Reduction of foot-and-mouth disease virus transmission in cattle vaccinated one or two weeks before challenge using a commercial polyvalent vaccine.

Immediate vaccination of the most susceptible and epidemiological relevant animals is a crucial part of control measures that facilitate virus elimination in case of entry of foot-and-mouth disease (FMD). The objective of this study was to evaluate the effect of cattle vaccination 7 and 14 days prior challenge using a vaccine commonly applied in systematic vaccination campaigns against transmission of FMD virus (FMDV). Transmission of FMDV was investigated in three groups of ten cattle each: one non-vaccinated group and two groups that were either vaccinated 7 days (-7/vaccinated group) or 14 days (-14/vaccinated group) before intranasal (IN) inoculation.

FMD vaccine matching: Inter laboratory study for improved understanding of r values.

Foot-and-mouth disease virus (FMDV) is a highly variable RNA virus existing as seven different serotypes. The antigenic variability between and within serotypes can limit the cross-reactivity and therefore the in vivo cross-protection of vaccines. Selection of appropriate vaccine strains is crucial in the control of FMD.

Efficacy of a high quality O/Campos foot-and-mouth disease vaccine upon challenge with a heterologous Korean O Mya98 lineage virus in pigs.

In 2010 serotype O foot-and-mouth disease virus of the Mya98 lineage/SEA topotype spread into most East Asian countries. During 2010-2011 it was responsible for major outbreaks in the Republic of Korea where a monovalent O/Manisa vaccine (belonging to the ME-SA topotype) was applied to help control the outbreaks. Subsequently, all susceptible animals were vaccinated every 6 months with a vaccine containing the O/Manisa antigen.

Antigenic and immunogenic spectrum of foot-and-mouth disease vaccine strain O Campos against representative viruses of topotypes that circulated in Asia over the past decade.

Identifying vaccine strains to control outbreaks of foot-and-mouth disease virus that could spread to new regions is essential for contingency plans. This is the first report on the antigenic/immunogenic relationships of the South American O1/Campos vaccine strain with representative isolates of the three currently active Asian type O topotypes. Virus neutralization tests using O1/Campos post-vaccination sera derived from cattle and pigs predicted for both species acceptable cross-protection, even after single vaccination, established by r1 values and by expectancy of protection using monovalent or polyvalent vaccines.

Combined administration of synthetic RNA and a conventional vaccine improves immune responses and protection against foot-and-mouth disease virus in swine.

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious disease and a major concern in animal health worldwide. We have previously reported the use of RNA transcripts mimicking structural domains in the non-coding regions of the FMDV RNA as potent type-I interferon (IFN) inducers showing antiviral effect in vivo, as well as their immunomodulatory properties in combination with an FMD vaccine in mice. Here, we describe the enhancing effect of RNA delivery on the immunogenicity and protection induced by a suboptimal dose of a conventional FMD vaccine in pigs.

Importance of foot and mouth disease vaccine purity in interpreting serological surveys.

The aim of this study was to determine whether the degree of purity achieved in conventional vaccines against the foot and mouth disease virus in Argentina interferes with the interpretation of seroepidemiological surveys for confirming the absence of viral activity, which are performed to support the recognition of free zones practising vaccination. The evaluation of 168 vaccine series due to be marketed in Argentina (2006-2012) and subjected to official control testing in cattle, as well as repeated vaccination of cattle and other species using vaccines with high antigen concentrations, demonstrated that they did not induce antibodies to non-structural proteins (NSPs). The results show clearly that vaccines with satisfactory potency do not induce a response to NSPs, even by forcing the immune response through more concentrated doses with multiple valences and revaccination protocols at shorter irtervals than in vaccination campaigns.

Early protection against foot-and-mouth disease virus in cattle using an inactivated vaccine formulated with Montanide ESSAI IMS D 12802 VG PR adjuvant.

