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1.
1,268 sera collected from slaughtered pigs in Hassia (FRG) from 1986 to 1988 were tested for antibodies against porcine and human influenza A virus strains using the single radial haemolysis test (SRHT). Antibodies against the porcine strains (subtype H1N1) A/Swine/Arnsberg/1/81, A/Swine/Iowa/15/30 and A/New Jersey/7/76 were detected in 411 (32.4%), 318 (25.1%) and 304 (24.0%) of sera, respectively. Up to 1988 a slight increase (10%) in the seroprevalence to A/Swine/Arnsberg/1/81 was noticed, whereas the results obtained with the other strains showed little variation. Antibodies against the human H1N1 strain A/Singapore/6/86 were only found in sera collected 1987 and 1988 in rates of 1.6% and 3.0%. Serological indication of infections with the human H3N2 strains A/Victoria/1/75, A/Hong Kong/1/68 and A/Philippines/2/82 could be shown in 286 (22.6%), 178 (14.4%) and 135 (10.6%) of the serum samples. Within the three year period the rate of sera positive for antibodies against A/Philippines/2/82 increased from 6.5% to 23.0%, whereas no variation in the rates were found using the other H3N2 strains. Antibodies simultaneously against porcine (H1N1) and human (H3N2) virus strains were detected in 9.9% of all sera tested.  相似文献   

2.
The introduction of the 2009 pandemic H1N1 (pH1N1) influenza virus in pigs changed the epidemiology of influenza A viruses (IAVs) in swine in Europe and the rest of the world. Previously, three IAV subtypes were found in the European pig population: an avian‐like H1N1 and two reassortant H1N2 and H3N2 viruses with human‐origin haemagglutinin (HA) and neuraminidase proteins and internal genes of avian decent. These viruses pose antigenically distinct HAs, which allow the retrospective diagnosis of infection in serological investigations. However, cross‐reactions between the HA of pH1N1 and the HAs of the other circulating H1 IAVs complicate serological diagnosis. The prevalence of IAVs in Greek swine has been poorly investigated. In this study, we examined and compared haemagglutination inhibition (HI) antibody titres against previously established IAVs and pH1N1 in 908 swine sera from 88 herds, collected before and after the 2009 pandemic. While we confirmed the historic presence of the three IAVs established in European swine, we also found that 4% of the pig sera examined after 2009 had HI antibodies only against the pH1N1 virus. Our results indicate that pH1N1 is circulating in Greek pigs and stress out the importance of a vigorous virological surveillance programme.  相似文献   

3.
A commercial indirect swine influenza virus (SIV) H1N1 enzyme-linked immunosorbent assay (ELISA) was compared with the hemagglutination inhibition (HI) assay by testing 72 samples from experimentally infected pigs and 780 field samples of undefined SIV status. The HI assay was performed using SIV isolates A/Swine/IA/73 for H1N1 and A/Swine/IA/8548-1/98 for H3N2. The ELISA used an SIV isolated in 1988. The results showed that HI and ELISA detected an antibody in 11 and 6, respectively, of 72 serum samples collected from pigs experimentally infected with a 1992 SIV isolate (A/Swine/IA/40776/92). The presence of antibodies in these experimental samples was confirmed by HI tests in which all 72 samples were positive against the homologous virus, a more recent H1N1 SIV isolate (A/Swine/NVSL/01) supplied by National Veterinary Services Laboratories, Ames, Iowa, and a 1999 H1N1 isolate currently used in a commercial vaccine. On testing 780 field samples, an overall agreement of 85.5% was generated between the HI and ELISA. This study demonstrated that the ELISA is a useful serodiagnostic screening test at herd level for detecting swine antibodies against SIV. However, a new SIV isolate representing current SIV strains circulating in the field is needed to replace the older isolates used in the HI and ELISA to increase the test accuracy for serodiagnosis of SIV.  相似文献   

