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1.
Foot-and-mouth disease (FMD) is a highly contagious and economically devastating disease of cloven-hoofed animals in the world. The disease can be effectively controlled by vaccination of susceptible animals with the conventional inactivated vaccine. However, one major concern of the inactivated FMD virus (FMDV) vaccine is that it does not allow serological discrimination between infected and vaccinated animals, and therefore interferes with serologic surveillance and the epidemiology of disease. A marker vaccine has proven to be of great value in disease eradication and control programs. In this study, we constructed a marker FMDV containing a deletion of residues 93 to 143 in the nonstructural protein 3A using a recently developed FMDV infectious cDNA clone. The marker virus, r-HN/3A93–143, had similar growth kinetics as the wild type virus in culture cell and caused a symptomatic infection in pigs. Pigs immunized with chemically inactivated marker vaccine were fully protected from the wild type virus challenge, and the potency of this marker vaccine was 10 PD50 (50% pig protective dose) per dose, indicating it could be an efficacious vaccine against FMDV. In addition, we developed a blocking ELISA targeted to the deleted epitope that could clearly differentiate animals infected with the marker virus from those infected with the wild type virus. These results indicate that a marker FMDV vaccine can be potentially developed by deleting an immunodominant epitope in NSP 3A.  相似文献   

2.
The control of foot-and-mouth disease virus (FMDV) outbreaks in non-endemic countries relies on the rapid detection and removal of infected animals. In this paper we use the observed relationship between the onset of clinical signs and direct contact transmission of FMDV to identify predictors for the onset of clinical signs and identify possible approaches to preclinical screening in the field. Threshold levels for various virological and immunological variables were determined using Receiver Operating Characteristic (ROC) curve analysis and then tested using generalized linear mixed models to determine their ability to predict the onset of clinical signs. In addition, concordance statistics between qualitative real time PCR test results and virus isolation results were evaluated. For the majority of animals (71%), the onset of clinical signs occurred 3–4 days post infection. The onset of clinical signs was associated with high levels of virus in the blood, oropharyngeal fluid and nasal fluid. Virus is first detectable in the oropharyngeal fluid, but detection of virus in the blood and nasal fluid may also be good candidates for preclinical indicators. Detection of virus in the air was also significantly associated with transmission. This study is the first to identify statistically significant indicators of infectiousness for FMDV at defined time periods during disease progression in a natural host species. Identifying factors associated with infectiousness will advance our understanding of transmission mechanisms and refine intra-herd and inter-herd disease transmission models.  相似文献   

3.
猪口蹄疫免疫防御是控制猪口蹄疫疫情的重要手段,免疫水平指标通常用免疫抗体水平判定。对于其细胞免疫水平检测尚缺乏成熟可靠的技术,本试验利用市售ELISpot试剂盒建立猪口蹄疫特异γ干扰素检测方法,刺激物分别采用疫苗全病毒颗粒（O/Mya98/XJ/2010）、口蹄疫病毒T细胞表位多肽池,以植物血凝素（PHA）为阳性对照,对细胞浓度、刺激物浓度、孵育时间等进行优化。优化条件为：外周血PBMC新鲜提取或冻存细胞成活率90%以上,最佳细胞数为2×105个/孔,最佳反应时间是16 h,病毒粒子146 S含量为100 ng/mL,多肽最佳浓度10 μg/mL,PHA的最佳浓度是20 μg/mL。ELISpot技术检测口蹄疫病毒感染猪γ干扰素方法的建立,为口蹄疫免疫力评价及口蹄疫疫苗免疫效果评估及进一步研究其与疫苗保护力（PD50）的相关性奠定基础。  相似文献   

4.
口蹄疫病毒(FMDV)是小RNA病毒科、口蹄疫病毒属成员,其感染后引起的口蹄疫是一种严重危害畜牧业发展的传染病,并对经济发展、国家声誉及国际关系造成重要影响.论文就FMDV的主要抗原位点、FMDV的细胞受体、机体对FMDV抗原的免疫反应、FMDV抗原的变异与进化等做一综述.  相似文献   

