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Occurrence and diagnosis of Swine vesicular disease: Past and present status
Abstract
Swine vesicular disease (SVD) was first observed in Italy in 1966, where it was clinically recognised as foot-and-mouth disease (FMD). SVD virus (SVDV) was subsequently isolated in an FMD vaccine trial in Hong Kong. At the beginning of the 1970s, it spread to several other European and Asian countries: Bulgaria, Austria, Italy, Great Britain, Poland, former Soviet Union (Ukraine), Romania, France, Germany, Belgium, Switzerland, the Netherlands and Japan, and lasted until the beginning of the 1980s. After that period, SVD outbreaks were sporadic. The disease was almost forgotten until it flamed up again in 1992 in the Netherlands. Once again it spread to several other European countries, such as Belgium, Spain, Portugal and Italy. Since 1995, SVD has been reported in Europe almost exclusively in Italy, except two isolated outbreaks in Portugal. Since the last two SVD outbreaks in 2014 in the Potenza province (Basilicata region), no new SVD outbreaks have been reported either in Italy or in any other European country. The clinical resemblance of SVD to FMD highlights the need for its reliable identification and discrimination. Differentiation from FMD, though not possible clinically, is feasible if appropriate diagnostic tests are applied. Improvements in diagnostic techniques are making differential diagnosis of vesicular disease increasingly affordable, feasible and easy, and nowadays, portable devices are capable of a rapid and accurate differentiation of SVDV from FMDV infections on site. As these tests become economical and as competent laboratory services become more and more accessible, the restrictions originally imposed on SVD because of its similarity to FMD will no longer be justified. This, together with the fact that in recent years SVD has been predominantly asymptomatic, makes it necessary to rethink the measures currently in place for the control and diagnosis of SVD. Therefore, by the decision of OIE, the SVD chapter was removed from the Terrestrial Code in January 2015. Consequently, the European Commission (EC) informed the Pirbright Institute that the EU Reference Laboratory for SVD would no longer receive financial support. Moreover, the EC position is that notification requirements have ceased in January 2015.
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This article lists the changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in April 2016.
Changes to virus taxonomy (the Universal Scheme of Virus Classification of the International Committee on Taxonomy of Viruses [ICTV]) now take place annually and are the result of a multi-stage process. In accordance with the ICTV Statutes (http://www.ictvonline.org/statutes.asp), proposals submitted to the ICTV Executive Committee (EC) undergo a review process that involves input from the ICTV Study Groups (SGs) and Subcommittees (SCs), other interested virologists, and the EC. After final approval by the EC, proposals are then presented for ratification to the full ICTV membership by publication on an ICTV web site (http://www.ictvonline.org/) followed by an electronic vote. The latest set of proposals approved by the EC was made available on the ICTV website by January 2016 (https://talk.ictvonline.org/files/proposals/). A list of these proposals was then emailed on 28 March 2016 to the 148 members of ICTV, namely the EC Members, Life Members, ICTV Subcommittee Members (including the SG chairs) and ICTV National Representatives. Members were then requested to vote on whether to ratify the taxonomic proposals (voting closed on 29 April 2016).
Swine vesicular disease virus (SVDV) is a porcine pathogen and a member of the
Enterovirus
genus within the
Picornaviridae
family. The SVDV genome is composed of a single-stranded RNA molecule of positive polarity. Here, we report the first complete sequence of the coding region of a Spanish SVDV isolate (SPA/1/'93).
Swine vesicular disease virus (SVDV) emerged around 1960 from a human enterovirus (EV) ancestor, coxsackievirus B5 (CVB5), and caused a series of epizootics in Europe and Asia. We characterize a CVB4 strain that caused an epizootic involving 24,488 pigs in the Soviet Union in 1975. Phylogenetic evidence suggests that the swine virus emerged from a human ancestor between 1945-1975, almost simultaneously with the transfer of CVB5.
In 2006 and 2007 pig farming in the region of Lombardy, in the north of Italy, was struck by an epidemic of Swine Vesicular Disease virus (SVDV). In fact this epidemic could be viewed as consisting of two sub-epidemics, as the reported outbreaks occurred in two separate time periods. These periods differed in terms of the provinces or municipalities that were affected and also in terms of the timing of implementation of movement restrictions. Here we use a simple mathematical model to analyse the epidemic data, quantifying between-farm transmission probability as a function of between-farm distance. The results show that the distance dependence of between-farm transmission differs between the two periods. In the first period transmission over relatively long distances occurred with higher probability than in the second period, reflecting the effect of movement restrictions in the second period. In the second period however, more intensive transmission occurred over relatively short distances. Our model analysis explains this in terms of the relatively high density of pig farms in the area most affected in this period, which exceeds a critical farm density for between-farm transmission. This latter result supports the rationale for the additional control measure taken in 2007 of pre-emptively culling farms in that area.
