共查询到20条相似文献，搜索用时 31 毫秒
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Ute Ziegler Joke Angenvoort Dominik Fischer Christine Fast Martin Eiden Ariel V. Rodriguez Sandra Revilla-Fernández Norbert Nowotny Jorge García de la Fuente Michael Lierz Martin H. Groschup 《Veterinary microbiology》2013,161(3-4):263-273
West Nile virus (WNV) is a zoonotic flavivirus that is transmitted by blood-suckling mosquitoes with birds serving as the primary vertebrate reservoir hosts (enzootic cycle). Some bird species like ravens, raptors and jays are highly susceptible and develop deadly encephalitis while others are infected subclinically only. Birds of prey are highly susceptible and show substantial mortality rates following infection. To investigate the WNV pathogenesis in falcons we inoculated twelve large falcons, 6 birds per group, subcutaneously with viruses belonging to two different lineages (lineage 1 strain NY 99 and lineage 2 strain Austria). Three different infection doses were utilized: low (approx. 500 TCID50), intermediate (approx. 4 log10 TCID50) and high (approx. 6 log10 TCID50). Clinical signs were monitored during the course of the experiments lasting 14 and 21 days. All falcons developed viremia for two weeks and shed virus for almost the same period of time. Using quantitative real-time RT-PCR WNV was detected in blood, in cloacal and oropharyngeal swabs and following euthanasia and necropsy of the animals in a variety of neuronal and extraneuronal organs. Antibodies to WNV were first time detected by ELISA and neutralization assay after 6 days post infection (dpi). Pathological findings consistently included splenomegaly, non-suppurative myocarditis, meningoencephalitis and vasculitis. By immunohistochemistry WNV-antigens were demonstrated intralesionally. These results impressively illustrate the devastating and possibly deadly effects of WNV infection in falcons, independent of the genetic lineage and dose of the challenge virus used. Due to the relatively high virus load and long duration of viremia falcons may also be considered competent WNV amplifying hosts, and thus may play a role in the transmission cycle of this zoonotic virus. 相似文献
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Müller H Johne R Schusser G Giese M Linke S Pauli G 《DTW. Deutsche tier?rztliche Wochenschrift》2006,113(12):435-439
The epidemic West Nile Virus (WNV) infections observed in the last years, particularly those in the USA in 1999 and the following years, have led to an increasing interest in this zoonotic infection. Here, the most prominent aspects of WNV biology and epidemiology are presented. Clinical signs observed in men and horses are described, as well as the current state of diagnostics and immunoprophylaxis. Preliminary results of investigations on the prevalence of WNV in Germany show that migrating birds have been in contact with WNV; there is however no indication for the presence of this virus. While WNV is endemic in many parts of the "Old World", thus inducing "natural immunity" in (migrating) birds and vertebrates, a susceptible bird population with no existing immunity against this virus was exposed in the "New World". 相似文献
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Niczyporuk JS Samorek-Salamonowicz E Kozdruń W Mizak Z 《Acta veterinaria Hungarica》2011,59(3):405-408
The aim of the study was to attempt the detection of West Nile virus (WNV) in wild birds in Poland. Forty-eight species of 1912 wild birds were used for the investigations. The birds were derived from various locations in Poland from early spring till late autumn of the years 2009-2011. The brain samples were homogenised and cellular RNA was isolated. Two methods (RT-PCR and nested RT-PCR) were used. The presence of WNV RNA was not detected in the samples examined. Additionally, a short analysis of the epizootiological situation regarding the presence of WNV in Poland is presented. 相似文献
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Gardner IA Wong SJ Ferraro GL Balasuriya UB Hullinger PJ Wilson WD Shi PY MacLachlan NJ 《Veterinary research》2007,38(1):109-116
