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An increasing number of emerging tick-borne diseases has been reported in the United States since the 1970s. Using metagenomic next generation sequencing, we detected nucleic acid sequences from 2 novel viruses in the family Bunyaviridae and an emerging human rickettsial pathogen, Rickettsia philipii, in a population of the Pacific Coast tick, Dermacentor occidentalis in Mendocino County sampled annually from 2011 to 2014. A total of 250 adults of this human-biting, generalist tick were collected from contiguous chaparral and grassland habitats, and RNA from each individually extracted tick was deep sequenced to an average depth of 7.3 million reads. We detected a Francisella endosymbiont in 174 ticks (70%), and Rickettsia spp. in 19 ticks (8%); Rickettsia-infected ticks contained R. rhipicephali (16 of 250, 6.4%) or R. philipii (3 of 250,1.2%), the agent of eschar-associated febrile illness in humans. The genomes of 2 novel bunyaviruses (>99% complete) in the genera Nairovirus and Phlebovirus were also identified and found to be present in 20-91% of ticks, depending on the year of collection. The high prevalence of these bunyaviruses in sampled Dermacentor ticks suggests that they may be viral endosymbionts, although further studies are needed to determine whether they are infectious for vertebrate hosts, especially humans, and their potential role in tick ecology.

An increasing number of emerging tick-borne diseases has been reported in the United States since the 1970s. Using metagenomic next generation sequencing, we detected nucleic acid sequences from 2 novel viruses in the family Bunyaviridae and an emerging human rickettsial pathogen, Rickettsia philipii, in a population of the Pacific Coast tick, Dermacentor occidentalis in Mendocino County sampled annually from 2011 to 2014. A total of 250 adults of this human-biting, generalist tick were collected from contiguous chaparral and grassland habitats, and RNA from each individually extracted tick was deep sequenced to an average depth of 7.3 million reads. We detected a Francisella endosymbiont in 174 ticks (70%), and Rickettsia spp. in 19 ticks (8%); Rickettsia-infected ticks contained R. rhipicephali (16 of 250, 6.4%) or R. philipii (3 of 250,1.2%), the agent of eschar-associated febrile illness in humans. The genomes of 2 novel bunyaviruses (>99% complete) in the genera Nairovirus and Phlebovirus were also identified and found to be present in 20-91% of ticks, depending on the year of collection. The high prevalence of these bunyaviruses in sampled Dermacentor ticks suggests that they may be viral endosymbionts, although further studies are needed to determine whether they are infectious for vertebrate hosts, especially humans, and their potential role in tick ecology.

The aims of the contract were to elucidate the coding and replication strategies of nairoviruses, and determine whether reagents derived from Dugbe (DUG) virus can be used to detect Crimean Congo hemorrhagic fever (CCHF) viral infections. The small (S) segment of DUG virus was shown to comprise 1712 nucleotides and encode a single protein, the 49.9K nucleoprotein (N), in viral complementary (vc) RNA. No sequence similarity was detected with representatives of the Hanta-, Bunya-, or Phlebovirus genera of the Bunyaviridae family. Approximately 75% (i.e. 4953 nucleotides) of the sequence of the M segment of DUG virus was derived and revealed a single open reading frame (ORF) in the vc RNA. The gene encoding the G1 structural glycoprotein appears to be located at the carboxy-terminal end of the M segment ORF. Cloned cDNA derived from the S and M genomic RNA segments of DUG virus was used to prepare 32p-labelled RNA probes.

From April 1987 through April 1988, 597 blood samples were collected from residents of 4 counties of northern Greece. Anti-bodies were detected in 8 and 7 individuals against Hantaan virus and Crimean-Congo Hemorrhagic Fever respectively. Two hundred and two blood samples were taken from patients with disease resembling HFRS and one hundred and sixty nine from patients with disease or syndromes resembling CCHF. Serological diagnosis showed that 7 patients were infected by Hantaan virus, whereas there was no evidence for recent infection by CCHF virus. Two out of 54 small rodents trapped were found to have anti-bodies against Hantaan virus. 29 pools of ticks were collected for CCHF virus isolation. Virus isolation from rodents (Hantaan) and ticks (CCHF) are in progress. Finally, the research performed for HFRS and CCHF viruses in Greece until April 1988 is discussed and the conclusion drawn are herein reported. Keywords: Epidemiology

Taxonomic characteristics and variances of a variety of arboviruses are discussed.

Crimean Congo hemorrhagic fever virus (CCHFV) is one of the most severe viral zoonozes. It is prevalent throughout Africa, Asia and southern Europe. Limited availability of sequence data has hindered phylogeographic studies. The complete genomic sequence of all three segments of 14 Crimean Congo hemorrhagic fever virus strains isolated from 1958-2000 in Russia, Central Asia and Africa was identified. Each genomic segment was independently subjected to continuous Bayesian phylogeographic analysis. The origin of each genomic segment was traced to Africa about 1,000-5,000 years ago. The virus was first introduced to South and Central Asia in the Middle Ages, and then spread to China, India and Russia. Reverse transfers of genomic segments from Asia to Africa were also observed. The European CCHFV genotype V was introduced to Europe via the Astrakhan region in South Russia 280-400 years ago and subsequently gradually spread westward in Russia, to Turkey and the Balkans less than 150 years ago. Only a few recombination events could be suggested in S and L genomic segments, while segment reassortment was very common. The median height of a non-reassortant phylogenetic tree node was 68-156 years. There were reassortment events within the European CCHFV lineage, but not with viruses from other locations. Therefore, CCHFV in Europe is a recently emerged zoonosis that represents a spillover from the global gene pool. © 2016 Lukashev et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.