Foot and mouth disease is an acute disease of cattle with a broad distribution around the world. Due to the fast spread of FMDV infections, control measures must be applied immediately after an outbreak, such as the use of vaccines that induce fast protection. Previously, it was shown that mice vaccinated with FMD inactivated virus (iFMDV) formulated with Montanide™ ESSAI IMS D 12802 VG PR adjuvant (802-iFMDV) were protected when they were challenged 4 and 7 days post-vaccination (dpv) with homologous virus.

Emergence of antigenic variants of Foot-and-Mouth Disease Virus serotype O in Ecuador and preliminary evaluation of a field strain as a vaccine candidate.

Foot-and-Mouth Disease Virus serotype O has been circulating regularly throughout most provinces of Ecuador, one of the two South American countries that still remain endemic, although satisfactory vaccination coverage was reported. This study concentrates in the characterization of isolates collected during 2008-2011, focusing particularly on the antigenic and immunogenic relationships of the field viruses with the O1/Campos vaccine strain in use in the region and with an experimental vaccine formulated with a representative strain of the 2010 epidemic. The results established that antigenically divergent variants poorly protected by the vaccine in use emerged and co-circulated in a limited period of time.

Foot and mouth disease (FMD) virus: quantification of whole virus particles during the vaccine manufacturing process by size exclusion chromatography.

Foot and mouth disease (FMD) is a highly infectious viral disease that affects cattle, sheep, goats and swine causing severe economic losses worldwide. The efficacy of inactivated vaccines is critically dependent on the integrity of foot and mouth disease virus (FMDV) particles. The recommended method to quantify the active ingredient of vaccines is the 140S quantitative sucrose density gradient analysis.

Reducing animal experimentation in foot-and-mouth disease vaccine potency tests.

The World Organisation for Animal Health (OIE) Terrestrial Manual and the European Pharmacopoeia (EP) still prescribe live challenge experiments for foot-and-mouth disease virus (FMDV) immunogenicity and vaccine potency tests. However, the EP allows for other validated tests for the latter, and specifically in vitro tests if a "satisfactory pass level" has been determined; serological replacements are also currently in use in South America. Much research has therefore focused on validating both ex vivo and in vitro tests to replace live challenge.

Confidence in indirect assessment of foot-and-mouth disease vaccine potency and vaccine matching carried out by liquid phase ELISA and virus neutralization tests.

The necessity of avoiding the use of animals in vaccine potency testing has been widely recognized. The repeatability and reproducibility of the Expected Percentage of Protection (EPP) as a serological potency surrogate for A24 Cruzeiro foot-and-mouth disease virus (FMDV) strain was assessed, and compared with the results obtained with challenge in the Protection against Podal Generalization (PPG) test. To determine the EPPs, the serum titers obtained by liquid phase blocking competitive ELISA (lpELISA) and virus neutralization (VNT) in 10 potency trials using the same A24 Cruzeiro vaccine, were interpolated into previously validated logit transformation curves that correlate PPG with serology.

Some guidelines for determining foot-and-mouth disease vaccine strain matching by serology.

The selection of matching strains for use in outbreaks of foot-and-mouth disease (FMD) virus can be assessed in vivo or by serological r-value determination. Sera from animals involved in vaccine potency and cross-protection trials performed using the "Protection against Podal Generalization" (PPG) test for two serotype A strains were collected and analyzed by the virus neutralization test (VNT) and liquid-phase ELISA (lpELISA) in three laboratories. The average VNT r-values for medium and high serum titer classes from the A(24) Cruzeiro vaccinated animals were in line with the A/Arg/01 heterologous PPG outcome for all testing laboratories, suggesting that the vaccine strain A(24) Cruzeiro is unlikely to protect against the field isolate A/Arg/01.

Foot-and-mouth disease vaccine potency testing in cattle using homologous and heterologous challenge strains: precision of the "Protection against Podal Generalisation" test.