A prospective cohort study was used to estimate the incidence of West Nile virus (WNV) infection in a group of unvaccinated horses (n = 37) in California and compare the effects of natural WNV infection in these unvaccinated horses to a group of co-mingled vaccinated horses (n = 155). Horses initially were vaccinated with either inactivated whole virus (n = 87) or canarypox recombinant (n = 68) WNV vaccines during 2003 or 2004, prior to emergence of WNV in the region. Unvaccinated horses were serologically tested for antibodies to WNV by microsphere immunoassay incorporating recombinant WNV E protein (rE MIA) in December 2003, December 2004, and every two months thereafter until November 2005. Clinical neurologic disease attributable to WNV infection (West Nile disease (WND)) developed in 2 (5.4%) of 37 unvaccinated horses and in 0 of 155 vaccinated horses. One affected horse died. Twenty one (67.7%) of 31 unvaccinated horses that were seronegative to WNV in December, 2004 seroconverted to WNV before the end of the study in November, 2005. Findings from the study indicate that currently-available commercial vaccines are effective in preventing WND and their use is financially justified because clinical disease only occurred in unvaccinated horses and the mean cost of each clinical case of WND was approximately 45 times the cost of a 2-dose WNV vaccination program. 相似文献
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Wodak E Richter S Bagó Z Revilla-Fernández S Weissenböck H Nowotny N Winter P 《Veterinary microbiology》2011,149(3-4):358-366
The emergence of West Nile virus (WNV) was expected in Austria since the initial discovery of the infection in neighbouring Hungary in 2003/2004. In 2008 six cases of West Nile disease were diagnosed at the Institute for Veterinary Disease Control M?dling, Austrian Agency for Health and Food Safety (AGES), involving five goshawks (Accipiter gentilis) and one gyrfalcon (Falco rusticolus), which were found dead in the eastern Austrian federal states of Lower Austria, Vienna and Styria, respectively. Pathomorphological and immunohistochemical findings suggested a WNV infection. Virus was isolated in embryonated specific pathogen free chicken eggs and propagated in mouse neuroblastoma cells (NA), in which a cytopathic effect occurred. The virus was identified and characterised by electron microscopic examination and molecular detection using RT-PCR, sequencing, and phylogenetic analysis. The Austrian WNV sequences exhibited nucleotide identities of 99.9% to the lineage 2 WNV sequences described in Hungary since 2004. In addition, 71 sera of 14 different bird species were screened for the presence of WNV antibodies using a commercial ELISA: 43.7% of the tested samples showed antibody titers. Selected positive sera were also subjected to WNV neutralisation tests, in which the ELISA results were verified in 66%. The results of this study confirm unambiguously the presence of a lineage 2 WNV infection in birds of prey in the eastern part of Austria. 相似文献
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Niczyporuk JS Samorek-Salamonowicz E Mizak WK 《Polish journal of veterinary sciences》2011,14(4):573-577
Two thousand one hundred and forty birds belonging to 39 different species from different locations in Poland were examined. The study has taken place from the early spring till late autumn 2007-2010 when the activity of the mosquitoes was the highest. The brain samples were taken from the birds and whole cellular RNA was isolated, then the RT-PCR and NRT-PCR were performed to detect the presence of West Nile virus (WNV). The obtained results were confirmed by the commercial WNV Kit. No genetic material of WNV was found in the examined samples. 相似文献
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P. Calistri A. Giovannini G. Savini F. Monaco L. Bonfanti C. Ceolin C. Terregino M. Tamba P. Cordioli R. Lelli 《Zoonoses and public health》2010,57(3):211-219
After 10 years, West Nile virus (WNV) re‐emerged in Italy in August 2008. As on 31 December 2008, the infection affected eight Provinces in three Regions (Emilia Romagna, Veneto, Lombardy), where a total of 794 cases of WNV infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. Only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in 18 different farms. The observed case‐fatality rate was 15.6% (5/32). The confirmed clinical cases were detected from end August to mid October. Significant levels of positivity by RT‐PCR were also observed in magpies (Pica pica) (9.1%, 95% confidence levels: 6.1–13.4%), carrion crows (Corvus corone) (7.4%, 95% confidence levels: 3.6–14.4%) and rock pigeons (Columba livia) (12.9%, 95% confidence levels: 7.6–21.2%). 相似文献
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西尼罗热病毒RT-PCR检测方法的建立 总被引：3，自引：0，他引：3
参考Genebank发表的西尼罗热病毒(West Nile virus，WNV)E糖蛋白基因序列，自行设计合成一对引物，对WNV进行RT—PCR扩增，产物经琼脂糖电泳分析，呈现一条约400bp的条带，将其克隆入pMD18-T—Vector载体中，并进行序列测定，与已发表的WNV基因比较发现，核苷酸的同源性为99．7％，证实为WNV的E基因，通过对样品多次检测，都能扩增出一条约400bp的条带，表明该方法比较稳定。 相似文献
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Pathology of fatal West Nile virus infections in native and exotic birds during the 1999 outbreak in New York City, New York 总被引：9，自引：0，他引：9
Steele KE Linn MJ Schoepp RJ Komar N Geisbert TW Manduca RM Calle PP Raphael BL Clippinger TL Larsen T Smith J Lanciotti RS Panella NA McNamara TS 《Veterinary pathology》2000,37(3):208-224