4.
This paper reports on a serological and virological survey for swine influenza virus (SIV) in densely populated pig areas in Spain. The survey was undertaken to examine whether the H1N2 SIV subtype circulates in pigs in these areas, as in other European regions. Six hundred sow sera from 100 unvaccinated breeding herds across Northern and Eastern Spain were examined using haemagglutination inhibition (HI) tests against H1N1, H3N2 and H1N2 SIV subtypes. Additionally, 225 lung samples from pigs with respiratory problems were examined for the presence of SIV by virus isolation in embryonated chicken eggs and by a commercial membrane immunoassay. The virus isolates were further identified by HI and RT-PCR followed by partial cDNA sequencing. The HI test on sera revealed the presence of antibodies against at least one of the SIV subtypes in 83% of the herds and in 76.3% of the animals studied. Of the 600 sow sera tested, 109 (18.2%), 60 (10%) and 41 (6.8%) had SIV antibodies to subtype H1N2 alone, H3N2 alone and H1N1 alone, respectively. Twelve H3N2 viruses, 9 H1N1 viruses and 1 H1N2 virus were isolated from the lungs of pigs with respiratory problems. The analysis of a 436 nucleotide sequence of the neuraminidase gene from the H1N2 strain isolated further confirmed its identity. Demonstrably, swine influenza is still endemic in the studied swine population and a new subtype, the H1N2, may be becoming established and involved in clinical outbreaks of the disease in Spain.  相似文献   

5.
对2009年H1N1甲型流感流行前后的上海地区养殖场户410份猪血清样品,分别采用血凝抑制试验（hemagglutination inhibition,HI）和酶联免疫吸附试验（enzyme-linked immunosorbent assay,ELISA）进行检测H1N1甲型流感病毒和猪流感病毒（Swine in？uenza virus,SIV）。检测结果表明,除2007年外,2008~2010年猪血清中均存在不同水平的HI抗体,阳性率呈显著上升趋势,且抗体水平与猪群饲养周期及饲养密度正相关,而与猪流感病毒的流行无相关性。  相似文献   

6.
天津地区猪流感血清学调查   总被引：9，自引：0，他引：9  
2002年-2005年期间,采用血凝抑制试验对天津市10个区县44个养猪场进行了猪流感病毒抗体检测,结果75%的被调查猪场抗体检测结果有阳性,检测的648份血清样品中,69.6%为阳性。流感病毒抗体亚型调查结果显示该地区流行的猪流感病毒主要为H1和H3亚型,抗体阳性率分别为55.4%和39.4%。部分猪群中存在抗H9亚型流感病毒抗体,阳性率为5.4%,但未发现H5亚型流感病毒抗体。此外,部分猪群中同时存在2种或3种亚型(H1,H3和H9)流感病毒的抗体,表明这些猪曾经同时被2种或3种不同亚型的流感病毒感染。  相似文献   

7.
Herd-level seroprevalence of swine-influenza virus in Korea   总被引：3，自引：0，他引：3  
A total of 911 serum samples from 130 herds (an average of nine serum samples per herd) in Korea were examined for antibody to swine H1N1-influenza virus using enzyme-linked immunosorbent assay (ELISA). The list of farms was obtained from the Korean Swine Association, and herds were included from all five of the country’s states. Farms were selected using a random-numbers table for swine within farms and for farms. All serum samples were collected from 22- to 24-week-old finishing pigs between September 2000 and March 2001. By ELISA, 93 out of 130 sampled herds (71.5%) were positive against swine H1N1-influenza virus. Our data suggested that seropositive herds for swine H1N1-influenza virus are distributed diffusely throughout the Republic of Korea.  相似文献   

8.
Although swine origin A/H1N1/2009 influenza virus (hereafter "pH1N1″) has been detected in swine in 20 countries, there has been no published surveillance of the virus in African livestock. The objective of this study was to assess the circulation of influenza A viruses, including pH1N1 in swine in Cameroon, Central Africa. We collected 108 nasal swabs and 98 sera samples from domestic pigs randomly sampled at 11 herds in villages and farms in Cameroon. pH1N1 was isolated from two swine sampled in northern Cameroon in January 2010. Sera from 28% of these herds were positive for influenza A by competitive ELISA and 92.6% of these swine showed cross reactivity with pandemic A/H1N1/2009 influenza virus isolated from humans. These results provide the first evidence of this virus in the animal population in Africa. In light of the significant role of swine in the ecology of influenza viruses, our results call for greater monitoring and study in Central Africa.  相似文献   

