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Foot-and-mouth disease (FMD) is a viral disease that affects cloven-hoofed animals including cattle, pigs, and sheep, hence causing export bans among others, causing high economic losses due to reduced productivity. The global effect of FMD is most felt where livestock rearing forms an important source of income. It is therefore important to understand the modes of transmission of FMD to control its spread and prevent its occurrence. This work intends to address these dynamics by including the efficacy of active migrant animals transporting the disease from one area to another in a fuzzy mathematical modeling framework. Historical models of epidemics are determinable with a set of deterministic parameters and this does not reflect on real-life scenarios as observed in FMD. Fuzzy theory is used in this model as it permits the inclusion of uncertainties in the model; this makes the model more of a reality regarding disease transmission. A time lag, in this case, denotes the incubation period and other time-related factors affecting the spread of FMD and, therefore, is added to the current model for FMD. To that purpose, the analysis of steady states and the basic reproduction number are performed and, in addition, the stability checks are conveyed in the fuzzy environment. For the numerical solution of the model, we derive the Forward Euler Method and the fuzzy delayed non-standard finite difference (FDNSFD) method. Analytical studies of the FDNSFD scheme are performed for convergence, non-negativity, boundedness, and consistency analysis of the numerical projection to guarantee that the numerical model is an accurate discretization of the continuous dynamics of FMD transmission over time. In the following simulation study, we show that the FDNSFD method preserves the characteristics of the constant model and still works if relatively large time steps are employed; this is a bonus over the normal finite difference technique. The study shows how valuable it is to adopt fuzzy theory and time delays when simulating the transmission of the epidemic, especially for such diseases as FMD where uncertainty and migration have a defining role in transmission. This approach gives more sound and flexible grounds for analyzing and controlling the outbreak of FMD in various situations. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is one of the most important animal diseases of economic significance globally. It is a highly infectious and contagious disease of cloven-hoofed animals including sheep and goat. For sero-diagnosis of FMD, recombinant antigen-based assays are considered as alternatives to conventional approaches such as the liquid phase blocking ELISA (LPBE). The early interventions towards control measures cannot be implemented unless the disease gets promptly diagnosed. It is relatively difficult to clinically diagnose FMD in goat due to the usual milder form or unapparent nature of symptoms. Under such situations where clinical samples are not available, demonstration of infection-specific FMD virus (FMDV) antibodies in serum sample may help identifying the animals exposed to the virus in retrospect. Antibody to 3AB nonstructural protein (NSP) has been considered to be the most reliable indicator for FMD diagnosis. The current study extended the earlier designed recombinant 3AB3 protein-based indirect ELISA originally validated on bovine serum samples to testing serum samples of goat. The performance of the indirect ELISA was validated using internationally accepted PrioCHECK® FMDV NS kit. The overall diagnostic sensitivity (DSn) of the indirect ELISA was estimated to be 95.52% (619/648), while the diagnostic specificity (DSp) on naïve and vaccinated animals varied at 98.06% (557/568) and 94.15% (435/462), respectively. In India, where FMD is prevalent and the goat population is so high, this 'in-house' optimized assay can be considered to be an adjunct in sero-epidemiological investigation of FMD in goat. [ABSTRACT FROM AUTHOR]

Abstract Foot and mouth disease (FMD) is a highly contagious, endemic, and acute viral cattle ailment that causes major economic damage in Ethiopia. Although several serotypes of the FMD virus have been detected in Ethiopia, there is no documented information about the disease's current serostatus and serotypes circulating in the Wolaita zone. Thus, from March to December 2022, a cross-sectional study was conducted to evaluate FMDV seroprevalence, molecular detection, and serotype identification in three Wolaita Zone sites. A multistage sample procedure was used to choose three peasant associations from each study region, namely Wolaita Sodo, Offa district, and Boloso sore district. A systematic random sampling technique was employed to pick 384 cattle from the population for the seroprevalence research, and 10 epithelial tissue samples were purposefully taken from outbreak individuals for molecular detection of FMDV. The sera were examined using 3ABC FMD NSP Competition ELISA to find antibodies against FMDV non-structural proteins, whereas epithelial tissue samples were analyzed for molecular detection using real-time RT-PCR, and sandwich ELISA was used to determine the circulating serotypes. A multivariable logistic regression model was used to evaluate the associated risk variables. The total seroprevalence of FMD in cattle was 46.88% (95% CI 41.86–51.88), with Wolaita Sodo Town having the highest seroprevalence (63.28%). As a consequence, multivariable logistic regression analysis revealed that animal age, herd size, and interaction with wildlife were all substantially related to FMD seroprevalence (p

