Refine search
Results 1-10 of 14
Meta-analysis of genetic diversity of the VP1 gene among the circulating O, A, and SAT2 serotypes and vaccine strains of FMD virus in Egypt
2020
El Nahas, Abeer F. | Salem, Sayed A.H.
Three strains of the FMD virus (A, O, and SAT 2) were recognised as causes of the FMD circulating in Egypt. The aims of this study were to trace the FMDV isolates from outbreaks in Egypt to understand their epidemiology and evolution and to understand the situation of the vaccine strains compared with the circulating serotypes. A meta-analysis was carried out by using the data available for FMD outbreaks in Egypt from GenBank and the World Reference Laboratory for Foot-and-Mouth Disease (WRLFMD); a comparison was done with both data sets for the three serotypes. MEGA-X was used for the evolution analysis, through constructions of phylogenetic trees for all sequences recorded in GenBank for each serotype in different Egyptian outbreaks in different years and also within the same year. Additionally, nucleotide substitution rate, molecular clock, and mean evolutionary rates were estimated for the three serotypes to understand and compare their evolution. Absence of some records of certain serotype outbreaks from the WRLFMD database was noted as were subsequent missing appropriate vaccine programmes. Genetic variation was recorded among the virus isolates within the same years and also the vaccine strain was associated with up to 26 amino acid substitutions. The evolution rate of the SAT2 strain was the highest of the circulating strains. SAT2 had high amino acid substitution per year at an important immunogenic site (130–170), serotype A had less, and serotype O the least. The need for different strategies for vaccine serotype selection is indicated.
Show more [+] Less [-]Comparative expression analysis of inflammatory and immune-related genes in cattle during acute infection with foot-and-mouth disease virus in Egypt
2021
El Nahas, Abeer F. | Abd El Naby, Walaa S.H. | Khatab, Shymaa A. | Fergany, Al-Zahraa A. | Rashed, Rashed R.
Foot-and-mouth disease is a highly infectious viral disease affecting all cloven-footed domestic animals. The three foot-and-mouth disease virus (FMDV) serotypes A, O and SAT2 are at present the greatest threat to susceptible animals in Egypt. The aim of the present study was, for the host factors associated with different FMDV infections in cattle during the acute phase, to compare these factors’ influence on the expression of the IL-10, TLR-2, TNF-α, CXCL10, CD48, NFATC4 and IFNG inflammatory and immune-related genes. Vesicular fluid and epithelium samples were obtained from at least three infected cattle on the same affected farm during three different FMDV outbreaks and were used for serotyping of the virus and for expression analysis of host genes. A two-step RT-PCR was used for diagnosis of the virus with primers specific for each serotype. In quantitative PCR analysis, the expression patterns of TLR-2 and IFNG were prominent, while NFATC4 expression was absent in all FMDV-infected cattle. The highest expression of CD48 was associated with increased expression of other inflammatory and immune-related genes (IL-10, TLR-2, TNF-α and IFNG), which may be an indication of rapid virus clearance. The use of vesicular fluid and epithelium for investigation of viral and immune-related gene expression levels in acute FMDV infection is possible. Host-dependent variation in the expression of the studied genes was observed in different FMDV serotype outbreaks.
Show more [+] Less [-]Description of an epidemic simulation model for use in evaluating strategies to control an outbreak of foot-and-mouth disease
2003
Bates, Thomas W. | Thurmond, Mark C. | Carpenter, Tim E.
Objective-To develop a spatial epidemic model to simulate intraherd and interherd transmission of footand- mouth disease (FMD) virus. Sample Population-2,238 herds, representing beef, dairy, swine, goats, and sheep, and 5 sale yards located in Fresno, Kings, and Tulare counties of California. Procedure-Using Monte-Carlo simulations, a spatial stochastic epidemic simulation model was developed to identify new herds that would acquire FMD following random selection of an index herd and to assess progression of an epidemic after implementation of mandatory control strategies. Results-The model included species-specific transition periods for FMD infection, locations of herds, rates of direct and indirect contacts among herds, and probability distributions derived from expert opinions on probabilities of transmission by direct and indirect contact, as well as reduction in contact following implementation of restrictions on movements in designated infected areas and surveillance zones. Models of supplemental control programs included slaughter of all animals within a specified distance of infected herds, slaughter of only high-risk animals identified by use of a model simulation, and vaccination of all animals within a 5- to 50-km radius of infected herds.
