ABSTRACT
BACKGROUND: Borealpox virus (BRPV, formerly known as Alaskapox virus) is a zoonotic member of the Orthopoxvirus genus first identified in a person in 2015. In the six patients with infection previously observed BRPV involved mild, self-limiting illness. We report the first fatal BRPV infection in an immunosuppressed patient. METHODS: A man aged 69 years from Alaska's Kenai Peninsula was receiving anti-CD20 therapy for chronic lymphocytic leukemia. He presented to care for a tender, red papule in his right axilla with increasing induration and pain. The patient failed to respond to multiple prescribed antibiotic regimens and was hospitalized 65 days postsymptom onset for progression of presumed infectious cellulitis. BRPV was eventually detected through orthopoxvirus real-time polymerase chain reaction testing of mucosal swabs. He received combination antiviral therapy, including 21 days of intravenous tecovirimat, intravenous vaccinia immunoglobulin, and oral brincidofovir. Serial serology was conducted on specimens obtained posttreatment initiation. FINDINGS: The patient's condition initially improved with plaque recession, reduced erythema, and epithelization around the axillary lesion beginning one-week post-therapy. He later exhibited delayed wound healing, malnutrition, acute renal failure, and respiratory failure. He died 138 days postsymptom onset. Serologic testing revealed no evidence the patient generated a humoral immune response. No secondary cases were detected. CONCLUSION: This report demonstrates that BRPV can cause overwhelming disseminated infection in certain immunocompromised patients. Based on the patient's initial response, early BRPV identification and antiviral therapies might have been beneficial. These therapies, in combination with optimized immune function, should be considered for patients at risk for manifestations of BRPV.
ABSTRACT
The antiviral drug tecovirimat* has been used extensively to treat U.S. mpox cases since the start of a global outbreak in 2022. Mutations in the mpox viral protein target (F13 or VP37) that occur during treatment can result in resistance to tecovirimat (1,2). CDC and public health partners have conducted genetic surveillance of monkeypox virus (MPXV) for F13 mutations through sequencing and monitoring of public databases. MPXV F13 mutations associated with resistance have been reported since 2022, typically among severely immunocompromised mpox patients who required prolonged courses of tecovirimat (3-5). A majority of patients with infections caused by MPXV with resistant mutations had a history of tecovirimat treatment; however, spread of tecovirimat-resistant MPXV was reported in California during late 2022 to early 2023 among persons with no previous tecovirimat treatment (3). This report describes a second, unrelated cluster of tecovirimat-resistant MPXV among 18 persons with no previous history of tecovirimat treatment in multiple states.
Subject(s)
Antiviral Agents , Disease Outbreaks , Drug Resistance, Viral , Monkeypox virus , Mpox (monkeypox) , Humans , United States/epidemiology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Mpox (monkeypox)/epidemiology , Mpox (monkeypox)/drug therapy , Monkeypox virus/isolation & purification , Monkeypox virus/genetics , Monkeypox virus/drug effects , Adult , Male , Female , Middle Aged , Adolescent , Young Adult , Aged , Child , Mutation , Dibenzothiepins , Benzamides/therapeutic use , Benzamides/pharmacology , PhthalimidesABSTRACT
CONTEXT: The first case of mpox was detected in the United States in a Laboratory Response Network (LRN) laboratory at the Massachusetts Department of Public Health on May 17, 2022. Through previous years of smallpox preparedness efforts by the United States government, testing capacity in LRN laboratories across the United States utilizing the FDA-cleared Centers for Disease Control and Prevention (CDC) Non-variola orthopoxvirus (NVO) test was approximately 6000 tests weekly across the nation prior to the mpox outbreak. By early June 2022, the LRN laboratories had capacity to perform up to 8000 tests per week. As the outbreak expanded, cases were identified in every United States state, peaking at ~3000 cases per week nationally in August 2022. OBJECTIVE: Although NVO testing capacity in LRN laboratories exceeded national mpox testing demand overall, LRN testing access in some areas was challenged and test expansion was necessary. PARTICIPANTS: CDC engaged with partners and select commercial laboratories early to increase diagnostic testing access by allowing these commercial laboratories to utilize the NVO test. SETTING: The expansion of testing to commercial laboratories increased testing availability, capacity, and volume nationwide. This was the first time that CDC shared an FDA 510k-cleared molecular test with commercial laboratories to support a public health emergency. DESIGN: Extensive efforts were made to ensure the CDC NVO test was used appropriately in the private sector and that the transfer process met regulatory requirements. MAIN OUTCOME MEASURES, RESULTS, CONCLUSIONS: These novel methods to expand NVO testing to commercial laboratories increased national testing capacity to 80 000 mpox tests/week. Test volumes among these laboratories never exceeded this expanded capacity. The rapid increase in the nation's testing capacity, in conjunction and coordination with other public and private health efforts, helped to detect cases rapidly. These actions demonstrated the importance of highly functional and efficient public health and private sector partnerships for responding to public health emergencies.