Foot and mouth disease (FMD) is a highly contagious, endemic, and acute viral cattle ailment that causes major economic damage in Ethiopia. Although several serotypes of the FMD virus have been detected in Ethiopia, there is no documented information about the disease's current serostatus and serotypes circulating in the Wolaita zone. Thus, from March to December 2022, a cross-sectional study was conducted to evaluate FMDV seroprevalence, molecular detection, and serotype identification in three Wolaita Zone sites. A multistage sample procedure was used to choose three peasant associations from each study region, namely Wolaita Sodo, Offa district, and Boloso sore district. A systematic random sampling technique was employed to pick 384 cattle from the population for the seroprevalence research, and 10 epithelial tissue samples were purposefully taken from outbreak individuals for molecular detection of FMDV. The sera were examined using 3ABC FMD NSP Competition ELISA to find antibodies against FMDV non-structural proteins, whereas epithelial tissue samples were analyzed for molecular detection using real-time RT-PCR, and sandwich ELISA was used to determine the circulating serotypes. A multivariable logistic regression model was used to evaluate the associated risk variables. The total seroprevalence of FMD in cattle was 46.88% (95% CI 41.86–51.88), with Wolaita Sodo Town having the highest seroprevalence (63.28%). As a consequence, multivariable logistic regression analysis revealed that animal age, herd size, and interaction with wildlife were all substantially related to FMD seroprevalence (p < 0.05). During molecular detection, only SAT-2 serotypes were found in 10 tissue samples. Thus, investigating FMD outbreaks and identifying serotypes and risk factors for seropositivity are critical steps in developing effective control and prevention strategies based on the kind of circulating serotype. Moreover, further research for animal species other than cattle was encouraged. [ABSTRACT FROM AUTHOR]

Shazali Mohammed Awel,1,2 Getachew Mulatu Dilba,3 Bruk Abraha,2 Demeke Zewde,4 Bayeta Senbata Wakjira,4 Abde Aliy4 1Jigjiga University, College of Veterinary Medicine, Jigjiga, Ethiopia; 2Haramaya University, College of Veterinary Medicine, Dire Dawa, Ethiopia; 3Ambo University, College of Agriculture and Veterinary Science, Department of Veterinary Laboratory Technology, Ambo, Oromia, Ethiopia; 4National Animal Health Diagnostic and Investigation Center, Sebeta, EthiopiaCorrespondence: Getachew Mulatu DilbaAmbo University, College of Agriculture and Veterinary Science, Department of Veterinary Laboratory Technology, P.O. Box:19, Ambo, Oromia, EthiopiaTel +251-912717217Email getachew.mulatu@ambou.edu.etBackground: Foot and mouth disease is a debilitating and highly contagious transboundary disease of cattle that can cause a huge economical loss globally. It is a notifiable disease in Ethiopia, and it is thought to be causing a decrease in cattle productivity and production.Methods: A cross-sectional study and outbreak investigation were performed to estimate seroprevalence, identify associated factors and serotypes of FMDV in dairy cattle around Addis Ababa. A multi-stage random sampling technique was employed for the selection of sampling units for the seroprevalence study. A total of 383 blood samples were collected using plain vacutainer tubes and the obtained sera were tested by 3ABC-Ab ELISA at the NAHDIC lab. Also, from outbreak cases, 20 epithelial tissue samples were collected purposively for the molecular detection of FMDV serotypes.Results: The overall seroprevalence of FMD in dairy cattle was 72.1% (95% CI=67.27– 76.50). The seroprevalence in dairy cattle of Ada Berga, Holeta, and Sululta districts was 97.2%, 71.4%, and 57.6%, respectively. Up on Chi-square analysis, age, body condition, and management system were significantly associated with FMD seroprevalence (p< 0.05). Besides, multivariable logistic regression analysis showed that district, age, body condition, and management were significantly associated with FMD seroprevalence (p< 0.05). The odds of being seropositive to FMD were 6.9 (95% CI=1.8– 24.9; p=0.005) and 2.3 (95% CI=1.2– 4.7; p=0.01) times higher in cattle found in Ada Berga and Holeta Woreda. From outbreak cases, 18 (90.0%) were identified positive for FMDV serotype O.Conclusion: The current study revealed higher seroprevalence was recorded in the study area and associated risk factors identified statically, serotype O of FMDV was identified from outbreak cases. Therefore, it is critical to design and implement feasible control and prevention mechanisms based on the type of circulating virus serotype.Keywords: central Ethiopia, dairy cattle, FMD virus, molecular detection, seroprevalence

