首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Partial 1D gene characterization was used to study phylogenetic relationships between 17 serotype O foot-and-mouth disease (FMD) viruses in Ethiopia as well as with other O-type isolates from Eritrea, Kenya, South and West Africa, the Middle East, Asia and South America. A homologous region of 495 bp corresponding to the C-terminus end of the 1D gene was used for phylogenetic analysis. This study described three lineages, viz. African/Middle East-Asia, Cathay and South American. Within lineage I, three topotypes were defined, viz. East and West Africa and the Middle East-Asia together with the South African isolate. The Ethiopian isolates clustered as part of topotype I, the East African topotype. Two clades (based on < 12 % nucleotide difference) A and B were identified within the East African isolates, with clade A being further classified into three significant branches, A1 (80% bootstrap support), A2 (89% bootstrap support) and A3 (94% bootstrap support). Clade B consisted of two Kenyan isolates. Within topotype I, the 17 Ethiopian isolates showed genetic heterogeneity between themselves with sequence differences ranging from 4.6-14 %. Lineage 2 and 3 could be equated to two significant topotypes, viz. Cathay and South America. Comparison of amino acid variability at the immunodominant sites between the vaccine strain (ETH/19/77) and other Ethiopian outbreak isolates revealed variations within these sites. These results encourage further work towards the reassessment of the type O vaccine strain currently being used in Ethiopia to provide protection against field variants of the virus.  相似文献   

2.
A total of 30 field isolates of foot-and-mouth disease virus (FMDV) serotype Asia1 belonging to two different lineages and five isolates belonging to a divergent group as delineated earlier in 1D (encodingVP1 protein) gene-based phylogeny were sequenced in the structural protein (P1) coding region. Phylogenetic comparison of these isolates along with some of the published exotic sequences revealed the presence of five different lineages around the world. Similar grouping pattern was observed for the P1 region and 1D gene-based phylogeny, where the Indian isolates were clustered in two genetic lineages. The recently identified divergent group of virus falls into a separate sub-cluster. Similar grouping was also observed in L gene-based phylogeny. Comparison of amino acid sequences identified lineage-specific signature residues in all the structural proteins. Comparison of Asia1 field isolates at the identified key residues of other FMD viruses involved in the formation of the heparan sulfate-binding ligand confirmed many of them to be conserved and the presence of VP3(56) Arg suggested their cell culture adaptation. Although a considerable genetic variation was observed among the isolates of present study, all of them tested in micro-neutralization test were serologically related to the vaccine strain.  相似文献   

3.
In 1999, 10 sporadic outbreaks of cattle foot-and-mouth disease (FMD) occurred in Taiwan. By the time, infection was limited to the Chinese yellow cattle (a native species of beef cattle in Mainland China), which did not develop vesicular lesions under field conditions. Five viruses isolates obtained from individual farms were confirmed to be the serotype O FMD virus (O/Taiwan/1999). During January-February 2000, however, this virus has spread to dairy cattle and goat herds, causing severe mortality in goat kids and vesicular lesions in dairy cattle. Partial nucleotide sequence of the capsid coding gene 1D (VP1) was determined for the virus isolates obtained in this study. Phylogenetic analysis of the VP1 sequences indicated that the O/Taiwan/1999 viruses shared 95-97% similarities to the virus strains isolated from the Middle East and India. The species susceptibility of the O/Taiwan/1999 virus was experimentally studied in several species of susceptible animals, showing that the virus did cause generalized lesions in dairy cattle and pigs, however, it would not cause vesicular lesions on the Chinese yellow cattle and the adult goats. These studies suggested that the O/Taiwan/1999 virus was a novel FMD virus of Taiwan and it presented various levels of susceptibility in cattle species.  相似文献   

4.
  相似文献   

5.
The nucleic acid and structural proteins of infectious bursal disease virus serotype I (six isolates) were compared with those of serotype II (two isolates). Five of the serotype I isolates originated from chickens, whereas both serotype II isolates were from turkeys. The growth curves of representative isolates of both serotypes were similar, but the latent period and virus yield were different. The seven isolates tested had two segments of double-stranded genomic RNA. The RNA migration patterns of viruses belonging to each serotype were similar, but differences were noticed between the two serotypes. There were differences in the molecular weights of viral proteins (VP) 3 and 4 from the two serotypes, and serotype II isolates lacked VP-2.  相似文献   