Show more [+] Less [-]Evaluation of commercial ELISA kits’ diagnostic specificity for FAST diseases in wild animals
2024
Vesna Milićević | Dimitrije Glišić | Ljubiša Veljović | Jovan Mirčeta | Branislav Kureljušić | Milutin Đorđević | Nikola Vasković
Wild animals, sharing pathogens with domestic animals, play a crucial role in the epidemiology of infectious diseases. Sampling from wild animals poses significant challenges, yet it is vital for inclusion in disease surveillance and monitoring programmes. Often, mass surveillance involves serological screenings using enzyme-linked immunosorbent assay (ELISA) tests, typically validated only for domestic animals. This study assessed the diagnostic specificity of commercially available ELISA tests on 342 wild ruminant serum samples and 100 from wild boars. We evaluated three tests for foot-and-mouth disease: two for Peste des petits ruminants, two for Rift Valley fever and one for Capripox virus. Diagnostic specificity was calculated using the formula True Negative/(False Positive + True Negative). Cohen’s kappa coefficient measured agreement between tests. Results showed high specificity and agreement across all tests. Specificity for foot-and-mouth disease (FMD) ranged from 93.89% for Prionics to 100% for IDEXX, with IDvet showing 99.6%. The highest agreement was between FMD IDvet and IDEXX at 97.1%. Rift Valley fever (RVF) tests, Ingezim and IDvet, achieved specificities of 100% and 98.83%, respectively. The optimal specificity was attained by retesting single reactors and inactivating the complement. Contribution: Commercially available ELISA kits are specific for foot-and-mouth disease and similar transboundary animal diseases and can be used for highly specific wild animal testing.
Show more [+] Less [-]Competitive Luminex immunoassays for detection of antibodies to foot-and-mouth disease and vesicular stomatitis viruses in multiple susceptible hosts
2018
Nfon, C. | Lusansky, D. | Goolia, M. | Yang, M. | Hole, K. | McIntyre, L.
Foot-and-mouth disease (FMD) and vesicular stomatitis (VS) cause such similar clinical signs and lesions that laboratory tests are required to distinguish between infections caused by each virus. Using mouse anti-foot-and-mouth disease virus (FMDV) 3B monoclonal or polyclonal anti-vesicular stomatitis virus-New Jersey (VSV-NJ) antibodies and recombinant FMDV 3ABC or VSV-NJ glycoprotein (G) antigens coated to MagPlex beads, competitive Luminex immunoassays (cLIAs) were developed for FMDV and VSV-NJ, respectively. The cLIAs successfully detected antibodies to FMDV 3ABC and VSV-NJ G in sera from infected animals. The diagnostic sensitivity and specificity were 93% and 98%, respectively for FMDV and 93% and 95.4%, respectively for VSV-NJ. These cLIAs are potential alternatives for competitive enzyme-linked immunosorbent assays (cELISAs) and provide the opportunity for multiplexing to reduce time and the amount of serum required for testing.
Show more [+] Less [-]Temporospatial clustering analysis of foot-and-mouth disease transmission in South Korea, 2010~2011
2013
Bae, S.H., Kangwon National University, Chuncheon, Republic of Korea | Shin, Y.K., Plant and Fisheries Quarantine and Inspection Agency, Anyang, Republic of Korea | Kim, B., Plant and Fisheries Quarantine and Inspection Agency, Anyang, Republic of Korea | Pak, S.I., Kangwon National University, Chuncheon, Republic of Korea
To investigate the transmission pattern of geographical area and temporal trends of the 2010~2011 footand- mouth disease (FMD) outbreaks in Korea, and to explore temporal intervals at which spatial clustering of FMD cases space-time analysis based on georeferenced database of 3,575 burial sites, from 30 November 2010 to 23 February 2011, was performed. The cases represent approximately 98.1% of all infected farms (n = 3,644) during the same period. Descriptive maps of spatial patterns of the outbreaks were generated by ArcGIS. Spatial Scan Statistics, using SaTScan software, was applied to investigate geographical clusters of FMD cases across the country. Overall, spatial heterogeneity was identified, and the transmission pattern was different by province. Cattle have more clusters in number but smaller in size, as compared to the swine population. In addition, spatiotemporal analysis and the comparison of clustering patterns between the first 7 days and days 8 to 14 of the outbreak revealed that the strongest spatial clustering was identified at the 7-day interval, although clustering over longer intervals (8~14 days) was also observed. We further discussed the importance of time period elapsed between FMD-suspected notice and the date of confirmation, and emphasized the necessity of region-specific and species-specific control measures.