FMDV can be shed with milk of infected animals and infect susceptible animals. The possibility of using real-time qRT-PCR for FMD virus detection in cattle milk was assessed. To prepare samples of FMDV infected milk the following strains were used: А No. 2177/ Amursky/2013, О No. 2123/South Ossetia/2011, Asia-1 No. 1987/Amursky/2005, С No. 564, SAT-1 No. 2033/Botswana, SAT-2/Saudi Arabia, SAT-3/Bech 1/65. For specifcity test swine vesicular disease O-72 strain, Vesicular Exanthema of Swine A-48 strain and vesicular stomatitis virus Indiana strain from FGBI “ARRIAH” collection were used. The obtained data showed that real time qRT-PCR can be successfully used for the virus detection in milk of infected cows as well as in epithelium and cell cultures. Analytical sensitivity of real-time qRT-PCR in milk samples is 1–10 TCD50/ml, the method specifcity is 100%. When identifying basic validation characteristics of the method it was proven that real-time qRT-PCR demonstrates precision and sensitivity and can detect FMDV in its genetic diversity. So, the detected data showed that the real-time qRT-PCR is a precious method of milk and dairy product control.

An indirect variant of ELISA used for detection of antibodies to nonstructural proteins of the FMD virus in porcine blood sera was developed. The results of the validation showed that the developed method is characterized by high sensitivity, specificity and reproducibility. When testing the blood serum panel obtained from experimentally infected animals, the method allowed to detect antibodies to FMD virus in 7 of 18 sera collected on day 6 post inoculation, in 13 of 19 sera – on day 7 post inoculation, in 16 of 19 sera – on day 8 post inoculation and in all 76 sera obtained on days 9–12 post inoculation. The diagnostic specificity of 3AB-ELISA was 100% when testing 100 knowingly negative blood sera from pigs imported to Russia from Norway. High specificity and sensitivity of the method, established during the development of the method, are confirmed in the course of routine diagnostic tests.

Introduction: Lack of cross protection between foot and mouth disease (FMD) virus (FMDV) serotypes as well as incomplete protection between some subtypes of FMDV affect the application of vaccine in the field. Further, the emergence of new variant FMD viruses periodically makes the existing vaccine inefficient. Consequently, periodical vaccine strain selection either by in vivo methods or in vitro methods become an essential requirement to enable utilization of appropriate and efficient vaccines. Areas covered: Here we describe the cross reactivity of the existing vaccines with the global pool of circulating viruses and the putative selected vaccine strains for targeting protection against the two major circulating serotype O and A FMD viruses for East Africa, the Middle East, South Asia and South East Asia. Expert commentary: Although in vivo cross protection studies are more appropriate methods for vaccine matching and selection than in vitro neutralization test or ELISA, in the face of an outbreak both in vivo and in vitro methods of vaccine matching are not easy, and time consuming. The FMDV capsid contains all the immunogenic epitopes, and therefore vaccine strain prediction models using both capsid sequence and serology data will likely replace existing tools in the future.