The level of protection conferred by foot-and-mouth disease (FMD) vaccines in primovaccinated animals primarily depends on the potency of the vaccine and the relatedness of the vaccine strain and circulating field isolate. The "Gold Standard" FMD vaccine potency test is the in vivo test performed in the target species. The objective of the study was to determine the precision of the in vivo "Protection against Podal Generalisation" (PPG) FMD vaccine potency test in cattle using homologous (vaccine quality control) and heterologous (vaccine matching) viral challenge.

Foot-and-mouth disease polyvalent oil vaccines inoculated repeteadly in cattle do not induce detectable antibodies to non-structural proteins when evaluated by various assays.

The use of foot-and-mouth disease (FMD) vaccines that do not induce antibodies against non-structural proteins (NSP) is extremely relevant for the demonstration of regions "free of FMDV infection" and control strategies. In this study cattle were primed and boosted with five doses of oil vaccines containing high antigenic payloads on days 0, 90, 130, 160 and 200. The serological response against NSP was measured using four commercially available assays: two 3ABC-ELISAs; one 3B-ELISA (and complementary 3A-ELISA) and an enzyme-immunotransfer blot assay (EITB).

Reintroduction of foot-and-mouth disease in Argentina: characterisation of the isolates and development of tools for the control and eradication of the disease.

This paper describes the antigenic and molecular characterisation of foot-and-mouth disease virus (FMDV) strains isolated during the 2000-2002 epidemic in Argentina, and the strategy implemented for disease control. Two different FMDV serotypes, O and A, were involved. Of the various field isolates studied, two distinct O1 lineages (strains Corrientes/00 and Misiones/00) and two serotype A lineages (A/Argentina/00 and A/Argentina/01 prototypes) were identified.

A comparison of methods for measuring the antibody response in mice and cattle following vaccination against foot and mouth disease.

We present a comparison of methods for evaluating the potency of foot and mouth disease vaccine in the laboratory. The anti-FMDV antibodies (Ab) in vaccinated mice were tested by liquid phase (lp) ELISA, solid phase (sp) ELISA and virus neutralization (VN), and were compared with the Ab titres detected by lpELISA, which is the official test in Argentina for testing the potency of FMD vaccines and protection against a virulent challenge in cattle. The results demonstrated that it is possible to relate the Ab levels induced in vaccinated mice with both the Ab and protective responses elicited in cattle.

Protective immunity against foot-and-mouth disease virus induced by a recombinant vaccinia virus.

We report the construction of a recombinant vaccinia virus expressing the precursor for the four structural proteins of FMD virus (FMDV) (P1) strain C3Arg85 using a procedure for isolation of recombinant vaccinia viruses based solely on plaque formation. Adult mice vaccinated with this recombinant vaccinia virus elicited high titers of neutralizing antibodies against both the homologous FMDV and vaccinia virus, measured by neutralization assays. Liquid phase blocking sandwich enzyme-linked immunosorbent assays (ELISAs) using whole virus as antigen showed high total antibody titers against homologous FMDV, similar to those induced by the conventional inactivated vaccine.

Improvement of the immune response to foot and mouth disease virus vaccine in calves by using Avridine as adjuvant.

The epidemiological analysis of the cattle population during the eradication plan of foot and mouth disease (FMD) in Argentina clearly indicated a higher incidence of the disease in animals within their first year of age. It is important to improve the efficacy of the vaccination in those animals. In a previous report, we have shown the effect of an immunomodulator, Avridine (Avr), in the enhancement of the immune response elicited by FMD virus (FMDV) vaccines in experimental hosts [Berinstein, A.

Detection of virus infection-associated antigen and 3D antibodies in cattle vaccinated against foot and mouth disease.