6.
Zhang GZ  Zhao JX  Wang HW  Yang AM  Bu CY  Wang M 《Avian diseases》2006,50(3):386-390
Four Yucaipa-like viruses of avian paramyxovirus serotype 2 (APMV-2) were isolated in China from the imported Gouldian Finch (Chloebia gouldiae) and broilers in 1998-2002, and were named F4, F6, F8, and NK, respectively. Examined under electron microscope, the isolates were found to be round in shape and varying in size. The results of the hemagglutination inhibition test and indirect enzyme-linked immunosorbent assay (using monoclonal antibodies) showed some differences between the isolates and the reference strain Yucaipa. The isolates derived from chickens had a closer relationship to Yucaipa virus than did those of finches. Sequence comparison of the fusion gene and the haemagglutinin-neuraminidase gene showed similar results, although the variations were lesser among APMV-2 viruses in nucleotide and amino acid sequence. By sequence comparison, it was also revealed that at the molecular level the four virus strains belong to APMV-2, and that two of the strains were isolated from the same group of imported Gouldian Finches.  相似文献   

7.
Foot-and-mouth disease is an endemic animal disease in Hong Kong. In this study, a total of 70 clinical specimens were collected from locally infected pigs from 2001 to 2010. Phylogenetic analysis of VP1 sequences reveal that all Hong Kong FMDV serotype O isolates are classified into three lineages: HK-A and HK-B in Cathay topotype, and HK-C in SEA topotype. Regression analysis projects that the time of divergence from the most recent common ancestor of HK-A and HK-B are 1964 ± 12 and 1987 ± 9 years respectively. Although HK-B shares a common ancestor with strains that caused outbreak in Taiwan and Philippines, there is no consolidated evidence demonstrating the order of introduction events among these regions. HK-C lineage is the latest FMDV isolated in Hong Kong. This virus is likely adopted from bovine into porcine. As local pigs confer immunity mainly against Cathay topotype viruses, introduction of HK-C viruses have led into an unexpectedly high severity and rapid spreading rate of the disease. A systematic surveillance and communication network is essential to provide accurate information in controlling the pandemics.  相似文献   

8.
Several phylogenetic lineages of the infectious bursal disease virus (IBDV) genome segment B have been identified. Although this genome segment has been shown to contribute to virulence, little is known about the genetic lineages that exist in the United States. The nucleotide genome segment B sequences of 67 IBDV strains collected from 2002 to 2011 in the United States were examined. Although they were from nine different states, a majority (47) of these viruses were from California. A 722-base pair region near the 5' end of genome segment B, starting at nucleotide 168 and ending at 889, was examined and compared to sequences available in GenBank. The nucleotide sequence alignment revealed that mutations were frequently observed and that they were uniformly spaced throughout the region. When the predicted amino acids were aligned, amino acids at positions 145, 146, and 147 were found to change frequently. Six different amino acid triplets were observed and the very virulent (vv) IBDV strains (based on presence of vvIBDV genome segment A sequence) all had the triplet T145, D146, and N147. None of the non-vvIBDV strains had this TDN triplet. Phylogenetic analysis of the 67 nucleotide sequences revealed four significant genome segment B lineages among the U.S. viruses. One of these included the genome segment B typically found in vvIBDV and three contained non-vvIBDV genome segment B sequences. When the available sequences in GenBank were added to the analysis, two additional lineages were observed that did not contain U.S. viruses; one included viruses from China and the other contained viruses from the Ivory Coast. Although the samples tested do not represent all poultry producing regions in the United States, serotype 1 viruses from states outside California all belonged to one genome segment B lineage. The other three lineages observed in the United States were populated with viruses exclusively found in California, except the serotype 2 lineage, where the type strain was a serotype 2 virus from Ohio. The data provide further evidence for the importance of genome segment B identification during routine molecular diagnosis of all IBDV strains.  相似文献   