The paper presents the results of adaptation of FMDV Type O isolates obtained from the Animal and Plant Quarantine Agency to pig cell cultures and organisms as well as studies of their infectivity, antigenic activity as well as stability during passages in the PSGK continuous cell culture. Antigenic matching of FMDV Type O isolates, 2014-2015, obtained from the Animal and Plant Quarantine Agency of the Republic of Korea, with Russian and foreign FMDV Type O production strains was studied. Special attention was given to determination of the inoculation dose for virus cultivation in PSGK-30 for the purpose of subsequent preparation of antigenic preparations and FMD vaccines. The results of strain studies served a basis for their depositing into the FGBI “ARRIAH” strain collection.

The 3AB-ELISA test-system for detection of antibodies to FMD virus nonstructural proteins in blood sera from cattle and small ruminants was validated. It was discovered that the reaction repeatability and reproducibility exceeded 90%, diagnostic specificity constituted 99,8%, diagnostic sensitivity came up to 96,6%. The high specificity and sensitivity of the 3AB-ELISA test-system was confirmed by international proficiency testings as far as FMD diagnostics and by routine diagnostic and monitoring studies.

Introduction: Foot and Mouth Disease (FMD) is the most contagious disease in cloven-hoofed animals which causes a lot of economical losses. FMD virus belongs to Picornaviridae family and Aphthovirus genus. The aim of the study is evaluation of humoral and cellular immune responses triggered by a Gamma-irradiated FMD vaccine in the guinea-pig model. Materials and Methods: FMD virus type Asia-1 was multiplied on BHK21 cell line and irradiated by gamma ray in different doses. According to dose/survival curve, D10 value and optimum dose of virus inactivation were calculated 7.69 and 50 kGy, respectively. Antigenic characteristic of irradiated and un-irradiated virus samples were evaluated by complement fixation test (CF test) and safety test was done by four blind passages cell culture on IBRS2 cell line. The inactivated virus sample was formulated as Radio- vaccine and immune responses were evaluated in three groups of ginea-pigs; the first group Radio-vaccine, the second group conventional vaccine and the last one was negative control. Results: The results of neutralizing antibody titration for two vaccinated groups were significant (P

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Livestock are critical component for supporting the sustainable agriculture in the current global scenario. In the era of artificial intelligence and automation in field of livestock, sensors play an important role. Electrochemical sensor is the type of sensor which holds reliability and tremendous promise in raising the animal productivity in developing world. An early and accurate diagnosis of the animal pathogen and metabolic status are the cornerstone for better animal productivity. The available diagnostic techniques require tedious sample preparation, sophisticated instrument, dedicated laboratory, trained personnel and it is time consuming also. The electrochemical biosensor technology might be a smart solution because of its sensitivity, simplicity, low cost, possible miniaturization and potential ability for real-time analysis. In the veterinary disease diagnostics, various biosensors including electrochemical biosensors have been developed recently, based on disease specific biomarkers. The main focus of article is on reviewing the research in detection of animal infectious and metabolic diseases, hormonal analysis and sweat analysis with electrochemical biosensor. [ABSTRACT FROM AUTHOR]

Serotype identification occupies the central part of foot and mouth disease (FMD) diagnosis workflow and vaccination decision tree. In this study, a reverse transcription-multiplex PCR (RT-mPCR) strategy wherein three assays with unique combinations of serotype specific primers targeting the VP1 region was developed to differentiate FMD virus serotypes O, A and Asia 1 based on differential size of the PCR amplicons on agarose gel. Their diagnostic performance relative to the mPCR assay in use in India was evaluated on 169 clinical samples and 210 cell culture grown virus isolates. The relative diagnostic sensitivity was found to be 99.69%, 98.78% and 99.08% for primer combinations 1, 2 and 3, respectively. These assays proved their worth by detecting serotype in three FMD suspected specimens that went undiagnosed in the existing mPCR and also by identifying multiple serotypes in the same sample. Their detection limits varied from log 10 2 to log 10 4 viral RNA dilution and from 100 to 0.1 TCID 50 virus depending on the serotype. The validated novel mPCR assays show promise to be included in the routine diagnostic tool-box to augment the efficiency of diagnosis of FMD virus serotypes that display extreme genetic diversity and a tendency of transboundary dispersal. • Multiplex PCR (mPCR) to differentiate FMD virus serotypes O, A and Asia 1 developed. • Serotype specific primers designed at VP1 produce differentially sized PCR products. • Relative diagnostic sensitivity were 99.69%, 98.78%, 99.08% compared to mPCR in use. • The assays detected serotype in additional FMD suspected samples and mixed infection. • The validated novel mPCR could be a back-up diagnostic to enhance serotyping efficacy. [ABSTRACT FROM AUTHOR]

