Foot-and-mouth disease-associated myocarditis is age dependent in suckling calves

Myocarditis is considered a fatal form of foot-and-mouth disease (FMD) in suckling calves. In the present study, a total of 17 calves under 4 months of age and suspected clinically for FMD were examined for clinical lesions, respiratory rate, heart rate, and heart rhythm. Lesion samples, saliva, nasal swabs, and whole blood were collected from suspected calves and subjected to Sandwich ELISA and reverse transcription multiplex polymerase chain reaction (RT-mPCR) for detection and serotyping of FMD virus (FMDV). The samples were found to be positive for FMDV serotype "O". Myocarditis was suspected in 6 calves based on tachypnoea, tachycardia, and gallop rhythm. Serum aspartate aminotransferase (AST), creatinine kinase myocardial band (CK-MB) and lactate dehydrogenase (LDH), and cardiac troponins (cTnI) were measured. Mean serum AST, cTn-I and LDH were significantly higher (P < 0.001) in < 2 months old FMD-infected calves showing clinical signs suggestive of myocarditis (264.833 ± 4.16; 11.650 ± 0.34 and 1213.33 ± 29.06) than those without myocarditis (< 2 months old: 110.00 ± 0.00, 0.06 ± 0.00, 1050.00 ± 0.00; > 2 months < 4 months: 83.00 ± 3.00, 0.05 ± 0.02, 1159.00 ± 27.63) and healthy control groups (< 2 months old: 67.50 ± 3.10, 0.047 ± 0.01, 1120.00 ± 31.62; > 2 months < 4 months: 72.83 ± 2.09, 0.47 ± 0.00, 1160.00 ± 18.44). However, mean serum CK-MB did not differ significantly amongst the groups. Four calves under 2 months old died and a necropsy revealed the presence of a pathognomic gross lesion of the myocardial form of FMD known as "tigroid heart". Histopathology confirmed myocarditis. This study also reports the relevance of clinical and histopathological findings and biochemical markers in diagnosing FMD-related myocarditis in suckling calves.

Pathogenesis of non-epithelial foot-and-mouth disease in neonatal animals

Foot-and-mouth disease virus (FMDV), which causes a highly contagious viral disease of cloven-hoofed animals, is notable for epithelial cell tropism, resulting in the appearance of vesicles on the feet and in and around the mouth in infected animals, while FMDV infection in neonatal animals is also associated with not only epithelial lesions, but also muscle-associated lesions, which leads to myocarditis, resulting in high-mortality. However, critical knowledge about the non-epithelial tropism of FMDV is still lacking. In this paper, the current progress of the FMDV non-epithelial tropisms is summarized and the possible role of the key viral and cellular components involved is discussed.

Impact of truck contamination and information sharing on foot-and-mouth disease spreading in beef cattle production systems

As cattle movement data in the United States are scarce due to the absence of mandatory traceability programs, previous epidemic models for U.S. cattle production systems heavily rely on contact rates estimated based on expert opinions and survey data. These models are often based on static networks and ignore the sequence of movement, possibly overestimating the epidemic sizes. In this research, we adapt and employ an agent-based model that simulates beef cattle production and transportation in southwest Kansas to analyze the between-premises transmission of a highly contagious disease, foot-and-mouth disease. First, we assess the impact of truck contamination on the disease transmission with the truck agent following an independent clean-infected-clean cycle. Second, we add an information-sharing functionality such that producers/packers can trace back and forward their trade records to inform their trade partners during outbreaks. Scenario analysis results show that including indirect contact routes between premises via truck movements can significantly increase the amplitude of disease spread, compared with equivalent scenarios that only consider animal movement. Mitigation strategies informed by information sharing can effectively mitigate epidemics, highlighting the benefit of promoting information sharing in the cattle industry. In addition, we identify salient characteristics that must be considered when designing an information-sharing strategy, including the number of days to trace back and forward in the trade records and the role of different cattle supply chain stakeholders. Sensitivity analysis results show that epidemic sizes are sensitive to variations in parameters of the contamination period for a truck or a loading/unloading area of premises, and indirect contact transmission probability and future studies can focus on a more accurate estimation of these parameters.

FOOT-AND-MOUTH DISEASE IN EXPERIMENTALLY INFECTED MULE DEER (ODOCOILEUS HEMIONUS)

The only known outbreak of foot-and-mouth disease (FMD) in wildlife in the US occurred in mule deer (Odocoileus hemionus) in California in 1924-25. There is little recorded information on the pathogenesis and epidemiology of the disease in deer in that outbreak. In this experimental study, we compared the susceptibility of mule deer to FMD virus (FMDV) serotype O to that of cattle (Bos taurus). We also determined the potential for intra- and interspecies transmission of FMDV serotype O in mule deer and cattle, and assessed conventional laboratory tests in their ability to detect FMDV in mule deer. Two mule deer and one steer were each infected by intraepithelial tongue inoculation with 10,000 bovine tongue infective doses of FMDV, strain O1 Manisa. The inoculated steer and deer were kept in the same room with contact animals of both species. Exposed contact animals were moved to rooms with unexposed animals after becoming febrile. All mule deer (n=14) and cattle (n=6) developed clinical signs and lesions consistent with FMDV infection. Deer had a high prevalence of myocarditis and high mortality. Virus was transmitted between mule deer, from cattle to mule deer, and from mule deer to cattle. Virus and antibodies against nonstructural FMDV proteins in mule deer and cattle were detected by conventional laboratory tests. Virus shedding was detected by PCR and virus isolation up to 9 d postexposure in deer.

Virulence beneath the fleece; a tale of foot-and-mouth disease virus pathogenesis in sheep

Foot-and-mouth disease virus (FMDV) is capable of infecting all cloven-hoofed domestic livestock species, including cattle, pigs, goats, and sheep. However, in contrast to cattle and pigs, the pathogenesis of FMDV in small ruminants has been incompletely elucidated. The objective of the current investigation was to characterize tissue- and cellular tropism of early and late stages of FMDV infection in sheep following three different routes of simulated natural virus exposure. Extensive post-mortem harvest of tissue samples at pre-determined time points during early infection (24 and 48 hours post infection) demonstrated that tissues specifically susceptible to primary FMDV infection included the paraepiglottic- and palatine tonsils, as well as the nasopharyngeal mucosa. Additionally, experimental aerosol inoculation of sheep led to substantial virus replication in the lungs at 24-48 hours post-inoculation. During persistent infection (35 days post infection), the paraepiglottic- and palatine tonsils were the only tissues from which infectious FMDV was recovered. This is strikingly different from cattle, in which persistent FMDV infection has consistently been located to the nasopharyngeal mucosa. Analysis of tissue sections by immunomicroscopy revealed a strict epithelial tropism during both early and late phases of infection as FMDV was consistently localized to cytokeratin-expressing epithelial cells. This study expands upon previous knowledge of FMDV pathogenesis in sheep by providing detailed information on the temporo-anatomic distribution of FMDV in ovine tissues. Findings are discussed in relation to similar investigations previously performed in cattle and pigs, highlighting similarities and differences in FMDV pathogenesis across natural host species.

