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Foot-and-mouth disease (FMD) is a trans-boundary viral disease of livestock, which causes huge economic losses and constitutes a serious infectious threat for livestock farming worldwide. Early diagnosis of FMD helps to diminish its impact by adequate outbreak management. In this study, we describe the development of a real-time reverse transcription recombinase polymerase amplification (RT-RPA) assay for the detection of FMD virus (FMDV). The FMDV RT-RPA design targeted the 3D gene of FMDV and a 260 nt molecular RNA standard was used for assay validation. The RT-RPA assay was fast (4-10 minutes) and the analytical sensitivity was determined at 1436 RNA molecules detected by probit regression analysis. The FMDV RT-RPA assay detected RNA prepared from all seven FMDV serotypes but did not detect classical swine fever virus or swine vesicular disease virus. The FMDV RT-RPA assay was used in the field during the recent FMD outbreak in Egypt. In clinical samples, reverse transcription polymerase chain reaction (RT-PCR) and RT-RPA showed a diagnostic sensitivity of 100% and 98%, respectively. In conclusion, FMDV RT-RPA was quicker and much easier to handle in the field than real-time RT-PCR. Thus RT-RPA could be easily implemented to perform diagnostics at quarantine stations or farms for rapid spot-of-infection detection.

Foot-and-mouth disease (FMD) continues to be one of the most important diseases of livestock globally based upon both biological features and regulatory aspects. Few pathogens have had comparable impact on global livestock production and regulation of international trade in animal-derived products. The pathogenesis (interaction between pathogen and host) is central to the importance of the disease ranging from how the causal pathogen, FMD virus (FMDV), transmits between hosts and is maintained in populations. Key accomplishments over the last decade include description of the primary sites of infection in domestic species, delineating critical differences in temporo-anatomic progression in different host species and emphasizing that knowledge gained regarding FMDV pathogenesis in one host cannot necessarily be extrapolated and applied to a different host. Host responses to infection and viral genomics have been characterized with ever-increasing granularity. Yet, the numerous knowledge gaps that remain in understanding FMDV pathogenesis impede advancements in FMD control and eradication. For instance, it remains unclear if long-term asymptomatic FMDV carriers are biologically relevant (contagious) and the manner in which host genomics and transcriptomics affect pathogenesis during different phases of infection. The characterization of neoteric subclinical infection as a disease stage that is distinct from the persistent “FMDV carrier state” has emphasized the importance of sample collection from clinically unaffected animals for FMDV surveillance. Similarly, incorporating a phase of pre-clinical infectiousness in simulation modeling can dramatically improve prediction of FMD outbreaks in non-endemic regions. The outcome of FMDV infection with regards to viral persistence differs between host species as well as between individuals of the same species. Yet, we lack a satisfactory explanation of the host factors that drive the FMDV carrier state divergence. This review was based upon a gap-analysis workshop organized by the Global Foot-and-Mouth Disease Research Alliance (GFRA) in Buenos Aires, Argentina, in December of 2022. The purpose of this work is to summarize the current understanding of the distinct compartments of FMD pathogenesis with an emphasis on progress made within the last decade and present the critical knowledge gaps that continue to limit FMD control and eradication.

We describe detection of SAT2 topotype XIV foot-and-mouth disease viruses in western Asia during 2022-2023. Sequences show the viruses originated in eastern Africa and were introduced into western Asia on >1 occasion. The rapid spread in naive animals highlights risks for onward transmission and potential endemicity in Asia.

Control of many infectious diseases relies on the detection of clinical cases and the isolation, removal, or treatment of cases and their contacts. The success of such \"reactive\" strategies is influenced by the fraction of transmission occurring before signs appear. We performed experimental studies of foot-and-mouth disease transmission in cattle and estimated this fraction at less than half the value expected from detecting virus in body fluids, the standard proxy measure of infectiousness. This is because the infectious period is shorter (mean 1.7 days) than currently realized, and animals are not infectious until, on average, 0.5 days after clinical signs appear. These results imply that controversial preemptive control measures may be unnecessary; instead, efforts should be directed at early detection of infection and rapid intervention.

Foot and mouth disease (FMD) is a highly contagious viral infection affecting cloven-hoofed ruminants, leading to significant economic losses. In 2022, Egypt faced a severe outbreak of Foot and Mouth Disease (FMD) caused by the A/Africa/G-IV variant. This study assessed the efficacy of local and imported FMDV vaccines (A Iran-05 lineage) against this new variant using in vitro and in vivo methods. Sera from vaccinated calves showed inadequate cross-protection, with mean r1-values of 0.235 and 0.243 for local and imported vaccines, respectively. Challenge tests indicated low protection levels (20% and 40%) against A/Africa/G-IV compared with A/Iran/05. Current vaccines were deemed ineffective, prompting a formulation update incorporating the variant. The modified vaccine is now deployed in proactive vaccination efforts to address the evolving FMD outbreak.