Foot and Mouth Disease (FMD) is the most economically important viral-induced livestock disease worldwide. From April to May of 2015, tongue epithelial tissue samples were collected from 36 cattle in six villages, which share the border with Iran. Samples were screened using RT-PCR to amplify a conserved region in the VP1 gene, and phylogenetic tree analysis was performed based on the VP1 nucleotide sequence results. Furthermore, the nucleotide sequence was converted to an amino acid sequence in order to detect similarities between the studied samples and those previously published in GenBank (NCBI). Epidemically, based on the amino acid residues, genetic similarity, and amino acid substitutions, the VP1 nucleotide sequences were determined to be close to a novel group, group VII, with 94% identity. The VP1 amino acid sequence analysis revealed a close relationship to the Asia/BAL/PAK/iso-2/2011 isolate (Accession no. JX435109), with 95.7% identity. Analysis of the studied samples revealed that the FMDV serotype Asia1 causing the outbreak in the Basne district belonged to group VII, which was introduced from the Balochistan province of Pakistan through illegal movement of animals from this region. [ABSTRACT FROM AUTHOR]

Introduction: Lack of cross protection between foot and mouth disease (FMD) virus (FMDV) serotypes as well as incomplete protection between some subtypes of FMDV affect the application of vaccine in the field. Further, the emergence of new variant FMD viruses periodically makes the existing vaccine inefficient. Consequently, periodical vaccine strain selection either by in vivo methods or in vitro methods become an essential requirement to enable utilization of appropriate and efficient vaccines. Areas covered: Here we describe the cross reactivity of the existing vaccines with the global pool of circulating viruses and the putative selected vaccine strains for targeting protection against the two major circulating serotype O and A FMD viruses for East Africa, the Middle East, South Asia and South East Asia. Expert commentary: Although in vivo cross protection studies are more appropriate methods for vaccine matching and selection than in vitro neutralization test or ELISA, in the face of an outbreak both in vivo and in vitro methods of vaccine matching are not easy, and time consuming. The FMDV capsid contains all the immunogenic epitopes, and therefore vaccine strain prediction models using both capsid sequence and serology data will likely replace existing tools in the future. [ABSTRACT FROM AUTHOR]

Inactivated purified whole virus vaccines are used for control of foot and mouth disease (FMD). ELISAs detecting antibodies to the nonstructural proteins (NSP), a marker of infection, are primarily used to differentiate FMD virus (FMDV) infected from vaccinated animals (DIVA). However, such DIVA assays have a limitation to their specificity since residual NSPs present in the relatively impure vaccines are suspected to induce an NSP-antibody response in the repeatedly vaccinated animals. Epitope-deleted negative marker vaccine strategy seems to have an advantage over the conventional vaccines in identifying the infected animals with accuracy. NSP 3AB contains an abundance of immunodominant B-cell epitopes of diagnostic importance. This study addresses the feasibility of producing 3AB-truncated FMDV mutant as a potential negative marker vaccine candidate. An infectious cDNA clone of FMDV serotype Asia 1 strain was used to engineer an array of deletion mutations in the established antigenic domain of 3AB. The maximum length of deletion tolerated by the virus was found to be restricted to amino acid residues 87–144 in the C-terminal half of 3A protein along with deletion of the first two copies of 3B peptide. The 3AB-truncated marker virus (Asia 1 IND 491/1997Δ3A 87-144 3B 1,2 +FLAG) demonstrated infectivity titres comparable to that of the parental virus in BHK-21 (log 10 7.42 TCID 50 /ml) and LFBK-α V β 6 (log 10 8.30 TCID 50 /ml) cell monolayer culture. The protein fragment corresponding to the viable deletion in the 3AB region was expressed in a prokaryotic system to standardize a companion assay (3A 87-153 3B 1,2 I-ELISA) for the negative marker virus which showed reasonably high diagnostic sensitivity (96.9%) and specificity (100% for naïve and 97.1% for uninfected vaccinated samples). The marker virus and its companion ELISA designed in this study provide a basis to devise a marker vaccine strategy for FMD control. [ABSTRACT FROM AUTHOR]