Innate immune sensor LGP2 is cleaved by the Leader protease of foot-and-mouth disease virus

The RNA helicase LGP2 (Laboratory of Genetics and Physiology 2) is a non-signaling member of the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), whose pivotal role on innate immune responses against RNA viruses is being increasingly uncovered. LGP2 is known to work in synergy with melanoma differentiation-associated gene 5 (MDA5) to promote the antiviral response induced by picornavirus infection. Here, we describe the activity of the foot-and-mouth disease virus (FMDV) Leader protease (Lpro) targeting LGP2 for cleavage. When LGP2 and Lpro were co-expressed, cleavage products were observed in an Lpro dose-dependent manner while co-expression with a catalytically inactive Lpro mutant had no effect on LGP2 levels or pattern. We further show that Lpro localizes and immunoprecipitates with LGP2 in transfected cells supporting their interaction within the cytoplasm. Evidence of LGP2 proteolysis was also detected during FMDV infection. Moreover, the inhibitory effect of LGP2 overexpression on FMDV growth observed was reverted when Lpro was co-expressed, concomitant with lower levels of IFN-β mRNA and antiviral activity in those cells. The Lpro target site in LGP2 was identified as an RGRAR sequence in a conserved helicase motif whose replacement to EGEAE abrogated LGP2 cleavage by Lpro. Taken together, these data suggest that LGP2 cleavage by the Leader protease of aphthoviruses may represent a novel antagonistic mechanism for immune evasion.

An assessment of a pediatric early warning system score in severe hand-foot-and-mouth disease children: To detect clinical deterioration in hospitalized children

Identification of deteriorating severe hand, foot, and mouth disease (HFMD) children for referral to intensive care remains problematic.The medical records of 2382 hospitalized children with severe HFMD from May 2013 to September 2015 were retrospectively reviewed. A Pediatric Early Warning System (PEWS) score was designed based on study parameters on admission, evaluated in a logistic regression model, and subsequently validated with different cut-off scores, to predict the risk for clinical deterioration.After admission, 191 cases were transferred to the pediatric intensive care unit (PICU) and 2191 were admitted to the infectious disease department. Of which, 116 cases were subsequently transferred to PICU, with younger age, consciousness levels of sluggishness, lethargy or drowsiness, rashes with vesicles on the hands or feet, moderate or high fever, increased or disordered lung marking or pulmonary infiltration, abnormal heart rate, fasting plasma glucose, blood platelet, and C-reactive protein. A corresponding 10-component PEWS score >7 was significantly associated with subsequent transfer to PICU.A 10-component PEWS score >7 has good specificity but poor sensitivity for identifying severe HFMD children vulnerable to clinical deterioration.

Involvement of the renin-angiotensin system in the progression of severe hand-foot-and-mouth disease

BACKGROUND

Hand-foot-and-mouth disease (HFMD) is generally considered as a mild exanthematous disease to infants and young children worldwide. HFMD cases are usually mild and self-limiting but for few cases leads to complicated severe clinical outcomes, and even death. Previous studies have indicated that serum Ang II levels in patients with H7N9 infection were related to the severity of infection. However, the mechanisms underlying the pathogenesis of severe HFMD remain unclear. This study was undertaken to clarify the role of the renin-angiotensin system (RAS) in the progression of severe HFMD.

METHODS

In the present study, 162 children including HFMD patients and healthy controls were recruited. The data was analyzed by time-series fashion. Concentrations of angiotensin II (Ang II) and noradrenaline (NA) in serum of patients were measured with ELISA. We established a mouse model for enterovirus 71 (EV71) infection and determined concentrations of Ang II, NA in tissue lysates at 3, 5 and 7 days post infection (dpi).

RESULTS

The concentrations of Ang II and NA in serum of the HFMD patients with mild or severe symptoms were significantly higher than that in healthy controls. Additionally, the concentrations of Ang II and NA in serum of severe cases were significantly higher than those mild cases and the increased concentrations of Ang II and NA showed the same time trend during the progression of HFMD in the severe cases. Furthermore, the concentrations of Ang II and NA in target organs of EV71-infected mice including brains, skeletal muscle, and lungs were increased with the progression of EV71 infection in mice. Histopathological alterations were observed in the brains, skeletal muscle and lungs of EV71-infected mice.

CONCLUSION

Our study suggested that activation of the RAS is implicated in the pathogenesis of severe HFMD.

Isolation and identification of bovine nasopharyngeal mucosal epithelial cells and establishment of cell models of acute infection by foot-and-mouth disease virus

Foot-and-mouth disease (FMD) commonly occurs via the respiratory tract, and bovine nasopharyngeal mucosal epithelial cells are the primary infection cells in cattle. The aim of the present study was to isolate and culture epithelial cells from the bovine nasopharyngeal mucosa in vitro using a mechanical separation method. The cells were expanded, established in continuous cell culture, and used for immunofluorescence cytochemistry and establishment of infection models. We detected pan-cytokeratin markers of bovine nasopharyngeal mucosal epithelial cells by immunofluorescence. Bovine nasopharyngeal mucosal epithelial cells were then infected with foot-and-mouth disease virus (FMDV) serum type O. RT-PCR demonstrated the successful establishment of acute FMDV infection in the cell models. This infection model provides the basis for clarification of the interaction between FMDV and host bovine nasopharyngeal mucosal epithelial cells in vitro.

