Characterization of the recent outbreak of foot-and-mouth disease virus serotype SAT2 in Egypt

Immunogenicity of a foot-and-mouth disease (FMD) vaccine against serotypes O, A, SAT-2, and Asia-1 in the Middle East and many parts of Africa, Southeast Asia and Europe

Control of foot-and-mouth disease (FMD) is hampered by inadequate biosecurity measures, border transcending serotype strains and unavailability of broad coverage vaccines. In this investigation, six FMD antibody-free calves, aged 1.5-2 years, received a tetravalent, inactivated, aluminum hydroxide gel vaccine (Aphthovac-4) containing 6 PD50/dose of certain strains for protection against a wide range of strains in the Middle East, Africa, Southeast Asia, and parts of Europe. The vaccine contained 2 strains of serotype A/Asia (A/Asia (A/Iran-05 and A/Ind/40/2000 G-VII), 2 of serotype O (O/Middle East-South Asia topotype and O/Manisa/TUR/69), and one strain each of serotype SAT-2 (topotype VII) and Asia-1 (Sindh-8). Primary and booster doses were administered 3 weeks apart and sera were collected one week after the booster vaccination, preserved frozen then shipped to The Pirbright Institute, UK, for antibody evaluation by virus neutralization test (VNT) against 22 lineages circulating in the targeted regions. Serum titers against test strains of serotype A were high (range = 355- < 1413 or 2.6- < 3.15 log10), and those demonstrating relatively lower values included A/Irn/25/18 (G-VII), A/Irn-05 Far-11, A/Iran05 SIS-13 and SEA-97. Serotype O test strains presented higher titers (≤ 1/1413 or ≤ 3.0 log10), but O/Cathay, O/Panasia-2 ant-10 and one O/Ind-2001e lineage exhibited somewhat lower values (range (355-1024 or 2.6-3.01 log10). Antibodies against SAT-2 test strains (XIV Topotype) ranged between 128 and 178 (1.9-2.2 log10) in 5 animals (5/6, 83%), despite the reported high r1 values. Likewise, Asia-1 strain elicited a similar titer range against IRN/1/2020 in the same 5 animals. The 6th animal generally showed one dilution less. The results portray a dynamic antigenic change between the vaccinal and test strains, underscoring the value of strain matching, use of high payload and incorporation of double antigen lineages within each serotype to broaden coverage in enzootic and epizootic situations.

Porcine antibodies reveal novel non-neutralizing universal epitopes on FMDV and their overlaps with neutralization sites

Foot-and-mouth disease virus (FMDV) is highly infectious and lacks cross-protection among serotypes, with antibodies playing a key role in antiviral immunity. To map conserved epitopes on the FMDV surface that exhibit cross-serotype reactivity, we constructed a pig-specific B-cell receptor (BCR) library through single B-cell sorting and high-throughput sequencing. This led to the identification of 16 broadly reactive, non-neutralizing monoclonal antibodies (mAbs), with 10 targeting VP2 (pOTB-1, pOTB-10, pOTB-13, pOTB-33, pOTB-37, pONY-14, pONY-17, pONY-23, pONY-30, pONY-60) and 6 targeting VP3 (pOTB-6, pOTB-11, pOTB-22, pOTB-23, pONY-3, pONY-59). Among these, a novel free linear epitope was identified at the C-terminus of VP2, recognized by pOTB-1, with the minimal recognition motif "KE." Key residues, T53 and W101, within the complementarity-determining region (CDR) of the pOTB-1 heavy chain, interact with the carboxyl group of the C-terminal glutamate through hydrogen bonding, contributing to the free-form nature of the epitope. Competitive enzyme-linked immunosorbent assays (cELISA) showed that most non-neutralizing antibodies (nNAbs) interfered with the binding of neutralizing antibodies B82 (site 2) and C4 (site 4), confirming the overlap between non-neutralizing and neutralizing epitopes. It has been confirmed that nNAbs mediate antiviral activity in vivo through various mechanisms, such as the formation of immune complexes. These findings reveal new epitopes on VP2 and VP3 and their spatial overlap with neutralizing sites, enhancing our understanding of FMDV immunogenicity and providing novel targets for vaccine and therapeutic development.

Detection and genomic characterisation of foot-and-mouth disease virus serotypes circulating in Cameroon using environmental sampling

Foot-and-mouth disease virus (FMDV) is a highly contagious, economically important disease of livestock and wildlife species. Active monitoring and understanding the epidemiology of FMDV underpin the foundations of control programmes. In many endemic areas, however, veterinary resources are limited, resulting in a requirement for simple sampling techniques to increase and supplement surveillance efforts. In this study, environmental sampling was used for the first time at livestock markets and abattoirs across Cameroon to assess the opportunities for broad scale, non-invasive disease surveillance at such sites. Environmental samples (n = 1994) were collected from six locations across Cameroon between May and July 2019. Concurrent with environmental sampling, a questionnaire was used to gather descriptive information on the use and practices of market and abattoir sites. Samples were screened for the presence of FMDV RNA using a pan-serotype FMDV specific real-time RT-PCR assay. Positive samples were characterised at the genomic level using next generation sequencing in combination with a novel probe-based enrichment strategy. A total of 173/1994 (8.68%) environmental samples were found to be positive for FMDV RNA. Genome length sequences were obtained from environmental samples, with phylogenetically relevant capsid sequences obtained from 14 samples, with representatives of serotypes O (n = 6), A (n = 7) and SAT 2 (n = 3). The questionnaire results revealed that animals in Cameroon can be transported long distances to markets and abattoirs, with varying levels of control and biosecurity practices in place. The approaches used in this study have highlighted that environmental sampling is an effective and non-invasive approach to assessing FMDV presence. Furthermore, the study has demonstrated that livestock markets, abattoirs and trucks could be targeted for the introduction of biosecurity interventions as well as providing opportunities for carrying out disease surveillance. Information resulting from such surveillance could provide valuable knowledge of circulating viruses within a region of interest, aiding strategic approaches for surveillance and control of FMDV.

Genetic characterization of foot-and-mouth disease virus in cattle in Northern Egypt

Background and Aim

Foot-and-mouth disease (FMD) is a highly contagious viral disease that poses significant economic threats to livestock globally. This study aimed to confirm the presence of FMD virus (FMDV) in Egyptian cattle and identify the predominant serotypes contributing to outbreaks in Sharkia and Dakahlia provinces in 2022.

