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August 01, 2021

Novel orthopoxvirus likely originated in rodents

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A novel orthopoxvirus likely spread from rodents to two Alaska residents, causing mild illnesses.

Officials from the Centers for Disease Control and Prevention said both women lived near Fairbanks and both recovered following the infections in 2015 and 2020 with what has since been named Alaskapox virus. The women each developed a lesion on one shoulder—one of the women suspected she had a spider bite—and they developed fatigue, fever, malaise, and tender lymph nodes.

A northern red-backed vole (Courtesy of Christian F. Schwarz)

Subsequent animal trapping and sampling showed 30 rodents in the area had detectable antibodies against a generic orthopoxvirus. Samples from 12 red-backed voles and one shrew were positive for DNA of the Alaskapox virus, and health authorities were able to isolate viable virus from one vole and one shrew.

Dr. Florence Whitehill, an officer in the CDC Epidemic Intelligence Service, said during the CDC’s Zoonoses and One Health Updates webinar in June that the virus seems to cause self-limiting illness and the public health experts who responded to the infections concluded person-to-person transmission is uncommon.

“The fact that both patients were identified in an outpatient setting and that their lesions resolved suggests that Alaskapox does not cause severe illness,” she said. “But, with just two documented cases, much is unknown.”