Attenuation of Foot-and-Mouth Disease Virus by Engineered Viral Polymerase Fidelity

Foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase (RdRp) (3Dpol) catalyzes viral RNA synthesis. Its characteristic low fidelity and absence of proofreading activity allow FMDV to rapidly mutate and adapt to dynamic environments. In this study, we used the structure of FMDV 3Dpol in combination with previously reported results from similar picornaviral polymerases to design point mutations that would alter replication fidelity. In particular, we targeted Trp237 within conserved polymerase motif A because of the low reversion potential inherent in the single UGG codon. Using biochemical and genetic tools, we show that the replacement of tryptophan 237 with phenylalanine imparts higher fidelity, but replacements with isoleucine and leucine resulted in lower-fidelity phenotypes. Viruses containing these W237 substitutions show in vitro growth kinetics and plaque morphologies similar to those of the wild-type (WT) A24 Cruzeiro strain in BHK cells, and both high- and low-fidelity variants retained fitness during coinfection with the wild-type virus. The higher-fidelity W237F (W237FHF) mutant virus was more resistant to the mutagenic nucleoside analogs ribavirin and 5-fluorouracil than the WT virus, whereas the lower-fidelity W237I (W237ILF) and W237LLF mutant viruses exhibited lower ribavirin resistance. Interestingly, the variant viruses showed heterogeneous and slightly delayed growth kinetics in primary porcine kidney cells, and they were significantly attenuated in mouse infection experiments. These data demonstrate, for a single virus, that either increased or decreased RdRp fidelity attenuates virus growth in animals, which is a desirable feature for the development of safer and genetically more stable vaccine candidates.IMPORTANCE Foot-and-mouth disease (FMD) is the most devastating disease affecting livestock worldwide. Here, using structural and biochemical analyses, we have identified FMDV 3Dpol mutations that affect polymerase fidelity. Recombinant FMDVs containing substitutions at 3Dpol tryptophan residue 237 were genetically stable and displayed plaque phenotypes and growth kinetics similar to those of the wild-type virus in cell culture. We further demonstrate that viruses harboring either a W237FHF substitution or W237ILF and W237LLF mutations were highly attenuated in animals. Our study shows that obtaining 3Dpol fidelity variants by protein engineering based on polymerase structure and function could be exploited for the development of attenuated FMDV vaccine candidates that are safer and more stable than strains obtained by selective pressure via mutagenic nucleotides or adaptation approaches.

Foot-and-mouth disease virus infection suppresses autophagy and NF-кB antiviral responses via degradation of ATG5-ATG12 by 3Cpro

Autophagy-related protein ATG5-ATG12 is an essential complex for the autophagophore elongation in autophagy, which has been reported to be involved in foot-and-mouth disease virus (FMDV) replication. Previous reports show that ATG5-ATG12 positively or negatively regulates type I interferon (IFN-α/β) pathway during virus infection. In this study, we found that FMDV infection rapidly induced LC3 lipidation and GFP-LC3 subcellular redistribution at the early infection stage in PK-15 cells. Along with infection time course to 2-5 h.p.i., the levels of LC3II and ATG5-ATG12 were gradually reduced. Further study showed that ATG5-ATG12 was degraded by viral protein 3Cpro, demonstrating that FMDV suppresses autophagy along with viral protein production. Depletion of ATG5-ATG12 by siRNA knock down significantly increased the FMDV yields, whereas overexpression of ATG5-ATG12 had the opposite effects, suggesting that degradation of ATG5-ATG12 benefits virus growth. Further experiment showed that overexpression of ATG5-ATG12 positively regulated NF-кB pathway during FMDV infection, marked with promotion of IKKα/β phosphorylation and IκBα degradation, inhibition of p65 degradation, and facilitation of p65 nuclear translocation. Meanwhile, ATG5-ATG12 also promoted the phosphorylation of TBK1 and activation of IRF3 via preventing TRAF3 degradation. The positive regulation of NF-кB and IRF3 pathway by ATG5-ATG12 resulted in enhanced expression of IFN-β, chemokines/cytokines, and IFN stimulated genes, including anti-viral protein PKR. Altogether, above findings suggest that ATG5-ATG12 positively regulate anti-viral NF-κB and IRF3 signaling during FMDV infection, thereby limiting FMDV proliferation. FMDV has evolved mechanisms to counteract the antiviral function of ATG5-ATG12, via degradation of them by viral protein 3Cpro.

Investigating intra-host and intra-herd sequence diversity of foot-and-mouth disease virus

Due to the poor-fidelity of the enzymes involved in RNA genome replication, foot-and-mouth disease (FMD) virus samples comprise of unique polymorphic populations. In this study, deep sequencing was utilised to characterise the diversity of FMD virus (FMDV) populations in 6 infected cattle present on a single farm during the series of outbreaks in the UK in 2007. A novel RT–PCR method was developed to amplify a 7.6 kb nucleotide fragment encompassing the polyprotein coding region of the FMDV genome. Illumina sequencing of each sample identified the fine polymorphic structures at each nucleotide position, from consensus level changes to variants present at a 0.24% frequency. These data were used to investigate population dynamics of FMDV at both herd and host levels, evaluate the impact of host on the viral swarm structure and to identify transmission links with viruses recovered from other farms in the same series of outbreaks. In 7 samples, from 6 different animals, a total of 5 consensus level variants were identified, in addition to 104 sub-consensus variants of which 22 were shared between 2 or more animals. Further analysis revealed differences in swarm structures from samples derived from the same animal suggesting the presence of distinct viral populations evolving independently at different lesion sites within the same infected animal.

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NGS was used to characterise FMD viruses in clinical samples from cattle.

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5 consensus and 104 sub-consensus level substitutions were identified.

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Distinct virus swarms were found in different lesions within the same host.

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Only 22 sub-consensus substitutions were shared between 2 or more animals.

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Data suggest that FMDV evolves independently at different lesion sites.

Effect of Foot-and-Mouth Disease Virus Infection on the Frequency, Phenotype and Function of Circulating Dendritic Cells in Cattle

Foot-and-mouth disease virus (FMDV) is a highly contagious virus that causes one of the most devastating diseases in cloven-hoofed animals. Disease symptoms develop within 2 to 3 days of exposure and include fever and vesicular lesions on the tongue and hooves. Dendritic cells (DC) play an essential role in protective immune responses against pathogens. Therefore, investigating their role during FMDV infection would lead to a better understanding of host-pathogen interactions. In this study, following infection of cattle with FMDV, we investigated the frequency and function of conventional (cDC) and plasmacytoid DC (pDC) in blood by using multi-color flow cytometry. We show that the frequency of cDC and pDC increased following FMDV infection and peaked 3 to 4 days post-infection. During peak viremia, the cattle became lymphopenic, the expression of MHC class II molecules on cDC and pDC was dramatically down-regulated, the processing of exogenous antigen by cDC and pDC was impaired, and there was an increase in IL-10 production by DC and monocytes. Notably, after clearance of FMDV from the blood, MHC class II expression returned to pre-infection levels. Altogether, our study demonstrates that in cattle, FMDV inhibits the function of DC, thereby retarding the initiation of adaptive immune responses, potentially enhancing virus shedding during the acute phase of infection.