9.
A total of 18 foot-and-mouth disease virus (FMDV) serotype Asia1 field isolates belonging to two different lineages (including the divergent group) as delineated earlier in VP1-based phylogeny were sequenced in the non-structural 3A and 3C protein-coding regions. The phylogenetic trees representing the regions coding for the non-structural proteins were very similar to that of the structural VP1 protein-coding region. Phylogenetic comparison at 3C region revealed clustering of Asia1 viruses with the isolates of serotypes O, A and C in the previously identified clade. Comparison of amino acid sequences identified lineage-specific signature residues in both the non-structural proteins. Overall analysis of the amino acid substitutions revealed that the 3A coding region was more prone to amino acid alterations than 3C region.  相似文献   

10.
Sequence diversity was assessed of the complete VP1 gene directly amplified from 49 clinical specimens during an explosive foot-and-mouth disease (FMD) outbreak in Taiwan. Type O Taiwan FMD viruses are genetically highly homogenous, as seen by the minute divergence of 0.2-0.9% revealed in 20 variants. The O/HCP-0314/TW/97 and O/TCP-022/TW/97 viral variants dominated FMD outbreaks and were prevalent in most affected pig-raising areas. Comparison of deduced amino acid sequences around the main neutralizable antigenic sites on the VP1 polypeptide showed no significant antigenic variation. However, the O/CHP-158/TW/97 variant had an alternative critical residue at position 43 in antigenic site 3, which may be due to selective pressure in the field. Two vaccine production strains (O1/Manisa/Turkey/69 and O1/Campos/Brazil/71) probably provide partial heterologous protection of swine against O Taiwan viruses. The type O Taiwan variants clustered in sublineage A1 of four main lineages in the phylogenetic tree. The O/Hong Kong/9/94 and O/1685/Moscow/Russia/95 viruses in sublineage A2 are closely related to the O Taiwan variants. The causative agent for the 1997 epidemic presumably originated from a single common source of type O FMD viruses prevalent in neighboring areas.  相似文献   

11.
At present, Foot-and-Mouth Disease (FMD) has been successfully controlled in most territories of South America, where only Ecuador and Venezuela remain as endemic countries. In this context, the precise characterization of circulating viruses is of utmost importance. This work describes the first molecular epidemiology study performed with the complete VP(1)-coding region of 114 field isolates of FMD virus (FMDV) type O, collected in the Andean countries mainly during 2002-2008. Sequences were aligned and compared to isolates responsible for emergencies in the Southern Cone of the continent between the years 2000 and 2006, and to other representative type O viruses worldwide. The results showed that FMD type O viruses isolated in South America and analyzed up to date are placed in 11 different lineages within the Euro SA topotype. Five of these lineages included viruses circulating in Ecuador and Venezuela during 2002-2008. The last emergencies reported in already-free areas in the Andean region, showed close relationships with viruses circulating in these endemic countries. Andean lineages showed a clear separation from the unique lineage containing viruses responsible for the emergencies in the Southern Cone, reflecting the different livestock circuits and providing evidence that support the ecosystem dynamics in the region. A wide geographical dissemination of the same strain in short time intervals has been observed, pointing to animal movements as the most significant risk parameter. This fact, together with an important generation of viral variants in areas under weak control strategies, reinforce the need of stronger official controls, as well as for establishing multinational cooperative measures in the border areas.  相似文献   

12.
Twenty-five field infectious bronchitis viruses (IBVs) similar to, but genetically distinct from, the DE072 serotype were isolated from several states in the United States from 1990 through 1999 and were examined molecularly and antigenically. A 421-bp sequence in the hypervariable region of the S1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. Cross-virus neutralization testing and entire S1 sequence analysis on selected isolates further confirmed that fact, and we divided the viruses into the DE072 serotype and two other unique groups. In a vaccine protection trial, the commercially available DE072 vaccine showed less than 50% protection against viruses in one of the groups. The majority of the recent isolates belong to that group and share very low antigenic relatedness to the DE072 strain as well as other serotypes of IBV. Consequently, we designated this group as a new serotype, Georgia 98. We developed a restriction fragment length polymorphism analysis that can differentiate this new serotype from all other serotypes of IBV.  相似文献   