Materials and Methods

A total of 65 cattle showing acute FMD symptoms were sampled. Desquamated epithelial tissues and oral secretions were analyzed using reverse transcriptase polymerase chain reaction with universal and serotype-specific primers. Seven representative samples underwent sequencing for phylogenetic and genetic variability analysis.

Results

All sampled animals tested positive for FMDV. Serotype A accounted for 72.3% of cases, while 27.7% were serotype O. Sequence analysis identified FMDV serotype A (African topotype, genotype IV) and serotype O (East Africa-3 topotype) as the outbreak-causing strains. The identified strains exhibited significant genetic divergence from the vaccine strains used in Egypt, with notable amino acid substitutions in the VP1 protein's G-H loop. These mutations raise concerns about the efficacy of existing vaccines against current field strains.

Conclusion

The study highlights the ongoing threat of FMD in Egypt, particularly among smallholder cattle farmers. The genetic divergence between circulating FMDV and vaccine strains underscores the need to continuously monitor and update vaccine formulations to enhance disease control efforts. Implementing stricter animal movement regulations and tailored vaccination strategies is essential for effective management.

Exploring Hollow Mesoporous Silica Nanoparticles as a Nanocarrier in the Delivery of Foot-And-Mouth Disease Virus-like Particle Vaccines

Virus-like particle (VLP) vaccine is considered to be the most promising candidate alternative to the traditional inactivated vaccine for foot-and-mouth disease (FMD). To elicit a desired immune response, hollow mesoporous silica nanoparticles (HMSNs) have been synthesized and utilized as a nanocarrier for FMD VLP vaccine delivery. The as-prepared HMSNs displayed a relatively small particle size (∼260 nm), large cavity (∼150 nm), and thin wall (∼55 nm). The inherent structural superiorities make them ideal nanocarriers for the FMD VLP vaccine, which exhibited good biocompatibility, great protein-loading capacity, high antibody-response level, and protective efficiency, even comparable to commercial adjuvant ISA 206. All the results suggested that HMSNs may be a valid nanocarrier in VLP-based vaccines.

Isolation, molecular characterization, and genetic diversity of recently isolated foot-and-mouth disease virus serotype A in Egypt

Foot-and-mouth Disease (FMD) is a highly contagious viral disease affecting all hoof-cloven animals. Serotypes A, O and SAT 2 of the foot-and-mouth disease virus (FMDV) are circulating in Egypt. The present study aimed to identify and molecularly characterize the FMDV strains circulating in Northern Egypt during an epidemic that struck the nation in 2022. RNA was extracted from the epithelial specimens, vesicular fluid from affected cattle. The samples were screened using real-time reverse-transcription polymerase chain reaction (RT-PCR) targeting the RNA-dependent RNA polymerase (RdRp) gene. Positive samples underwent individual serotype-specific amplification using primers designed for VP1 of O, A, and SAT 2 serotypes. Subsequently, direct sequencing was performed on the positive samples. The real-time RT-PCR detected positive samples from epithelial and vesicular fluid samples, but not in the blood of infected animals. Out of the 16 samples, seven tested positive for FMDV serotype A. Of these seven positive samples, six were categorized as serotype A-African topotype-G-IV, and these positive samples were isolated in BHK-21 cells, yielding an overt cytopathic effect caused by the virus. In conclusion, it is necessary to sustain continuous surveillance of the evolution of circulating FMDV strains to facilitate the assessment and aid in the selection of vaccine strains for the effective control of FMDV in Egypt.

Pathological and genetic characterization of foot and mouth disease viruses collected from cattle and water buffalo in Egypt

Foot-and-mouth disease (FMD), a highly contagious viral disease caused by FMD virus (FMDV) that threatens Egypt's livestock industry. FMDV causes severe economic losses in the livestock, with restriction of international trade from endemic regions. Surveillance for FMDV serotypes circulating in Egypt is urgently needed to assess the epidemiological situation in the country. FMD outbreaks reported in Egypt in between December 2016 and January-March 2017. A cross-sectional study was conducted to identify the FMDV serotypes responsible for the outbreaks and to collect information on the virus's morphopathological effects. Postmortem tissue and clinical samples (oral swabs, vesicular fluids from ruptured vesicles, and blood) were collected from recently deceased and infected animals. Pathological examination revealed classical FMD lesions as vesicular and erosive lesions on epithelial tissues with non-suppurative lymphoplasmacytic myocarditis. Phylogenetic and sequencing analyses demonstrated that FMDV serotype O, EA-3 topotype, VP1 is the prevalent serotype responsible for the pathological alterations and the high mortality in young calves, adult cattle, and water buffalo. The outcomes indicate continuous mutations in the circulating FMDV, which result in the occasional failure of vaccination. Based on these findings, extensive continuous monitoring and serotyping of the existing circulating FMDV isolates and regular vaccination with reevaluation of the currently used vaccine in Egypt are recommended to prevent the recurrence of such outbreaks.

A Newly Emerging Serotype A Strain in Foot-and-Mouth Disease Virus with Higher Severity and Mortality in Buffalo than in Cattle Calves in North Egypt

A severe foot-and-mouth disease (FMD) epidemic struck several Egyptian provinces recently, causing significant losses among animals even in vaccinated farms. This study indicated the existence of the newly emerging foot-and-mouth disease virus (FMDV) and first investigated its effect on the Egyptian water buffalo (Bubalus bubalis) and cattle calves in the Beheira province, north Egypt. Twenty tongue epithelial samples from diseased calves in five infected farms were randomly collected, prepared, and propagated using baby hamster kidney-21 (BHK-21) cells. Whole genomic RNA was extracted from the cells of the third passage. A FMDV genome was detected and serotyped using one-step reverse transcription polymerase chain reactions (RT-PCRs). Nucleotide sequencing of the purified serotype-specific PCR bands was performed, and a maximum likelihood phylogenetic tree based on 600 base pairs of VP1 was constructed. The results identified FMDV, serotype A in all infected samples, whereas the serotypes O and SAT2 were negative. The obtained 20 sequences were identical to each other and similar to the newly reported strain in Egypt that belongs to the Europe-South America (Euro-SA) topotype. The epidemiological and clinical parameters associated with such a strain were fully recorded by veterinarians and analyzed in a single infected farm including 70 cattle and buffalo calves. It caused higher peracute mortalities in buffalo (25.7%; 95% CI: 13-43) than in cattle (8.6%; 95% CI: 2-24) calves. Severe clinical signs such as dullness, hypothermia, bradycardia, and cardiac arrhythmia were common to both except in fatal cases, whereas hyperthermia and respiratory signs were prevalent in cattle calves. In conclusion, we first characterized the newly emerging FMDV in the calves of Beheira as more fatal and severe in buffalo than in cattle calves.