ABSTRACT
During the 2022 multinational outbreak of monkeypox virus (MPXV) infection, the antiviral drug tecovirimat (TPOXX; SIGA Technologies, Inc., https://www.siga.com) was deployed in the United States on a large scale for the first time. The MPXV F13L gene homologue encodes the target of tecovirimat, and single amino acid changes in F13 are known to cause resistance to tecovirimat. Genomic sequencing identified 11 mutations previously reported to cause resistance, along with 13 novel mutations. Resistant phenotype was determined using a viral cytopathic effect assay. We tested 124 isolates from 68 patients; 96 isolates from 46 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of tecovirimat treatment, whereas most isolates identified by routine surveillance of patients not treated with tecovirimat remained sensitive. The frequency of resistant viruses remains relatively low (<1%) compared with the total number of patients treated with tecovirimat.
Subject(s)
Mpox (monkeypox) , Humans , United States/epidemiology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Benzamides/therapeutic use , Biological Assay , Monkeypox virusABSTRACT
BACKGROUND: The largest West African monkeypox outbreak began September 2017, in Nigeria. Four individuals traveling from Nigeria to the United Kingdom (n = 2), Israel (n = 1), and Singapore (n = 1) became the first human monkeypox cases exported from Africa, and a related nosocomial transmission event in the United Kingdom became the first confirmed human-to-human monkeypox transmission event outside of Africa. METHODS: Epidemiological and molecular data for exported and Nigerian cases were analyzed jointly to better understand the exportations in the temporal and geographic context of the outbreak. RESULTS: Isolates from all travelers and a Bayelsa case shared a most recent common ancestor and traveled to Bayelsa, Delta, or Rivers states. Genetic variation for this cluster was lower than would be expected from a random sampling of genomes from this outbreak, but data did not support direct links between travelers. CONCLUSIONS: Monophyly of exportation cases and the Bayelsa sample, along with the intermediate levels of genetic variation, suggest a small pool of related isolates is the likely source for the exported infections. This may be the result of the level of genetic variation present in monkeypox isolates circulating within the contiguous region of Bayelsa, Delta, and Rivers states, or another more restricted, yet unidentified source pool.
Subject(s)
Monkeypox virus , Mpox (monkeypox) , Disease Outbreaks , Humans , Mpox (monkeypox)/epidemiology , Monkeypox virus/genetics , Nigeria/epidemiology , United KingdomABSTRACT
On May 17, 2022, the Massachusetts Department of Public Health (MDPH) Laboratory Response Network (LRN) laboratory confirmed the presence of orthopoxvirus DNA via real-time polymerase chain reaction (PCR) from lesion swabs obtained from a Massachusetts resident. Orthopoxviruses include Monkeypox virus, the causative agent of monkeypox. Subsequent real-time PCR testing at CDC on May 18 confirmed that the patient was infected with the West African clade of Monkeypox virus. Since then, confirmed cases* have been reported by nine states. In addition, 28 countries and territories, none of which has endemic monkeypox, have reported laboratory-confirmed cases. On May 17, CDC, in coordination with state and local jurisdictions, initiated an emergency response to identify, monitor, and investigate additional monkeypox cases in the United States. This response has included releasing a Health Alert Network (HAN) Health Advisory, developing interim public health and clinical recommendations, releasing guidance for LRN testing, hosting clinician and public health partner outreach calls, disseminating health communication messages to the public, developing protocols for use and release of medical countermeasures, and facilitating delivery of vaccine postexposure prophylaxis (PEP) and antivirals that have been stockpiled by the U.S. government for preparedness and response purposes. On May 19, a call center was established to provide guidance to states for the evaluation of possible cases of monkeypox, including recommendations for clinical diagnosis and orthopoxvirus testing. The call center also gathers information about possible cases to identify interjurisdictional linkages. As of May 31, this investigation has identified 17§ cases in the United States; most cases (16) were diagnosed in persons who identify as gay, bisexual, or men who have sex with men (MSM). Ongoing investigation suggests person-to-person community transmission, and CDC urges health departments, clinicians, and the public to remain vigilant, institute appropriate infection prevention and control measures, and notify public health authorities of suspected cases to reduce disease spread. Public health authorities are identifying cases and conducting investigations to determine possible sources and prevent further spread. This activity was reviewed by CDC and conducted consistent with applicable federal law and CDC policy.¶.