Knowledge of Bovine Tuberculosis, Cattle Husbandry and Dairy Practices amongst Pastoralists and Small-Scale Dairy Farmers in Cameroon

BACKGROUND

Control of bovine tuberculosis (bTB) and zoonotic tuberculosis (zTB) has relied upon surveillance and slaughter of infected cattle, milk pasteurisation and public health education. In Cameroon, like many other sub-Saharan African countries, there is limited understanding of current cattle husbandry or milk processing practices or livestock keepers awareness of bTB. This paper describes husbandry and milk processing practices within different Cameroonian cattle keeping communities and bTB awareness in comparison to other infectious diseases.

STUDY DESIGN

A population based cross-sectional sample of herdsmen and a questionnaire were used to gather data from pastoralists and dairy farmers in the North West Region and Vina Division of Cameroon.

RESULTS

Pastoralists were predominately male Fulanis who had kept cattle for over a decade. Dairy farmers were non-Fulani and nearly half were female. Pastoralists went on transhumance with their cattle and came into contact with other herds and potential wildlife reservoirs of bTB. Dairy farmers housed their cattle and had little contact with other herds or wildlife. Pastoralists were aware of bTB and other infectious diseases such as foot-and-mouth disease and fasciolosis. These pastoralists were also able to identify clinical signs of these diseases. A similar proportion of dairy farmers were aware of bTB but fewer were aware of foot-and-mouth and fasciolosis. In general, dairy farmers were unable to identify any clinical signs for any of these diseases. Importantly most pastoralists and dairy farmers were unaware that bTB could be transmitted to people by consuming milk.

CONCLUSIONS

Current cattle husbandry practices make the control of bTB in cattle challenging especially in mobile pastoralist herds. Routine test and slaughter control in dairy herds would be tractable but would have profound impact on dairy farmer livelihoods. Prevention of transmission in milk offers the best approach for human risk mitigation in Cameroon but requires strategies that improved risk awareness amongst producers and consumers.

Analysis of the interaction between host factor Sam68 and viral elements during foot-and-mouth disease virus infections

BACKGROUND

The nuclear protein Src-associated protein of 68 kDa in mitosis (Sam68) is known to bind RNA and be involved in cellular processes triggered in response to environmental stresses, including virus infection. Interestingly, Sam68 is a multi-functional protein implicated in the life cycle of retroviruses and picornaviruses and is also considered a marker of virus-induced stress granules (SGs). Recently, we demonstrated the partial redistribution of Sam68 to the cytoplasm in FMDV infected cells, its interaction with viral protease 3C(pro), and found a significant reduction in viral titers as consequence of Sam68-specific siRNA knockdowns. Despite of that, details of how it benefits FMDV remains to be elucidated.

METHODS

Sam68 cytoplasmic localization was examined by immunofluorescent microscopy, counterstaining with antibodies against Sam68, a viral capsid protein and markers of SGs. The relevance of RAAA motifs in the IRES was investigated using electromobility shift assays with Sam68 protein and parental and mutant FMDV RNAs. In addition, full genome WT and mutant or G-luc replicon RNAs were tested following transfection in mammalian cells. The impact of Sam68 depletion to virus protein and RNA synthesis was investigated in a cell-free system. Lastly, through co-immunoprecipitation, structural modeling, and subcellular fractionation, viral protein interactions with Sam68 were explored.

RESULTS

FMDV-induced cytoplasmic redistribution of Sam68 resulted in it temporarily co-localizing with SG marker: TIA-1. Mutations that disrupted FMDV IRES RAAA motifs, with putative affinity to Sam68 in domain 3 and 4 cause a reduction on the formation of ribonucleoprotein complexes with this protein and resulted in non-viable progeny viruses and replication-impaired replicons. Furthermore, depletion of Sam68 in cell-free extracts greatly diminished FMDV RNA replication, which was restored by addition of recombinant Sam68. The results here demonstrated that Sam68 specifically co-precipitates with both FMDV 3D(pol) and 3C(pro) consistent with early observations of FMDV 3C(pro)-induced cleavage of Sam68.

CONCLUSION

We have found that Sam68 is a specific binding partner for FMDV non-structural proteins 3C(pro) and 3D(pol) and showed that mutations at RAAA motifs in IRES domains 3 and 4 cause a decrease in Sam68 affinity to these RNA elements and rendered the mutant RNA non-viable. Interestingly, in FMDV infected cells re-localized Sam68 was transiently detected along with SG markers in the cytoplasm. These results support the importance of Sam68 as a host factor co-opted by FMDV during infection and demonstrate that Sam68 interact with both, FMDV RNA motifs in the IRES and viral non-structural proteins 3C(pro) and 3D(pol).

Pathogenesis of Primary Foot-and-Mouth Disease Virus Infection in the Nasopharynx of Vaccinated and Non-Vaccinated Cattle

A time-course pathogenesis study was performed to compare and contrast primary foot-and-mouth disease virus (FMDV) infection following simulated-natural (intra-nasopharyngeal) virus exposure of cattle that were non-vaccinated or vaccinated using a recombinant adenovirus-vectored FMDV vaccine. FMDV genome and infectious virus were detected during the initial phase of infection in both categories of animals with consistent predilection for the nasopharyngeal mucosa. A rapid progression of infection with viremia and widespread dissemination of virus occurred in non-vaccinated animals whilst vaccinated cattle were protected from viremia and clinical FMD. Analysis of micro-anatomic distribution of virus during early infection by lasercapture microdissection localized FMDV RNA to follicle-associated epithelium of the nasopharyngeal mucosa in both groups of animals, with concurrent detection of viral genome in nasopharyngeal MALT follicles in vaccinated cattle only. FMDV structural and non-structural proteins were detected in epithelial cells of the nasopharyngeal mucosa by immunomicroscopy 24 hours after inoculation in both non-vaccinated and vaccinated steers. Co-localization of CD11c+/MHC II+ cells with viral protein occurred early at primary infection sites in vaccinated steers while similar host-virus interactions were observed at later time points in non-vaccinated steers. Additionally, numerous CD8+/CD3- host cells, representing presumptive natural killer cells, were observed in association with foci of primary FMDV infection in the nasopharyngeal mucosa of vaccinated steers but were absent in non-vaccinated steers. Immunomicroscopic evidence of an activated antiviral response at primary infection sites of vaccinated cattle was corroborated by a relative induction of interferon -α, -β, -γ and -λ mRNA in micro-dissected samples of nasopharyngeal mucosa. Although vaccination protected cattle from viremia and clinical FMD, there was subclinical infection of epithelial cells of the nasopharyngeal mucosa that could enable shedding and long-term persistence of infectious virus. Additionally, these data indicate different mechanisms within the immediate host response to infection between non-vaccinated and vaccinated cattle.

