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 by the patient's cohabiting partner, or from 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 following exposure in or near Fairbanks. This conclusion raises questions about the geographic origins (Old World versus North American) of the genus Orthopoxvirus. Clinicians should remain vigilant for signs of poxvirus infection and alert public health officials when cases are suspected.

BACKGROUND: Alaska Native (AN) infants from the Yukon-Kuskokwim Delta (YKD) experienced respiratory syncytial virus (RSV) hospitalization rates five times higher and an RSV season twice as long as the general US infant population. We describe trends in hospitalization rates and seasonality during 18 years of continuous RSV surveillance in this population and explore contributions of climate and sociodemographic factors. METHODS: We abstracted clinical and RSV test information from computerized medical records at YKD Regional Hospital and Alaska Native Medical Center from 1994-2012 to determine hospitalization rates and RSV season timing. Descriptive village and weather data were acquired through the US Census and Alaska Climate Research Center, University of Alaska, Fairbanks, respectively. RESULTS: During 1994-2012, YKD infant RSV hospitalization rates declined nearly 3-fold, from 177/1,000 infants/year to 65. RSV season onset shifted later, from mid-October to late December, contributing to a significantly decreased season duration, from 30 weeks to 11 weeks. In a multivariate analysis, children from villages with more crowded households and lacking plumbed water had higher rates of RSV hospitalizations (RR 1.17, p=0.0005, and RR 1.45, p=0.0003). No association of temperature or dew point was found with the timing or severity of RSV season. CONCLUSIONS: Although the RSV hospitalization rate decreased 3-fold, YKD infants still experience a hospitalization rate 3-fold higher than the general US infant population. Overcrowding and lack of plumbed water were associated with RSV hospitalization. Dramatic changes occurred in RSV seasonality, not explained by changes in climate.