The prevalence of foot-and-mouth disease in Asia

Foot-and-mouth disease (FMD) is listed among the highly contagious diseases in animals and is endemic throughout the Asian continent. The disease is caused by the Foot-and-mouth disease virus (FMDV) and affects a wide variety of domesticated animals as well as wild ungulates. Clinically, the disease is described as a vesicular lesion on the tongue, muzzle, lips, gum, dental pad, interdigital cleft, coronary band, and heel of the foot. Sometimes these lesions give rise to lameness. Mastitis is also caused due to teat lesions. A biochemical test reveals that during FMD infection, there are elevated levels of interleukin-1 (IL-1), tumor necrosis factor-alpha, interferon-gamma (IFN-γ), interleukin-6, serum amyloid A protein, lactoferrin, mannose-binding lectin, and monocytes chemo-attractant protein-1 in the serum of infected animals. There is no specific treatment for FMD although some antivirals are given as prophylaxis and antibiotics are given to prevent secondary bacterial infection. This review presents comprehensive data on the prevalence of FMD and serotypes of FMDV that are attributable to the cause of FMD from a regional point of view. It also explains the worldwide dynamics of the seven serotypes of FMD and tries to identify epidemiological clusters of FMD in various geographical areas. Furthermore, the pathology associated with the foot and mouth disease virus along with the pathophysiology is discussed. The continent-wide prevalence and diversity patterns of FMD suggest that there is a need for stringent policies and legislation implementation regarding research and development aimed at manufacturing strain-specific vaccination, infection prevention, and control of the disease.

B and T Cell Epitopes of the Incursionary Foot-and-Mouth Disease Virus Serotype SAT2 for Vaccine Development

Failure of cross-protection among interserotypes and intratypes of foot-and-mouth disease virus (FMDV) is a big threat to endemic countries and their prevention and control strategies. However, insights into practices relating to the development of a multi-epitope vaccine appear as a best alternative approach to alleviate the cross-protection-associated problems. In order to facilitate the development of such a vaccine design approach, identification and prediction of the antigenic B and T cell epitopes along with determining the level of immunogenicity are essential bioinformatics steps. These steps are well applied in Eurasian serotypes, but very rare in South African Territories (SAT) Types, particularly in serotype SAT2. For this reason, the available scattered immunogenic information on SAT2 epitopes needs to be organized and clearly understood. Therefore, in this review, we compiled relevant bioinformatic reports about B and T cell epitopes of the incursionary SAT2 FMDV and the promising experimental demonstrations of such designed and developed vaccines against this serotype.

Decision tree risk analysis for FMD outbreak prevention in Egyptian feedlots

Foot and Mouth Disease (FMD) is one of the most contagious and economically influential viral diseases on animal health and productivity. Introduction of newly purchased animals to beef farms constitutes a greater risk for the FMD outbreaks in endemic countries. Physical examination of newly purchased animals in live animal markets and/or at the receiving farm, and the timing of preventative FMD vaccination may reduce the risk of FMD outbreaks under endemic conditions. Small (< 50 animals) and medium (50-500 animals) sized beef farms in Egypt constitute more than 60% of the country's beef industry where protocols for receiving newly purchased animals vary widely between farms. The current risk analysis aimed to build a decision tree model to reduce FMD outbreaks associated with introduction of replacement cattle on Egypt's medium sized beef farms. Management practices explored were the use of physical examinations and FMD vaccination and their timing for replacements with the goal of reducing losses due to FMD outbreaks. A producer survey revealed that more than 50% of the study herds relied on live animal markets as a source for replacements and reported more FMD outbreaks (P-value=0.09), FMD herd morbidity > 50% (p-value=0.05), and weight loss > 15 kg/animal in FMD clinical cases (P-value=0.01) in comparison to herds that received replacements from other farms, imported, or purchased from small stakeholders. More than 70% of the surveyed farms received replacements ≤ 1year old and reported significantly higher FMD outbreaks (P-value=0.02) in comparison to farms that received older animals. More than 80% of the surveyed farms performed physical examination of newly purchased animals before arrival at their premises. Of the surveyed farms, 73% reported FMD outbreaks with 67% of the outbreaks being reported during the Fall and Winter seasons. The decision tree identified physical examination of newly purchased animals prior to arrival and mixing with a premises beef herd followed by vaccination against FMD upon arrival as the intervention resulting in the lowest probability of FMD outbreak (8.9%). In contrast, herds that did not perform physical examination and delay the FMD vaccination for two or more weeks had the highest probability of FMD outbreaks (33.5%).

Development and evaluation of one-step real-time RT-PCR assay for improved detection of foot-and-mouth-disease virus serotypes circulating in Egypt

Foot-and-mouth disease (FMD) is an extremely contagious and economically important viral disease affecting livestock. Rapid and precise diagnosis of FMD is critical for efficient control and surveillance strategies of the disease. In this study, one-step real-time reverse transcription-polymerase chain reaction (RT-qPCR) assays using newly designed primers/probe sets in the conserved regions within the VP1 coding sequence were developed for specific detection of FMDV serotypes SAT 2 and O with their different lineage circulating in Egypt. The assays were validated for the efficacy to detect different lineages of these endemic serotypes in Egypt; the detection limit was 10 genomic copies for serotype SAT 2 and one genomic copy for serotype O, with no cross-reactivity observed. These findings were confirmed by the specific and sensitive detection of FMDV in clinical samples obtained from different regions in Egypt and representing a range of subtypes within the SAT 2 and O serotypes. The results illustrate the potential of tailored RT-qPCR tools for the rapid detection and serotyping of FMDV belonging to different lineages of serotypes SAT 2 and O circulating in Egypt with high sensitivity and specificity. The developed assays could be easily deployed for routine surveillance and hence improving the disease control measures.