Foot-and-mouth disease (FMD) is a highly contagious viral disease that severely impacts global food security and is one of the greatest constraints on international trade of animal products. Extensive viral population diversity and rapid, continuous mutation of circulating FMD viruses (FMDVs) pose significant obstacles to the control and ultimate eradication of this important transboundary pathogen. The current study investigated mechanisms contributing to within-host evolution of FMDV in a natural host species (cattle). Specifically, vaccinated and non-vaccinated cattle were infected with FMDV under controlled, experimental conditions and subsequently sampled for up to 35 days to monitor viral genomic changes as related to phases of disease and experimental cohorts. Consensus-level genomic changes across the entire FMDV coding region were characterized through three previously defined stages of infection: early, transitional, and persistent. The overall conclusion was that viral evolution occurred via a combination of two mechanisms: emergence of full-genomic minority haplotypes from within the inoculum super-swarm, and concurrent continuous point mutations. Phylogenetic analysis indicated that individuals were infected with multiple distinct haplogroups that were pre-existent within the ancestral inoculum used to infect all animals. Multiple shifts of dominant viral haplotype took place during the early and transitional phases of infection, whereas few shifts occurred during persistent infection. Overall, this work suggests that the establishment of the carrier state is not associated with specific viral genomic characteristics. These insights into FMDV population dynamics have important implications for virus sampling methodology and molecular epidemiology.

Foot-and-mouth disease (FMD) is endemic in Eastern Africa with circulation of multiple serotypes of the virus in the region. Most of the outbreaks are caused by serotype O followed by serotype A. The lack of concerted FMD control programmes in Africa has provided little incentive for vaccine producers to select vaccines that are tailored to circulating regional isolates creating further negative feedback to deter the introduction of vaccine-based control schemes. In this study a total of 80 serotype O FMD viruses (FMDV) isolated from 1993 to 2012 from East and North Africa were characterized by virus neutralisation tests using bovine antisera to three existing (O/KEN/77/78, O/Manisa and O/PanAsia-2) and three putative (O/EA/2002, O/EA/2009 and O/EA/2010) vaccine strains and by capsid sequencing. Genetically, these viruses were grouped as either of East African origin with subdivision into four topotypes (EA-1, 2, 3 and 4) or of Middle-East South Asian (ME-SA) topotype. The ME-SA topotype viruses were mainly detected in Egypt and Libya reflecting the trade links with the Middle East countries. There was good serological cross-reactivity between the vaccine strains and most of the field isolates analysed, indicating that vaccine selection should not be a major constraint for control of serotype O FMD by vaccination, and that both local and internationally available commercial vaccines could be used. The O/KEN/77/78 vaccine, commonly used in the region, exhibited comparatively lower percent in vitro match against the predominant topotypes (EA-2 and EA-3) circulating in the region whereas O/PanAsia-2 and O/Manisa vaccines revealed broader protection against East African serotype O viruses, even though they genetically belong to the ME-SA topotype.

Foot-and-mouth disease (FMD) is a highly contagious disease affecting cloven-hoofed ungulates. This study aimed to enhance our understanding of the role of small ruminants and environmental contamination in the epidemiology and endemicity of FMD. A longitudinal study was conducted between March 2021 and October 2021 in northern Nigeria, where monthly samples were collected from five households, one livestock market and one transhumance location in two local government areas (LGA) identified as being at high risk of FMD. Serum samples ( n  = 783), oral swabs ( n  = 424) and environmental swabs ( n  = 458) were collected and tested for the presence of foot-and-mouth disease virus (FMDV) RNA by rRT-PCR. Serum samples ( n  = 780) were also tested for the presence of antibodies against FMDV non-structural proteins. The proportion of FMDV RNA positive samples increased in all sample types collected in one LGA during the period when an FMD outbreak was reported in the same LGA. In contrast, sero-positive samples did not differ by month but differed between LGAs and amongst species. The force of infection estimated from age-seroprevalence data for each household was significantly lower in goats compared with both cattle or sheep. Five O/EA-3 topotype sequences were obtained from selected FMDV RNA positive samples; findings which support the use of environmental swabs to detect circulating FMDV strains in endemic settings. These results show oral and environmental swabs are suitable sampling methods for early detection at animal and herd level, respectively and provide insights on the role of small ruminants on FMD epidemiology.