Surveillance for Tick-Borne Viruses Near the Location of a Fatal Human Case of Bourbon Virus (Family Orthomyxoviridae: Genus Thogotovirus) in Eastern Kansas, 2015

Abstract

Bourbon virus (Family Orthomyxoviridae: Genus Thogotovirus) was first isolated from a human case-patient residing in Bourbon County, Kansas, who subsequently died. Before becoming ill in late spring of 2014, the patient reported several tick bites. In response, we initiated tick surveillance in Bourbon County and adjacent southern Linn County during spring and summer of 2015. We collected 20,639 host-seeking ticks representing four species from 12 sites. Amblyomma americanum (L.) (Acari: Ixodidae) and Dermacentor variabilis (Say) (Acari: Ixodidae) accounted for nearly all ticks collected (99.99%). Three tick pools, all composed of adult A. americanum ticks collected in Bourbon County, were virus positive. Two pools were Heartland virus (Family Bunyaviridae: Genus Phlebovirus) positive, and one was Bourbon virus positive. The Bourbon virus positive tick pool was composed of five adult females collected on a private recreational property on June 5. Detection of Bourbon virus in the abundant and aggressive human-biting tick A. americanum in Bourbon County supports the contention that A. americanum is a vector of Bourbon virus to humans. The current data combined with virus detections in Missouri suggest that Bourbon virus is transmitted to humans by A. americanum ticks, including both the nymphal and adult stages, that ticks of this species become infected as either larvae, nymphs or both, perhaps by feeding on viremic vertebrate hosts, by cofeeding with infected ticks, or both, and that Bourbon virus is transstadially transmitted. Multiple detections of Heartland virus and Bourbon virus in A. americanum ticks suggest that these viruses share important components of their transmission cycles.

Establishment of a Replicon System for Bourbon Virus and Identification of Small Molecules that Efficiently Inhibit Virus Replication

“…BRBV replicates in cell lines derived from the hard ticks Amblyomma, Hyalomma and Rhipicephalus . Together with the geographic location of the BRBV infection and the geographic distribution of a number of Amblyomma americanum ticks (Savage, et al, 2017;Savage, et al, 2018), these studies strongly suggest that the lone star tick is a vector of BRBV transmission to humans.…”

Epidemiological Study of Thogoto and Dhori Virus Infection in People Bitten by Ticks, and in Sheep, in an Area of Northern Spain

“…Ticks can harbor and transmit viruses from wild animals to humans and livestock. The ticks themselves become infected by feeding on viremic hosts, and by co-feeding with infected ticks [19,24,25]. Ixodid ticks generally feed once at each developmental stage (larva, nymph, and adult) and thus have only one opportunity per stage to transmit viruses (inter-stadial transmission).…”

“…L'vov et al isolated DHOV from Hyalomma marginatum ticks on hares in Astrakhan (in the Volga delta) [17]. In Kyoto, Japan, THOV has been recently isolated from Haemaphysalis longicornis [18], and Amblyomma americanum has been shown to be a vector of Thogoto virus to humans in the USA [19]. The first report of DHOV from Kenya implicated Amblyomma gemma as a vector in this region [20].…”

A 117 year retrospective analysis of Pennsylvania tick community dynamics

“…Am. americanum is a competent vector of ehrlichiosis, tularemia, RMSF, multiple Borrelia species (Including B. lonestari, B. andersonii , and B. americanum ), and competent vector of heartland virus)[2,58,59]. Am.…”