Subject(s)
Malaria , Mpox (monkeypox) , Sexual and Gender Minorities , Disease Outbreaks , Homosexuality, Male , Humans , Malaria/diagnosis , Male , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Population Surveillance , Travel , United States/epidemiologyABSTRACT
Monkeypox is a rare, sometimes life-threatening zoonotic infection that occurs in west and central Africa. It is caused by Monkeypox virus, an orthopoxvirus similar to Variola virus (the causative agent of smallpox) and Vaccinia virus (the live virus component of orthopoxvirus vaccines) and can spread to humans. After 39 years without detection of human disease in Nigeria, an outbreak involving 118 confirmed cases was identified during 2017-2018 (1); sporadic cases continue to occur. During September 2018-May 2021, six unrelated persons traveling from Nigeria received diagnoses of monkeypox in non-African countries: four in the United Kingdom and one each in Israel and Singapore. In July 2021, a man who traveled from Lagos, Nigeria, to Dallas, Texas, became the seventh traveler to a non-African country with diagnosed monkeypox. Among 194 monitored contacts, 144 (74%) were flight contacts. The patient received tecovirimat, an antiviral for treatment of orthopoxvirus infections, and his home required large-scale decontamination. Whole genome sequencing showed that the virus was consistent with a strain of Monkeypox virus known to circulate in Nigeria, but the specific source of the patient's infection was not identified. No epidemiologically linked cases were reported in Nigeria; no contact received postexposure prophylaxis (PEP) with the orthopoxvirus vaccine ACAM2000.
Subject(s)
Mpox (monkeypox) , Humans , Male , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Mpox (monkeypox)/prevention & control , Monkeypox virus/genetics , Nigeria/epidemiology , Texas/epidemiologyABSTRACT
Since May 2022, approximately 20,000 cases of monkeypox have been identified in the United States, part of a global outbreak occurring in approximately 90 countries and currently affecting primarily gay, bisexual, and other men who have sex with men (MSM) (1). Monkeypox virus (MPXV) spreads from person to person through close, prolonged contact; a small number of cases have occurred in populations who are not MSM (e.g., women and children), and testing is recommended for persons who meet the suspected case definition* (1). CDC previously developed five real-time polymerase chain reaction (PCR) assays for detection of orthopoxviruses from lesion specimens (2,3). CDC was granted 510(k) clearance for the nonvariola-orthopoxvirus (NVO)-specific PCR assay by the Food and Drug Administration. This assay was implemented within the Laboratory Response Network (LRN) in the early 2000s and became critical for early detection of MPXV and implementation of public health action in previous travel-associated cases as well as during the current outbreak (4-7). PCR assays (NVO and other Orthopoxvirus laboratory developed tests [LDT]) represent the primary tool for monkeypox diagnosis. These tests are highly sensitive, and cross-contamination from other MPXV specimens being processed, tested, or both alongside negative specimens can occasionally lead to false-positive results. This report describes three patients who had atypical rashes and no epidemiologic link to a monkeypox case or known risk factors; these persons received diagnoses of monkeypox based on late cycle threshold (Ct) values ≥34, which were false-positive test results. The initial diagnoses were followed by administration of antiviral treatment (i.e., tecovirimat) and JYNNEOS vaccine postexposure prophylaxis (PEP) to patients' close contacts. After receiving subsequent testing, none of the three patients was confirmed to have monkeypox. Knowledge gained from these and other cases resulted in changes to CDC guidance. When testing for monkeypox in specimens from patients without an epidemiologic link or risk factors or who do not meet clinical criteria (or where these are unknown), laboratory scientists should reextract and retest specimens with late Ct values (based on this report, Ct ≥34 is recommended) (8). CDC can be consulted for complex cases including those that appear atypical or questionable cases and can perform additional viral species- and clade-specific PCR testing and antiorthopoxvirus serologic testing.