Molecular Characterization of newly emerging Foot-and-Mouth Disease Virus Serotype SAT2 of Lib-12 Lineage Isolated from Egypt

An outbreak of foot-and-mouth disease virus (FMDV) serotype SAT2 occurred in Egypt in 2018, which affected cattle and water buffalo. Previous phylogenetic studies on FMDV circulating in Egypt have mainly focused on genomic regions encoding structural proteins that determine the FMDV serotype. Still, none of them have analyzed the open reading frame (ORF) sequence of the Egyptian SAT2/Lib-12 lineage. The present study aimed to analyze and identify the ORF genome sequence of Lib-12 lineage that belongs to FMDV SAT2 topotype VII in Egypt. The protocol workflow was optimized and tested using a representative field isolate of FMDV/SAT2/Lib-12 from a bovine tongue sample collected in 2018 from Ismailia governorate (SAT2/EGY/Ismailia/2018). The protocol was based on reverse transcription polymerase chain reaction with multiple overlapping primers, amplicons sequencing, and assembly to complete the ORF consensus sequence. Alignments of the sequence fragments formed consensus genome sequence of 7219 nucleotides in length. The complete nucleotide sequence of the Egyptian isolate was related to Ethiopian, Nigerian, and Ghanaian strains, with identity not exceeding 95%. The divergence in the genetic identity of the Egyptian SAT2/Lib-12 lineage from other Egyptian strains and the neighboring Libyan isolates reached 7%, and this may be attributed to the absence of the Lib-12 lineage ORF sequence from Egypt and Libya in the database. The present study significantly advances the knowledge of the molecular analysis of FMDV SAT2 and the design of vaccine selection for FMDV SAT2 in Egypt. The study protocol could be applied to other FMDV serotypes.

Two Cross-Protective Antigen Sites on Foot-and-Mouth Disease Virus Serotype O Structurally Revealed by Broadly Neutralizing Antibodies from Cattle

Foot-and-mouth disease virus (FMDV) is a highly contagious virus that infects cloven-hoofed animals. Neutralizing antibodies play critical roles in antiviral infection. Although five known antigen sites that induce neutralizing antibodies have been defined, studies on cross-protective antigen sites are still scarce. We mapped two cross-protective antigen sites using 13 bovine-derived broadly neutralizing monoclonal antibodies (bnAbs) capable of neutralizing 4 lineages within 3 topotypes of FMDV serotype O. One antigen site was formed by a novel cluster of VP3-focused epitopes recognized by bnAb C4 and C4-like antibodies. The cryo-electron microscopy (cryo-EM) structure of the FMDV-OTi (O/Tibet/99)-C4 complex showed close contact with VP3 and a novel interprotomer antigen epitope around the icosahedral 3-fold axis of the FMDV particle, which is far beyond the known antigen site 4. The key determinants of the neutralizing function of C4 and C4-like antibodies on the capsid were βB (T65), the B-C loop (T68), the E-F loop (E131 and K134), and the H-I loop (G196), revealing a novel antigen site on VP3. The other antigen site comprised two group epitopes on VP2 recognized by 9 bnAbs (B57, B73, B77, B82, F28, F145, F150, E46, and E54), which belong to the known antigen site 2 of FMDV serotype O. Notably, bnAb C4 potently promoted FMDV RNA release in response to damage to viral particles, suggesting that the targeted epitope contains a trigger mechanism for particle disassembly. This study revealed two cross-protective antigen sites that can elicit cross-reactive neutralizing antibodies in cattle and provided new structural information for the design of a broad-spectrum molecular vaccine against FMDV serotype O. IMPORTANCE FMDV is the causative agent of foot-and-mouth disease (FMD), which is one of the most contagious and economically devastating diseases of domestic animals. The antigenic structure of FMDV serotype O is rather complicated, especially for those sites that can elicit a cross-protective neutralizing antibody response. Monoclonal neutralization antibodies provide both crucial defense components against FMDV infection and valuable tools for fine analysis of the antigenic structure. In this study, we found a cluster of novel VP3-focused epitopes using 13 bnAbs against FMDV serotype O from natural host cattle, which revealed two cross-protective antigen sites on VP2 and VP3. Antibody C4 targeting this novel epitope potently promoted viral particle disassembly and RNA release before infection, which may indicate a vulnerable region of FMDV. This study reveals new structural information about cross-protective antigen sites of FMDV serotype O, providing valuable and strong support for future research on broad-spectrum vaccines against FMD.

High selectivity detection of FMDV- SAT-2 using a newly-developed electrochemical nanosensors

Foot-and-mouth disease virus serotype South-Africa territories-2 (FMDV-SAT-2) is the most fastidious known type in Aphthovirus which is subsequently reflected in the diagnosis regime. Rapid and early diagnostic actions are usually taken in response to the FMDV outbreak to prevent the dramatic spread of the disease. Virus imprinted sensor (VIP sensor) is gathering huge attention for the selective detection of pathogens. Thus, the whole virus particles of SAT-2 together with an electropolymerized film of poly(o-phenylenediamine) (PoPD) on gold-copper modified screen-printed electrode were applied to fabricate SAT-2-virus imprinted polymer (SAT-2-VIP). The SAT-2-VIPs were fully characterized using cyclic voltammetry (CV), linear sweep voltammetry (LSV), Atomic force microscopy (AFM), Scanning electron microscope (SEM), and Fourier transform Infra-Red (FTIR) spectroscopy. Excellent selective binding affinity towards the targeted virus particle was achieved with limits of detection and quantification of 0.1 ng/mL and 0.4 ng/mL, respectively. In terms of viral interference, the sensor did not show cross-reactivity towards other animal viruses including FMDV serotype A, O, or even SAT-2 subtype Libya and the un-related virus Lumpy skin disease virus (LSDV). This high selectivity provides a sensible platform with 70 folds more sensitivity than the reference RT-PCR as revealed from the application of SAT-2-VIP sensor for rapid analysis of clinical samples with no need for treatment or equipped labs. Thus, as diagnostic and surveillance technologies, on-site point of care diagnostics for SAT-2 virus are supported.

Molecular characterization and phylogenetic analysis of foot and mouth disease virus isolates in Sulaimani province, Iraq

Foot-and-mouth disease (FMD) is endemic in Iraq. The current study can be considered as the first molecular characterization of serotype O in Iraq. The present investigation reported the determination of FMDV serotype O from local farms in Sulaimani districts in 2016 outbreaks. Samples were collected from suspected cattle. The virus was primarily detected with RT-PCR directly from mouth epithelial samples. The direct sequencing and subsequent analysis of amplified PCR products for the VP1 gene indicated the circulation of serotype O of FMD in studied areas. Moreover, phylogenetic analysis revealed that the field isolated serotype O belonged to topotype ME-SA and lineage PanAsia II and clustered with Pakistan and Iran isolates (KU365843 and KY091283) with identity (96.00%, 95.00%) respectively. Furthermore, according to the phylogenic tree, the field isolates had different lineage with the three O/Manisa vaccine strains and Iraq/2000 strains. These findings highlighted the continuous circulation of serotype O of FMD in the region.

