Alaska: Two human infections (2015 and 2020) with novel poxvirus named "Alaskapox"
Obviously, this is a bad name for a novel virus, but seeing as we don't know any more about it other than that it is a poxvirus and both confirmed cases were in Alaska....
Published Date: 2020-10-04 10:48:05
Subject: PRO/AH/EDR> Alaskapox: USA (AK) orthopoxvirus new species, 2nd rep.
Archive Number: 20201004.7833951
ALASKAPOX: USA (ALASKA) ORTHOPOXVIRUS NEW SPECIES, SECOND REPORT
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International Society for Infectious Diseases
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Date: Fri 2 Oct 2020
Source: Anchorage Daily News [edited]
https://www.adn.com/alaska-news/2020...-of-alaskapox/
In August [2020], a Fairbanks resident visited her doctor's office with a mysterious gray lesion on her left upper arm, along with shoulder pain, fatigue, and a fever.
According to a report issued by the state Wednesday [30 Sep 2020], this woman was later diagnosed with the 2nd-ever known case of a new species of a double-stranded DNA virus called "Alaskapox," which comes from the same genus as smallpox.
While very little is known about Alaskapox at this point, it is encouraging to see that the only 2 known cases were relatively mild, meaning they did not involve hospitalizations or aggressive medical treatment, according to Eric Mooring. Mooring is a lieutenant in the US Public Health Service Commissioned Corps who works for the federal Centers for Disease Control and Prevention as a disease detective in Alaska, and is the lead epidemiology investigator on this case.
Evidence of human-to-human transmission is nonexistent, which is also a good sign, Mooring said.
The discovery of a new viral disease in humans is relatively rare: Alaskapox is only the 3rd orthopoxvirus that has been discovered in the last decade, Mooring said. He doesn't think the discovery is a cause for alarm, just caution.
"People should be aware but not scared by this," he said.
The 1st and only other case of Alaskapox was identified in 2015, when a different Fairbanks-area resident developed a similar lesion on her right shoulder that was surrounded by a rash and accompanied by fatigue and fever. Her doctor at the time suspected a viral infection, and the lesion went away after 6 months.
How exactly Alaskapox was contracted by either patient, whether the infection poses a real health risk, and where it originated remain a bit of a mystery. No link has been identified between the 2 cases, which occurred 5 years apart.
"There's a lot of uncertainty about how this happened," Mooring said. "Our leading hypothesis is that animals have some role to play, but it's still in the realm of hypothesis because we don't have direct evidence, which is what we're working on right now."
There are other clues that inform that hypothesis.
"Both cases occurred during mid- to late summer in residents of forested areas near Fairbanks," the report said. "While the similar time of year may be purely coincidental, it may also reflect the fact that small mammal populations are likely at or near their peak population size in late summer and that humans in Interior Alaska spend more time outdoors during the summer than other times of year."
Although the infected patient in the earlier case from 2015 apparently had contact with "small mammals and their droppings," no evidence of the infection was found in samples from a "taxonomically narrow sample" of 12 small mammals trapped on her property.
Still, Mooring encouraged Alaskans to not handle wild animals, to avoid areas with animal droppings, and to wash their hands regularly.
In the most recent case, the patient had visited southcentral Alaska about 3 weeks before the lesion appeared. She reported that none of her family members or co-workers had recently traveled outside the country, and the only other person she lived with at the time reported no recent history of any illnesses or skin lesions.
Her 2 cats reportedly captured and killed small mammals, but she said she'd never touched any of them. She'd also gone raspberry picking within 2 weeks of developing symptoms, but she said she hadn't interacted with any small mammals during that trip. And as far as she was aware, no one she'd been in contact with had reported similar symptoms to hers, she told Mooring and others investigating the epidemiology of the cases.
Her shoulder pain lasted about 2 weeks, and her lesion had healed a month later.
Mooring said it is "definitely possible" that there's more than just 2 cases of Alaskapox out there. But it is impossible to know for sure because the symptoms of Alaskapox could easily be confused with other viruses, and many people with mild symptoms are not likely to seek medical care.
"It's also definitely possible that this virus has been around for a long, long time and is only just now being discovered," he said.