We report the first complete nucleotide sequence of the picornavirus coxsackievirus B5 (CB5), strain 1954/UK/85, an isolate from a case of hand-foot-and-mouth disease. We have compared the sequence with those of other coxsackie B viruses, coxsackievirus A9, poliovirus and swine vesicular disease virus (SVDV). The genes encoding the three major capsid proteins are most closely related to those of SVDV but the 5' and 3' noncoding regions and the P3 gene are more similar to the corresponding regions in the other coxsackie B viruses than to those of SVDV. These observations are considered in the light of the antigenic and biochemical relationships between SVDV and CB5.
Phylogenetic analysis was used to examine the evolutionary relationships within a group of coxsackie B viruses that contained representatives of the major serotypes of this group and 45 isolates of swine vesicular disease virus (SVDV) from Asia and Europe. Separate analyses of sequence data from two regions of the viral genomes encoding the VP1 and 3BC genes both revealed that the SVDV belonged to a single monophyletic group which could be clearly distinguished from all other sampled coxsackieviruses. Regression analysis revealed that within the SVDV clade at least 80% of the synonymous variation in evolutionary divergence between isolates was explained by time, indicating the existence of an approximate molecular clock. Calibration of this clock according to synonymous substitutions per year indicated the date of occurrence of a common ancestor for the SVDV clade to be between 1945 and 1965.
This report describes the development of a one-step reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) assay for the detection of swine vesicular disease virus (SVDV). The assay detects the virus rapidly, within 30-60 min and the result is visualised either by gel-electrophoresis or by the naked eye through the addition of SybrGreen. A collection of 28 SVDV isolates were tested positive, while heterologous viruses such as foot-and-mouth disease virus and vesicular stomatitis virus remained negative. The performance of the RT-LAMP was compared directly with real-time PCR using RNA from clinical samples including nasal swabs, serum and faeces. For nasal swabs and serum the sensitivity of the RT-LAMP was shown to be at least equivalent to real-time PCR. Interestingly, for faecal samples the RT-LAMP assay was shown to be even more sensitive than real-time PCR, possibly because it is less sensitive to inhibitory substances. This RT-LAMP assay provides a number of benefits for the diagnosis of SVD, since the assay is sensitive and rapid, and the isothermal amplification strategy used is not reliant upon expensive equipment it is particularly suited for "front line" diagnosis of SVD in modestly equipped laboratories, in field stations or in mobile diagnostic units.
A highly sensitive and specific one-step multiplex RT-PCR assay has been developed and standardised for the simultaneous and differential detection of the most important vesicular viruses affecting livestock: foot-and-mouth disease virus (FMDV), swine vesicular disease virus (SVDV), and vesicular stomatitis virus (VSV). The method uses three primer sets, each one specific for the corresponding virus, selected to detect of all serotypes of FMD and VS. The detection range was confirmed by examination of a collection of 31 isolates of the three target viruses. The specificity of the assay was also demonstrated by testing other related viruses, uninfected cell line cultures and healthy pig tissues. The testing of blood and serum samples from animals infected experimentally proved that the method can be useful for early diagnosis of the diseases, even before the first vesicular lesions are visualized in the infected pigs. An assessment of the performance of the multiplex RT-PCR was carried out using a panel of more than 100 samples from animals infected experimentally, showing the suitability of the method for a rapid (less than 6h), sensitive and specific differential diagnosis in clinical samples. Additionally, a uniplex RT-PCR for VSV, that amplifies the two viral serotypes, was also developed and tested as a rapid tool for the diagnosis of this vesicular disease.
A disease which clinically could not be distinguished from foot and mouth disease, was observed in pigs imported from Poland, in December 1972. The infection could be experimentally transmitted to pigs, while one bovine failed to react. A cytopathic agent was isolated from vesicle extracts cultivated on pig kidney cells and IB RS 2 cells. Following intravenous and local skin infection this agent produced typical symptoms in pigs, and was identified as the agent of swine vesicular disease. Recently, four other cases of this disease have been observed in swine herds in Austria. Serological reactions of isolated virus strains were similar to those of the strains recovered in Great Britain and Italy.