9.
The recent pandemic caused by human influenza virus A(H1N1) 2009 contains ancestral gene segments from North American and Eurasian swine lineages as well as from avian and human influenza lineages. The emergence of this A(H1N1) 2009 poses a potential global threat for human health and the fact that it can infect other species, like pigs, favours a possible encounter with other influenza viruses circulating in swine herds. In Europe, H1N1, H1N2 and H3N2 subtypes of swine influenza virus currently have a high prevalence in commercial farms. To better assess the risk posed by the A(H1N1) 2009 in the actual situation of swine farms, we sought to analyze whether a previous infection with a circulating European avian-like swine A/Swine/Spain/53207/2004 (H1N1) influenza virus (hereafter referred to as SwH1N1) generated or not cross-protective immunity against a subsequent infection with the new human pandemic A/Catalonia/63/2009 (H1N1) influenza virus (hereafter referred to as pH1N1) 21 days apart. Pigs infected only with pH1N1 had mild to moderate pathological findings, consisting on broncho-interstitial pneumonia. However, pigs inoculated with SwH1N1 virus and subsequently infected with pH1N1 had very mild lung lesions, apparently attributed to the remaining lesions caused by SwH1N1 infection. These later pigs also exhibited boosted levels of specific antibodies. Finally, animals firstly infected with SwH1N1 virus and latter infected with pH1N1 exhibited undetectable viral RNA load in nasal swabs and lungs after challenge with pH1N1, indicating a cross-protective effect between both strains.  相似文献   

10.
为了解猪流感病毒(SIV)的变异情况,我们2009年11月从河北某养殖场采集呈流感症状的猪鼻拭子40份,接种10日龄SPF鸡胚,分离到一株猪流感病毒,通过RT-PCR和血凝抑制试验鉴定为H1N1亚型,命名为A/swine/Hebei/15/2009(H1N1),其全基因序列测定及同源性分析发现,8个基因片段均与2000年左右H1N1人流感病毒有较高的同源性。系统遗传演化显示,该病毒分离株是由2000年人源H1N1流感病毒A/Dunedin/2/2000(H1N1)进化而来。抗原性分析显示该株与甲型H1N1流感病毒和经典H1N1病毒株抗原性差异较大。对小鼠致病性试验表明该病毒株可以直接感染小鼠并导致小鼠轻微临床症状和组织病理学变化,但不致死小鼠,表现为低致病性。  相似文献   

11.

Background

Swine influenza is an infectious acute respiratory disease of pigs caused by influenza A virus. We investigated the time of entry of swine influenza into the Finnish pig population. We also describe the molecular detection of two types of influenza A (H1N1) viruses in porcine samples submitted in 2009 and 2010.This retrospective study was based on three categories of samples: blood samples collected for disease monitoring from pigs at major slaughterhouses from 2007 to 2009; blood samples from pigs in farms with a special health status taken in 2008 and 2009; and diagnostic blood samples from pigs in farms with clinical signs of respiratory disease in 2008 and 2009. The blood samples were tested for influenza A antibodies with an antibody ELISA. Positive samples were further analyzed for H1N1, H3N2, and H1N2 antibodies with a hemagglutination inhibition test. Diagnostic samples for virus detection were subjected to influenza A M-gene-specific real-time RT-PCR and to pandemic influenza A H1N1-specific real-time RT-PCR. Positive samples were further analyzed with RT-PCRs designed for this purpose, and the PCR products were sequenced and sequences analyzed phylogenetically.

