Multiple origins of foot-and-mouth disease virus serotype Asia 1 outbreaks, 2003-2007.

We investigated the molecular epidemiology of foot-and-mouth disease virus (FMDV) serotype Asia 1, which caused outbreaks of disease in Asia during 2003-2007. Since 2004, the region affected by outbreaks of this serotype has increased from disease-endemic countries in southern Asia (Afghanistan, India, Iran, Nepal, Pakistan) northward to encompass Kyrgyzstan, Tajikistan, Uzbekistan, several regions of the People's Republic of China, Mongolia, Eastern Russia, and North Korea. Phylogenetic analysis of complete virus capsid protein 1 (VP1) gene sequences demonstrated that the FMDV isolates responsible for these outbreaks belonged to 6 groups within the Asia 1 serotype. Some contemporary strains were genetically closely related to isolates collected historically from the region as far back as 25 years ago. Our analyses also indicated that some viruses have spread large distances between countries in Asia within a short time.

Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil.

BACKGROUND: Foot-and-mouth disease (FMD) is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA) are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed. RESULTS: A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay with high sensitivity and specificity under laboratorial and experimental conditions was used in the current study. To verify the applicability of this assay under field conditions in Brazil, 460 oral swabs from cattle were collected in areas free of FMD (n = 200) and from areas with outbreaks of FMD (n = 260). Three samples from areas with outbreaks of FMD were positive by real-time RT-PCR, and 2 of those samples were positive by virus isolation and ELISA. Four other samples were considered inconclusive by real-time RT-PCR (threshold cycle [Ct] > 40); whereas all 200 samples from an area free of FMD were real-time RT-PCR negative. CONCLUSION: real-time RT-PCR is a powerful technique for reliable detection of FMDV in a fraction of the time required for virus isolation and ELISA. However, it is noteworthy that lack of infrastructure in certain areas with high risk of FMD may be a limiting factor for using real-time RT-PCR as a routine diagnostic tool.

Strengthening One Health Through Investments in Agricultural Preparedness.

There are links among agriculture and zoonotic diseases, transboundary diseases in domesticated and wild animals, climate patterns, and human population migrations. A natural or intentionally occurring high-consequence infectious disease ("biothreat") often has no geographic boundaries and has the potential to result in disease epidemics in humans, animals, or both. Although significant strides have been made globally in preparing for a natural or intentional introduction of an emerging and/or zoonotic disease, much remains to be accomplished. Enhancing animal health and well-being is a vital component to enable a sustainable, safe, and nutritious food supply for global food economies. This article explores the biothreat environment, its One Health interrelationship, and the significance and role of US agriculture in One Health. We provide an overview of the US Emergency Medical Countermeasure Enterprise (EMCE) and current state of veterinary and zoonotic medical countermeasures portfolio management in the US government, veterinary biologic industry, not-for-profit groups, and public-private partnerships. The highest zoonotic and epizootic threats to the US livestock industry are briefly reviewed, and currently available veterinary medical countermeasures are presented. Lastly, important gaps and priorities are identified, followed by specific recommendations to address these gaps.

The Convergence of High-Consequence Livestock and Human Pathogen Research and Development: A Paradox of Zoonotic Disease.

The World Health Organization (WHO) estimates that zoonotic diseases transmitted from animals to humans account for 75 percent of new and emerging infectious diseases. Globally, high-consequence pathogens that impact livestock and have the potential for human transmission create research paradoxes and operational challenges for the high-containment laboratories that conduct work with them. These specialized facilities are required for conducting all phases of research on high-consequence pathogens (basic, applied, and translational) with an emphasis on both the generation of fundamental knowledge and product development. To achieve this research mission, a highly-trained workforce is required and flexible operational methods are needed. In addition, working with certain pathogens requires compliance with regulations such as the Centers for Disease Control (CDC) and the U.S. Department of Agriculture (USDA) Select Agent regulations, which adds to the operational burden. The vast experience from the existing studies at Plum Island Animal Disease Center, other U.S. laboratories, and those in Europe and Australia with biosafety level 4 (BSL-4) facilities designed for large animals, clearly demonstrates the valuable contribution this capability brings to the efforts to detect, prepare, prevent and respond to livestock and potential zoonotic threats. To raise awareness of these challenges, which include biosafety and biosecurity issues, we held a workshop at the 2018 American Society for Microbiology (ASM) Biothreats conference to further discuss the topic with invited experts and audience participants. The workshop covered the subjects of research funding and metrics, economic sustainment of drug and vaccine development pipelines, workforce turnover, and the challenges of maintaining operational readiness of high containment laboratories.

Detection of foot-and-mouth disease virus: comparative diagnostic sensitivity of two independent real-time reverse transcription-polymerase chain reaction assays.

