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pathogen exposure patterns among sympatric populations of bighorn sheep, mule deer and cattle.we sampled sympatric bighorn sheep (ovis canadensis, n = 31), mule deer (odocoileus hemionus, n = 38), and domestic cattle (n = 26) in the san bernadino mountains of southern california (usa) for the presence of psoroptes spp. mites and for serologic evidence of exposure to bluetongue virus (btv) and babesia spp. from 1991 through 1994, psoroptes spp. infestations were found on 12 (44%) of 27 bighorn sheep. no mites were found on mule deer or cattle. the btv serum antibody prevalence in a cohort ...19979131583
bluetongue disease and the molecular epidemiology of viruses from the western united states.prototype and field isolates of united states bluetongue viruses were evaluated for genetic heterogeneity by sequence analyses. prototype viruses btv 2, 10, 11, 13 and 17 from the united states, btv 10 vaccine virus, and field isolates of btv 10 and 17 from california were analyzed. gene segment 2 from btv 10 and 17 isolated in 1980-81 and 1990 was sequenced along with gene segment 9 from btv 10 isolates. the wisconsin package was used to analyze nucleotide sequences and to predict amino acid co ...19968800543
evolution of the l2 gene of strains of bluetongue virus serotype 10 isolated in california.the genetic characteristics and phylogenetic relationships between the u.s. prototype strain of bluetongue virus serotype 10 (btv 10), the modified live virus vaccine currently used in california, and three field isolates of btv 10 obtained in 1980 and three in 1990 in california were determined by comparison of their l2 gene sequences. the l2 genes of the 1980 field isolates were very closely related to the l2 genes of the prototype strain and the vaccine strain, differing by only 0.1 to 0.5%. ...19948178484
variation in the ns3/ns3a gene of bluetongue viruses contained in culicoides sonorensis collected from a single site in southern california.to determine the variability of the ns3/ns3a gene of field strains of btv contained in culicoides sonorensis collected from a single site in california (ca), the ns3/ns3a gene was directly amplified and sequenced from 22 pools of c. sonorensis and compared with those of previously characterized field isolates from ca, as well as to viruses that caused recent outbreaks of bluetongue disease in ruminants in ca. phylogenetic analysis established that the ns3/ns3a gene of strains of btv contained in ...200211900839
analysis of the genomes of bluetongue virus serotype 10 vaccines and a recent btv-10 isolate from washington.the 10 double-stranded rna gene segments of 2 vaccinal strains of bluetongue virus (btv) serotype 10 that are used in the united states (btv ca8 california and bt-8 colorado), and a btv-10 isolate recently obtained from infected sheep in washington (state) were characterized by oligonucleotide fingerprint analyses. it was determined that although the 2 btv-10 vaccinal strains are genotypically distinct, they are closely related both to each other and to the united states prototype btv-10 virus. ...19836299144
survey of desert bighorn sheep in california for exposure to selected infectious diseases.from february 1983 to june 1985, 188 desert bighorn sheep (ovis canadensis nelsoni, = 161 and oc cremnobates, = 27) from 18 herds in 17 mountain ranges and one captive herd were caught, marked, and had blood, fecal, and nasal mucus samples collected. nasal swab specimens were cultured bacteriologically and virologically specifically for parainfluenza-3 (pi-3) virus. bacterial flora differed from herd to herd. pathogenic pneumophilic bacteria (eg, pasteurella sp) seldom were found. parainfluenza- ...19853878356
seasonal transmission of bluetongue virus by culicoides sonorensis (diptera: ceratopogonidae) at a southern california dairy and evaluation of vectorial capacity as a predictor of bluetongue virus transmission.vectorial capacity of culicoides sonorensis wirth & jones for the transmission of bluetongue (blu) virus was examined at a southern california dairy from january 1995 to december 1997. insects were collected one to two times per week in five cdc-type suction traps (without light) baited with co2 at a constant release rate of 1,000 ml/min. blu virus was detected in midges collected from may through december with an estimated overall infection rate of 0.08%. the blu virus infection rate of field-c ...200111296823