Results

In the blood samples from pigs in special health class farms producing replacement animals and in diagnostic blood samples, the first serologically positive samples originated from the period July–August 2008. In samples collected for disease monitoring, < 0.1%, 0% and 16% were positive for antibodies against influenza A H1N1 in the HI test in 2007, 2008, and 2009, respectively. Swine influenza A virus of avian-like H1N1 was first detected in diagnostic samples in February 2009. In 2009 and 2010, the avian-like H1N1 virus was detected on 12 and two farms, respectively. The pandemic H1N1 virus (A(H1N1)pdm09) was detected on one pig farm in 2009 and on two farms in 2010.

Conclusions

Based on our study, swine influenza of avian-like H1N1 virus was introduced into the Finnish pig population in 2008 and A(H1N1)pdm09 virus in 2009. The source of avian-like H1N1 infection could not be determined. Cases of pandemic H1N1 in pigs coincided with the period when the A(H1N1)pdm09 virus was spread in humans in Finland.  相似文献   

12.
Following a series of H5N1 cases in chickens and birds in a few states in Malaysia, there was much interest in the influenza A viruses subtypes that circulate among the local pig populations. Pigs may act as a mixing vessel for avian and mammal influenza viruses, resulting in new reassorted viruses. This study investigated the presence of antibodies against influenza H1N1 and H3N2 viruses in pigs from Peninsular Malaysia using Herdcheck Swine Influenza H1N1 and H3N2 Antibody Test Kits. At the same time, the presence of influenza virus was examined from the nasal swabs of seropositive pigs by virus isolation and real time RT-PCR. The list of pig farms was obtained from the headquarters of the Department of Veterinary Services, Malaysia, and pig herds were selected randomly from six of 11 states in Peninsular Malaysia. A total of 727 serum and nasal swab samples were collected from 4- to 6-month-old pigs between May and August 2005. By ELISA, the seroprevalences of swine influenza H1N1 and H3N2 among pigs were 12.2% and 12.1% respectively. Seropositivity for either of the virus subtypes was detected in less than half of the 41 sampled farms (41.4%). Combination of both subtypes was detected in 4% of all pigs and in 22% of sampled farms. However, no virus or viral nucleic acid was detected from nasal samples. This study identified that the seropositivity of pigs to H1N1 and H3N2 based on ELISA was significantly associated with factors such as size of farm, importation or purchase of pigs, proximity of farm to other pig farms and the presence of mammalian pets within the farm.  相似文献   

13.
Swine influenza virus (SIV) was isolated from a farm in Miyazaki Prefecture in Japan in July 2006. An isolate was genetically subtyped as H1N2 and was designated A/swine/Miyazaki/1/2006 (H1N2). The nucleotide sequences of all eight viral RNA segments were determined, and then phylogenetic analysis was performed using the neighbor-joining method. All segments were shown to be closely related to those of Japanese SIV H1N2 isolates, which have been circulating since the 1980s. The results indicate the persistence of the SIV H1N2 subtype in the Japanese pig population for more than two decades and emphasize the importance of continuous surveillance for SIV.  相似文献   

14.
Two US swine influenza virus (SIV) isolates, A/Swine/Iowa/15/1930 H1N1 (IA30) and A/Swine/Minnesota/00194/2003 H1N2 (MN03), were evaluated in an in vivo vaccination and challenge model. Inactivated vaccines were prepared from each isolate and used to immunize conventional pigs, followed by challenge with homologous or heterologous virus. Both inactivated vaccines provided complete protection against homologous challenge. However, the IA30 vaccine failed to protect against the heterologous MN03 challenge. Three of the nine pigs in this group had substantially greater percentages of lung lesions, suggesting the vaccine potentiated the pneumonia. In contrast, priming with live IA30 virus provided protection from nasal shedding and virus replication in the lung in MN03 challenged pigs. These data indicate that divergent viruses that did not cross-react serologically did not provide complete cross-protection when used in inactivated vaccines against heterologous challenge and may have enhanced disease. In addition, live virus infection conferred protection against heterologous challenge.  相似文献   