The analysis of sera obtained from animals vaccinated or revaccinated with inactivated vaccines against foot and mouth disease (FMD) virus showed that these vaccines induced antibodies against the virus infection-associated (VIA) antigen, detectable by agar gel immunodiffusion (AGID). The present study evaluates the antibody response to protein 3D and the VIA antigen (VIAA) of FMD virus induced by different vaccines in a group of 51 calves. This response was detected using AGID and a liquid-phase blocking sandwich enzyme-linked immunosorbent assay (ELISA) for anti-3D antibodies (ELISA-3D).

[Seroepidemiologic indicators for the evaluation of campaigns for the control of foot-and-mouth disease].

A sero-epidemiological survey was conducted in two districts in Argentina between 1993 and 1995, to provide additional information on the epidemiology of foot and mouth disease (FMD) in Argentina and to assess the level of immunity in cattle populations, and the circulation of FMD virus. As part of the final stage of this survey, a comparison was made of the results obtained by the enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion techniques. Levels of population immunity against the four types of virus included in the vaccine increased progressively during the period of the survey until, in 1995, at the end of the vaccination period, the percentage of animals possessing adequate levels of protection was approximately 77% in yearlings, and more than 94% in cattle over one year old.

Assessment using ELISA of the herd immunity levels induced in cattle by foot-and-mouth disease oil vaccines.

The development of a liquid-phase blocking sandwich ELISA (LPBE) to measure antibodies (Ab) produced in cattle with the O, A and C foot-and-mouth disease virus (FMDV) types of commercial vaccines used in Argentina is described. The test was specific: 99% of naïve cattle sera (n = 130) gave titres below log10 = 1.2, and none had a titre above log10 = 1.

Detection of antibodies against foot-and-mouth disease virus using a liquid-phase blocking sandwich ELISA (LPBE) with a bioengineered 3D protein.

A liquid-phase blocking sandwich enzyme-linked immunosorbent assay (ELISA-3D) was developed to detect specific antibodies to the 3D protein in sera from foot-and-mouth disease (FMD) virus (FMDV)-infected animals. The assay uses a nonstructural 3D recombinant protein and two polyclonal antisera, one for capture (bovine) and the other for detector (guinea pig). The specificity of the assay was demonstrated by negative results with 101 sera of cattle from the FMD-free zone in Argentina and with bovine and porcine sera raised against various RNA and DNA viruses.

Isotype profiles induced in Balb/c mice during foot and mouth disease (FMD) virus infection or immunization with different FMD vaccine formulations.

The IgG isotype response in Balb/c mice infected with FMDV or immunized with different vaccine formulations using inactivated virus particles as antigen was analyzed at various times post-inoculation. For this purpose an ELISA based on polyclonal antibodies for detection and quantification of mouse IgG isotypes with FMD virus (FMDV) specificity was developed. Three immunomodulators, which have been shown to be very effective in inducing strong and long-lasting antibody responses (Bahnemann, Arch.

Immune response of calves to foot-and-mouth disease virus vaccine emulsified with oil adjuvant. Strategies of vaccination.

Calves born to vaccinated cows under the regular annual vaccination programme were vaccinated at different ages using commercial quadrivalent (01, A79, A87 and C85 FMDV strains) vaccine emulsified in oil adjuvant. The antibody responses of vaccinated calves were evaluated using liquid-phase blocking sandwich ELISA. All calves 20, 30 and 40 days old having high maternal antibody titres responded well to vaccination.

Validation of an inhibition ELISA using a monoclonal antibody for foot-and-mouth disease (FMD) primary diagnosis.

An inhibition ELISA (IH-ELISA) test for foot-and-mouth disease virus (FMDV) was validated using 106 epithelial samples from suspected cases of FMD in Argentina submitted to the Argentine National Diagnostics Laboratory (GELAB) over a period of 12 months and examined in parallel with the complement fixation test (CFT). IH-ELISA was found to be more sensitive, detecting 25% (26 samples) more FMDV positives than the CFT in original suspensions of field samples. The effect of storage conditions on 12S stability was examined.