The use of swine oral fluid (OF) for the detection of nucleic acids and antibodies is gaining significant popularity. Assays have been developed for this purpose for endemic and foreign animal diseases of swine. Here, we report the use of OF for the detection of virus and antibodies in pigs experimentally infected with swine vesicular disease virus (SVDV), a virus that causes a disease clinically indistinguishable from the economically devastating foot-and-mouth disease. Viral genome was detected in OF by real-time reverse transcription polymerase chain reaction (RRT-PCR) from 1 day post-infection (DPI) to 21 DPI. Virus isolation from OF was also successful at 1–5 DPI. An adapted competitive ELISA based on the monoclonal antibodies 5B7 detected antibodies to SVDV in OF starting at DPI 6. Additionally, using isotype-specific indirect ELISAs, SVDV-specific IgM and IgA were evaluated in OF. IgM response started at DPI 6, peaking at DPI 7 or 14 and declining sharply at DPI 21, while IgA response started at DPI 7, peaked at DPI 14 and remained high until the end of the experiment. These results confirm the potential use of OF for SVD surveillance using both established and partially validated assays in this study.
The rapid and accurate diagnosis of foot-and-mouth disease (FMD) is critical for effective disease control. Most of laboratory-based methods can provide objective results within a few hours of sample receipt. However, the time taken to transport suspect material to the laboratory can be unacceptably long, often precluding laboratory confirmation in the event of an outbreak. Therefore, rapid and easy-to-perform tests, which can be used in the field (on-site) in case of a suspected disease outbreak, would be a valuable tool for veterinarians in the initial diagnosis of FMDV. The lateral flow immunochromatographic (LFI) test has been efficiently used for the detection of specific antibodies against FMDV non-structural proteins. FMDV serotypes O, A, Asia 1, SAT 2 and non-serotype-specific FMDV. Recently, several FMD-specific real-time RT-PCR (rRT-PCR) assays have been transferred to portable mobile platforms and evaluated for the detection of FMDV in the field: the Cepheid SmartCycler Real-time PCR machine, Enigma FL and LightCycler Nano System. The BioSeeq-Vet (Smiths Detection) was the first commercially available truly portable PCR instrument for the detection of viral RNA in the field. Additionally, a new portable amplification platform Genie I for the on-site detection of viral RNA by reverse-transcription loop-mediated isothermal amplification (RT-LAMP) has also been developed and evaluated. Infrared thermography (IRT), a quantitative method for the assessment of body surface temperature, may also be a useful tool for the early detection of FMDV in the field. In the absence of overt clinical signs, the IRT rapid screening test, which measures heat emission, can be essential in selecting potentially infected animals. Microarrays, a recently introduced technology for the laboratory diagnosis of FMD, offers greater screening capabilities for FMDV detection and can be regarded as an alternative to classical diagnostic methods.
Reverse transcription coupled with PCR has been applied for the detection of swine vesicular disease (SVD) viral RNA in clinical samples from experimentally infected piglets. The viral RNA was extracted by a quanidine thiocyanate-phenol-chloroform method. Each of the samples of purified nucleic acid was reverse transcribed using AMV reverse transcriptase and antisense (-) SVD3505 primer chosen from highly conserved sequences of the viral genome. Amplification of cDNA was performed in a reaction mixture containing two different pairs of primers. One primer set (SVDV1A and SVDV1B) amplified 620 bps of the capsid coding region (VP1) and nonstructural protein 2A. The other primer set (SVDV3503 and SVDV3244) amplified 245 bps from the conserved region of the genome. RNA from uninfected clinical materials gave negative results. The PCR technique is rapid, specific and accurate diagnostic method and it can be useful for the detection of SVDV in clinical samples.
The aim of this studies was the genetic analysis of Polish SVDV isolates from 1972-73. The direct nucleotide sequencing technique of PCR products from the 1D (VP1) structural polipeptyde coding region was applied. The genetic differences between Polish isolates and other European and Japanese ones from 1966-1994 were determined by comparing their nucleotide sequences. No considerable genetic divergences were found between Polish isolates and the others in 1972-1981. This suggests a close relation and common origin of all isolates belonging to genogroup II. The considerable genetic differences (10-15%) were found between Polish strains from 1972-73 and West European isolates from 1991/92 (genogroup III) and 1993/94 (genogroup IV). These results indicated that distribution of isolates within these genogroups appears to be more related to the year of their collection than to their geographical origin. The obtained results can be important information for epidemiological studies of SVD in Europe.
