaska, but based on studies conducted in the state's Fairbanks North Star Borough, the virus is thought to primarily infect small mammals, such as red-backed voles (Myodes rutilus) and shrews.

It's suspected that humans pick up the virus from these wild animals, with their pet cats or dogs sometimes acting as intermediaries. While the exact route of transmission is not fully understood, other orthopoxviruses are known to spread through direct contact with skin lesions, so people may get Alaskapox through close contact with infected animals. Human-to-human spread of the disease has never been observed.

Related: Woman gets rare cowpox infection from her pet cat

Since the virus's discovery, five additional people in the Fairbanks area have caught Alaskapox. In these individuals, the pathogen caused a localized rash and swelling of the lymph nodes, but the illnesses resolved on their own.

However, the state's latest case is the first to take place outside the Fairbanks area, in a coastal region called the Kenai Peninsula, and it's the first known case to lead to hospitalization and death.

The patient had a weakened immune system, which likely contributed to the severity of his case, the Alaska Department of Health said in a bulletin released Feb. 9. The case "indicates that AKPV [Alaskapox virus] appears to be more geographically widespread in Alaska's small mammals than previously known and warrants increased statewide awareness among clinicians," department representatives wrote.

Officials from the Alaska Section of Epidemiology (SOE) and the University of Alaska Museum of the North are now working with the Centers for Disease Control and Prevention (CDC) to test more small mammals for the virus outside the Fairbanks region.

The Kenai Peninsula resident who caught Alaskapox lived alone in a forested area and had not traveled prior to developing symptoms in mid-September 2023. However, he was caring for a stray cat that "regularly hunted small mammals and frequently scratched the patient," according to the bulletin.

Samples later taken from the cat came back negative for orthopoxviruses and related antibodies. However, the cat had scratched the man's armpit shortly before he fell ill, and that's where his symptoms began. The man also didn't report any other contact with small mammals, so the cat isn't being ruled out as a possible source of infection, the bulletin notes.

The man's immune system was suppressed as a knock-on effect of cancer treatment, and he noticed a tender, red bump had formed in his right armpit. He visited his primary care doctor and an emergency department several times for evaluation and received various antibiotics. A biopsy of the site eventually conducted on the bump revealed no signs of cancer or bacterial infection there.

As weeks passed, the man grew more fatigued and the pain in his armpit increased and spread to his shoulder. He was hospitalized in mid-November due to presumed cellulitis — a serious bacterial infection — that was impeding the range of motion in his arm.

At the hospital, the man developed a burning pain, which can point to nerve damage. Body scans revealed extensive inflammation of the muscles in his armpit and shoulder. The site where he'd previously had tissue biopsied wasn't healing properly, and it oozed "copious" fluids and was surrounded by gray-colored tissue. "Four smaller pox-like lesions were also present in diffuse locations across his body," the bulletin noted.

The patient was tested for a long list of potential pathogens. One test came up positive for cowpox, but when the sample was sent to an Alaska State Public Health Laboratory, the scientists determined it was some other type of orthopoxvirus. The CDC finally confirmed the virus's identity as Alaskapox, and the analysis revealed that the virus's genetics looked different from those previously found in Fairbanks. That suggests these different Alaskapox viruses aren't very closely related.

The patient was then given several treatments approved for smallpox, and his symptoms began to improve over the course of a week. "However, despite intensive medical support in a long-term care setting, he later exhibited delayed wound healing, malnutrition, acute renal [kidney] failure, and respiratory failure," the bulletin said. The man died in late January 2024.

Officials are now encouraging clinicians across Alaska to familiarize themselves with Alaskapox. They can report suspected Alaskapox cases to the SOE at 907-269-8000, and SOE staff can help facilitate testing.

This article is for informational purposes only and is not meant to offer medical advice.

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Nicoletta Lanese
Channel Editor, Health

Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers' work.