5.
The RNA genome sequence of the rabbit passage-attenuated strain of foot-and-mouth disease virus (FMDV) Asia 1, ZB/CHA/58(att), was determined to be 8165 nt in length excluding the poly(C) tract in the 5′ UTR and the poly(A) tail at the 3′ end. ZB/CHA/58(att) was most similar to the vaccine strain Asia 1/YNBS/58 in genome sequence and there were no deletions or insertions within the deduced polyprotein between ZB/CHA/58(att) and YNBS/58, but there were a total of 25 substitutions at the amino acid level and an extra 19-nt stretch in the 5′ UTR was found in ZB/CHA/58(att). An infectious full-length cDNA clone of ZB/CHA/58(att) was developed. Infectious virus could be recovered in BHK-21 cells transfected with the synthetic viral RNA transcribed in vitro. The plaque morphology, growth kinetics and antigenic profile of the infectious clone-derived virus (termed tZB) were indistinguishable from those induced by the parental virus. Furthermore, the virulence properties of ZB/CHA/58(att) and tZB were found to be highly similar in the mouse model. The availability of genome sequence information and infectious cDNA clone of the FMDV ZB/CHA/58(att) lays a new ground for further investigation of FMDV virulence determinants and development of new potent vaccine to FMD.  相似文献   

6.
This study was conducted to determine if humoral antibody response of foot-and-mouth disease (FMD) vaccine improved in 8-week-old growing pigs born to well-vaccinated sows pre-treated with 60 mg of poly-γ-glutamic acid (γ-PGA) three days before vaccination. Antibody against FMD virus serotype O was measured 0, 2, 4 and 6 weeks post-vaccination, using a PrioCHECK FMDV type O ELISA kit. The results showed that positive antibody reactions against FMDV serotype O antigen among a component of the vaccine significantly increased in response to pre-injection with γ-PGA.  相似文献   

7.
Foot-and-mouth disease (FMD) is a highly contagious aphthoviral infection of cloven-hoofed animals, inducing vesiculopustular stomatitis, pododermatitis, and thelitis. Vesicular fluid represents a major pathway of virus excretion, but bovine milk is another important source of virus shedding. We describe here the time course of FMD virus (FMDV) excretion in the milk and characterize associated lesions in the mammary gland. Three dairy cows were infected by nasopharyngeal instillation of FMDV and monitored over 12 d. Autopsy was performed at the end of the study, and specimens were collected for histopathology, IHC, and RT-qPCR. All 3 cows developed fever, drooling, vesiculopustular stomatitis, interdigital dermatitis, and thelitis. FMDV RNA was detectable in whole milk until the end of the trial, but only transiently in saliva, nasal secretions, and blood serum. Although histology confirmed vesiculopustular lesions in the oral and epidermal specimens, the mammary glands did not have unequivocal evidence of FMDV-induced inflammation. FMDV antigen was detectable in skin and oral mucosa, but not in the mammary gland, and FMDV RNA was detectable in 9 of 29 samples of squamous epithelia but only in 1 of 12 samples of mammary gland.  相似文献   

8.
Transmission of foot-and-mouth disease virus (FMDV) by aerosol spread can occur over considerable distances. However, this is less effective in hot, dry environmental conditions, and a detailed study of an outbreak within a large dairy herd in Saudi Arabia has shown that contact spread is the main mode of transmission within a herd: both physical and spatial barriers curtailed the course of disease across the farm. Hence, the speed and path of an outbreak can be altered by changing the positioning of spatial or physical barriers. Extending the distances between pens, increasing the number of farm pens, decreasing the number of animals within the pens, and placing pens of well-protected stock between those of susceptible stock, can all contribute to the control of FMD involving contact and short-distance aerosol spread. Such management techniques offer a cost-effective supplement to control by vaccination.  相似文献   

9.
Microarray-based detection and typing of foot-and-mouth disease virus   总被引：8，自引：0，他引：8  
Foot-and-mouth disease virus (FMDV) is the most economically important veterinary pathogen because of its highly infectious nature and the devastating effects the virus has on the livestock industry. Rapid diagnostic methods are needed for detection and typing of FMDV serotypes and differentiation from other viruses causing vesicular diseases. We developed a microarray-based test that uses a FMD DNA chip containing 155 oligonucleotide probes, 35-45 base pair (bp) long, virus-common and serotype-specific, designed from the VP3-VP1-2A region of the genome. A set of two forward primers and one reverse primer were also designed to allow amplification of approximately 1100 bp of target sequences from this region. The amplified target was labelled with Alexa-Fluor 546 dye and applied to the FMD DNA chip. A total of 23 different FMDV strains representing all seven serotypes were detected and typed by the FMD DNA chip. Microarray technology offers a unique capability to identify multiple pathogens in a single chip.  相似文献   