response of culicoides sonorensis (diptera: ceratopogonidae) to 1-octen-3-ol and three plant-derived repellent formulations in the field.the potential attractant 1-octen-3-ol and 3 potential repellents were assayed for activity for culicoides sonorensis, the primary vector of bluetongue virus in north america. collections using octenol were low, but numbers in suction traps were greater in the high-octenol treatment (11.5 mg/h) than in the low-octenol treatment (1.2 mg/h) or unbaited control for both sexes. collections using high octenol, co2 (approximately 1,000 ml/min), or both showed octenol alone to be significantly less attr ...200010901641
seasonal abundance and survivorship of culicoides sonorensis (diptera: ceratopogonidae) at a southern california dairy, with reference to potential bluetongue virus transmission and persistence.seasonal abundance and survivorship of culicoides sonorensis wirth & jones were examined at a dairy in southern california from january 1995 to december 1997. insects were collected one to two times per week using five cdc-type suction traps (without light) baited with co2 at a constant release rate of 1,000 ml/min. female and male abundance was greatest during late summer and early fall and was directly correlated with mean monthly air temperature. parity of females was lowest during late summe ...200011004778
bluetongue virus in exotic ruminants. 19734355046
a seroepidemiological study on bluetongue virus in dairy cattle in the central valley of california.a seroepidemiological study on bluetongue virus (btv) infection in california dairy cattle was conducted to estimate the prevalence and distribution by age and season of btv group-reactive antibodies and to look for possible associations between the presence of antibodies and cattle age or breed and farm. between december 1985 and march 1987, a sample of cattle was tested at approximately two-month intervals for btv group-reactive antibodies using an enzyme-linked immunosorbent assay (elisa). da ...19902161142
identification of genetic variation between strains of bluetongue virus serotype 11 using cdna probes.recombinant plasmids containing inserts representing genome segments 2, 5, 6, 8, and 9 of bluetongue virus (btv) serotype 11, with tentative coding assignments for viral proteins p2, p5, ns1, ns2, and p6, respectively, have been used to study the genetic diversity within a btv serotype using northern blot hybridization. btv 11 strains were isolated in california, nevada, oklahoma, and mexico from elk, deer, and cattle. diversity was indirectly indicated in the btv 11 strains by comparisons of el ...19892543132
a preliminary report on the isolation and identification of the bluetongue virus from sheep in california. 195313044684
spatial and seasonal distribution of potential vectors of hemorrhagic disease viruses to peninsular bighorn sheep in the santa rosa mountains of southern california.blood-feeding midges (culicoides sp. and leptoconops sp.) were sampled in the santa rosa mountains, riverside county, california (usa), to determine which species might be involved in the transmission of bluetongue and epizootic hemorrhagic disease viruses to peninsular bighorn sheep (ovis canadensis cremnobates). host-seeking midges were sampled with co2-baited suction traps over a period of 30 mo. nineteen species of culicoides and seven of leptoconops were collected. five of the culicoides sp ...19921602570
variation amongst the neutralizing epitopes of bluetongue viruses isolated in the united states in 1979-1981.neutralizing epitopes present on field isolates of bluetongue virus (btv) serotypes 10, 11, 13 and 17 were evaluated with a panel of polyclonal and neutralizing monoclonal antibodies (mabs). a total of 91 field isolates were evaluated, including 15 isolates of btv-10, 29 isolates of btv-11, 26 isolates of btv-13, and 21 isolates of btv-17. the viruses were isolated from cattle, goats, sheep, elk and deer in idaho, louisiana, nebraska and, predominantly, california, in the years 1979, 1980 and 19 ...19921379766
fatal bluetongue virus infection in an alpaca (vicugna pacos) in california.in october 2008, a 15-year-old female alpaca (vicugna pacos) housed at a breeding farm in northern california died after a brief illness characterized by sudden onset of weakness, recumbency, and respiratory distress. postmortem examination revealed severe hydrothorax and hydropericardium, marked pulmonary edema, and acute superficial myocardial hemorrhage affecting the left ventricle. bluetongue virus (btv) was detected in the spleen by quantitative real-time reverse transcription polymerase ch ...201020093703