13.
  相似文献   

14.
  相似文献   

15.
Suarez DL  Senne DA 《Avian diseases》2000,44(2):356-364
The last highly pathogenic outbreak of avian influenza in the United States was caused by an H5N2 influenza virus in Pennsylvania and New Jersey in 1983-84. Through a combined federal and state eradication effort, the outbreak was controlled. However, in 1986-89, multiple H5N2 viruses were isolated from poultry farms and the live bird markets (LBMs) in the United States. To determine the epidemiologic relationships of these viruses, the complete coding sequence of the nonstructural gene and the hemagglutinin protein subunit 1 of the hemagglutinin gene was determined for 11 H5N2 viruses and compared with previously available influenza sequences. The H5N2 isolates from 1986-89 were all closely related to the isolates from the 1983-84 Pennsylvania outbreak by nucleotide and amino acid sequence analysis for both genes, providing additional evidence that the Pennsylvania/83 (PA/83) virus lineage was not completely eradicated. The PA/83 lineage also had a large number of unique amino acid changes not found in other avian influenza viruses, which was suggestive that this lineage of virus had been circulating in poultry for an extended period of time before the first isolation of virus in 1983. High substitution and evolutionary rates were measured by examining the number of nucleotide or amino acid substitutions over time as compared with the index case, CK/PA/21525/83. These rates, however, were similar to other outbreaks of avian influenza in poultry. This study provides another example of the long-term maintenance and evolution of influenza viruses in the U.S. LBMs and provides further evidence of the connection of the LBMs and the Pennsylvania 1983 H5N2 outbreak.  相似文献   

16.
In 2004 and then in 2006 several outbreaks of infectious bursal disease (IBD) were reported in broiler and broiler breeder flocks in Slovenia. In this report ten recently emerged IBD viruses (IBDV) were characterised by sequence analysis of the VP2 hypervariable region and compared to previous Slovene IBDV strains from 1995/1996 and to some representative serotype 1 IBDV strains of different pathotypes. On the basis of nucleotide and amino acid identities, phylogenetic analyses and the presence of very virulent IBDV (vvIBDV) conserved amino acid substitutions, all Slovene isolates from recent outbreaks were identified as vvIBDV. Although some unique nucleotide exchanges and amino acid substitutions have been observed, the results of this study indicated that recent vvIBDV isolates are closely related with those from outbreaks in the 1990s. However, acute IBD has not been reported in commercial flocks in Slovenia for some years. This could lead to the conclusion that poor biosecurity and relaxed vaccination could be responsible for the re-emergence of vvIBDV.  相似文献   

17.
The study was conducted in three regional states of Ethiopia: Amhara, Oromia, and Addis Ababa from August 2008 to April 2009 with the objectives of identifying the genetic diversity of serotypes and topotypes in Ethiopia, and determining the attack rate and associations of potential risk factors with foot-and-mouth disease (FMD) seropositivity. A total of 496 cattle were clinically and serologically examined for presence of specific lesions and nonstructural protein for FMD, respectively. Of which, 140 (28.2%) manifested clinical signs and lesions suggestive of FMD, and 219 (44.2%) were seropositive. From a total of 7,781 animals observed and recorded on a designed format in six districts, 1,409 (19.6%) were infected, and 15 (0.12%) died during outbreaks of FMD. Epidemiological investigations revealed that the morbidity rate of the disease was 21.1% in Akaki-kality sub-city, but the mortality rate was <2% in all districts. Furthermore, the mortality and case fatality rates were relatively higher, 1.6% and 8.9% in calves than the other age groups, respectively. From a total of 33 bovine epithelial tissue-cultured samples, 19 (57.6%) showed CPE for FMD virus, in which 16 samples had serotype O and EA-3 topotype, while three samples had found serotype A, Africa topotype, and G-VII strain. Various strains of FMD viruses were isolated in Ethiopia in this study, and therefore, further detailed studies on the evaluation of available vaccines and the development of a vaccine which contains cocktails of antigens of FMD virus strains in the country should be encouraged.  相似文献   