Recovery of viral RNA and infectious foot-and-mouth disease virus from positive lateral-flow devices

Foot-and-mouth disease Virus (FMDV) is an economically important, highly contagious picornavirus that affects both wild and domesticated cloven hooved animals. In developing countries, the effective laboratory diagnosis of foot-and-mouth disease (FMD) is often hindered by inadequate sample preservation due to difficulties in the transportation and storage of clinical material. These factors can compromise the ability to detect and characterise FMD virus in countries where the disease is endemic. Furthermore, the high cost of sending infectious virus material and the biosecurity risk it presents emphasises the need for a thermo-stable, non-infectious mode of transporting diagnostic samples. This paper investigates the potential of using FMDV lateral-flow devices (LFDs) for dry transportation of clinical samples for subsequent nucleic acid amplification, sequencing and recovery of infectious virus by electroporation. FMDV positive samples (epithelial suspensions and cell culture isolates) representing four FMDV serotypes were applied to antigen LFDs: after which it was possible to recover viral RNA that could be detected using real-time RT-PCR. Using this nucleic acid, it was also possible to recover VP1 sequences and also successfully utilise protocols for amplification of complete FMD virus genomes. It was not possible to recover infectious FMDV directly from the LFDs, however following electroporation into BHK-21 cells and subsequent cell passage, infectious virus could be recovered. Therefore, these results support the use of the antigen LFD for the dry, non-hazardous transportation of samples from FMD endemic countries to international reference laboratories.

Investigation of foot-and-mouth disease outbreaks in the Mbala and Kazungula districts of Zambia

Foot-and-mouth disease (FMD) is an acute, highly contagious viral infection of domestic and wild cloven-hoofed animals. It is known to be endemic in Zambia, with periodic outbreaks occurring in different geographical areas of the country. This study was conducted to investigate the presence of FMD virus (FMDV) in reported FMD-suspected cases in cattle from the Kazungula and Mbala districts of Zambia. Sixty epithelial tissues or oesophageal-pharyngeal (OP) scrapings (probang samples) were collected from Mbala (n = 51) and Kazungula (n = 9) and examined for FMDV. The FMDV viral RNA and serotypes were examined by realtime reverse transcription polymerase chain reaction (qRT-PCR) and antigen Enzyme- linked immunosorbent assay (ELISA), respectively. Twenty-two samples (36.7%) were positive for the FMDV genome by qRT-PCR with Cycle threshold (Ct) values ranging from 13 to 31. The FMDV-positive samples from epithelial tissues showed relatively higher Ct values compared to those obtained from OP scrapings, irrespective of geographical location. Forty percent (40%; n = 4) of epithelial tissues from Mbala were serotyped into SAT 2 serotype by antigen ELISA. Kazungula samples were serotyped into SAT 1. These findings indicated that Mbala and Kazungula districts had FMD outbreaks in 2012 that were ascribed to at least FMDV serotype SAT 2 and SAT 1 field strains. Furthermore, regular interaction between buffalos from the Mosi-o Tunya Park and domestic animals from surrounding areas could contribute to the occurrence of regular FMD outbreaks in Kazungula, whilst the uncontrolled animal movements across borders between Mbala and Nsumbawanga could be responsible for disease outbreaks in Mbala. In-depth molecular biological studies, including sequencing and phylogeny of the viruses, should be conducted to elucidate the complex epidemiology of FMD in Zambia, thereby providing valuable information needed for the rational control strategy of FMD in Zambia and neighbouring countries.

Dynamic impacts of a catastrophic production event: the foot-and-mouth disease case

In foot-and-mouth disease (FMD) free countries, the occurrence of an FMD outbreak is a rare event with potentially large economic losses. We explore the dynamic effects of an FMD outbreak on market variables and economic surplus taking into account the largely neglected issue of farm bankruptcy. Simulations are performed on a stylized agricultural economy, which is a net exporter before the outbreak. We find complex dynamic market effects when the farm credit market suffers from information imperfections leading to farm closure. Welfare effects are also dramatically altered. Domestic consumers may lose in the long run from an FMD outbreak because domestic supply contracts. On the other hand, farmers able to resist this event may ultimately gain. Our analysis also shows that these effects are not monotone, making any efficient policy response to this catastrophic event quite challenging.

[Foot-and-mouth disease and its differential diagnoses]

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals, which leads to the formation of vesicles, erosions und ulcerations in the mouth and hairless parts of the skin, in particular on the feet. Due to its dramatic economic consequences, FMD is considered to be one of the most important diseases of animals. There is a permanent risk of introduction of the virus into Europe due to travel and illegal importation of agricultural products. Cloven-hoofed animals (cattle, sheep, goats, pigs and related game animals) are the typical hosts of the FMD virus. However, some zoo and wild animals belonging to other taxonomical groups, such as giraffes, elephants and camels, are also susceptible. Stomatitis and infections of the feet in livestock occur quite frequently, and often the causes of these conditions remain obscure. Sometimes, a differentiation from FMD is not possible on the basis of clinical signs and gross lesions, necessitating further laboratory investigations. This applies in particular to cases caused by the agents of vesicular stomatitis (VS) and swine vesicular disease (SVD). Additionally, other infectious agents can cause stomatitis, e.g. the viruses of mucosal disease (MD), malignant catarrhal fever (MCF), rinderpest, peste des petits ruminants (PPR), papular stomatitis, orf, blue tongue (BT) and epizootic haemorrhagic disease (EHD). In sheep, a stomatitis of unclear etiology was described as "OMAGOD". Furthermore, bacteria, chemicals and mechanical trauma can cause stomatitis and pododermatitis.

Experimental transmission of foot-and-mouth disease among Indian buffalo (Bubalus bubalis) and from buffalo to cattle

Indian buffalo and cattle were infected experimentally with a serotype O strain of foot-and-mouth disease virus of buffalo origin. Whereas intradermolingual inoculation of buffalo produced largely sub-clinical infection, inoculation in the dental pad produced vesicles in the mouth and on the feet. A buffalo infected via the dental pad transmitted infection to cattle and buffalo by direct contact with them for 24h. The contact-exposed buffalo developed (1) delayed-onset clinical signs, and (2) shedding of virus from the nose, commencing before the appearance of vesicles and continuing until the experiment was terminated 10 weeks after exposure. The covert nature of the disease in Indian buffalo, coupled with the prolonged shedding of virus, suggests that this species represents a host of epidemiological importance.

