The biological stability of the genus Brucella

The constancy of the three species of Brucella (Br. abortus, Br. suis and Br. melitensis) is discussed with regard to both the historical background and current research, and the pertinent literature is reviewed and interpreted. The authors maintain that members of the genus Brucella are not labile nor are they subject to spontaneous species alteration; stability of the recognized species is confirmed when test reactions used in speciation are standardized and controlled. Particular stress is laid on the epidemiological value of retaining the original species designations. The conclusion that Brucella species are biologically stable is substantiated by the authors'' combined experience of more than 30 years in the isolation and typing of Brucella derived from a variety of sources.     

Assessment of Air Quality at Neighbor Residences in the Vicinity of Swine Production Facilities

Abstract

Air sampling was completed on the front lawn of 35 homes neighboring swine farms in three different regions in the Upper Midwest of the United States. One region was dominated by large scale, swine confined animal feeding operations (CAFO's) noted as swine confinement area (SCA). The second area was dominated by smaller scale operations utilizing hoop structure facilities (HA). The third area was basically devoid of livestock, dominated by row-crop production, and served as the control area (CA). The time weighted average concentrations of hydrogen sulfide (8.42 ppb) was higher (p = 0.047) in SCA area than the control (3.48 ppb). However, carbon dioxide (449.6 ppm), ammonia (12.78 ppb) and PM10 (42.25 μg/m³) were higher in the hoop structure area than the other areas. Swine population density, distance between the homes and swine facilities, and wind direction had an interactive effect on the average levels of ammonia (p = 0.04). The contaminant levels at the homes were relatively low compared to typical concentrations inside animal buildings. However, exceedences of federal recommended limits for hydrogen sulfide in outdoor air were observed in the swine CAFO area. Concentration of hydrogen sulfide exceeded the recommended limits of the ATSDR (30 ppb) for chronic exposure at two of the 12 homes in the CAFO area (17%). Average hydrogen sulfide concentration exceeded the EPA recommended community standards (0.7 ppb) in all three areas assessed (SCA, HA, and CA). As chronic exposure to hydrogen sulfide may be present in areas of production agriculture, a potential health risk may be present. Further studies to provide additional information regarding exposures to hydrogen sulfide in rural environments are warranted.     

Molecular taxonomy,phylogeny and biogeography of nematodes belonging to the Trichinella genus

Studying parasites of the genus Trichinella provides scientists of today many advantages. This is a group of zoonotic nematodes that circulates freely among wildlife hosts with one in particular, Trichinella spiralis that is exceptionally well adapted to domestic swine. Recent reports suggest that human infections from hunted animals are on the rise worldwide and numerous countries still experience problems with T. spiralis in their domestic food supplies. Trichinella is a genus whose members are easily propagated in the laboratories, have been used as models to investigate host–parasite relationships and parasitism among clade I organisms, and represent a poorly investigated link between the phylum Nematoda and other Metazoans. The importance of T. spiralis in better understanding the tree of life was so recognized that in 2004, its genome was carefully selected as one of only nine key non-mammalian organisms to be sequenced to completion. Since it was first discovered in 1835, this genus has expanded from being monospecific to eight species including four other genotypes of undetermined taxonomic rank. Inasmuch as discriminating morphological data have been scant, our understanding of the genus has been relegated to a compilation of molecular, biochemical and biological data. Herein, we provide a collection of information and up-to-date interpretations on the taxonomy, diagnostics, systematics, micro- and macroevolution, and the biogeographical and biohistorical reconstruction of the genus Trichinella.     

Comparative genomics and phylogenetic analysis of Bacillus anthracis strains isolated from domestic animals in Japan