Rapid and accurate diagnosis is central to the effective control of foot-and-mouth disease (FMD). It is now recognized that reverse-transcription polymerase chain reaction (RT-PCR) assays can play an important role in the routine detection of FMD virus (FMDV) in clinical samples. The aim of this study was to compare the ability of 2 independent real-time RT-PCR (rRT-PCR) assays targeting the 5' untranslated region (5'UTR) and RNA polymerase (3D) to detect FMDV in clinical samples. There was concordance between the results generated by the 2 assays for 88.1% (347 of 394) of RNA samples extracted from suspensions of epithelial tissue obtained from suspect FMD cases. The comparison between the 2 tests highlighted 19 FMDV isolates (13 for the 5'UTR and 6 for the 3D assay), which failed to produce a signal in 1 assay but gave a positive signal in the other. The sequence of the genomic targets of selected isolates highlighted nucleotide substitutions in the primer or probe regions, thereby providing an explanation for negative results generated in the rRT-PCR assays. These data illustrate the importance of the continuous monitoring of circulating FMDV field strains to ensure the design of the rRT-PCR assay remains fit for purpose and suggest that the use of multiple diagnostic targets could further enhance the sensitivity of molecular methods for the detection of FMDV.

Comparison of six RNA extraction methods for the detection of classical swine fever virus by real-time and conventional reverse transcription-PCR.

Six RNA extraction methods, i.e., RNAqueous kit, Micro-to-midi total RNA purification system, NucleoSpin RNA II, GenElute mammalian total RNA kit, RNeasy mini kit, and TRIzol LS reagent, were evaluated on blood and 7 tissues from pig infected with classical swine fever virus (CSFV). Each of the 6 extraction methods yielded sufficient RNA for positive results in a real-time reverse transcription-PCR (RT-PCR) for CSFV, and all RNA, except the one extracted from blood by TRIzol LS reagent, yielded positive results in both a conventional RT-PCR for CSFV and a conventional RT-PCR for an endogenous gene encoding beta-actin. The RNA extracted from blood by TRIzol LS reagent became positive in both conventional RT-PCR assays when it was diluted to 1:2, 1:4, or up to 1:64 in nuclease-free water. It is concluded that all 6 methods are more or less useful for the detection of CSFV by real-time and conventional RT-PCR in swine blood and tissues. However, some of the 6 reagents offer certain advantages not common to all 6 extraction procedures. For example, RNA extracted by the TRIzol LS reagent constantly had the highest yield; that by the RNAqueous kit had the highest A260/A280 ratio for almost all samples; and that by the NucleoSpin RNA II and the GenElute mammalian total RNA kit was most likely to be free of contaminations with genomic DNA.

Integrating novel data streams to support biosurveillance in commercial livestock production systems in developed countries: challenges and opportunities.

Reducing the burden of emerging and endemic infectious diseases on commercial livestock production systems will require the development of innovative technology platforms that enable information from diverse animal health resources to be collected, analyzed, and communicated in near real-time. In this paper, we review recent initiatives to leverage data routinely observed by farmers, production managers, veterinary practitioners, diagnostic laboratories, regulatory officials, and slaughterhouse inspectors for disease surveillance purposes. The most commonly identified challenges were (1) the lack of standardized systems for recording essential data elements within and between surveillance data streams, (2) the additional time required to collect data elements that are not routinely recorded by participants, (3) the concern over the sharing and use of business sensitive information with regulatory authorities and other data analysts, (4) the difficulty in developing sustainable incentives to maintain long-term program participation, and (5) the limitations in current methods for analyzing and reporting animal health information in a manner that facilitates actionable response. With the significant recent advances in information science, there are many opportunities to develop more sophisticated systems that meet national disease surveillance objectives, while still providing participants with valuable tools and feedback to manage routine animal health concerns.

Development of a universal RT-PCR for amplifying and sequencing the leader and capsid-coding region of foot-and-mouth disease virus.

Foot-and-mouth disease (FMD) is a highly infectious viral disease of cloven-hoofed animals with debilitating and devastating consequences for livestock industries throughout the world. Key antigenic determinants of the causative agent, FMD virus (FMDV), reside within the surface-exposed proteins of the viral capsid. Therefore, characterization of the sequence that encodes the capsid (P1) is important for tracking the emergence or spread of FMD and for selection and development of new vaccines. Reliable methods to generate sequence for this region are challenging due to the high inter-serotypic variability between different strains of FMDV. This study describes the development and optimization of a novel, robust and universal RT-PCR method that may be used to amplify and sequence a 3kilobase (kb) fragment encompassing the leader proteinase (L) and capsid-coding portions (P1) of the FMDV genome. This new RT-PCR method was evaluated in two laboratories using RNA extracted from 134 clinical samples collected from different countries and representing a range of topotypes and lineages within each of the seven FMDV serotypes. Sequence analysis assisted in the reiterative design of primers that are suitable for routine sequencing of these RT-PCR fragments. Using this method, sequence analysis was undertaken for 49 FMD viruses collected from outbreaks in the field. This approach provides a robust tool that can be used for rapid antigenic characterization of FMDV and phylogenetic analyses and has utility for inclusion in laboratory response programs as an aid to vaccine matching or selection in the event of FMD outbreaks.