Subject(s)
Communicable Diseases , Mpox (monkeypox) , Orthopoxvirus , Sexual and Gender Minorities , Animals , Child , Female , Homosexuality, Male , Humans , Male , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Monkeypox virus/genetics , Orthopoxvirus/genetics , Travel , United States/epidemiologyABSTRACT
As part of public health preparedness for infectious disease threats, CDC collaborates with other U.S. public health officials to ensure that the Laboratory Response Network (LRN) has diagnostic tools to detect Orthopoxviruses, the genus that includes Variola virus, the causative agent of smallpox. LRN is a network of state and local public health, federal, U.S. Department of Defense (DOD), veterinary, food, and environmental testing laboratories. CDC developed, and the Food and Drug Administration (FDA) granted 510(k) clearance* for the Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set (non-variola Orthopoxvirus [NVO] assay), a polymerase chain reaction (PCR) diagnostic test to detect NVO. On May 17, 2022, CDC was contacted by the Massachusetts Department of Public Health (DPH) regarding a suspected case of monkeypox, a disease caused by the Orthopoxvirus Monkeypox virus. Specimens were collected and tested by the Massachusetts DPH public health laboratory with LRN testing capability using the NVO assay. Nationwide, 68 LRN laboratories had capacity to test approximately 8,000 NVO tests per week during June. During May 17-June 30, LRN laboratories tested 2,009 specimens from suspected monkeypox cases. Among those, 730 (36.3%) specimens from 395 patients were positive for NVO. NVO-positive specimens from 159 persons were confirmed by CDC to be monkeypox; final characterization is pending for 236. Prompt identification of persons with infection allowed rapid response to the outbreak, including isolation and treatment of patients, administration of vaccines, and other public health action. To further facilitate access to testing and increase convenience for providers and patients by using existing provider-laboratory relationships, CDC and LRN are supporting five large commercial laboratories with a national footprint (Aegis Science, LabCorp, Mayo Clinic Laboratories, Quest Diagnostics, and Sonic Healthcare) to establish NVO testing capacity of 10,000 specimens per week per laboratory. On July 6, 2022, the first commercial laboratory began accepting specimens for NVO testing based on clinician orders.
Subject(s)
Diagnostic Techniques and Procedures , Disease Outbreaks , Mpox (monkeypox) , Disease Outbreaks/prevention & control , Humans , Laboratories , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Orthopoxvirus , United States/epidemiology , Variola virusABSTRACT
BACKGROUND: Monkeypox is a poorly described emerging zoonosis endemic to Central and Western Africa. METHODS: Using surveillance data from Tshuapa Province, Democratic Republic of the Congo during 2011-2015, we evaluated differences in incidence, exposures, and clinical presentation of polymerase chain reaction-confirmed cases by sex and age. RESULTS: We report 1057 confirmed cases. The average annual incidence was 14.1 per 100 000 (95% confidence interval, 13.3-15.0). The incidence was higher in male patients (incidence rate ratio comparing males to females, 1.21; 95% confidence interval, 1.07-1.37), except among those 20-29 years old (0.70; .51-.95). Females aged 20-29 years also reported a high frequency of exposures (26.2%) to people with monkeypox-like symptoms.The highest incidence was among 10-19-year-old males, the cohort reporting the highest proportion of animal exposures (37.5%). The incidence was lower among those presumed to have received smallpox vaccination than among those presumed unvaccinated. No differences were observed by age group in lesion count or lesion severity score. CONCLUSIONS: Monkeypox incidence was twice that reported during 1980-1985, an increase possibly linked to declining immunity provided by smallpox vaccination. The high proportion of cases attributed to human exposures suggests changing exposure patterns. Cases were distributed across age and sex, suggesting frequent exposures that follow sociocultural norms.