Anthrax, caused by Bacillus anthracis, is a severe zoonosis with a great impact on both human and animal health. In the present study, we identified the phylogenetic relationships among 16 Japanese strains of B. anthracis, including eight bovine strains, two equine strains, five swine strains, and one former vaccine strain, using in silico canonical single nucleotide polymorphism (canSNP) and core genome SNP analyses. The results of our in silico canSNP analysis suggest that these 16 Japanese strains could be divided into four lineages: i) one equine strain in A.Br.Ames, ii) one equine and six bovine strains in A.Br.001/002, iii) five swine and one bovine strain in A.Br.Aust94, and iv) one bovine and one vaccine strain in A.Br.008/011. A comparison with non-Japanese B. anthracis strains revealed a total of 3787 SNPs identified from the whole genome sequences of the Japanese strains; these SNP data were subjected to a phylogenetic analysis using the maximum parsimony (MP) method. Our core genome SNP analysis was also able to detect differences of a few chromosomal SNPs across clonal strains from the same cases that had different storage and passage histories.Additionally, our whole genome SNP analysis clearly indicated that the Japanese swine anthrax cases of 1982 were caused by at least three independent strains; however, their phylogeny revealed no clear relationship with swine strains from other countries. The bovine strain belonging to the A.Br.008/011 lineage differed from a former Japanese vaccine strain by only 12 SNPs. Together with the phylogenic results and epidemiological circumstances, the diversity of strains reveals that the B. anthracis available in Japan probably resulted from multiple relatively recent import events, rather than reflecting the persistence of a more ancient ecologically established group.     

Some observations on urinary tract infections in patients undergoing long-term bladder catheterization

In this study five laboratory media have been used to characterize the bacterial flora of urine from patients with spinal injuries who are undergoing long-term indwelling bladder catheterization. Single organisms were rarely isolated from these urines, in general complex mixed communities of bacteria were recovered composed of up to seven species. Observations were also made on how these populations change with time and in response to antibiotic therapy and bladder irrigation with antiseptics. During periods when patients were not receiving antibacterials, Escherichia coli, Klebsiella pneumoniae, Citrobacter diversus, Providencia stuartii, Pseudomonas aeruginosa, Proteus mirabilis and Pr. morganii were stable inhabitants of the urine, Streptococcus faecalis, Acinetobacter anitratus and Staphylococcus epidermidis were transient members of the communities. The effect of antibacterials on these communities was merely to select species that were resistant to the agents used. These results suggest that if these patients are to be treated, then efforts should be made to fully characterize the bacterial populations of the urines. Any therapy should then be based upon a consideration of the resistance profiles of all the members of the mixed bacterial flora.     

Phylogeny of a relapsing fever Borrelia species transmitted by the hard tick Ixodes scapularis

The discovery of Borrelia species that were related to the agents of relapsing fever but were transmitted by hard ticks rather than soft ticks challenged previous taxonomies based largely on microbe–host specificities and geographic considerations. One of these newly-identified organisms is the Borrelia miyamotoi sensu lato strain LB-2001 from North America and transmitted by Ixodes scapularis. This or related strains have been identified as the cause of human disease, but comparatively little is known about their biology or genetics. Using recently acquired chromosome sequence of LB-2001 together with database sequences and additional sequences determined here, I carried out comparisons of the several species of Borrelia, including those in the two major clades: the relapsing fever group of species and the Lyme disease group of species. Phylogenetic inference at the species level was based on four data sets: whole chromosomes of ∼1 Mb each, and concatenated sequences of 19 ribosomal protein genes, 3 conserved nucleic acid enzymes (rpoC, recC, and dnaE), and 4 contiguous genes for nucleotide salvage on a large plasmid. Analyses using neighbor-joining, maximum likelihood, and Bayesian methods were largely concordant for each of the trees. They showed that LB-2001 and related hard tick-associated organisms, like Borrelia lonestari, are deeply positioned within the RF group of species and that these organisms did not, as some earlier estimations had suggested, constitute a paraphyletic group. The analyses also provided further evidence that major changes in host ranges and life cycles, such as hard to soft ticks or vice versa, may not correlate well with overall sequence differences. The genetic differences between LB-2001 and B. miyamotoi sensu stricto justify provisional use of the “sensu lato” designation for LB-2001.     

Close Relationship of Ruminant Pestiviruses and Classical Swine Fever Virus

To determine why serum from small ruminants infected with ruminant pestiviruses reacted positively to classical swine fever virus (CSFV)–specific diagnostic tests, we analyzed 2 pestiviruses from Turkey. They differed genetically and antigenically from known Pestivirus species and were closely related to CSFV. Cross-reactions would interfere with classical swine fever diagnosis in pigs.     