15.
Outbreaks of classical swine influenza in pigs in England in 1986   总被引：1，自引：0，他引：1  
Serum samples from pig herds in Great Britain have been examined for antibodies to influenza virus since 1968. Antibodies to H3N2 virus strains have been found since 1968 and the serological data presented here suggests that H3N2 virus strains continue to persist in the pig population. An outbreak of acute respiratory disease occurred in a 400-sow unit. The outbreak was characterised by coughing, anorexia, fever, inappetence and loss of condition. The gilts and weaners were affected and the morbidity approached 100 per cent. An influenza A virus designated A/Swine/Weybridge/117316/86 (H1N1) was isolated from the herd and 28 paired serum samples from the affected animals showed increases in the haemagglutination inhibition titres to this isolate. Haemagglutinin and neuraminidase characterisation indicated that the virus is similar to H1N1 viruses isolated recently from pigs in Europe. A total of 91 herds experiencing respiratory disease were investigated, of which 42 gave positive reactions in the haemagglutination inhibition test. Antibodies to A/Port Chalmers/1/73 (H3N2) were also detected in some of the herds but it is not known whether this strain plays any role in the current respiratory disease problems in pigs.  相似文献   

16.
Several highly pathogenic H5N1 avian influenza viruses were isolated from swine populations in Fujian Province, China, since 2001. Because it is thought that H5N1 infection in pigs might result in virus adaptation to humans, we surveyed swine populations in Fujian Province in 2004 and 2007 for serological evidence of the infection. Twenty‐five pig farms covering all nine administrative districts of Fujian Province were sampled and a total of 1407 serum specimens were collected. The haemagglutination inhibition (HI) tests revealed no evidence of H5 infection and only a few cases of H9 infection. The negative results for H5 infection were further verified by micro‐neutralization tests. By contrast, H1 influenza virus infections were prevalent in swine in both surveys according to the results of enzyme‐linked immunosorbent assay (ELISA). The H3 infection rate was reduced dramatically in 2007 compared with 2004, when examined by HI and ELISA. In summary, the results imply that the swine populations in Fujian Province had not been affected greatly by the H5N1 avian influenza virus, given that there is no serological evidence that H5N1 influenza virus has infected the pig populations. The reported isolates represent only sporadic cases.  相似文献   

17.
Yang H  Chen Y  Shi J  Guo J  Xin X  Zhang J  Wang D  Shu Y  Qiao C  Chen H 《Veterinary microbiology》2011,152(3-4):229-234
Influenza A (H1N1) virus has caused human influenza outbreaks in a worldwide pandemic since April 2009. Pigs have been found to be susceptible to this influenza virus under experimental and natural conditions, raising concern about their potential role in the pandemic spread of the virus. In this study, we generated a high-growth reassortant virus (SC/PR8) that contains the hemagglutinin (HA) and neuraminidase (NA) genes from a novel H1N1 isolate, A/Sichuan/1/2009 (SC/09), and six internal genes from A/Puerto Rico/8/34 (PR8) virus, by genetic reassortment. The immunogenicity and protective efficacy of this reassortant virus were evaluated at different doses in a challenge model using a homologous SC/09 or heterologous A/Swine/Guangdong/1/06(H1N2) virus (GD/06). Two doses of SC/PR8 virus vaccine elicited high-titer serum hemagglutination inhibiting (HI) antibodies specific for the 2009 H1N1 virus and conferred complete protection against challenge with either SC/09 or GD/06 virus, with reduced lung lesions and viral shedding in vaccine-inoculated animals compared with non-vaccinated control animals. These results indicated for the first time that a high-growth SC/PR8 reassortant H1N1 virus exhibits properties that are desirable to be a promising vaccine candidate for use in swine in the event of a pandemic H1N1 influenza.  相似文献   