Subject(s)
Mpox (monkeypox) , Adolescent , Adult , Child , Democratic Republic of the Congo/epidemiology , Female , Humans , Male , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Monkeypox virus/genetics , Smallpox Vaccine , Young AdultSubject(s)
Mpox (monkeypox) , Humans , Mpox (monkeypox)/complications , United States , Fatal OutcomeABSTRACT
In March 2015, a patient in Colombia with HIV/AIDS was hospitalized for disseminated ulcers after milking cows that had vesicular lesions on their udders. Vaccinia virus was detected, and the case met criteria for progressive vaccinia acquired by zoonotic transmission. Adherence to an optimized antiretroviral regimen resulted in recovery.
Subject(s)
HIV Infections , Vaccinia virus/isolation & purification , Vaccinia/diagnosis , Acquired Immunodeficiency Syndrome , Adult , Animals , Antiretroviral Therapy, Highly Active , Antiviral Agents/therapeutic use , Colombia , Humans , Male , Vaccinia/drug therapy , Vaccinia/transmission , Zoonoses/virologyABSTRACT
In 2013, a novel orthopoxvirus was detected in skin lesions of two cattle herders from the Kakheti region of Georgia (country); this virus was named Akhmeta virus. Subsequent investigation of these cases revealed that small mammals in the area had serological evidence of orthopoxvirus infections, suggesting their involvement in the maintenance of these viruses in nature. In October 2015, we began a longitudinal study assessing the natural history of orthopoxviruses in Georgia. As part of this effort, we trapped small mammals near Akhmeta (n = 176) and Gudauri (n = 110). Here, we describe the isolation and molecular characterization of Akhmeta virus from lesion material and pooled heart and lung samples collected from five wood mice (Apodemus uralensis and Apodemus flavicollis) in these two locations. The genomes of Akhmeta virus obtained from rodents group into 2 clades: one clade represented by viruses isolated from A. uralensis samples, and one clade represented by viruses isolated from A. flavicollis samples. These genomes also display several presumptive recombination events for which gene truncation and identity have been examined.IMPORTANCE Akhmeta virus is a unique Orthopoxvirus that was described in 2013 from the country of Georgia. This paper presents the first isolation of this virus from small mammal (Rodentia; Apodemus spp.) samples and the molecular characterization of those isolates. The identification of the virus in small mammals is an essential component to understanding the natural history of this virus and its transmission to human populations and could guide public health interventions in Georgia. Akhmeta virus genomes harbor evidence suggestive of recombination with a variety of other orthopoxviruses; this has implications for the evolution of orthopoxviruses, their ability to infect mammalian hosts, and their ability to adapt to novel host species.
Subject(s)
Murinae/virology , Orthopoxvirus/classification , Orthopoxvirus/isolation & purification , Phylogeny , Poxviridae Infections/virology , Animals , Genes, Viral/genetics , Genome, Viral , Georgia (Republic) , Humans , Longitudinal Studies , Orthopoxvirus/genetics , Poxviridae Infections/transmission , Poxviridae Infections/veterinary , Rodent Diseases/transmission , Rodent Diseases/virologyABSTRACT
Smallpox vaccine is contraindicated in immunosuppression due to increased risk for adverse reactions (eg, progressive vaccinia). We describe the first-ever use of tecovirimat as a preemptive vaccinia virus treatment strategy during induction chemotherapy in an active duty service member who presented with acute leukemia and inadvertent autoinoculation after smallpox vaccination.