Characterization of Foot and Mouth Disease Virus Serotype SAT-2 in Swamp Water Buffaloes (Bubalus bubalis) under the Egyptian Smallholder Production System

Simple Summary

Continuous mutations of the foot and mouth disease virus (FMDV) result in the emergence of new topotypes and lineages of FMDV, which contribute to an occasional vaccination failure. Thus, molecular characterization of the circulating FMDV strains associated with a recent outbreak in Egyptian water buffaloes is essential for the control strategies. The results revealed that the circulating virus was SAT-2 serotype, closely related to the lineage of lib12, topotype VII, with a similarity of 98.9%. The new incursions reported in this study explain the considerable high morbidity of FMDV outbreaks in Egypt in early 2019.

Abstract

Spontaneous mutations are a common characteristic of the foot and mouth disease virus (FMDV), leading to wide antigenic variations resulting in the emergence of new topotypes and lineages of FMDV, which contributes to occasional vaccination failures. The objectives of the present study were to genetically characterize FMDV isolated from water buffaloes and study the biochemical and histopathological indicators of infected animals. Fifty-four water buffaloes of both sexes and different ages suffered from acute symptoms of FMD were clinically examined and randomly selected for inclusion in this study. Oral desquamated epithelial and oropharyngeal fluid samples have been tested for FMDV by reverse transcriptase PCR (RT-PCR). Tissue and serum samples were also collected from the diseased buffaloes and subjected to histopathological and biochemical analysis. Our findings showed that all examined samples were confirmed to be positive to FMDV serotype SAT-2 and were adjusted to be responsible for the recent disease outbreak in this study. Phylogenetic analysis revealed that the circulating viruses were of the SAT-2 serotype, closely related to the lineage of lib12, topotype VII, with 98.9% identity. The new lineage of SAT-2 showed a high virulence resulting in the deaths of water buffaloes due to heart failure, confirmed by high serum levels of inflammatory and cardiac markers, including haptoglobin, ceruloplasmin, cardiac troponin I and creatine phosphokinase-MB, indicating an unfavorable FMD-infection prognosis. In conclusion, we document the presence of new incursions circulating in water buffalo populations in Egypt in early 2019, explaining the high morbidity rate of FMD outbreak in early 2019. Furthermore, the newly identified serotype SAT-2 lib12 lineage, topotype VII, showed an aggressive pattern in water buffaloes of the smallholder production system.

Structures of Foot-and-mouth Disease Virus with neutralizing antibodies derived from recovered natural host reveal a mechanism for cross-serotype neutralization

The development of a universal vaccine against foot-and-mouth disease virus (FMDV) is hindered by cross-serotype antigenic diversity and by a lack of knowledge regarding neutralization of the virus in natural hosts. In this study, we isolated serotype O-specific neutralizing antibodies (NAbs) (F145 and B77) from recovered natural bovine hosts by using the single B cell antibody isolation technique. We also identified a serotype O/A cross-reacting NAb (R50) and determined virus-NAb complex structures by cryo-electron microscopy at near-atomic resolution. F145 and B77 were shown to engage the capsid of FMDV-O near the icosahedral threefold axis, binding to the BC/HI-loop of VP2. In contrast, R50 engages the capsids of both FMDV-O and FMDV-A between the 2- and 5-fold axes and binds to the BC/EF/GH-loop of VP1 and to the GH-loop of VP3 from two adjacent protomers, revealing a previously unknown antigenic site. The cross-serotype neutralizing epitope recognized by R50 is highly conserved among serotype O/A. These findings help to elucidate FMDV neutralization by natural hosts and provide epitope information for the development of a universal vaccine for cross-serotype protection against FMDV.

FMDV is the causative agent of foot-and-mouth disease, one of the most contagious and economically devastating diseases of cloven-hoofed animals. The antigenic diversities of the currently known epitopes throughout FMDV serotypes and the lack of understanding of FMDV neutralization in natural hosts limit the development of a vaccine that is able to provide cross-serotype protection. In this work, we isolated FMDV serotype O-specific neutralizing antibodies (NAbs) (F145 and B77) and a serotype O/A cross-reacting NAb (R50) from recovered natural bovine hosts and determined virus-NAb complex structures by cryo-electron microscopy at near-atomic resolution. Structures of virus-NAb complex reveal F145 and B77 engage the capsid of FMDV-O near the icosahedral threefold axis. In contrast, R50 engages the capsids of both FMDV-O and FMDV-A between the 2- and 5-fold axes, revealing a previously unknown antigenic site. This is the first time to present structure details of FMDV neutralization by natural hosts. And this work also provides epitope information for the development of a universal vaccine for cross-serotype protection against FMDV.

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.

Molecular characterization of foot-and-mouth disease viruses collected from Northern and Central Ethiopia during the 2018 outbreak

Background and Aim

Foot-and-mouth disease (FMD) is endemic in several developing countries and affects poor farmers through loss of production, death of diseased animals, and loss of animal byproducts. Forty-three samples were collected from 12 sites of five geographical located areas from suspected FMD virus (FMDV)-infected cattle during 2018. This study aimed to isolate and characterize the FMDVs using reverse transcription-polymerase chain reaction (RT-PCR) and gene sequencing.

Materials and Methods

Forty-three FMDV-suspected clinical samples cultured on BHK-21 cell were examined, followed by virus serotype identification using RT-PCR and gene sequencing.

Results

Twenty-nine (67.44%) samples were cultured on BHK-21 cell, of which 14 (32.56%) were not isolated; the 43 samples were analyzed using FMDV screening primers and serotype-specific primers. The contribution of the disease-causing serotype was serotype O of 8 (18.60%) samples, serotype A of 20 (46.51%) samples, and mixed infection (O and A) of 1 (2.33%) sample. Serotypes O and A were further characterized by phylogenetic analysis, which grouped them under East Africa 3 and Africa topotypes of genotype IV, respectively. Interestingly, serotype A was isolated for the 1^st time from Keyet sub-woreda and Mulo woreda of Ethiopia, and mixed serotypes (O and A) were identified from the purchased animal.

Conclusion

Molecular test result, sequencing, and phylogenetic tree reconstruction analysis revealed that the 2018 FMD outbreak in Ethiopia was caused by FMDV serotypes O and A. FMDV serotype A was the predominant strain circulating in most study areas of the country. Infections in one sample with mixed serotypes of O and A were also reported. The authors recommend a vaccine matching study of those field isolated viruses with the vaccine strain.