probability of introduction of exotic strains of bluetongue virus into the us and into california through importation of infected cattle.strategies designed to minimize the probability of bluetongue virus (btv) introduction to new areas should be based on a quantitative assessment of the probability of actually establishing the virus once it is introduced. the risk of introducing a new strain of bluetongue virus into a region depends on the number of viremic animals that enter and the competency of local vectors to transmit the virus. we used monte carlo simulation to model the probability of introducing btv into california, usa, ...200415579336
colostral transmission of bluetongue virus nucleic acid among newborn dairy calves in california.there have been substantial recent changes in the global distribution and nature of bluetongue virus (btv) infection of ungulates, perhaps as a result of climate change. to evaluate the epidemiology of btv infection in california, an area historically endemic for the virus, we monitored newborn dairy calves at different sites for 1 year for the presence of btv rna and virus-specific antibodies. the data confirm both localized, vector-mediated, seasonal transmission of btv as well as disseminatio ...201020557494
a deterministic model to quantify risk and guide mitigation strategies to reduce bluetongue virus transmission in california dairy cattle.the global distribution of bluetongue virus (btv) has been changing recently, perhaps as a result of climate change. to evaluate the risk of btv infection and transmission in a btv-endemic region of california, sentinel dairy cows were evaluated for btv infection, and populations of culicoides vectors were collected at different sites using carbon dioxide. a deterministic model was developed to quantify risk and guide future mitigation strategies to reduce btv infection in california dairy cattl ...201627812161
phylogenetic comparison of the s3 gene of united states prototype strains of bluetongue virus with that of field isolates from california.to better define the molecular epidemiology of bluetongue virus (btv) infection, the genetic characteristics and phylogenetic relationships of the s3 genes of the five u.s. prototype strains of btv, the commercially available serotype 10 modified live virus vaccine, and 18 field isolates of btv serotypes 10, 11, 13, and 17 obtained in california during 1980, 1981, 1989, and 1990 were determined. with the exception of the s3 gene of the u.s. prototype strain of btv serotype 2 (btv 2), these virus ...19968764098
seasonal and interseasonal dynamics of bluetongue virus infection of dairy cattle and culicoides sonorensis midges in northern california--implications for virus overwintering in temperate zones.bluetongue virus (btv) is the cause of an economically important arboviral disease of domestic and wild ruminants. the occurrence of btv infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of btv infection (using btv-specific real time reverse transcriptase polymerase chain reaction) among sentinel cattle and vector culicoides sonorensis (c. sonorensis) midges on a dairy farm in northern california throughout both the seasonal and inte ...201425215598
epidemiology of two orbiviruses in california's native wild ruminants: preliminary report.between 1978 and 1983 we collected more than 1,500 serum samples from california's native black-tailed deer (odocoileus hemionus columbianus), 4 races of mule deer (o. h. sp.), tule elk (cervus elaphus nannodes), roosevelt elk (c. e. roosevelti), pronghorn antelope (antilocapra americana), california bighorn sheep (ovis canadensis californiana), peninsular bighorn sheep (o. c. cremnobates) and desert bighorn sheep (o. c. nelsoni) and analyzed them for agar gel precipitating (agp) antibodies to b ...19852989899
antibody prevalence of eight ruminant infectious diseases in california mule and black-tailed deer (odocoileus hemionus).we tested 276 sera from 18 free-ranging black-tailed and mule deer (odocoileus hemionus) herds in california (usa) collected from 1987 to 1991 in five biogeographical habitat types, for antibodies against eight infectious disease agents. overall antibody prevalence was 56% for anaplasma marginale, 31% for borrelia burgdorferi, 16% for bluetongue virus serotype 17, 15% for epizootic hemorrhagic disease virus, 7% for coxiella burnetii and toxoplasma gondii, respectively, and 0% for bovine leukosis ...19948151824
trap placement and attractant choice affect capture and create sex and parity biases in collections of the biting midge, culicoides sonorensis.culicoides sonorensis wirth & jones (diptera: ceratopogonidae) is the primary north american vector of bluetongue virus (btv), which can cause high morbidity and mortality in ruminant livestock or wildlife. worldwide, most culicoides surveillance relies on light (usually uv) traps typically placed near animals or larval development sites. however, the trapping method can cause sex, species and parity biases in collections. we collected c. sonorensis from three dairies in california using suction ...201627257164