The period of swine vesicular disease (SVD) virus persistence in clinical and tissue samples from experimentally infected pigs was investigated. A range of samples including epithelial tissue from vesicles, nasal swabs, blood, faeces and organs were collected to examine for the presence of infectious SVD particles, genomes and antigen. For this purpose, the conventional and PCR techniques were applied. The RT-nPCR assay appeared to be the most sensitive for the detection of SVDV in samples taken late in the course of infection. Only by nested PCR we could found the presence of vRNA in blood and nasal swabs as long as 4 and 48 d.p.i., respectively. Using virus isolation and RT-nPCR it was possible to detect viral genome in faeces up to 70 d.p.i. By RT-nPCR, the vRNA could be detected in somatic muscles and tonsil till 25 and 48 d.p.i., respectively. The virus could not generally be found in other organs beyond 7 d.p.i. The described RT-nPCR procedure can be useful for the duration estimation of infection of pigs with SVDV.
A trapping-indirect ELISA was used to determine the isotype of the antibody against SVDV in pigs experimentally infected with SVDVPOL/73. The first antibodies were detectable as early as 4 days after experimental infection. Up to the 9th day, demonstrable antibodies were exclusively of the IgM class. At this day the IgG developed and remained as a plateaux level up to the 28th d.p.i. The similar results were obtained in pigs immunized with experimental vaccine prepared from SVDV antigen. The use of trapping-indirect ELISA allowed to significantly reduce the number of non-specific positive results (singleton reactors) obtained by virus neutralization test and MAC-ELISA method.
A lateral flow device (LFD) for the detection of swine vesicular disease (SVD) virus (SVDV) and differential diagnosis from foot-and-mouth disease (FMD) was developed using a monoclonal antibody (Mab C70). The performance of the LFD was evaluated in the laboratory on suspensions of vesicular epithelia and cell culture passage derived supernatants of SVDV and porcine teschovirus (enterovirus; PEV). The collection of test samples included 157 which were positive for SVDV (84 vesicular epithelial suspensions and 73 cell culture antigens) from suspected cases of vesicular disease in pigs collected from 14 countries between 1966 and 2008 and 663 samples which were either shown to be negative for SVDV and FMD virus (FMDV) or else collected from healthy pigs or demonstrated to be positive for FMDV, PEV or vesicular exanthema (VEV) and collected from 16 countries between 1965 and 2008 or else were derived from experimental animals. Three further samples containing vesicular stomatitis virus (VSV) were also tested. The diagnostic sensitivity of the LFD for SVDV was similar at 82% compared to 86% obtained by the reference method of antigen ELISA, and the diagnostic specificity was 100% compared to 99.7% for the ELISA. The device recognized virus strains of each of the known genotypes of the sole SVDV serotype. Reactions with FMDV, VEV, VSV and PEV which can produce clinically indistinguishable syndromes in pigs, did not occur. These data illustrate the potential for the LFD to be used next to the animal for providing rapid and objective support to veterinarians in their clinical judgment of vesicular disease in pigs and for the specific pen-side diagnosis of SVD and differential diagnosis from FMD.
At the end of 2006, a recrudescence of swine vesicular disease (SVD) was recorded in Italy and the disease spread widely throughout the northern regions. Lombardy, a densely populated pig area, was most affected and the presence of the disease caused heavy economic losses to the entire pig industry. Although SVD is considered only moderately contagious, the epidemic in the north was characterised by a rapid spread of the condition. Numerous difficulties were encountered in eradicating it. Over the past decade, there has been a significant increase in the population of pigs in Lombardy, concentrated mainly in a few areas which were the most severely affected during the 2006 to 2007 SVD epidemic. Increases in both the pig population and animal movements, combined with weak biosecurity measures, increased the spread rate of the disease and hampered eradication activities.
Application of real-time RT-PCR (rRT-PCR) for detection of swine vesicular disease virus (SVDV) in samples of archival SVDV isolates and clinical samples collected from SVDV infected pigs was described. A primer set that targets the IRES region of the SVDV genome and TaqMan probe specific for a highly conserved region in SVDV RNA IRES region were used. The assay detected viral RNA in all tested archival strains of SVDV isolated in Europe during years 1972-73 and 1992 as well as in clinical samples collected from experimentally infected pigs. The rRT-PCR can provide quantitative and qualitative information and is more sensitive and faster to perform than the conventional RT-PCR.