[Byline: Annie Berman]
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Communicated by:
Jon Nash
<jnashfreeland@gmail.com>
[Recommended reading [duplicated in part below]:
Gigante CM, Gao J, Tang S, et al.: Genome of Alaskapox Virus, A Novel Orthopoxvirus Isolated from Alaska. Viruses. 2019; 11(8): 708. DOI:10.3390/v11080708.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723315/
Abstract. "Since the eradication of smallpox, there have been increases in poxvirus infections and the emergence of several novel poxviruses that can infect humans and domestic animals. In 2015, a novel poxvirus was isolated from a resident of Alaska. Diagnostic testing and limited sequence analysis suggested this isolate was a member of the _Orthopoxvirus_ (OPXV) genus but was highly diverged from currently known species, including Akhmeta virus. Here, we present the complete 210 797 bp genome sequence of the Alaska poxvirus isolate, containing 206 predicted open reading frames. Phylogenetic analysis of the conserved central region of the genome suggested the Alaska isolate shares a common ancestor with Old World OPXVs and is diverged from New World OPXVs. We propose this isolate as a member of a new OPXV species, Alaskapox virus (AKPV). The AKPV genome contained host range and virulence genes typical of OPXVs but lacked homologs of C4L and B7R, and the hemagglutinin gene contained a unique 120 amino acid insertion. Seven predicted AKPV proteins were most similar to proteins in non-OPXV Murmansk or NY_014 poxviruses. Genomic analysis revealed evidence suggestive of recombination with ectromelia virus in 2 putative regions that contain 7 predicted coding sequences, including the A-type inclusion protein."
Discussion. "The isolation and original characterization of the poxvirus isolated from a patient in Alaska suggested that this isolate represents a novel, divergent OPXV capable of infecting humans. The complete genome sequence of the AKPV isolate provided unique observations when compared with other OPXVs. The large genome and broad host range of cowpox virus has led to the hypothesis that extant OPXVs evolved from a CPXV-like ancestor through gene loss and modification. Compared to CPXV-BR, the AKPV genome exhibited loss of 23 genes and gain of 6 genes, including 2 genes found in Murmansk poxvirus but not in currently known species of the OPXV lineage."
"Careful analysis of the AKPV isolate genome revealed unexpected recombination with ECTV. ECTV was first identified in 1930 in a laboratory mouse and is the causative agent of mousepox, a disease found in mouse colonies in Europe, Asia, and the Americas [61,62]. Although the distribution and natural reservoir of ECTV remains unknown, it is suspected to circulate among wild rodents in Europe [62]. The geographic distribution of AKPV is also unclear, and the source of exposure to the Alaska resident has not yet been resolved [30]. While concrete data about the distribution of either species is largely lacking, AKPV was isolated in the Americas, and ECTV is thought to circulate in Europe. Given the current estimates of when Old and New World OPXVs separated, the high sequence similarity in suspect recombinant regions between AKPV and ECTV suggests either a short time since recombination or very low rate of evolution for this region of the genome.
"Taken together, this study highlights the need for future studies of natural poxvirus circulation in wildlife to generate a better understanding of OPXV ecology and better preparedness for zoonotic infections in humans. The discovery of new, divergent OPXVs introduces the opportunity to re-evaluate the _Orthopoxvirus_ genus. The discovery of new diverse species can strengthen existing understanding and provide further insight or improve the resolution of previous analyses. It is very likely that the wealth of sequencing information reflecting OPXV diversity will continue to increase. This information can be used to inform diagnostics and may provide increasingly more accurate information about OPXV evolution and origins."
[For references, see the link in the citation.]
The finding that this strain of Alaskapox is likely a recombinant with ectromelia virus is a good demonstration of how viruses evolve. Sequencing is important to determine the genetics of these new viruses and to develop good diagnostics to identify them. With increasing emergence of zoonotic viruses that infect humans, it is important to adopt a One Health approach, uniting human and veterinary medicine. This is highlighted by the increase in poxvirus infections and the emergence of several novel poxviruses that can infect humans and domestic animals, as noted by the authors. Fortunately, in the 2 cases of Alaskapox that have been identified, the infections were mild and did not spread further. - Mod.LK