Characterization of SAT2 foot-and-mouth disease 2013/2014 outbreak viruses at the wildlife-livestock interface in South Africa

The Southern African Territories (SAT)-type foot-and-mouth disease viruses (FMDV) are endemic to the greater Kruger National Park (KNP) area in South Africa, where they are maintained through persistent infections in African buffalo. The occurrence of FMDV within the Greater KNP area constitutes a continual threat to the livestock industry. To expand on knowledge of FMDV diversity, the genetic and antigenic relatedness of SAT2-type viruses isolated from cattle during a FMD outbreak in Mpumalanga Province in 2013 and 2014 were investigated. Cattle from twelve diptanks tested positive on polymerase chain reaction (PCR), and molecular epidemiological relationships of the viruses were determined by VP1 sequencing. Phylogenetic analysis of the SAT2 viruses from the FMD outbreak in Mpumalanga in 2013/2014 revealed their genetic relatedness to other SAT2 isolates from topotype I (South Africa, Zimbabwe and Mozambique), albeit genetically distinct from previous South African outbreak viruses (2011 and 2012) from the same topotype. The fifteen SAT2 field isolates clustered into a novel genotype with ≥98.7% nucleotide identity. High neutralization antibody titres were observed for four 2013/2014 outbreak viruses tested against the SAT2 reference antisera representative of viruses isolated from cattle and buffalo from South Africa (topotype I) and Zimbabwe (topotype II). Comparison of the antigenic relationship (r₁ values) of the outbreak viruses with reference antisera indicated a good vaccine match with 90% of r₁ values > 0.3. The r₁ values for the 2013/2014 outbreak viruses were 0.4 and above for the three South African vaccine/reference strains. These results confirm the presence of genetic and antigenic variability in SAT2 viruses and suggest the emergence of new variants at the wildlife-livestock interface in South Africa. Continuous characterization of field viruses should be performed to identify new virus strains as epidemiological surveillance to improve vaccination efforts.

Serological evaluation for the current epidemic situation of foot and mouth disease among cattle and buffaloes in Egypt

AIM

The present study was aimed to investigate the epidemic situation of foot-and-mouth disease (FMD) in Egypt from 2016 to 2018 based on the detection of FMD virus (FMDV) in carrier or previously infected animals, by determination of antibodies against non-structural protein (NSP), implementation a pilot study on circulating FMDV serotypes and assure the efficacy of locally produced inactivated trivalent vaccine.

MATERIALS AND METHODS

A total of 1500 sera were collected from apparent healthy vaccinated cattle and buffaloes from three Egyptian geographical sectors, representing ten governorates. Determination of FMD antibodies against NSP was carried out using 3ABC enzyme-linked immunosorbent assay (ELISA) test. Serotyping of the circulating FMDV and assure the vaccine efficacy was performed using solid-phase competitive ELISA.

RESULTS

The 3ABC ELISA test revealed 26.4% and 23.7% positive for FMDV-NSP antibodies in cattle and buffalo sera, respectively. The highest positivity was in Delta Sector among both cattle 42.3% and buffaloes 28.8%. Serotyping of FMDV-positive NSP sera in El-Qalyubia Governorate for the circulating FMDV serotypes O, A, and Southern African Territories (SAT) 2 was 52.2%, 17.4%, and 30.4% in cattle and 31.8%, 27.3%, and 40.9% in buffaloes, respectively. The overall protection level due to the vaccination program was 62.1 and 60.9% in cattle and buffaloes, respectively, while the protective level of the FMDV serotypes O, A, and SAT2 included in the inactivated trivalent vaccine was 73.9, 84.6, and 63.8% in cattle and 72.3, 82.3, and 63.5% in buffaloes, respectively.

CONCLUSION

The present study recommended full determination for the immunogenic relationship between the vaccine strains and the field strains to attain maximum protection against the circulating viruses.

Review on Outbreak Dynamics, the Endemic Serotypes, and Diversified Topotypic Profiles of Foot and Mouth Disease Virus Isolates in Ethiopia from 2008 to 2018

Foot and mouth disease (FMD) endemicity in Ethiopia's livestock remains an ongoing cause for economic concern, with new topotypes still arising even in previously unaffected areas. FMD outbreaks occur every year almost throughout the country. Understanding the outbreak dynamics, endemic serotypes, and lineage profiles of FMD in this country is very critical in designing control and prevention programs. For this, detailed information on outbreak dynamics in Ethiopia needs to be understood clearly. In this article, therefore, we review the spatial and temporal patterns and dynamics of FMD outbreaks from 2008 to 2018. The circulating serotypes and the topotypic profiles of the virus are also discussed. FMD outbreak data were obtained from; reports of MoARD (Ministry of Agriculture and Rural Development)/MoLF (Ministry of livestock and Fishery, NVI (National Veterinary Institute), and NAHDIC (National Animal Health Diagnostic and Investigation Center); published articles; MSc works; PhD theses; and documents from international organizations. To effectively control and prevent FMD outbreaks, animal health agencies should focus on building surveillance systems that can quickly identify and control ongoing outbreaks and implement efficient preventive measures.

Beneficial effects of antioxidants in improving health conditions of sheep infected with foot-and-mouth disease

The effect of multinutrient antioxidant treatment on sheep naturally infected with FMD virus was investigated in terms of general health conditions, serum proteins profile, and antioxidant/oxidant parameters. Twenty diseased sheep were divided into 4 equal groups (n = 5) and underwent certain therapeutic protocols for 8 weeks as follows: GI, infected not treated group; GII, infected and treated with the ideal and usual line of treatment against FMD virus infection; GIII, infected animals supplemented orally zinc methionine at a dose of 5 g/head/day and vitamin E with selenium-enriched yeast at the same dose level; GIV, infected animals received both the ideal treatment and antioxidants. The animals under experiment were clinically evaluated. Blood samples were obtained for the comet assay and biochemical examination at zero time and at the 8th week after treatment. Results revealed that DNA damage reduced in both GIII and GIV groups which received antioxidants. In the GI group, the activity of SOD and GPx and the level of total antioxidant capacity (TAC) markedly decreased. However, in both GIII and GIV groups treated with multinutrient antioxidants, GPx and TAC values significantly increased after treatment in comparison with the values of the same groups before treatment. After treatment with multinutrient antioxidants, α1-, β-, and γ-globulins levels markedly increased in GII and GIII groups while α2-globulin level decreased. The improvement in healing of clinical signs and general health conditions was clear in the GIV group. Finally, FMD infection in sheep was found to be associated with oxidative stress. The use of antioxidants as therapeutic approaches recovers and improves general health conditions and performance of affected animals.