The clinical signs, diagnosis and epizootiology of swine vesicular disease (SVD) are described. The clinical appearance is illustrated by photographs of experimentally and naturally infected pigs. Special attention is paid to differences between SVD and foot-and-mouth disease (FMD) and to the choice of disinfectants.
The complete nucleotide sequence of the genome of the enterovirus swine vesicular disease virus (SVDV; H/3 '76) isolated from a healthy pig has been determined using molecular cloning and DNA sequencing techniques. The RNA genome was 7400 nucleotides long, excluding the poly(A) tract, and appeared to encode a single polyprotein of 2185 amino acids. The predicted amino acid sequence of the polyprotein showed close homology (around 90%) to that of the previously sequenced coxsackieviruses B1, B3 and B4, and also showed homology (around 60%) to that of poliovirus. This homology allows us to predict the possible cleavage sites of the polyprotein and to identify other features of structural and functional significance, which seem to be important to the biological integrity of the virus. A detailed analysis of homology between SVDV and coxsackieviruses shows that non-structural proteins are highly conserved whereas the structural proteins are less well conserved. The 5' and 3' non-coding regions are also conserved, although there are several divergent nucleotide stretches. These stretches may differentiate SVDV from coxsackieviruses.
IN October 1966 a disease was observed among pigs in Lombardy, Italy,
which was indistinguishable from foot and mouth disease. Biological and
serological tests indicated that the Italian disease was unlikely to be
foot and mouth disease, so further studies were carried out at Brescia
and Pirbright to characterize the causal agent.
Two novel formats of ELISA for the detection of antibodies against swine vesicular disease (SVD) virus were developed. One of the tests described is a monoclonal antibody-based competitive ELISA (MAC-ELISA). In this test, specific antibodies in serum are detected due to their ability to compete with a neutralizing monoclonal antibody (MAb). The second is an indirect trapping ELISA which employs isotype-specific MAbs to detect swine IgG or IgM specific for SVD virus. The diagnostic sensitivity and specificity of the MAC-ELISA was studied on 5671 field sera of known origin, enabling the cut-off level to be defined. Using the MAC-ELISA, 100% of sera from infected pigs were found positive, whereas only 0.45% of negative sera gave a false-positive result. A positive correlation between MAC-ELISA and virus neutralizing titres was recorded for pig sera collected sequentially after experimental infections. The results from the isotype-specific ELISA revealed the dynamics of the antibody response to SVD virus in pigs. The first antibodies were detectable as early as 3 days after experimental infection. Up to the 10th day, demonstrable antibodies were exclusively of the IgM class. IgG developed later, between 11 and 14 days postinfection and remained at a plateaux level throughout the whole investigation period. The two tests satisfy different diagnostic requirements: the MAC-ELISA is useful as a screening test, the isotype-specific ELISA has potential application for the determination of stage of infection. Both tests benefit from the use of MAbs in terms of specificity and standardization and have advantages over the virus neutralization test.
A RT-PCR assay based on specific amplification of RNA sequences from each of the etiological agents of three important vesicular diseases that affect swine, foot-and-mouth disease virus (FMDV), swine vesicular disease virus (SVDV), and vesicular stomatitis virus (VSV), was developed. Genotype-specific primers that amplified DNA fragments of differential size from SVDV 3D gene or VSV L gene were selected with the aid of a computer program. Experimental testing of the primers predicted as SVDV-specific identified a primer pair, SA2/SS4, that rendered a specific product from SVDV RNAs, but did not amplify RNA from either FMDV or coxsackie B5 virus (CV-B5), a highly related picornavirus. Primers SA2/SS4 were used in combination with primers 3D2/3D1, which amplify a product of different size on FMDV 3D gene (Rodriguez et al., 1992). This combined RT-PCR reaction allowed a sensitive and specific differential detection of FMDV and SVDV RNAs in a single tube, by means of the analysis of the amplified products in agarose gels. The results obtained were similar when RNA extracted from viral stocks or plastic wells coated with either viral supernatants or extracts from lesions of infected animals, were used as starting material in the reactions. Using a similar approach, VSV serotype-specific primers IA/IS and NA/NS were selected for the specific amplification of VSV-Indiana and VSV-New Jersey RNAs, respectively. The combined use of SVDV, FMDV and VSV specific primers in a single reaction resulted in a genotype-specific amplification of each of the viral RNAs. Thus, differential diagnosis of FMDV from SVDV and/or VSV can be carried out in a single RT-PCR reaction, using a rapid and simplified methodology.