Swine Production Impact on Residential Ambient Air Quality

ABSTRACT

Numerous residents in agricultural areas are concerned about the impact that the swine industry may have on the ambient air quality. They assume there is a risk because there is limited information on the airborne contaminant that may originate from these facilities. The objective of the project was to assess the impact of swine production on ambient air quality related to public health in farming communities. Of the six chosen communities, three were considered not to be in a swine production area, whereas the three others were considered to be within a swine production area. Data were collected during three periods in spring and summer 2006. Ammonia and hydrogen sulfide concentrations were monitored on a continuous basis whereas odor concentrations and intensities were monitored twice a week. Odor concentrations were measured by dynamic olfactometry and odor intensities were determined by trained odor assessors. Public health was evaluated by survey questionnaires sent to a sample of residents in each of the six communities. Average NH₃ concentrations ranged from 6.9 to 12.6 ppb for nonexposed communities and from 8.9 to 18.3 ppb for exposed communities. Average H₂S concentrations ranged from 1.1 to 1.5 ppb for nonexposed communities and from 1.1 to 1.6 ppb for exposed communities. For a community in a swine production area, ambient NH₃ and H₂S concentrations were found to be higher than those communities not in a swine production area; however, that difference was not significant and they were within air quality standards for public health and safety. Odor concentrations showed no significant difference between the nonexposed and exposed communities and between evening and morning periods. Odor intensities were found to be significantly higher in the communities within swine production areas. More research will be required to fully understand the correlation between specific physical symptoms from residents and the presence of odors from swine production.     

Cordyceps militaris Extract Protects Human Dermal Fibroblasts against Oxidative Stress-Induced Apoptosis and Premature Senescence

Oxidative stress induced by reactive oxygen species (ROS) is the major cause of degenerative disorders including aging and disease. In this study, we investigated whether Cordyceps militaris extract (CME) has in vitro protective effects on hydrogen peroxide-induced oxidative stress in human dermal fibroblasts (HDFs). Our results showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CME was increased in a dose-dependent manner. We found that hydrogen peroxide treatment in HDFs increased ROS generation and cell death as compared with the control. However, CME improved the survival of HDFs against hydrogen peroxide-induced oxidative stress via inhibition of intracellular ROS production. CME treatment inhibited hydrogen peroxide-induced apoptotic cell death and apoptotic nuclear condensation in HDFs. In addition, CME prevented hydrogen peroxide-induced SA-β-gal-positive cells suggesting CME could inhibit oxidative stress-induced premature senescence. Therefore, these results suggest that CME might have protective effects against oxidative stress-induced premature senescence via scavenging ROS.     

Brucella suis strain 2 vaccine is safe and protective against heterologous Brucella spp. infections

Brucellosis is a wide spread zoonotic disease that causes abortion and infertility in mammals and leads to debilitating, febrile illness in humans. Brucella abortus, Brucella melitensis and Brucella suis are the major pathogenic species to humans. Vaccination with live attenuated B. suis strain 2 (S2) vaccine is an essential and critical component in the control of brucellosis in China. The S2 vaccine is very effective in preventing brucellosis in goats, sheep, cattle and swine. However, there are still debates outside of China whether the S2 vaccine is able to provide protection against heterologous virulent Brucella species. We investigated the residual virulence, immunogenicity and protective efficacy of the S2 vaccine in BALB/c mice by determining bacteria persistence in spleen, serum antibody response, cellular immune response and protection against a heterologous virulent challenge. The S2 vaccine was of low virulence as there were no bacteria recovered in spleen four weeks post vaccination. The vaccinated mice developed Brucella-specific IgG in 2–3 weeks, and a burst production of IFN-γ at one week as well as a two-fold increase in TNF-α production. The S2 vaccine protected mice from a virulent challenge by B. melitensis M28, B. abortus 2308 and B. suis S1330, and the S2 vaccinated mice did not develop any clinical signs or tissue damage. Our study demonstrated that the S2 vaccine is of low virulence, stimulates good humoral and cellular immunity and protects animals against infection by heterologous, virulent Brucella species.     