Subject(s)
Antiviral Agents/administration & dosage , Benzamides/administration & dosage , Isoindoles/administration & dosage , Leukemia, Myeloid, Acute/diagnosis , Military Personnel , Smallpox Vaccine/adverse effects , Smallpox Vaccine/immunology , Smallpox/prevention & control , Vaccination , Vaccinia virus/drug effects , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Humans , Immunoglobulins, Intravenous/therapeutic use , Leukemia, Myeloid, Acute/etiology , Leukemia, Myeloid, Acute/therapy , Male , Premedication , Smallpox Vaccine/administration & dosage , Symptom Assessment , Treatment Outcome , Vaccination/adverse effects , Vaccination/methods , Vaccinia virus/immunologyABSTRACT
In 2014, vaccinia virus (VACV) infections were identified among farmworkers in Caquetá Department, Colombia; additional cases were identified in Cundinamarca Department in 2015. VACV, an orthopoxvirus (OPXV) used in the smallpox vaccine, has caused sporadic bovine and human outbreaks in countries such as Brazil and India. In response to the emergence of this disease in Colombia, we surveyed and collected blood from 134 farmworkers and household members from 56 farms in Cundinamarca Department. We tested serum samples for OPXV antibodies and correlated risk factors with seropositivity by using multivariate analyses. Fifty-two percent of farmworkers had OPXV antibodies; this percentage decreased to 31% when we excluded persons who would have been eligible for smallpox vaccination. The major risk factors for seropositivity were municipality, age, smallpox vaccination scar, duration of time working on a farm, and animals having vaccinia-like lesions. This investigation provides evidence for possible emergence of VACV as a zoonosis in South America.
Subject(s)
Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Emerging/virology , Vaccinia virus , Vaccinia/epidemiology , Vaccinia/virology , Zoonoses/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Agriculture , Animals , Child , Colombia/epidemiology , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , Orthopoxvirus/immunology , Risk Factors , Seroepidemiologic Studies , Vaccinia virus/immunology , Young AdultSubject(s)
SARS-CoV-2 , United States/epidemiology , Humans , Population Surveillance , Adult , Male , Female , Middle Aged , COVID-19/epidemiology , Aged , Phylogeny , AdolescentABSTRACT
Vaccinia virus (VACV) is an orthopoxvirus used in smallpox vaccines, as a vector for novel cancer treatments, and for experimental vaccine research (1). The Advisory Committee on Immunization Practices (ACIP) recommends smallpox vaccination for laboratory workers who handle replication-competent VACV (1). For bioterrorism preparedness, the U.S. government stockpiles tecovirimat, the first Food and Drug Administration-approved antiviral for treatment of smallpox (caused by variola virus and globally eradicated in 1980*,) (2). Tecovirimat has activity against other orthopoxviruses and can be administered under a CDC investigational new drug protocol. CDC was notified about an unvaccinated laboratory worker with a needlestick exposure to VACV, who developed a lesion on her left index finger. CDC and partners performed laboratory confirmation, contacted the study sponsor to identify the VACV strain, and provided oversight for the first case of laboratory-acquired VACV treated with tecovirimat plus intravenous vaccinia immunoglobulin (VIGIV). This investigation highlights 1) the misconception among laboratory workers about the virulence of VACV strains; 2) the importance of providing laboratorians with pathogen information and postexposure procedures; and 3) that although tecovirimat can be used to treat VACV infections, its therapeutic benefit remains unclear.
Subject(s)
Laboratory Personnel , Needlestick Injuries/virology , Occupational Diseases/therapy , Occupational Injuries/virology , Vaccinia/therapy , Adult , California , Female , HumansABSTRACT
BACKGROUND.: Human infection by orthopoxviruses is being reported with increasing frequency, attributed in part to the cessation of smallpox vaccination and concomitant waning of population-level immunity. In July 2015, a female resident of interior Alaska presented to an urgent care clinic with a dermal lesion consistent with poxvirus infection. Laboratory testing of a virus isolated from the lesion confirmed infection by an Orthopoxvirus. METHODS.: The virus isolate was characterized by using electron microscopy and nucleic acid sequencing. An epidemiologic investigation that included patient interviews, contact tracing, and serum testing, as well as environmental and small-mammal sampling, was conducted to identify the infection source and possible additional cases. RESULTS.: Neither signs of active infection nor evidence of recent prior infection were observed in any of the 4 patient contacts identified. The patient's infection source was not definitively identified. Potential routes of exposure included imported fomites from Azerbaijan via the patient's cohabiting partner or wild small mammals in or around the patient's residence. Phylogenetic analyses demonstrated that the virus represents a distinct and previously undescribed genetic lineage of Orthopoxvirus, which is most closely related to the Old World orthopoxviruses. CONCLUSIONS.: Investigation findings point to infection of the patient after exposure in or near Fairbanks. This conclusion raises questions about the geographic origins (Old World vs North American) of the genus Orthopoxvirus. Clinicians should remain vigilant for signs of poxvirus infection and alert public health officials when cases are suspected.