10.
Foot and mouth disease (FMD) is caused by foot-and-mouth disease virus (FMDV) and affects cloven hoofed animals,it is an acute and potent infectious disease which has caused great loss in some regions. Up to now, people still use vaccines to prevent and control FMD which has become the the popular ways. Prepared by virus'antigen epitopes and carried with multiple epitopes and helper epitope,the epitope-based vaccine against FMD which has caught people's attention to it owing to it has high safety and is easy to be manipulated and controlled.In recent years,the research based on epitope of FMDV has made great progress.Now we review the latest progress of the FMDV epitopes and the epitope-based vaccine against FMD in this paper, in order to provide relevant preferences for the development of the vaccines with high security and efficiency.  相似文献   

11.
口蹄疫是由口蹄疫病毒引起偶蹄动物发生的一种急性、烈性传染病,给发病地区的畜牧业造成巨大的损失,目前应用疫苗来防控口蹄疫仍是最主要的手段。作为一种新型疫苗,表位疫苗是用病毒相关抗原表位制备,可同时携带多个抗原表位及辅助性表位的疫苗,具有安全性好、易操作和可控等优势,受到人们密切的关注。近些年来,对于口蹄疫表位及疫苗的研究取得了很大的进展,现对口蹄疫病毒相关的细胞表位及其以此为基础的表位疫苗的最新进展进行综述,为研制更加安全有效的口蹄疫疫苗提供参考。  相似文献   

12.
The aims of this study were to statistically reassess the likelihood that windborne spread of foot-and-mouth disease (FMD) virus (FMDV) occurred at the start of the UK 1967 to 1968 FMD epidemic at Oswestry, Shropshire, and to derive dose-response probability of infection curves for farms exposed to airborne FMDV. To enable this, data on all farms present in 1967 in the parishes near Oswestry were assembled. Cases were infected premises whose date of appearance of first clinical signs was within 14 days of the depopulation of the index farm. Logistic regression was used to evaluate the association between infection status and distance and direction from the index farm. The UK Met Office's NAME atmospheric dispersion model (ADM) was used to generate plumes for each day that FMDV was excreted from the index farm based on actual historical weather records from October 1967. Daily airborne FMDV exposure rates for all farms in the study area were calculated using a geographical information system. Probit analyses were used to calculate dose-response probability of infection curves to FMDV, using relative exposure rates on case and control farms. Both the logistic regression and probit analyses gave strong statistical support to the hypothesis that airborne spread occurred. There was some evidence that incubation period was inversely proportional to the exposure rate.  相似文献   

13.
Transmission of foot and mouth disease (FMD) virus by infected animals may already occur before clinical signs are evident. Quantitative data for FMD transmission rates during this so-called high-risk period are currently lacking and would provide useful information to develop surveillance systems in which the number of new outbreaks is an outcome variable. In order to address this, we used experimental data to quantify transmission in cattle, swine and sheep during the non-clinical phase of the disease. Groups consisted of vaccinated or non-vaccinated animals of one species; half of each group was inoculated with FMDV, the other half was contact-exposed. We estimated the reproduction ratio R(nonclin) using a mathematical SIR model. R(nonclin) was defined as the average number of secondary infections caused by one infectious individual in its non-clinical phase. Animals not showing clinical signs shed lower amounts of virus than clinically affected ones. Therefore, we estimated transmission proportionally to the virus excretion. Low estimates for R(nonclin) in groups with non-vaccinated and vaccinated calves; 0.30 [0.03; 3.43] and 1.03x10(-8) [0; infinity] respectively and 0.21 [0.02; 2.48] for the non-vaccinated and 0.16 [0.009; 2.96] for the vaccinated lambs, were observed. These results indicate that only few secondary infections are to be expected from infected calves and lambs when they are not clinically affected. In groups of non-vaccinated piglets estimates were R(nonclin)=13.20 [4.08; 42.68], and in vaccinated piglets R(nonclin)=1.26 [0.18; 8.96]. The estimate for R(nonclin) for non-vaccinated dairy cows was R(nonclin)=176.65 [80.38; 388.24], whereas R(nonclin) in the vaccinated groups could not be estimated. Our findings suggest that a large number of individuals might have been infected before clinical signs are noticed, especially in non-vaccinated swine and dairy herds. These findings suggest that after clinical recognition of FMD, priority should be given to trace back contacts with swine and dairy farms, as they may already have been infectious in the herd's incubation period.  相似文献   

14.
AIM: To quantify the numbers and extent of movements off sheep and cattle farms in New Zealand, in order to construct more realistic simulation models to investigate how infectious diseases such as foot-and-mouth disease (FMD) might spread.