prevalence of antibodies of selected infectious disease agents in the peninsular desert bighorn sheep (ovis canadensis cremnobates) of the santa rosa mountains, california. 19826285010
serosurveillance for livestock pathogens in free-ranging mule deer (odocoileus hemionus).routine disease surveillance has been conducted for decades in mule deer (odocoileus hemionus) in california for pathogens shared between wildlife and domestic ruminants that may have implications for the animal production industry and wildlife health. deer sampled from 1990 to 2007 (n = 2,619) were tested for exposure to six pathogens: bluetongue virus (btv), epizootic hemorrhagic disease virus (ehdv), bovine viral diarrhea virus (bvdv), leptospira spp., anaplasma spp. and brucella spp. we eval ...201223209790
molecular evolution of american field strains of bluetongue and epizootic haemorrhagic disease viruses.recent orbivirus occurrences in the americas have been investigated using whole genome amplification and sequencing followed by phylogenetic analysis. the bluetongue virus (btv) and epizootic haemorrhagic disease virus (ehdv) whole genomes were amplified without prior sequence knowledge and deep sequenced. this technology was applied to evaluate btv‑3 isolates spanning 4 decades from florida, arkansas, mississippi, south dakota, central america, and the caribbean basin. the results of the datase ...201626741243
epidemiologic study of bluetongue virus on the tejon ranch, california: vector, host, virus relationships.culicoides gnats were monitored from april through november, 1981, on the tejon ranch, kern county. levels of gnat breeding were determined by quantitative sampling of substrate from intermittent and permanent water sources. adult populations were measured by light trap collections taken around pens holding sentinel beef cattle, dairy calves, sheep, goats and deer. adult gnats were collected in the environs of the study area, and blood samples were obtained from sentinel animals for laboratory d ...19852989907
epizootiological study of bluetongue virus infection in california livestock: an overview.an epidemiologic program was undertaken in california to study bluetongue virus (btv) infection in domestic livestock. the study was designed to determine: a) prevalence of btv infection, b) serotypes of btv actively causing infection, c) seasonality of infection and d) species infected. a total of 8,751 cattle, 14,639 sheep and 4,785 goats were tested over the 3 1/2 year study. serologically, 41% of the cattle, 42% of the sheep and 21% of the goats were positive. virologically, 2.4% of the catt ...19852989906
whole genome sequencing and phylogenetic analysis of bluetongue virus serotype 2 strains isolated in the americas including a novel strain from the western united states.bluetongue is a potentially fatal arboviral disease of domestic and wild ruminants that is characterized by widespread edema and tissue necrosis. bluetongue virus (btv) serotypes 10, 11, 13, and 17 occur throughout much of the united states, whereas serotype 2 (btv-2) was previously only detected in the southeastern united states. since 1998, 10 other btv serotypes have also been isolated from ruminants in the southeastern united states. in 2010, btv-2 was identified in california for the first ...201424916442
culicoides boydi (diptera: ceratopogonidae): a potential vector of hemorrhagic disease viruses to desert bighorn sheep in southern california.culicoides boydi new species is described from riverside county, ca. a taxonomic key, table of numerical characters, and female wing photographs are presented to distinguish it from the three other species of the culicoides pusillus species group of the subgenus avaritia. brief notes are presented on its biology and distribution and suspected vector potential in the transmission of bluetongue virus to desert bighorn sheep in california.19921334151
systemic adenovirus infection associated with high mortality in mule deer (odocoileus hemionus) in california.seventeen counties in northern california experienced epizootics of high mortality in the mule deer (odocoileus hemionus) population during the latter half of 1993. thirteen deer submitted to the california veterinary diagnostic laboratory system as part of this natural die-off had systemic adenovirus infection. pulmonary edema was present in all 13 deer. erosions, ulceration, and abscessation of the upper alimentary tract occurred in 7/13 deer. four of 13 deer had hemorrhagic enteritis. all 13 ...19968801705