Comparison of methods for improved RNA extraction from blood for early detection of Classical swine fever virus by real-time reverse transcription polymerase chain reaction.

Classical swine fever (CSF) is a highly contagious disease of pigs. Early detection of the Classical swine fever virus (CSFV) in infected animals and routine surveillance is important for a rapid response and control of an outbreak of CSF. The current study investigated whole blood as a clinical specimen for the detection of CSFV by real-time reverse transcription polymerase chain reaction (real-time RT-PCR) in experimentally infected pigs. The virus was detectable in pre-clinical animals in whole blood and in different fractions of blood, including white blood cells, red blood cells (RBC), and serum. Based on an in-vitro binding assay, CSFV is retained in the RBC fraction. Naturally occurring PCR inhibitors of whole blood were shown to inhibit detection, and several commercial RNA extraction kits failed to remove these inhibitors. The commercial blood RNA extraction protocols were modified to achieve optimized single tube and high-throughput 96-well plate RNA extraction that efficiently removed PCR inhibitors from whole blood and enhanced detection of CSFV in experimentally inoculated pigs. This enabled detection 1-2 days earlier than observed using unmodified RNA extraction protocols. The results show effective use of whole blood as a clinical specimen for diagnosis and surveillance of CSF in pre-clinical animals.

Development, optimization, and validation of a Classical swine fever virus real-time reverse transcription polymerase chain reaction assay.

Classical swine fever (CSF) is an economically devastating disease of pigs. Instrumental to the control of CSF is a well-characterized assay that can deliver a rapid, accurate diagnosis prior to the onset of clinical signs. A real-time fluorogenic-probe hydrolysis (TaqMan) reverse transcription polymerase chain reaction (RT-PCR) for CSF was developed by the United States Department of Agriculture (USDA) at the Plum Island Animal Disease Center (CSF PIADC assay) and evaluated for analytical and diagnostic sensitivity and specificity. A well-characterized panel including Classical swine fever virus (CSFV), Bovine viral diarrhea virus (BVDV), and Border disease virus (BDV) isolates was utilized in initial feasibility and optimization studies. The assay was initially designed and validated for use on the ABI 7900HT using the Qiagen QuantiTect® Probe RT-PCR chemistry. However, demonstrating equivalency with multiple one-step RT-PCR chemistries and PCR platforms increased the versatility of the assay. Limit of detection experiments indicated that the Qiagen QuantiTect® Multiplex (NoROX) and the Invitrogen SuperScript® III RT-PCR kits were consistently the most sensitive one-step chemistries for use with the CSF PIADC primer/probe set. Analytical sensitivity of the CSF PIADC assay ranged from <1-2.95 log(10) TCID(50)/ml on both the ABI 7900HT and ABI 7500 platforms. The CSF PIADC assay had 100% diagnostic sensitivity and specificity when tested on a panel of 152 clinical samples from the Dominican Republic and Colombia. The ability to perform this newly developed assay in 96-well formats provides an increased level of versatility for use in CSF surveillance programs.

Genetic characterization and molecular epidemiology of foot-and-mouth disease viruses isolated from Afghanistan in 2003-2005.

Foot-and-mouth disease virus (FMDV) isolates collected from various geographic locations in Afghanistan between 2003 and 2005 were genetically characterized, and their phylogeny was reconstructed utilizing nucleotide sequences of the complete VP1 coding region. Three serotypes of FMDV (types A, O, and Asia 1) were identified as causing clinical disease in Afghanistan during this period. Phylogenetic analysis revealed that the type A viruses were most closely related to isolates collected in Iran during 2002-2004. This is the first published report of serotype A in Afghanistan since 1975, therefore indicating the need for inclusion of serotype A in vaccine formulations that will be used to control disease outbreaks in this country. Serotype O virus isolates were closely related to PanAsia strains, including those that originated from Bhutan and Nepal during 2003-2004. The Asia 1 viruses, collected along the northern and eastern borders of Afghanistan, were most closely related to FMDV isolates collected in Pakistan during 2003 and 2004. Data obtained from this study provide valuable information on the FMDV serotypes circulating in Afghanistan and their genetic relationship with strains causing FMD in neighboring countries.