METHODS: Farmers from 500 randomly selected farms, comprising 100 from each of the following sectors, viz beef, dairy, grazing/dairy heifer rearing, sheep, and mixed sheep and beef, were asked to fill in diaries in which they recorded the movements of all animals, products, people, vehicles and equipment coming on to or leaving their farms during two separate 3-week periods, representing relatively ‘busy’ and ‘quiet’ times of the year with respect to livestock movements. Where possible, the destination of each movement was identified and geo-coded, to allow the distance travelled to be calculated. Each movement was then classified according to the risk of transfer of FMD virus (FMDV), should the disease have been present on the study farm at the time of the movement. The data were then analysed to establish movement frequencies and distributions of distances travelled, by the different pastoral livestock sectors.

RESULTS: Two hundred and seventeen farmers returned one or more diaries. One hundred and ninety-three farmers completed a Busy-period diary, recording a total of 12,052 movements off their farms, a crude average of 62.4 per 3-week period, or 2.97 per day. Of these, 4.0% involved the transport of livestock, equating to 0.12 livestock consignments per day. In contrast, 186 Quiet-period diaries were returned, recording a total of 10,885 movements off, representing a crude average of 58.5 during the 3-week period, or 2.78 per day. Of these, 2.1% involved livestock, equating to 0.06 livestock consignments per day. The mean and median distances travelled during the Busy periods were 30.9 km and 13.1 km, respectively (range 0–1,167 km). In comparison, the mean and median distances travelled during Quiet periods were 41.3 and 14 km, respectively (range 0.4–1,203 km).

CONCLUSIONS: People, vehicles, livestock and other items can travel off pastoral livestock farms in New Zealand to other farms either directly or via saleyards over extensive distances. This has implications for the potential spread of infectious diseases such as FMD. Movement parameters intended for use in the InterSpread Plus inter-farm simulation model of FMD were established, which will facilitate the prediction of likely spread and efficacy of controls in the unlikely event of a real-life outbreak.  相似文献   

15.
口蹄疫是危害我国畜牧业的主要传染病之一,主要感染猪、牛、羊等偶蹄动物,其中猪口蹄疫不同于牛、羊口蹄疫,有其独特特点。本文聚焦猪口蹄疫,从其病毒分子生物学特性、毒株全球流行态势以及我国疫苗使用现状等方面进行了阐述和分析,以期为我国猪口蹄疫的防控提供基础参考。  相似文献   

16.
We evaluated the potential ability of germanium biotite (GB) to stimulate the production of antibodies specific for foot-and-mouth disease virus (FMDV). To this aim, we measured the total FMDV-specific antibody responses and IgM production after vaccination against FMD both experimentally and in the field. GB supplementation with FMDV vaccination stimulated the production of anti-FMDV antibodies, and effectively increased IFN-γ and TNF-α levels. These results suggest that GB may be a novel alternative feed supplement that can serve as a boosting agent and an immunostimulator for increasing the efficacy of FMDV vaccination in pigs.  相似文献   

17.
There is strong evidence to suggest that foot-and-mouth disease (FMD) can be transmitted by airborne virus up to many kilometres from a virus source. Atmospheric dispersion models are often used to predict where this disease might spread. This study investigated whether FMD virus (FMDV) aerosol has specific characteristics which need to be taken into consideration in these models. The characteristics and infectiousness of particles emitted by 12 pigs have been studied pre- and post-infection with O UKG 2001 FMDV. Aerosol generated by individual pigs was found log normally distributed in the range 0.015-20.0microm with concentrations between 1000 and 10000cm(-3) at the smallest size and <1cm(-3) above 10microm. No differences in either the total number of particles produced or their size distribution were detected between uninfected and infected pigs. However, a correlation between aerosol concentration and animal activity was found with a more active pig producing significantly greater concentrations than those that were less active. Viable virus was found up to a maximum of 6.3 log TCID(50)/24h/animal. The virus was distributed almost equally across the three size ranges; <3, 3-6 and >6microm. No correlation could be established between the production of virus and animal activity. In general the production of airborne virus closely followed the detection of viraemia in the blood and the presence of clinical symptoms. However, in one instance a pig excreted as much airborne virus as the other animals in the study, but with less virus detected in its blood. The results suggest that there is little merit in including a sophisticated virus release pattern based on physical activity periods or FMDV aerosol size spectrum, together with the appropriate dry deposition calculations, in models used to predict airborne spread of FMD. An estimate of the total daily virus production based on the clinical assessment of disease and virus strain is sufficient as input.  相似文献   