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Serologic evidence of West Nile virus and Usutu virus infections in Eurasian coots in the Netherlands 
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下载免费PDF全文 S. M. Lim M. Geervliet J. H. Verhagen G. J. D. M. Müskens F. A. Majoor A. D. M. E. Osterhaus B. E. E. Martina 《Zoonoses and public health》2018,65(1):96-102
West Nile virus (WNV) and Usutu virus (USUV) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. As arboviruses are currently expanding their geographic range and emerging in often unpredictable locations, surveillance is considered an important element of preparedness. To determine whether sera collected from resident and migratory birds in the Netherlands as part of avian influenza surveillance would also represent an effective source for proactive arbovirus surveillance, a random selection of such sera was screened for WNV antibodies using a commercial ELISA. In addition, sera of jackdaws and carrion crows captured for previous experimental infection studies were added to the selection. Of the 265 screened serum samples, 27 were found to be WNV–antibody‐positive, and subsequent cross‐neutralization experiments using WNV and USUV confirmed that five serum samples were positive for only WNV‐neutralizing antibodies and seven for only USUV. The positive birds consisted of four Eurasian coots (Fulica atra) and one carrion crow (Corvus corone) for WNV, of which the latter may suggest local presence of the virus, and only Eurasian coots for USUV. As a result, the screening of a small selection of serum samples originally collected for avian influenza surveillance demonstrated a seroprevalence of 1.6% for WNV and 2.8% for USUV, suggesting that this sustained infrastructure could serve as a useful source for future surveillance of arboviruses such as WNV and USUV in the Netherlands. 相似文献
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Tasnim Ayadi Abdesslem Hammouda Ceclie Beck Thierry Boulinier Sylvie Lecollinet Slaheddine Selmi 《Zoonoses and public health》2019,66(5):495-503
Bird migration has long been hypothesized as the main mechanism for long‐distance dispersal of flaviviruses, but the role of migratory birds in flaviviruses spillover is not well documented. In this study, we investigated the eco‐epidemiology of West Nile virus (WNV) and Usutu virus (USUV) in trans‐Saharan passerines during their spring stopover in southern Tunisian oases. To do, we combined oral swab analysis and serological tools to assess whether migratory birds could be reaching these stopover sites while infectious or have been previously exposed to viruses. All sampled birds tested negative for oral swab analysis. However, anti‐WNV and anti‐USUV antibodies were detected in 32% and 1% of tested birds, respectively. Among WNV‐seropositive species, the Golden oriole (Oriolus oriolus) showed the highest anti‐WNV occurrence probability. In this species, anti‐WNV occurrence was twice larger in males than females. Inter‐specific and intraspecific morphological, physiological and behavioural differences could explain these results. Although our findings did not show evidence for passerines migrating while infectious, they did not exclude an existing enzootic WNV transmission cycle in Tunisian oases. Further investigations including larger samples of migratory birds are needed for a better understanding of this issue. 相似文献
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Equine West Nile virus (WNV) encephalomyelitis cases - based on clinical signs and ELISA serology test results - reported to Texas disease control authorities during 2002 were analyzed to provide insights into the epidemiology of the disease within a previously disease-free population. The epidemic occurred between June 27 and December 17 (peaking in early October) and 1,698 cases were reported. Three distinct epidemic phases were identified, occurring mostly in southeast, northwest and then central Texas. Significant (P<0.05) disease clusters were identified in northwest and northern Texas. Most (91.1%) cases had no recent travel history, and most (68.9%) cases had not been vaccinated within the previous 12 months. One-third of cases did not survive, 71.2% of which were euthanatized. The most commonly reported presenting signs included ataxia (69%), abnormal gait (52%), muscle fasciculations (49%), depression (32%) and recumbency (28%). Vaccination status, ataxia, falling down, recumbency and lip droop best explained the risk of not surviving WNV disease. Results suggest that the peak risk period for encephalomyelitis caused by WNV may vary substantially among regions within Texas. Recumbent horses have a poor prognosis for survival. Vaccines, even if not administered sufficiently in advance of WNV infection within a district, may reduce the risk of death by at least 44%. 相似文献