18.
本研究由疑似猪流感病料样品中分离一株病毒,通过HA、HI、电镜观察、生物学特性测定及全基因序列测定表明,分离病毒株为H3N2亚型人流感病毒和H1N1亚型古典猪流感病毒(SIV)的重组体,命名为A/Swine/Fujian/F2/07(H3N2).该分离株含有8个基因片段,共13 442 bp,与GenBank中登录的H3N2亚型人流感病毒、H1N1亚型古典SIV和H3N2亚型SIV进行比较分析显示:分离株的HA、NS、NA基因与H3N2亚型人流感病毒株的同源性分别为84.7 ％～98.1％、94.4 ％～99.5％和88.6 ％～97.6％;与H3N2亚型SIV的核苷酸同源性分别为87.7％～98.5％、82.5 ％～99.9％和87.6 ％～98.4％;M基因与H3N2亚型人流感病毒和SIV的同源性均在90.1％以下,而与H1N1亚型古典SIV的同源性在97.6％以上.基因型分析表明分离株的PB2、PBI、PA、HA、NP、NA和NS基因片段来源于1975年～1982年的人流感病毒,而M基因来源于H1N1亚型古典SIV,充分证明猪作为流感病毒“混合器”的作用.  相似文献   

19.
The objective of this study was to explore the epidemic situation and pathogenic characteristics of swine influenza virus (SIV) in Shandong Province. In the spring of 2019, 130 swine nasal swab samples were collected from a slaughterhouse in Tai'an city, Shandong Province for virus isolation and identification. The whole genome of isolated virus was sequenced and analyzed. Meanwhile, 1 527 swine serum samples were collected from swine farms in 8 regions of Shandong province and their anti-SIV antibody were detected by HI assay using standard avian H9N2 antigen. The results showed that a H9N2 subtype influenza virus strain was isolated and named as A/swine/Shandong/TA009/2019(H9N2). The homology analysis showed that the isolated virus had close genetic relationship with A/environment-air/Kunshan/NIOSH-BL20/2018(H9N2) and A/environment-air/Kunshan/NIOSH-BL25/2018(H9N2), and the nucleotide homology of the gene fragments were above 99.5%. Phylogenetic analysis results demonstrated that HA and NA genes of the isolated virus belong to the Y280-like lineage, PB2 and M genes belong to the G1-like lineage, and PB1, PA, NP and NS genes belong to the SH/F98-like lineage. The cleavage site in HA protein is “PSRSSR/GL”, which was in accordance with the molecular biological characteristics of low pathogenic avian influenza virus.The position 216 of HA protein is L, and it has the ability to bind human-derived sialic acid α 2,6-Gal. The results of HI showed that 9 among 1 527 serum samples were positive with a positive rate of 0.59%. The isolated virus was swine-derived H9N2 virus, and serological investigations revealed that H9N2 subtype virus infection was present in swine herds in Shandong Province. The results of this study suggest that continuous surveillance of the SIV epidemiological situation and its pathogenic characteristics should be strengthened.  相似文献   

20.
旨在进一步了解山东省猪流感的流行情况及其病原特征,笔者于2019年春季,在山东省泰安某屠宰场采集130份猪鼻拭子,进行病毒分离鉴定;并对分离病毒进行全基因组测序和分子特征分析;用禽H9N2亚型标准抗原联合血凝抑制方法检测2018—2019年从山东省8个地区猪场采集的1 527份猪血清样品中的猪流感病毒抗体。结果显示：分离到1株H9N2亚型流感病毒,命名为A/swine/Shandong/TA009/2019（H9N2）。分离病毒与A/environment-air/Kunshan/NIOSH-BL20/2018（H9N2）和A/environment-air/Kunshan/NIOSH-BL25/2018（H9N2）遗传关系最近,其基因片段的核苷酸相似性均在99.5%以上。分离病毒的HA和NA基因属于Y280-like分支,PB2和M基因属于G1-like分支,PB1、PA、NP和NS基因属于SH/F98-like分支。分离病毒HA蛋白裂解位点处的氨基酸序列为“PSRSSR/GL”,符合低致病性禽流感病毒的分子生物学特性。HA蛋白的216位为L,具有结合人源唾液酸α 2,6-Gal的能力。血清学分析结果显示,9份血清中H9N2抗体呈阳性,其总阳性率为0.59%。综上：本研究分离到1株猪源H9N2亚型流感病毒,并在猪血清中检测到H9N2抗体,提示应加强对猪流感的流行情况及其病原特征的持续监测。  相似文献   

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