mass screening of cattle sera against 14 infectious disease agents, using an elisa system for monitoring health in livestock.mass screening elisa methods were developed for testing cattle serum for antibodies against 14 common livestock diseases simultaneously. the absorbance values were transformed to a %elisa (spectrophotometric antibody end point) by a computer interfaced with a microplate reader. a histogram indicating a cutoff point and a report for the veterinarian also was generated. the computer program produced a print-out of the antibody profile for each animal tested, the antibody concentration against each ...19911767993
overwintering of bluetongue virus in temperate zones.within northern california, culicoides sonorensis is the major vector of bluetongue virus (btv) and annual infection of livestock is distinctly seasonal (typically july‑november). our recent studies compare the population dynamics of c. sonorensis midges with occurrence of btv infection of c. sonorensis and sentinel dairy cattle throughout both the seasonal and interseasonal ('overwintering') periods of btv activity. spring emergence and seasonal abundance of adult c. sonorensis on the sampled f ...201627723033
heterogeneity of the l2 gene of field isolates of bluetongue virus serotype 17 from the san joaquin valley of california.genome segment 2 (l2) from six field isolates of bluetongue virus (btv) serotype 17 was sequenced by cycling sequencing after the amplification of the viral cdna by the polymerase chain reaction. the viruses were isolated from sheep, cattle and a goat in the san joaquin valley of california during the years 1981 and 1990. these viruses exhibit divergent patterns of neutralization with btv 17-specific monoclonal antibodies. the six l2 genes of the btv 17 field isolates all encode a protein of 955 ...19948165870
the combination of abundance and infection rates of culicoides sonorensis estimates risk of subsequent bluetongue virus infection of sentinel cattle on california dairy farms.bluetongue (bt) is an important viral disease of ruminants that is transmitted by hematophagous culicoides midges. we examined the seasonal patterns of abundance and infection of culicoides sonorensis at four dairy farms in the northern central valley of california to develop estimates of risk for bluetongue virus (btv) transmission to cattle at each farm. these four farms were selected because of their similar meteorological conditions but varying levels of vector abundance and btv infection of ...201222281150
analysis of the genomes of bluetongue viruses recovered from different states of the united states and at different times.the ribonucleic acid (rna) genomes of the original representatives of the four serotypes of bluetongue virus (btv) isolated from the united states (btv-10, btv-11, btv-13 and btv-17) have been analyzed by polyacrylamide gel electrophoresis. ten double-stranded rna species were resolved for each virus and categorized into the size classes of large (l segments #1-3), medium (m segments #4-6) and small (s segments #7-10). minor electrophoretic mobility differences were observed for the m5 and s10 r ...19826278927
serological survey for bovine bacterial and viral pathogens in captive arabian oryx (oryx leucoryx pallas, 1776).tests for antibodies to bovine bacterial and viral pathogens were conducted on 239 sera from 128 arabian oryx (oryx leucoryx) from seven locations (taif, riyadh and mahazat as said, saudi arabia; san diego, united states of america [usa]; shaumari, jordan; qatar; and bahrain). no antibodies to pasteurella multocida type e or epizootic haemorrhagic disease 1 virus were found. antibodies to brucella abortus, p. multocida type b, p. multocida type d, lumpy skin disease virus and akabane virus were ...19921305861
anthropogenic and meteorological factors influence vector abundance and prevalence of bluetongue virus infection of dairy cattle in california.bluetongue is an economically important arboviral disease of ruminants that is transmitted by hematophagous culicoides midges. in light of dramatic recent changes in the global distribution of bluetongue virus (btv), the goals of this study were to re-evaluate the prevalence of btv infection of cattle and abundance of culicoides midges on individual dairy farms in california. a serosurvey of adult dairy cattle confirmed that btv infection is prevalent throughout much of the state, although the c ...201121930352
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