18.
Intraherd transmission of foot and mouth disease virus (FMDV) was examined using a simulation model for a hypothetical 1,000-cow dairy, assuming clinical diagnosis was made when at least 1% (10 cows) or 5% (50 cows) had clinical signs of FMD, I index case cow, and transition state distributions for the latent, subclinically infectious, and clinically infectious periods of FMD calculated from published data. Estimates assumed for the number of animal-to-animal contacts (k) adequate for transmission ranged from 0.6 to 9.0 per hour (13.7-216.0 per day). A total of 40,000 iterations (5,000 for each scenario, assessing 4 adequate contact rates and 2 detection criteria) were run. The model predicted that FMD would not be diagnosed in the herd until 10.0-13.5 days after the index case cow had become infected, at which time between 65% and 97% of the cows (646-967 cows) to nearly 100% (978-996 cows) would already have become infected with the virus, if the number of cows showing clinical signs of FMD at the time of diagnosis were 10 or 50, respectively. At the time of diagnosis, the simulated number of infectious cattle varied substantially from 82-472 to 476-537 cows, depending on adequate contact rate and whether the diagnosis was made when 10 or 50 animals were showing clinical signs, respectively. The simulated number of infectious cows increased rapidly during the first few days after diagnosis. In the scenario where at least 10 cows showing clinical signs was necessary before a clinical diagnosis was made, each day after diagnosis, the number of infectious animals increased by nearly 100 to more than 200 cases per day up to day 5, assuming 0.57-9.0 animal-to-animal contacts per hour, respectively. Results obtained when it was assumed that at least 50 clinical cases were present at the time of diagnosis showed smaller relative increases because nearly one-half of the herd was projected to be infected at the time of diagnosis. From these results, it is clear that once an individual in a herd becomes infected with FMDV, herd infectivity is not static, rather it accelerates as would be expected as long as there are sufficient susceptible animals to sustain the increasing transmission rate, after which time the rate at which new infections occurs will diminish. Results indicate that biosecurity strategies aimed at minimizing both intraherd and interherd contact will be critical in minimizing the spread of FMD before the initial diagnosis is made. In addition, simulations suggest that very early clinical diagnosis of FMD and effective isolation or depopulation and disposal will be critical in limiting the number of infectious animals capable of transmitting the virus to other herds and thus in timely control of an epidemic. Early diagnosis will rely on early virus detection from animals in the preclinical phase of infection, rather than waiting for clinical signs to manifest in sufficient numbers to be noticed and to warrant investigation.  相似文献   

19.
口蹄疫(foot-and-mouth disease, FMD)是发生于偶蹄动物的一种急性高度传染性疫病,曾多次在世界范围内暴发流行。FMD致病原口蹄疫病毒(foot-and-mouth disease virus, FMDV)于感染后利用多种策略操纵宿主免疫机制和逃避抗病毒反应,以利于其感染复制。现对最近几年来影响调控FMDV感染与复制的多种因素从不同角度进行总结分析,以期为后续研究提供参考。  相似文献   

20.
Reconstructing the evolutionary history, demographic signal and dispersal processes from viral genome sequences contributes to our understanding of the epidemiological dynamics underlying epizootic events. In this study, a Bayesian phylogenetic framework was used to explore the phylodynamics and spatio-temporal dispersion of the O CATHAY topotype of foot-and-mouth disease virus (FMDV) that caused epidemics in the Philippines between 1994 and 2005. Sequences of the FMDV genome encoding the VP1 showed that the O CATHAY FMD epizootic in the Philippines resulted from a single introduction and was characterised by three main transmission hubs in Rizal, Bulacan and Manila Provinces. From a wider regional perspective, phylogenetic reconstruction of all available O CATHAY VP1 nucleotide sequences identified three distinct sub-lineages associated with country-based clusters originating in Hong Kong Special Administrative Region (SAR), the Philippines and Taiwan. The root of this phylogenetic tree was located in Hong Kong SAR, representing the most likely source for the introduction of this lineage into the Philippines and Taiwan. The reconstructed O CATHAY phylodynamics revealed three chronologically distinct evolutionary phases, culminating in a reduction in viral diversity over the final 10 years. The analysis suggests that viruses from the O CATHAY topotype have been continually maintained within swine industries close to Hong Kong SAR, following the extinction of virus lineages from the Philippines and the reduced number of FMD cases in Taiwan.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0090-y) contains supplementary material, which is available to authorized users.  相似文献   

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