Spleen and lung virome analysis of South American fur seals (Arctocephalus australis) collected on the southern Brazilian coast

South American fur seals (Arctocephalus australis) are believed to reach the coast of Rio Grande do Sul (RS) through sea currents. They live in colonies and are frequently found resting on the beach. However, it is also common to find dead pinnipeds on beaches, sharing the environment with humans, domestic animals and other wild species on the coast and facilitating the transmission of pathogens. In the present study, a metagenomic approach was applied to evaluate the viral diversity in organs of fur seals found deceased along the coast of the state of RS, southern Brazil. The lungs and spleens of 29 animals were collected, macerated individually, pooled separately (one pool for lungs and another for spleens) and sequenced using the Illumina MiSeq platform. Sequences more closely related to members of the Anelloviridae and Circoviridae families were detected. Nine putative new species of anellovirus and one putative new genus, named Nitorquevirus, were described. Additionally, the circovirus sequences found in the lungs of A. australis have a common ancestor with PCV3, a proposed swine pathogen. Our study expanded the knowledge about viral communities in pinnipeds and could be useful for monitoring new viruses and potential viral sharing among wildlife, domestic animals, and humans.     

Metals and Nonsteroidal Anti-inflammatory Pharmaceuticals Drugs Present in Water from Madín Reservoir (Mexico) Induce Oxidative Stress in Gill,Blood, and Muscle of Common Carp (Cyprinus carpio)

Many toxic xenobiotics that enter the aquatic environment exert their effects through redox cycling. Oxidative stress, which incorporates both oxidative damage and antioxidant defenses, is a common effect induced in organisms exposed to xenobiotics in their environment. The results of the present study aimed to determine the oxidative stress induced in the common carp Cyprinus carpio by contaminants [metals and nonsteroidal anti-inflammatory drugs (NSAIDs)] present in Madín Reservoir. Five sampling stations (SSs), considered to have the most problems due to discharges, were selected. Carp were exposed to water from each SS for 96 h, and the following biomarkers were evaluated in gill, blood, and muscle: hydroperoxide content, lipid peroxidation, protein carbonyl content, and the activity of antioxidant enzymes superoxide dismutase and catalase. Results show that contaminants (metals and NSAIDs) present in water from the different SSs induce oxidative stress. Thus, water in this reservoir is contaminated with xenobiotics that are hazardous to C. carpio, a species consumed by the local human population.     

Comparative genomics of Bacillus anthracis from the wool industry highlights polymorphisms of lineage A.Br.Vollum

BackgroundWith the advent of affordable next-generation sequencing (NGS) technologies, major progress has been made in the understanding of the population structure and evolution of the B. anthracis species. Here we report the use of whole genome sequencing and computer-based comparative analyses to characterize six strains belonging to the A.Br.Vollum lineage. These strains were isolated in Switzerland, in 1981, during iterative cases of anthrax involving workers in a textile plant processing cashmere wool from the Indian subcontinent.ResultsWe took advantage of the hundreds of currently available B. anthracis genomes in public databases, to investigate the genetic diversity existing within the A.Br.Vollum lineage and to position the six Swiss isolates into the worldwide B. anthracis phylogeny. Thirty additional genomes related to the A.Br.Vollum group were identified by whole-genome single nucleotide polymorphism (SNP) analysis, including two strains forming a new evolutionary branch at the basis of the A.Br.Vollum lineage. This new phylogenetic lineage (termed A.Br.H9401) splits off the branch leading to the A.Br.Vollum group soon after its divergence to the other lineages of the major A clade (i.e. 6 SNPs). The available dataset of A.Br.Vollum genomes were resolved into 2 distinct groups. Isolates from the Swiss wool processing facility clustered together with two strains from Pakistan and one strain of unknown origin isolated from yarn. They were clearly differentiated (69 SNPs) from the twenty-five other A.Br.Vollum strains located on the branch leading to the terminal reference strain A0488 of the lineage. Novel analytic assays specific to these new subgroups were developed for the purpose of rapid molecular epidemiology.ConclusionsWhole genome SNP surveys greatly expand upon our knowledge on the sub-structure of the A.Br.Vollum lineage. Possible origin and route of spread of this lineage worldwide are discussed.     