Swine vesicular disease (SVD) is a notifiable viral disease of pigs included on the Office International des Epizooties List A. The first outbreak of the disease was recognized in Italy in 1966. Subsequently, the disease has been reported in many European and Asian countries. The causative agent of the disease is SVD virus which is currently classified as a porcine variant of human coxsackievirus B5 and a member of the genus enterovirus in the family picornaviridae. From a clinical point of view, SVD is relatively unimportant, rarely causing deaths and usually only a minor setback to finishing schedules. However, the clinical signs which it produces are indistinguishable from those caused by foot-and-mouth disease, and its presence prevents international trade in pigs and pig products. This article reviews recent findings on all aspects of the virus and the disease which it causes.
Swine vesicular disease (SVD) is a contagious viral disease of swine. It causes vesicular lesions indistinguishable from those observed of foot-and-mouth disease. Infection with SVD virus (SVDV) can lead to viraemia within 1 day and can produce clinical signs 2 days after a pig has come into contact with infected pigs or a virus-contaminated environment. Virus can be detected 3.5 hours after infection using immunohistochemistry. In these in vitro studies, this technique was superior to in-situ hybridization. In SVDV-infected tissues, however, more infected cells were positive using in-situ hybridization, and these were already seen 4.5 hours after infection. For serological diagnosis of SVD several new enzyme-linked immunosorbent assays (ELISA's) have been developed. The newest ELISAs, based on monoclonal antibodies, are superior to the previous tests. The new tests produce fewer less false-negative results and enable large-scale serological screening. In screening programmes a small percentage of false positive reactors have been detected. The cause of these false-positive reactions has not been identified, though infections with human Coxsackie B5 virus can be excluded.
Differential detection of swine vesicular disease virus (SVDV) from the other vesicular disease viruses of foot-and-mouth disease (FMD), vesicular stomatitis (VS) and vesivirus is important as the vesicular lesions produced by these viruses are indistinguishable in pigs. Two independent sets of primers and probe, designed from nucleotide sequences within the 5' untranslated region (UTR) of the SVDV genome, were evaluated in a real-time (5' nuclease probe-based or fluorogenic) PCR format. Although both primers/probe sets failed to detect one isolate, the assays successfully amplified RNA extracted from epithelial suspensions (ES) and cell culture grown virus preparations from clinical samples representing all currently designated phylogenetic groups of SVDV. Furthermore, no cross-reactivity was demonstrated when these primer/probe sets were tested with RNA prepared from all seven serotypes of FMD virus (FMDV) and from selected isolates of VS virus (VSV), vesivirus and teschoviruses. These assays provide sensitive and rapid alternatives to supplement the routine procedures of ELISA and virus isolation for SVDV diagnosis. The two independent sets of primers/probe can be used routinely while only one of the primers/probe sets would typically be used in SVDV diagnosis during an outbreak.
SIR, — We report here the genetic typing of a virus from the first occurrence of swine vesicular disease (svd) in Portugal since 2004.
This outbreak was reported to the World Organisation for Animal Health (oie) on June 27, 2007, by the Portuguese Ministry of Agriculture and involved a farm in
Swine vesicular disease (SVD) was first observed in Italy in 1966, and was initially diagnosed as foot and mouth disease (FMD). The causative agent of SVD was classified as an Enterovirus within the family Picornaviridae. It was included in the list of diseases notifiable to the World Organisation for Animal Health (OIE) because of the similarity of its lesions to those produced by FMD; however SVD is often mild in nature and may infect pigs subclinically. During the last decade SVD has been persistently reported in Italy, and surveillance and eradication activities are in place. The central and northern parts of Italy have been designated SVD free since 1997, while the southern regions have not achieved disease-free status. However, occasional outbreaks of SVD have occurred in central and northern Italy and have been eradicated using rigorous control measures. Most recent SVD outbreaks in Italy have been subclinical; SVD can rarely be diagnosed now on the basis of clinical signs and it is necessary to use laboratory diagnosis. This paper examines the epidemiology of SVD in Italy, and considers the measures adopted in Europe for SVD control on the basis of current knowledge of the disease.
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