Novel orthopoxvirus seemingly originated in rodents

A novel orthopox virus likely spread to two Alaska residents by rodents, causing mild illness.

Officials with the Centers for Disease Control and Prevention said both women lived near Fairbanks and both recovered from infections in 2015 and 2020 with the virus, since then known as the Alaskapox virus. The women each developed a lesion on one shoulder – one of the women suspected a spider bite – and they developed fatigue, fever, malaise, and tender lymph nodes.

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

Subsequent animal trapping and sampling showed that 30 rodents in the area had detectable antibodies to a generic orthopox virus. Samples from 12 red-backed voles and one shrew were positive for Alaska pox virus DNA and health officials were able to isolate viable viruses from one vole and one shrew.

Dr. Florence Whitehill, an official with the CDC Epidemic Intelligence Service, said during the CDC’s Zoonoses and One Health Updates webinar in June that the virus appears to be causing a self-limiting disease, and the public health experts who responded to the infections personally closed to person transfer is uncommon.

“The fact that both patients have been identified on an outpatient basis and their lesions have subsided suggests that Alaska capox does not cause serious illness,” she said. “But with only two documented cases, a lot is unknown.”