Bourbon Virus Transmission, New York, USA

Abstract

B ourbon virus (BRBV; genus Thogotovirus, family Orthomyxoviridae) is a suspected tickborne human pathogen isolated in 2014 from a patient residing in Bourbon County, Kansas, USA (1). BRBV is closely related to Oz virus, which was isolated from Amblyomma testudinarium ticks in Japan (2,3). Since the initial discovery of BRBV, human cases have been identified in Kansas, Missouri, and Oklahoma (4). The Amblyomma americanum lone star tick has been identified as the likely vector of BRBV transmission and maintenance (5,6). Small and medium-sized mammals and ground-dwelling birds such as wild turkeys (Meleagris gallopavo) are hosts for the immature ticks. Adults feed on large mammals, such as coyotes (Canis latrans) and white-tailed deer (Odocoileus virginianus). All 3 active developmental stages of the tick will bite humans (7). Virus detection in ticks and serologic evidence in mammalian hosts, including white-tailed deer, have been demonstrated in Missouri, Kansas, and North Carolina (6,8-10). The StudyIn July 2019, New York State Department of Health (NYSDOH) epidemiologists were notified that BRBV RNA was detected in an individual, partially engorged female A. americanum tick removed from a Long Island, New York, resident. Comprehensive testing performed through the University of Massachusetts TickReport service (https://www.tickreport.com) revealed the tick was also positive for Ehrlichia ewingii bacteria. Notes on the tick submission form indicated the person was experiencing fever, chills, and fatigue; officials with NYSDOH and Suffolk County Department of Health Services (SCDHS) attempted to contact the resident for a follow-up investigation. No additional information was provided, and no blood samples were available to assess potential infection with BRBV.In 2016, NYSDOH and SCDHS initiated active tick surveillance targeting A. americanum ticks for BRBV and Heartland virus (HRTV). HRTV-infected ticks and seropositive deer were detected on Long Island in 2018 and reported in 2021 (11). We used standardized flag sampling for the collection of hostseeking A. americanum ticks on public lands in Suffolk County. During 2016-2020, a total of 1,265 pools, representing 4,189 adults, 7,227 nymphs, and 97 larvae, tested negative for BRBV RNA by real-time reverse transcription PCR using an in-house multiplex assay to detect HRTV and BRBV (11). The BRBV primers for this assay were designed based on the St. Louis strain (GenBank accession no. MK453528) (12). During 2021, we expanded sampling for A. americanum ticks on Long Island to collect a greater number of ticks from more locations, and we modified molecular detection protocols to use BRBV-specific primers developed at TickReport (Table 1). We designed BRBV-specific primers based on the original virus strain deposited in GenBank (accession no. KU708254) (13). We collected a total of 1,058 pools, consisting of 4,406 adults

Lone star ticks (Acari: Ixodidae) infected with Bourbon virus in New Jersey, USA

“…Map of eastern US counties with published evidence of BRBV in humans, animals, and ticks. Inset: Monmouth County 2021 surveillance sites with RT-qPCR-positive ticks.Sources: Kosoy et al (2015), Savage et al (2017, 2018), Bricker et al (2019), Jackson et al (2019), Komar et al (2020), Cumbie et al (2022), Aziati et al (2023), Dupuis et al (2023). …”

“…We report the first detection of BRBV in New Jersey, and its second detection within the northeastern United States. Previously, BRBV RNA was detected in A. americanum ticks from Suffolk County, NY, and serologic evidence of exposure was found in white-tailed deer ( Odocoileus virginianus Zimmerman) from Suffolk and other NY counties (Dupuis et al 2023). It has also been detected in ticks ( A. americanum and Haemaphysalis longicornis Neumann) in Virginia, and deer in both Virginia and North Carolina were seropositive (Komar et al 2020, Cumbie et al 2022).…”

“…While initially found in the eastern-central United States, both HRTV and BRBV have been detected in Suffolk County, NY (Dupuis et al 2021, 2023), signaling a need for enhanced screening throughout the range of A. americanum , and especially where they have only recently become the dominant human-biting tick. To characterize the risk of HRTV and BRBV to residents of Monmouth County, NJ, we screened 1,205 nymphal A. americanum collected from 12 sites in May–June 2021 for these 2 viruses using RT-qPCR.…”

Bourbon virus, a newly discovered zoonotic thogotovirus

“…Aransas Bay virus (ABV) was isolated from Ornithodoros ticks found in seabird nests in South Texas in 1979 [41]. Therefore, the isolation of BRBV from ticks and severely diseased patients in the Midwest United States [1,2] and at the Northern Atlantic coast [6] was surprising.…”

“…The prototype member of the thogotovirus genus, THOV, was first isolated in 1960 from ticks questing on cattle in the Thogoto forest area near Nairobi, Kenya [42]. Since then, 15 genetically distinct thogotoviruses have been described (including eight THOV-like isolates) [38,39] and their prevalence was additionally demonstrated in serological surveys [6,18,19]. The two newly described tick isolates from Japan were identified in different regions of the country, the THOV-like Kami-25 virus from Haemaphysalis ticks in Kyoto prefecture [16] and the DHOV-like OZV from Amblyomma ticks in Ehime prefecture [14].…”