Show more [+] Less [-]Molecular characterization of SAT-2 foot-and-mouth disease virus isolates obtained from cattle during a four-month period in 2001 in Limpopo Province, South Africa
2008
Phologane, B.S.(Agricultural Research Council Onderstepoort Veterinary Institute Exotic Diseases Division,Tshwane University of Technology Department of Biomedical Science) | Dwarka, R.M.(Agricultural Research Council Onderstepoort Veterinary Institute Exotic Diseases Division) | Haydon, D.T.(University of Glasgow Division of Environmental and Evolutionary Biology) | Gerber, L.J.(Tshwane University of Technology Department of Biomedical Science) | Vosloo, W.(Agricultural Research Council Onderstepoort Veterinary Institute Exotic Diseases Division,University of Pretoria Faculty of Veterinary Science Department of Veterinary Tropical Diseases)
Foot-and-mouth disease (FMD) is an acute, highly contagious viral infection of domestic and wild cloven-hoofed animals. The virus is a single-stranded RNA virus that has a high rate of nucleotide mutation and amino acid substitution. In southern Africa the South African Territories (SAT) 1-3 serotypes of FMD virus are maintained by large numbers of African buffaloes (Syncerus caffer), which provide a potential source of infection for domestic livestock and wild animals. During February 2001, an outbreak of SAT-2 was recorded in cattle in the FMD control zone of South Africa, adjacent to the Kruger National Park (KNP). They had not been vaccinated against the disease since they form the buffer between the vaccination and free zones but in the face of the outbreak, they were vaccinated as part of the control measures to contain the disease. The virus was, however, isolated from some of them on several occasions up to May 2001. These isolates were characterized to determine the rate of genetic change in the main antigenic determinant, the 1D/2A gene. Nucleotide substitutions at 12 different sites were identified of which five led to amino acid changes. Three of these occurred in known antigenic sites, viz. the GH-loop and C-terminal part of the protein, and two of these have previously been shown to be subject to positive selection. Likelihood models indicated that the ratio of non-synonymous to synonymous changes among the outbreak sequences recovered from cattle was four times higher than among comparable sequences isolated from wildlife, suggesting that the virus may be under greater selective pressure during rapid transmission events.
Show more [+] Less [-]A quantitative modeling approach to estimate the risks posed by the smuggled animal products contaminated with Foot-and-Mouth Disease (FMD) virus
2005
Hong, K.O. (National Veterinary Research and Quarantine Service, MAF, Anyang, Republic of Korea) | Pak, S.I. (Kangwon National University, Chunchon, Republic of Korea), E-mail: paksi@kangwon.ac.kr | Lee, G.H. (National Veterinary Research and Quarantine Service, MAF, Anyang, Republic of Korea)
A quantitative risk assessment tool was used to provide estimates of the probability that footand-mouth (FMD) virus-contaminated, smuggled animal products are fed to susceptible swine in Korea. Sensitivity analyses were conducted to attempt to distinguish between parameter uncertainty and variability, using different assumptions on the effect of cooking at home, the effect of the fresh meat, and the effect of heat treatment at garbage processing facility. The median risk estimate was about 20.1% with a mean value of 27.4%. In a scenario regarding all beef and pork were considered as fresh meat the estimated median risk was 3.4%.
Show more [+] Less [-]Results of epidemic simulation modeling to evaluate strategies to control an outbreak of foot-and-mouth disease
2003
Bates, Thomas W. | Thurmond, Mark C. | Carpenter, Tim E.
Objective-To assess estimated effectiveness of control and eradication procedures for foot-andmouth disease (FMD) in a region of California. Sample Population-2,238 herds and 5 sale yards in Fresno, Kings, and Tulare counties of California. Procedure-A spatial stochastic model was used to simulate hypothetical epidemics of FMD for specified control scenarios that included a baseline eradication strategy mandated by USDA and supplemental control strategies of slaughter or vaccination of all animals within a specified distance of infected herds, slaughter of only high-risk animals identified by use of a model simulation, and expansion of infected and surveillance zones. Results-Median number of herds affected varied from 1 to 385 (17% of all herds), depending on type of index herd and delay in diagnosis of FMD. Percentage of herds infected decreased from that of the baseline eradication strategy by expanding the designated infected area from 10 to 20 km (48%), vaccinating within a 50-km radius of an infected herd (41%), slaughtering the 10 highest-risk herds for each infected herd (39%), and slaughtering all animals within 5 km of an infected herd (24%). Conclusions and Clinical Relevance-Results for the model provided a means of assessing the relative merits of potential strategies for control and eradication of FMD should it enter the US livestock population. For the study region, preemptive slaughter of highest-risk herds and vaccination of all animals within a specified distance of an infected herd consistently decreased size and duration of an epidemic, compared with the baseline eradication strategy.
Show more [+] Less [-]Critical response time (time available to implement effective measures for epidemic control): Model building and evaluation
2003
Rivas, A.L. | Tennenbaum, S.E. | Aparicio, J.P. | Hoogesteijn, A.L. | Mohammed, H.O. | Castillo-Chávez, C. | Schwager, S.J.
The time available to implement successful control measures against epidemics was estimated. Critical response time (CRT), defined as the time interval within which the number of epidemic cases remains stationary (so that interventions implemented within CRT may be the most effective or least costly), was assessed during the early epidemic phase, when the number of cases grows linearly over time. The CRT was calculated from data of the 2001 foot-and-mouth disease (FMD) epidemic that occurred in Uruguay. Significant regional CRT differences (ranging from 1.4 to 2.7 days) were observed. The CRT may facilitate selection of control measures. For instance, a CRT equal to 3 days would support the selection of measures, such as stamping-out, implementable within 3 days, but rule out measures, such as post-outbreak vaccination, because intervention and immunity building require more than 3 days. Its use in rapidly disseminating diseases, such as FMD, may result in regionalized decision-making.
Show more [+] Less [-]