A Systematic Review of Occupational Exposure to Hydrogen Sulfide in Livestock Operations

ABSTRACT

This systematic review summarizes the current state of knowledge in hydrogen sulfide (H₂S) concentrations within intensive livestock operations. The review was undertaken to better understand H₂S concentrations in intensive livestock operations, in relation to the American Conference of Governmental Industrial Hygienists (ACGIH) limit reduction to a 1 ppm time-weighted average (TWA). Several online academic databases were searched using two conceptual groups of search terms: “livestock” and “hydrogen sulfide.” Industry gray literature was additionally identified via targeted searches of online agriculture-specific Web sites. Title, abstract, and full-text screening were performed to select articles reporting H₂S measurements made within livestock facilities. Forty-five articles were included in this review. The bulk (70%) of articles described swine operations, whereas the remaining represented poultry and dairy operations. Although 14% of the articles described task-based monitoring of H₂S, the majority of articles (86%) involved only area monitoring. Weighted means from all three livestock types were below 1 ppm, although swine operations displayed a wider range of exposure (from 0 to 97 ppm). Despite most mean task-based exposures being close to 1 ppm, the peak concentrations measurements may be higher during power washing (97 ppm) and miscellaneous tasks (11.4 ppm). This review provides a novel overview of H₂S levels in intensive livestock operations, including information on task-based measurements. The review highlights numerous influences that produce a wide variability of H₂S levels in intensive livestock operations. The review also highlights the need for research focused on personal monitoring of daily worker exposures to hydrogen sulfide in intensive livestock operations.     

Phylogenomics and comparative genomic studies delineate six main clades within the family Enterobacteriaceae and support the reclassification of several polyphyletic members of the family

The family Enterobacteriaceae harbors many important pathogens, however it has proven difficult to reliably distinguish different members of this family or discern their interrelationships. To understand the interrelationships among the Enterobacteriaceae species, we have constructed two comprehensive phylogenetic trees for 78 genome-sequenced Enterobacteriaceae species based on 2487 core genome proteins, and another set of 118 conserved proteins. The genome sequences of Enterobacteriaceae species were also analyzed for genetic relatedness based on average amino acid identity and 16S rRNA sequence similarity. In parallel, comparative genomic studies on protein sequences from the Enterobacteriaceae have identified 88 molecular markers in the form of conserved signature indels (CSIs) that are uniquely shared by specific members of the family. All of these multiple lines of investigations provide consistent evidence that most of the species/genera within the family can be assigned to 6 different subfamily level clades which are designated as the “Escherichia clade”, “Klebsiella clade”, “Enterobacter clade”, “Kosakonia clade”, “Cronobacter clade” and “Cedecea clade”. The members of the six described clades, in addition to their distinct branching in phylogenetic trees, can now be reliably demarcated in molecular terms on the basis of multiple identified CSIs that are exclusively shared by the group members. Several additional CSIs identified in this work that are either specific for individual genera (viz. Kosakonia, Kluyvera and Escherichia-Shigella), or are present at various taxonomic depths, offer information regarding the interrelationships among the different clades. The described molecular markers provide novel means for diagnostic as well as genetic and biochemical studies on the Enterobacteriaceae species and for resolving the polyphyly of its several genera viz. Escherichia, Enterobacter and Kluyvera. On the bases of our results, we are proposing the reclassification of Escherichia vulneris and Enterobacter massiliensis into two novel genera viz. Pseudescherichia gen. nov. and Metakosakonia gen. nov., respectively. Additionally, our results also support the transfer of “Enterobacter lignolyticus” and “Kluyvera intestini” to the genera Pluralibacter and Metakosakonia, respectively.     

Zoonotic Chlamydiaceae Species Associated with Trachoma,Nepal

Trachoma is the leading cause of preventable blindness. Commercial assays do not discriminate among all Chlamydiaceae species that might be involved in trachoma. We investigated whether a commercial Micro-ArrayTube could discriminate Chlamydiaceae species in DNA extracted directly from conjunctival samples from 101 trachoma patients in Nepal. To evaluate organism viability, we extracted RNA, reverse transcribed it, and subjected it to quantitative real-time PCR. We found that 71 (70.3%) villagers were infected. ArrayTube sensitivity was 91.7% and specificity was 100% compared with that of real-time PCR. Concordance between genotypes detected by microarray and ompA genotyping was 100%. Species distribution included 54 (76%) single infections with Chlamydia trachomatis, C. psittaci, C. suis, or C. pecorum, and 17 (24%) mixed infections that includied C. pneumoniae. Ocular infections were caused by 5 Chlamydiaceae species. Additional studies of trachoma pathogenesis involving Chlamydiaceae species other than C. trachomatis and their zoonotic origins are needed.     