Seroprevalence of some Infectious transboundry diseases in cattle imported from Sudan to Egypt

OBJECTIVE

Animal trade has an important role in the economy but in contrast, it causes the spread of infectious diseases overall the world, in particular, the trans-boundary animal diseases. Therefore, the aim of this study is to report the prevalence rate of some transboundary infectious diseases to assess the effectiveness of quarantine measure in the detection of exotic disease and clarify the role of live animal trade in infectious transboundary diseases spread.

MATERIALS AND METHODS

The study was done on 176 serum samples obtained from cattle imported from Sudan in order to determine the prevalence of foot and mouth disease (FMD), Peste Des Petits Ruminants (PPR), and Infectious Bovine Rhinotracheitis (IBR). Three serological tests were used; Serum neutralization test for FMD, Indirect enzyme-linked immunosorbent assay (i-ELISA) for PPR, and Competitive ELISA for IBR.

RESULTS

The seroprevalence of FMD in tested sera was; 77.27% in the serotype A (A-Iran), 68.18% in the serotype A (A-Africa), 93.82% in the serotype O (O-Pan Asia), and 35.227% in the serotype South African Territories-2 (SAT-2) SAT-2. While the overall seroprevalence of PPR was 49.431% and the IBR was 93.75%.

CONCLUSION

The result indicates the serious role of live animal trade as "hubs" for infectious diseases spread. Subsequently, the common control measures must be taken to avoid the spread of the diseases through the animal trade; which include screening, surveillance, precautions at borders, and vaccination.

Co-infection with different serotypes of FMDV in vaccinated cattle in Southern Egypt

During 2015-2016 period, an outbreak of foot-and-mouth disease virus (FMDV) was observed in cattle in four governorates of the upper of Egypt. The infection was extended to the vaccinated cattle. A total of 54 mouth swabs and serum samples were collected from vaccinated cattle for serological and virological investigation. The typical clinical signs of FMDV infection were observed in all cattle under investigation. All samples were positive for FMDV using molecular methods, while the serological method showed 85% positive of tested samples. Typing of FMDV-positive samples using serotype-specific primers showed that 51.8% of samples were serotype O, 9.2% were serotype A, and 18.5% were SAT 2. Surprisingly, co-infections of serotypes A/SAT 2 (12.9%) and O/SAT 2 (7.4%) were also detected. By geographical location, the 3 serotypes A, O, and SAT2 were detected in all four governorates. The phylogenetic assessment of the detected viruses showed that two distinct groups of FMDV serotype O of East Africa-3 (EA-3) topotype were most closely related to circulating viruses in Sudan, as well as FMDV strains belonging to the topotype VII of serotype SAT 2. The detected SAT 2 strains clustered in separate clades in topotype VII, indicating new incursions. The VP1 signatures and protein sequences of some characterized viruses were analyzed. Multiple mutations were detected in VP1. Therefore, to enhance the control of FMD in Egypt, we recommend establishing an active surveillance system to characterize newly emerging virus strains/serotypes and subsequently updating vaccine strains.

Foot-and-mouth disease outbreaks in Egypt during 2013-2014: Molecular characterization of serotypes A, O, and SAT2

Background and Aim

Foot-and-mouth disease virus (FMDV) serotypes A, O and South African Territories (SAT2) are endemic in Egypt; each is presented by a number of partially related topotypes and lineages, depending on their geographical origin. Continuous mutations and the emergence of new topotypes that lead to occasional vaccination failures were frequently recorded, so this study aimed to genetically characterize the circulating FMD virus strains in Egypt during 2013 and 2014 outbreaks, focusing on amino acids variations in VP1 region.

Materials and Methods

A total of 51 oral tissue samples were collected from cattle and buffaloes in 13 farms, and 38 individual cases showed clinical signs suspected to be FMD in six Egyptian Governorates (Cairo, Giza, Qaliubia, Fayoum, Sharquia, and Assiut). FMDV in collected samples was characterized by reverse transcription-polymerase chain reaction (RT-PCR) amplification of full VP1 region, sequencing, and phylogenetic analysis.

Results

Out of 51 samples, 44 (86.27%) were positive by RT-PCR using universal primers. Serotype O was predominant and detected in 31 samples (70.45%), serotype A was detected in 9 samples (20.45%), and then serotype SAT2 was identified in 4 samples (9.10%). Sequencing and phylogenetic analysis of VP1 demonstrated clustering of serotype O, A, and SAT2 in EA-3 topotype, ASIA topotype, and topotype VII, respectively. Serotype O is closely related to O/SUD/8/2008 with 94.6% identity but showed 14.6% differences from vaccine strain (O/PanAsia-2) of ME-SA topotype. Furthermore, Serotype A and SAT2 were closely related to recent circulating Egyptian isolates and vaccine strains type A/EGY/1/2012 (Asia topotype, lineage Iran-05) with identity 96.4% and vaccine strain of SAT2/EGY/A/2012 (topotype VII, lineage SAT2/VII/ALX-12) with identity 95.3%, respectively.

Conclusion

The present study recommended further studies of serotype O to determine the immunogenic relationship between the vaccine strain and the new strains to attain maximum protection against circulating viruses.

Detection and genetic characterization of bovine kobuvirus from calves in Egypt

Kobuviruses are small non-enveloped RNA viruses that probably cause diarrhea in cattle and swine. Since its discovery in 2003, few studies have addressed bovine kobuvirus (BKoV; a species of Aichivirus B) infections. BKoV has been reported in Europe, Asia, and South America, suggesting a worldwide distribution. To investigate the presence of BKoV in Egypt, 36 fecal specimens from diarrheic calves in two different Egyptian provinces (Cairo and Sharkia) were screened by RT-PCR and 24 (66.7%) were found positive for BKoV. RNA from one of the positive samples (BKoV/Egy-1/KY407744) was subjected to next-generation sequencing to determine the complete BKoV genome sequence. When compared to the only recorded BKoV genome sequence (BKoV/U-1/AB084788), the studied strain showed 94 amino acid (aa) substitutions through its entire polyprotein (2463 aa), one nucleotide (nt) insertion and one nt deletion in the 2B gene and 4-nt deletions in the UTRs (2 each). Additionally, five VP1 and seven 3D sequences were obtained from other samples by using RT-PCR and Sanger sequencing. A discrepancy in the phylogenetic topography of VP1 and 3D was observed, where the Egyptian VP1 sequences were classified as a distinct cluster within the proposed lineage 1 (genotype A), which also contained strains from the UK, Brazil, and Japan. While, the 3D sequences from Cairo were related to those of Chinese strains unlike Sharkia ones that were more closer to Korean  strains. To the best of our knowledge, this is the first detection and genomic characterization of BKoV in Egypt or indeed Africa.