Pathogenic characteristics of the Korean 2002 isolate of foot-and-mouth disease virus serotype O in pigs and cattle

Experimental infection of susceptible cattle and pigs showed that the O/SKR/AS/2002 pig strain of foot-and-mouth disease virus (FMDV) causes an infection that is highly virulent and contagious in pigs but very limited in cattle. Pigs directly inoculated with, or exposed to swine infected with, strain O/SKR/AS/2002 showed typical clinical signs, including gross vesicular lesions in mouth and pedal sites. In addition, FMDV was isolated from, and FMDV genomic RNA was detected in, blood, serum, nasal swabs and oesophageal-pharyngeal (OP) fluid early in the course of infection. Antibodies against the non-structural protein (NSP) 3ABC were detected in both directly inoculated and contact pigs, indicating active virus replication. In contrast, the disease in cattle was atypical. After inoculation, lesions were confined to the infection site. A transient viraemia occurred 1 and 2 days after inoculation, and this was followed by the production of antibodies to NSP 3ABC, indicating subclinical infection. No clinical disease was seen, and no antibodies to NSP 3ABC were present in contact cattle. Additionally, no virus or viral nucleic acid was detected in blood, nasal swab and OP fluid samples from contact cattle. Thus, the virus appeared not to be transmitted from infected cattle to contact cattle. In its behaviour in pigs and cattle, strain O/SKR/AS/2002 resembled the porcinophilic FMDV strain of Cathay origin, O/TAW/97. However, the latter, unlike O/SKR/AS/2002, has reduced ability to grow in bovine-derived cells. The porcinophilic character of O/TAW/97 has been attributed to a deletion in the 3A coding region of the viral genome. However, O/SKR/AS/2002 has an intact 3A coding region.

[Foot and mouth disease and bluetongue: differences and similarities]

On 26th of july 2007 a new case of bluetongue was notified in the Netherlands and on 2nd of august 2007 foot-and-mouth disease was diagnosed in Surrey, England, which raised the threat of having both infections simultaniously in one area. Bluetongue and foot-and-mouth disease have a different pathogenesis, but symptoms may resemble each other at a later stage of infection. The pathogenesis and possible clinical symptoms of both infections are discussed and illustrated with pictures.

Foot-and-mouth disease virus infection in young lambs: pathogenesis and tissue tropism

Foot-and-mouth disease (FMD) in adult sheep usually causes milder clinical signs than in cattle or pigs, and is often subtle enough to go undiagnosed. In contrast, FMD in lambs has been reported to cause high mortality during field outbreaks. In order to investigate the pathogenesis of FMD in lambs, two groups, aged 10-14 days, were infected with foot-and-mouth disease virus (FMDV) type O UKG. One group of lambs (n=8) was inoculated with FMDV in the coronary band, while the other (n=4) was infected by direct contact with FMDV-inoculated ewes. Daily serum samples and temperature measurements were taken. Lambs were killed sequentially and tissue samples taken for analysis. Using real-time RT-PCR, viral RNA levels in tissue samples and serum were measured, and a novel strand-specific real-time RT-PCR assay was used to quantify viral replication levels in tissues. Tissue sections were examined for histopathological lesions, and in situ hybridisation (ISH) was used to localise viral RNA within histological sections. The contact-infected lambs became infected approximately 24h after the ewes were inoculated. Vesicular lesions developed on the feet of all lambs and on the caudo-lateral part of the tongues of six of the eight inoculated lambs and three of the four contact-infected lambs. Although no lambs developed severe clinical signs, one of the contact-infected lambs died acutely at 5 days post-exposure. Histological examination of the heart from this lamb showed multi-focal areas of lymphocytic-plasmacytic myocarditis; similar lesions were also observed in the hearts of three of the inoculated lambs. Using ISH, viral RNA was localised within cardiac and skeletal muscle cells from the lamb which had died, and also from vesicular lesions on the coronary band and tongue of inoculated lambs. These results provide a detailed description of the pathogenesis of the disease in lambs.

Plus- and minus-stranded foot-and-mouth disease virus RNA quantified simultaneously using a novel real-time RT-PCR

Even though tagged RT-PCR and rTth RT-PCR have been developed to improve strand-specific detection of RNA virus, these assays are not quantitative. In this study, a novel real-time RT-PCR assay, which combines the benefits of both the tagged and rTth RT-PCR has been developed to quantify the strand-specific RNA of foot-and-mouth disease virus (FMDV). The tagged-primers plus a TaqMan probe located within the highly conserved viral 3D region were used. The in vitro synthesized minus-and plus-stranded RNA templates were used as a dual control along with the copy number of viral RNA molecules, which is more reliable than reported RT-PCR employing a DNA-based standard. This assay was used to quantify FMDV RNA from 10(9) to 10(1) copies with a maximum sensitivity of between ten and five copies and was shown to be highly reproducible with low intra-and inter-assay variation. Coefficients of variation (CV) values were 0.70-1.39% and 0.98-2.1%, respectively. Importantly, the method was applied to simultaneously quantify both plus-stranded and minus-stranded FMDV RNA using tagged-RT and tagged-FP primer during a high-temperature reverse transcription. Highly sensitive and strand-specific real-time RT-PCR assay has been established. We tested the ratio of viral plus-stranded to minus-stranded RNA in acutely infected and persistently infected BHK-21 cells, for which the values ranged from 22/1 to 143/1 and from 287/1 to 334/1, respectively, suggesting different replication patterns of plus-and minus-stranded RNA in acutely infected and persistently infected cells. This value ranged from 83/1 to 93/1 in enriched FMDV virions, indicating that FMDV encapsidation is highly specific for plus-stranded RNAs. In addition, the method was applied to surveille the FMDV replication at animal level.