Highlights on molecular identification of closely related species

The term “complex” emerged in the literature at the beginning of the genomic era associated to taxonomy and grouping organisms that belong to different species but exhibited similar patterns according to their morphological, physiological and/or other phenotypic features. DNA–DNA hybridization values ⩾70% and high identity on 16S rRNA gene sequences were recommended for species delineation. Electrophoretic methods showed in some cases to be useful for species identification and population structure but the reproducibility was questionable. Later, the implementation of polyphasic approaches involving phenotypic and molecular methods brought new insights into the analysis of population structure and phylogeny of several “species complexes”, allowing the identification of new closely related species. Likewise, the introduction of multilocus sequence typing and sequencing analysis of several genes offered an evolutionary perspective to the term “species complex”. Several centres worldwide have recently released increasing genetic information on distinct microbial species. A brief review will be presented to highlight the definition of “species complex” for selected microorganisms, mainly the prokaryotic Acinetobacter calcoaceticus – Acinetobacter baumannii, Borrelia burgdorferi sensu lato, Burkholderia cepacia, Mycobacterium tuberculosis and Nocardia asteroides complexes, and the eukaryotic Aspergillus fumigatus, Leishmania donovani and Saccharomyces sensu stricto complexes. The members of these complexes may show distinct epidemiology, pathogenicity and susceptibility, turning critical their correct identification. Dynamics of prokaryotic and eukaryotic genomes can be very distinct and the term “species complex” should be carefully extended.     

Host-feeding patterns and behaviour of 4 Culex species in an endemic area of Japanese encephalitis

Studies were made on the host-feeding patterns and behaviour of 4 Culex species in China (Province of Taiwan) to further assess their importance as vectors of Japanese encephalitis. A relatively unbiased, non-attractant technique (vacuum sweep-net) was used for collecting mosquitos resting outdoors on rural premises; blood meals from engorged specimens were identified by precipitin tests. Additional information was obtained by analysing data from related studies. Precipitin-test results indicated that C. annulus, C. tritaeniorhynchus, and C. fuscocephalus feed principally on mammals, the first species mainly on swine and the latter two largely on bovine hosts. Mosquito forage ratios suggested that the apparent preference of C. annulus for swine over bovine hosts might be a function of host density. C. annulus was found to be zoophilic, exophilic, and exophagic; however, in view of its abundance during the JE epidemic season, contact with human hosts may reach a significant level, even indoors. The other 3 species of Culex were considered to be of lesser importance as JE vectors during the 1971 epidemic season because of their host-feeding patterns and/or population densities.     

A chemically defined protein-free liquid medium for the cultivation of some species of Neisseria

Chemically defined, protein-free, liquid culture media are needed for research with pathogenic bacteria and for the preparation of vaccines from them. Variations in growth or yield of organisms should be due only to differences in strain, and the medium itself should have little or no antigenic properties or toxicity. The medium should maintain the integrity of the bacterial species fully and it is particularly important that the complete antigenic complement of the organism should remain unaltered. The medium should be inexpensive and simple to prepare. Such a medium for the cultivation of some species of Neisseria, known to be fastidious, is described.     

Evolution of the sequence composition of Flaviviruses

The adaption of pathogens to their host(s) is a major factor in the emergence of infectious disease and the persistent survival of many of the infectious diseases within the population. Since many of the smaller viral pathogens are entirely dependent upon host machinery, it has been postulated that they are under selection for a composition similar to that of their host. Analyses of sequence composition have been conducted for numerous small viral species including the Flavivirus genus. Examination of the species within this particular genus that infect vertebrate hosts revealed that sequence composition proclivities do not correspond with vector transmission as the evolutionary history of this species suggests. Recent sequencing efforts have generated complete genomes for many viral species including members of the Flavivirus genus. A thorough comparison of the sequence composition was conducted for all of the available Flaviviruses for which the complete genome is publicly available. This effort expands the work of previous studies to include new vector-borne species as well as members of the insect-specific group which previously have not been explored. Metrics, including mono-, di-, and tri-nucleotide abundances as well as N_C values and codon usage preferences, were explored both for the entire polyprotein sequence as well as for each individual coding region. Preferences for compositions correspond to host-range rather than evolutionary history; species which infect vertebrate hosts exhibited particular preferences similar to each other as well as in correspondence with their host's preferences. Flaviviruses which do not infect vertebrate hosts, however, did not show these proclivities, with the exception of the Kamiti River virus suggesting its recent (either past or present) infectivity of an unknown vertebrate host.