Molecular characterization of circulating Foot and mouth disease virus (FMDV) serotype O topotype EA-3 and serotype A (African topotype) genotype IV in Egypt, 2016

In January-April 2016, cattle and buffalo farm owners and veterinarians reported clinical signs suggestive of foot and mouth disease virus (FMDV) outbreaks among non-vaccinated cattle and buffalo herds in Egypt. The clinical disease observed was either mild (small oral lesions and speedy recovery) or severe (extensive oral lesions and/or mortalities), and the form of the disease (either mild or severe) segregated by farm. This study aimed to confirm the presence of FMDV and to characterize the circulating strains associated with the outbreaks. Vesicular epithelia were collected from 41 animals representing 15 affected cattle and buffalo farms in five governorates (Behira, Cairo, Daqahlia, Giza and Ismailia), and tested by real time (rt) RT-PCR. Consequently, 92% (38/41) of examined samples were positive. Furthermore, the VP1 coding region of 60% (23/38) of positive specimens were amplified by RT-PCR and sequenced. The phylogenetic analysis identified two distinct strains characterized as serotype O topotype EA-3 and serotype A (African topotype) of genotype IV in the severe and mild disease forms, respectively. The newly identified strains clustered in distinct clades in the phylogenetic trees, indicating the likelihood of new incursions into Egypt. Those strains were most closely related to previously described Sudanese strains.

Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genome detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle.

Structure-based energetics of protein interfaces guides foot-and-mouth disease virus vaccine design

Virus capsids are primed for disassembly, yet capsid integrity is key to generating a protective immune response. Foot-and-mouth disease virus (FMDV) capsids comprise identical pentameric protein subunits held together by tenuous noncovalent interactions and are often unstable. Chemically inactivated or recombinant empty capsids, which could form the basis of future vaccines, are even less stable than live virus. Here we devised a computational method to assess the relative stability of protein-protein interfaces and used it to design improved candidate vaccines for two poorly stable, but globally important, serotypes of FMDV: O and SAT2. We used a restrained molecular dynamics strategy to rank mutations predicted to strengthen the pentamer interfaces and applied the results to produce stabilized capsids. Structural analyses and stability assays confirmed the predictions, and vaccinated animals generated improved neutralizing-antibody responses to stabilized particles compared to parental viruses and wild-type capsids.

Molecular investigation of foot-and-mouth disease virus in domestic bovids from Gharbia, Egypt

An outbreak of foot-and-mouth disease (FMD) affecting cattle and water buffalo (Bubalus bubalis) occurred in Egypt during 2012/2013. The present study was undertaken to determine the current strains of the FMD virus (FMDV) and the prevalence of FMD among cattle and buffalo in Gharbia, Egypt. The diagnostic sensitivity of two RT-PCR assays for the detection of FMDV was evaluated. The results revealed that SAT2 was the causative agent. The percentage of infected of animals varied with the detection method, ranging from 62.5 % by the untranslated region (UTR) RT-PCR to 75.6 % by SAT2 RT-PCR. The overall prevalence and mortality rates were 100 and 21 %, respectively. The mortality was higher in buffalo (23.3 %) than it was in cattle (17 %). A partial sequence of SAT2 was identical (90-100 %) to Egyptian isolates and was close in similarity to sequences from Sudan and Libya. In conclusion, FMD in Egypt is caused by SAT2. No other serotypes were detected. The results of this study provided the valuable data regarding the epidemiology of SAT2 in cattle and water buffalo from Egypt, which strengthens the need to change the strategies of both control and prevention that help to prevent the spread of the disease.

Morphologic and phenotypic characteristics of myocarditis in two pigs infected by foot-and mouth disease virus strains of serotypes O or A

Myocarditis is often cited as the cause of fatalities associated with foot-and-mouth disease virus (FMDV) infection. However, the pathogenesis of FMDV-associated myocarditis has not been described in detail. The current report describes substantial quantities of FMDV in association with a marked mononuclear inflammatory reaction, interstitial edema and cardiomyocyte degeneration in the myocardium of two pigs that died during acute infection with either of two different strains of FMDV. Despite similar clinical progression, there was a marked variation in morphological characteristics of myocarditis with a significant difference in intensity of myocardial inflammation between the two cases. Phenotypic characterization of leukocyte populations revealed that in both cases, the inflammatory infiltrate consisted mainly of combinations of CD172a+, CD163+ and CD44+ cells, with a distinct subset of CD8+ cells, but with consistent lack of detection of CD3+ and CD21+ cells. This suggests that the FMDV-associated acute myocardial inflammation in the two observed cases consisted mainly of leukocytes of monocyte lineage, with a distinct population of CD8+ cells which, based on lack of CD3 detection in serial sections, are likely to represent NK cells.

Reconstructing geographical movements and host species transitions of foot-and-mouth disease virus serotype SAT 2

Of the three foot-and-mouth-disease virus SAT serotypes mainly confined to sub-Saharan Africa, SAT 2 is the strain most often recorded in domestic animals and has caused outbreaks in North Africa and the Middle East six times in the last 25 years, with three apparently separate events occurring in 2012. This study updates the picture of SAT 2 phylogenetics by using all available sequences for the VP1 section of the genome available at the time of writing and uses phylogeographic methods to trace the origin of all outbreaks occurring north of the Sahara since 1990 and identify patterns of spread among countries of endemicity. Transitions between different host species are also enumerated. Outbreaks in North Africa appear to have origins in countries immediately south of the Sahara, whereas those in the Middle East are more often from East Africa. The results of the analysis of spread within sub-Saharan Africa are consistent with it being driven by relatively short-distance movements of animals across national borders, and the analysis of host species transitions supports the role of the African buffalo (Syncerus caffer) as an important natural reservoir.

Foot-and-mouth disease virus is a livestock pathogen of major economic importance, with seven distinct serotypes occurring globally. The SAT 2 serotype, endemic in sub-Saharan Africa, has caused a number of outbreaks in North Africa and the Middle East during the last decades, including three separate incidents in 2012. A comprehensive analysis of all available RNA sequences for SAT 2 has not been published for some years. In this work, we performed this analysis using all previously published sequences and 49 newly determined examples. We also used phylogenetic methods to infer the source country for all outbreaks occurring outside sub-Saharan Africa since 1990 and to reconstruct the spread of viral lineages between countries where it is endemic and movements between different host species.