DNA vaccines expressing B and T cell epitopes can protect mice from FMDV infection in the absence of specific humoral responses

Despite foot-and-mouth disease virus (FMDV) being responsible for one of the most devastating animal diseases, little is known about the cellular immune mechanisms involved in protection against this virus. In this work we have studied the potential of DNA vaccines based on viral minigenes corresponding to three major B and T-cell FMDV epitopes (isolate C-S8c1) originally identified in natural hosts. The BTT epitopes [VP1 (133-156)-3A (11-40)-VP4 (20-34)] were cloned into the plasmid pCMV, either alone or fused to ubiquitin, the lysosomal targeting signal from LIMPII, a soluble version of CTLA4 or a signal peptide from the human prion protein, to analyze the effect of processing through different antigenic presentation pathways on the immunogenicity of the FMDV epitopes. As a first step in the analysis of modulation exerted by these target signals, a FMDV infection inhibition assay in Swiss outbred mice was developed and used to analyze the protection conferred by the different BTT-expressing plasmids. Only one of the 37 mice immunized with minigene-bearing plasmids developed specific neutralizing antibodies prior to FMDV challenge. As expected, this single mouse that had been immunized with the BTT tandem epitopes fused to a signal peptide (pCMV-spBTT) was protected against FMDV infection. Interestingly, nine more of the animals immunized with BTT-expressing plasmids did not show viremia at 48 h post-infection (pi), even in the absence of anti-FMDV antibodies prior to challenge. The highest protection (50%, six out of 12 mice) was observed with the plasmid expressing BTT alone, indicating that the targeting strategies used did not result in an improvement of the protection conferred by BTT epitopes. Interestingly, peptide specific CD4+ T-cells were detected for some of the BTT-protected mice. Thus, a DNA vaccine based on single FMDV B and T cell epitopes can protect mice, in the absence of specific antibodies at the time of challenge. Further work must be done to elucidate the mechanisms involved in protection and to determine the protective potential of these vaccines in natural FMDV hosts.

Protection of Balb/c mice against infection with FMDV by immunostimulation with CpG oligonucleotides

Oligodeoxynucleotides (ODN) containing unmethylated CpG motifs are potent stimulators of the innate immune system, and are capable of aborting several infections in a non-specific manner. We here report studies of the capacity of such ODN to protect mice against infection with foot and mouth disease virus (FMDV). Susceptibility of Balb/c mice to infection with isolates from the different serotypes of FMDV was investigated, and, at the same time, the capacity of CpG ODN to modulate the infection was evaluated. Treatment with CpG significantly reduced viremia, disease and death in five of six serotypes, when compared to no treatment or treatment with a control ODN. The effect was observed when ODN was administered simultaneously with, or up to 12h after, infection with FMDV, and lasted for 14 days post treatment. The potential application of CpG ODN for control of FMDV during an outbreak is discussed.

Foot-and-Mouth Disease: Host Range and Pathogenesis

In this chapter the host range of foot-and-mouth disease (FMD) under natural and experimental conditions is reviewed. The routes and sites of infection, incubation periods and clinical and pathological findings are described and highlighted in relation to progress in understanding the pathogenesis of FMD.

Linear hoof defects in sheep infected with foot-and-mouth disease

During the epidemic of foot-and-mouth disease (FMD) in The Netherlands in 2001, a sheep farm was identified that had been subclinically infected with the disease. The FMD virus genome was detected in 12 of 16 probang samples collected from the sheep and the virus was isolated from four of these samples. Linear defects were observed, 1 to 3 cm from the coronary band, in the hooves of several of the sheep. The defects were thought to have been caused by the FMD infection. It was thought that the distance of the defects from the coronary band might be an indication of the time since the animals had been infected. To determine the growth rate of the claws of sheep, the growth of the hoof horn of uninfected lambs and ewes was measured; in the lambs the growth rate was 0.44 mm per day and in the ewes it was 0.29 mm per day.

Foot-and-Mouth Disease in Tropical Wildlife

This review of foot-and-mouth disease in cloven-hoofed, free-living animals, describes the disease, the wide range of the hosts, the carrier state, and the interrelationship between disease in domestic livestock and wildlife. This information becomes even more crucial to the development of control strategies when linked to the process of pathogenesis and the epidemiology of the disease.

A practitioner's primer on foot-and-mouth disease

Foot-and-mouth disease (FMD) is caused by an RNA virus of the genus Aphthovirus; 7 immunologically distinct serotypes of the virus have been identified. Susceptible species are mainly domestic and wild even-toed ungulates, such as cattle, sheep, goats, pigs, bison, and deer. All body fluids of infected animals can contain the virus and are considered infective. The primary mode of transmission is animal-to-animal transmission through inhalation or ingestion of aerosols containing the virus. The virus can also be spread mechanically by contaminated organic debris and fomites and can survive for 48 hours on human oral and nasal mucosa and be spread to uninfected animals in this manner. There is a rapid progression of clinical signs after an animal becomes infected, and the virus spreads rapidly throughout a herd. Clinical signs include excessive salivation; fever; vesicles and erosions of the oral and nasal mucosa, coronary band, interdigital area, and teats; lameness; sloughing of claws; reluctance to move; anorexia; mastitis; decreased milk production; and abortion or weak newborns. In mature animals, FMD has high morbidity and low mortality rates. Infected animals can become inapparent carriers of the virus.

Clinical variation in foot and mouth disease: sheep and goats

Foot and mouth disease (FMD) in adult sheep and goats is frequently mild or unapparent, but can cause high mortality in young animals. The recent outbreak of FMD in the United Kingdom has highlighted the importance of sheep in the epidemiology of the disease, although there have been numerous examples in the past where small ruminants have been responsible for the introduction of FMD into previously disease-free countries. The difficulty in making a clinical diagnosis should encourage the development of more rapid screening tests to assist in future control programmes.

Foot and mouth disease

Foot and mouth disease (FMD) affects cloven-footed animals. It is caused by seven species ("types") of Foot and Mouth virus (FMDV) in the genus aphthovirus, family Picornaviridae (). FMDV is a single-stranded RNA virus, with a protein coat consisting of four capsid proteins enumerated as VP1, VP2, VP3, and VP4 (Garland and Donaldson 1990).

Clinical variation in foot and mouth disease: pigs

In intensively reared pigs, the introduction of foot and mouth disease (FMD) results in severe clinical disease and vesicular lesions in adult and fattening animals, and high mortality in piglets. Vaccination of uninfected herds can assist FMD control and eradication programmes by reducing susceptibility of pigs older than 12 to 14 weeks and providing early protection to piglets through maternal antibody, but once FMD is established on a farm, vaccination alone will not prevent recurrent outbreaks of clinical disease.

Clinical variation in foot and mouth disease: cattle

Foot and mouth disease (FMD) in cattle is usually clinically obvious in the unvaccinated herds of countries in which the disease occurs only occasionally. However, in vaccinated herds and in some breeds indigenous to areas in which FMD is endemic, the disease may circulate undetected.