18.
Foot-and-mouth disease virus (FMDV) serotype Asia1 field isolates (n = 100) were compared using a panel of 11 monoclonal antibodies (Mab) in sandwich ELISA. The majority (over 89%) of the isolates showed either homologous (76% and above reactivity) or reduced affinity (20-75% reactivity) for the Mabs 2A, 13, 40, 34 and 81, suggesting that these Mab binding epitopes are conserved, whereas a more variable reactivity was observed for the Mabs B3, 1A, 24, 72, 82 and 89. Polyclonal relationship ('r' value) of the field isolates in liquid phase blocking (LPB) ELISA was examined, and the mean 'r' value was 0.62 relative to vaccine virus IND 63/72. Some of the field isolates (n = 34) were tested in virus neutralization test (VNT) and showed an 'r' value of >0.40. Although a minor antigenic difference was observed in the Mab profiling study, there has not been large antigenic divergence between reference virus and field viruses, thereby providing evidence of wide antigenic coverage of the vaccine strain.  相似文献   

19.
This article reports the genetic and pathogenic characteristics of 34 isolates of H6N1 avian influenza viruses isolated in Taiwan between 1972 and 2005. Genetic analyses showed that a unique lineage of H6N1 viruses has been established in domestic chickens in Taiwan since 1997, and this lineage of viruses differs from the H6N1 viruses circulating in Hong Kong and Southeastern China. Pathogenicity tests showed that all Taiwanese H6N1 viruses were of low pathogenicity but might lead to economic loss when associated with other diseases. Hemagglutination inhibition tests showed that antigenic drift has occurred in Taiwanese H6N1 viruses, and sequence comparison has identified a total of five possible antigenic sites on the hemagglutinin molecule of the H6N1 viruses. Some Taiwanese H6N 1 viruses could replicate in mice without preadaptation, indicating that these viruses have the potential to cause cross-species infection into mammals.  相似文献   

20.
FMD clinically positive 250 tissue samples (mouth and hoof epithelium and vesicle swabs, tongue tissue) and 175 secretion samples (milk, saliva, serum, plasma) were evaluated by RT-PCR for the diagnosis of FMD with different pair of universal and serotype-specific primers from 2006 to 2007 in Punjab, Pakistan. Universal primer pair P1/P2 from VP1 gene detected FMD in 182 out of 250 (72.8%) tissues and 92 out of 175 (52.6%) secretion samples, while universal primer 1F/1R from 5′UTR region detected FMD in 218 out of 250 (87.2%) tissues and 142 out of 175 (81.1%) secretion samples. 1F/1R proved better than the P1/P2 primer pair for primary diagnosis of FMD, direct from the clinical positive samples. Direct sequencing of the universal primer pair P1/P2 revealed that O serotype of FMD was circulating in this region. O serotype of FMD was detected with O-1C(ARS4)/PNK 61, AU(O)/AU(rev), AU(O)/PNK61 primer pairs, these primer pairs also compared with each other. AU(O)/AU(rev) and AU(O)/PNK61 detected O serotype of FMD in 88.9% tissue and swab (mouth and hoof vesicle swabs) samples and 71.9% different secretion (milk, saliva, serum, plasma) samples, while O-1C(ARS4)/PNK 61 detected 48.1% tissue and swab (mouth and hoof vesicle swabs) samples and 37.5% different secretion (milk, saliva, serum, plasma) samples. AU(O)/AU(rev), AU(O)/PNK61 primer pairs detected 40.8% more tissue and swab samples, while these pairs detected 34.4% more secretion samples. Cloning of PCR product of AU(O)/AU(rev) VP1 gene and sequencing for phylogenetic studies revealed that O serotype of FMD circulating in Punjab, Pakistan was genetically very diverse from the ‘O’ serotype in Middle East and Europe. The dendrogram showed that Pakistan ‘O’ serotype was very much similar genetically to its neighbor countries (Sri Lanka, India, Iran, Iraq, and China) and PanAsia 1 lineage which caused 2001-outbreak in UK and 1994-outbreak in Saudi Arabia, etc.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号