Foot-and-mouth disease. A review for the practitioner

Foot-and-mouth disease (FMD) is perhaps the most infectious disease known to human and veterinary medicine. This article is written with the practitioner in mind, concentrating on early recognition, epidemiology, occurrence around the world, and sampling and diagnostic methods. The article stresses that there are numerous FMD viruses, and not all behave in a similar fashion. The practitioner must be acute in his or her herd inspection of animals in which vesicular disease is suspected and knowledgeable as to differential diagnosis.

Evaluation of the portable Cepheid SmartCycler real-time PCR machine for the rapid diagnosis of foot-and-mouth disease

The ability of the portable Cepheid SmartCycler real-time PCR machine to detect foot-and-mouth disease (FMD) virus sensitively and accurately was evaluated by comparing the results of the analyses of nasal swab and serum samples from experimentally infected animals with those obtained from the real-time PCR assay currently in use in the laboratory. The results indicated that the ability of the machine to detect viral RNA is greatly affected by the PCR reagents used for the assay. When it was used with PCR beads it was unable to detect weakly positive samples, but when TaqMan core reagents were used for the assay, its sensitivity was significantly increased. The machine could be used for the laboratory-based detection of FMD; however, as with all assays, significant optimisation of assay conditions as well as solid validation of the technique is required.

[Clinical picture and differential diagnosis of foot and mouth disease in cattle]

Foot-and-mouth disease (FMD) in cattle is characterized by the formation of vesicles and erosions in the mouth, teats and feet. Despite extremely high morbidity, mortality in adults is usually very low, however up to 50% of calves dies due to cardiac involvement or secondary infections. This paper describes the signs of FMD in cattle as well as those of other diseases which causes similar lesions in this species.

[Clinical signs and differential diagnosis of foot and mouth disease in pigs]

FMD in pigs is primarily a foot disease. It is dominated by rather painful formation of vesicles in the epidermis of the feet (coronary band, interdigital clefts, bulbs) combined with severe lameness. Complications will be seen as detachment of the hoof and secondary infection of disrupted aphthae which may cause purulent arthritis of the pedal joint. Concerning differential diagnosis are to be considered all cases of acute lameness, vesicle-formation as typical lesions of exudative epidermites of pemphigus in the course of infections with S. hyicus or S. aureus as well as degenerative changes after selenium-intoxication, specially near the coronary band, sometimes linked with exungulation.

Foot-and-mouth disease: a review of the virus and the symptoms

Foot-and-mouth disease virus (FMDV) is the etiologic agent of foot-and-mouth disease (FMD), which is a disease of cattle, swine, and other cloven-footed animals. FMD is characterized by the formation of vesicles on the tongue, nose, muzzle, and coronary bands of infected animals. The virus has several unique characteristics that enable it to cause one of the most economically devastating diseases in today's world. The ease with which it may be transmitted by contact and aerosol, combined with its enhanced ability to initiate infections, virtually ensures that most, if not all, animals in a herd will contract FMD. The long-term survival of FMDV in infected animals' tissues and organs, especially when refrigerated, offers an opportunity for its national and international transmission through the food chain. Multiple serotypes and numerous subtypes reduce the effectiveness and reliability of vaccines. The possible development of carriers in vaccinated animals and those that have recovered from FMD provides additional potential sources of new outbreaks. These features create a disease that can have a major economic impact on farmers and entire nations.

A single amino acid substitution in nonstructural protein 3A can mediate adaptation of foot-and-mouth disease virus to the guinea pig

The genetic changes selected during the adaptation of a clonal population of foot-and-mouth disease virus (FMDV) to the guinea pig have been analyzed. FMDV clone C-S8c1 was adapted to the guinea pig by serial passage in the animals until secondary lesions were observed. Analysis of the virus directly recovered from the lesions developed by the animals revealed the selection of variants with two amino acid substitutions in nonstructural proteins, I(248)-->T in 2C and Q(44)-->R in 3A. On further passages, an additional mutation, L(147)-->P, was selected in an important antigenic site located in the G-H loop of capsid protein VP1. The amino acid substitution Q(44)-->R in 3A, either alone or in combination with the replacement I(248)-->T in 2C, was sufficient to give FMDV the ability to produce lesions. This was shown by using infectious transcripts which generated chimeric viruses with the relevant amino acid substitutions. Clinical symptoms produced by the artificial chimeras were similar to those produced by the naturally adapted virus. These results obtained with FMDV imply that one or very few replacements in nonstructural viral proteins, which should be within reach of the mutant spectra of replicating viral quasispecies, may result in adaptation of a virus to a new animal host.

The localization of persistent foot and mouth disease virus in the epithelial cells of the soft palate and pharynx

After contact with foot and mouth disease virus (FMDV), cattle may become persistently infected, regardless of their pre-existing immune status or whether they develop clinical disease. The cellular sites of FMDV persistence have not previously been determined. The use of in-situ hybridization in combination with tyramide signal amplification (TSA) provided the first direct evidence that FMDV RNA is localized within the epithelial cells of the soft palate and pharynx during persistent infection, indicating that these cells remain persistently infected after contact with FMDV.

Development of replication-defective adenovirus serotype 5 containing the capsid and 3C protease coding regions of foot-and-mouth disease virus as a vaccine candidate

A recombinant replication-defective human adenovirus serotype 5 vector containing FMDV capsid, P1-2A, and viral 3C protease coding regions was constructed. Two viral clones were isolated, Ad5-P12X3CWT, containing the wild-type (WT) 3C protease that processes capsid polyprotein precursor into mature capsid proteins, and Ad5-P12X3CMUT, containing a point mutation in the protease coding region that inhibits processing. In 293 cells infected with either virus, synthesis of the FMDV capsid polyprotein precursor occurred, but processing of the polyprotein into structural proteins VP0, VP3, and VP1 occurred only in 3CWT virus-infected cells. Immunoprecipitation with monospecific and monoclonal antibodies indicates possible higher order structure formation in Ad5-P12X3CWT virus-infected cells. The viruses were used to elicit immune responses in mice inoculated intramuscularly (im). Only virus containing the 3CWT elicited a neutralizing antibody response. After boosting, this neutralizing antibody response increased. Swine inoculated im with Ad5-P12X3CWT virus developed a neutralizing antibody response and were either completely or partially protected from contact challenge with an animal directly inoculated with virulent FMDV. This adenovirus vector may be an efficient system for the delivery of FMDV cDNA into animals, leading to a high level of neutralizing antibody production and protection from FMDV challenge.