Introduction: Foot and Mouth Disease (FMD) is the most contagious disease in cloven-hoofed animals which causes a lot of economical losses. FMD virus belongs to Picornaviridae family and Aphthovirus genus. The aim of the study is evaluation of humoral and cellular immune responses triggered by a Gamma-irradiated FMD vaccine in the guinea-pig model. Materials and Methods: FMD virus type Asia-1 was multiplied on BHK21 cell line and irradiated by gamma ray in different doses. According to dose/survival curve, D10 value and optimum dose of virus inactivation were calculated 7.69 and 50 kGy, respectively. Antigenic characteristic of irradiated and un-irradiated virus samples were evaluated by complement fixation test (CF test) and safety test was done by four blind passages cell culture on IBRS2 cell line. The inactivated virus sample was formulated as Radio- vaccine and immune responses were evaluated in three groups of ginea-pigs; the first group Radio-vaccine, the second group conventional vaccine and the last one was negative control. Results: The results of neutralizing antibody titration for two vaccinated groups were significant (P<0.05), but between Radio-vaccine and conventional vaccine was no significant. The increase in splenocyte multiplication for two vaccinated groups by MTT test was significant (P<0.05). Discussion and conclusion: The Gamma irradiated inactivated FMD type Asia-1 vaccine is a good candidate for immunization of guinea-pig without the problems such as residue, virus escape and etc. And it can use for vaccination of cattle in the future. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease virus (FMDV) capsid precursor protein P1-2A is cleaved by viral-encoded 3C protease (3C pro ) to generate VP0, VP3, VP1 and 2A proteins. It was reported earlier that substitution of a single amino acid residue within the 2A peptide sequence (L2P) blocked the 3C pro mediated VP1/2A cleavage and produced ‘self-tagged’ FMDV particles containing uncleaved 2A-peptide. To determine whether the uncleaved 2A-peptide can function as a target structure to harbour and display exogenous epitope on FMDV particles, a full-length FMDV cDNA clone containing a HA-tag within the uncleaved 2A-peptide sequence was constructed. Subsequently, chimeric marker FMDV, displaying a HA-tag on the viral surface was rescued through reverse genetics approach. The 2A-HA epitope tag-inserted recombinant chimeric FMDV serotype O was genetically stable through up to ten serial passages in cell culture and exhibited growth properties similar to the parental virus. Furthermore the surface displayed HA-epitope tag was able to react with anti-HA antibodies as determined by various immuno-assays. The results from our study suggest that the uncleaved 2A-peptide of FMDV is suitable to present foreign antigenic epitopes on the surface of FMD virion. [ABSTRACT FROM AUTHOR]

• VP1 region nucleotide sequence for 26 Indian FMD virus serotype A strains determined. • Emergence of a novel lineage 'A/ASIA/G-18/2019′ in India and Bangladesh. • The node age for the lineage was predicted to be 2014 through tMRCA analysis. • Rate of evolution of the VP1 region estimated to be 6.747 × 10−3 substitutions/site/year. • AIND27/2011 could be more appropriate vaccine strain in the scenario than AIND40/2000. Foot and mouth disease (FMD) has engendered large scale socioeconomic crises on numerous occasions owing to its extreme contagiousness, transboundary nature, complicated epidemiology, negative impact on productivity, trade embargo, and need for intensive surveillance and expensive control measures. Emerging FMD virus variants have been predicted to have originated and spread from endemic Pool 2, native to South Asia, to other parts of the globe. In this study, 26 Indian serotype A isolates sampled between the year 2015 and 2022 were sequenced for the VP1 region. BLAST and maximum likelihood phylogeny suggest emergence of a novel genetic group within genotype 18, named here as 'A/ASIA/G-18/2019′ lineage, that is restricted so far only to India and its eastern neighbour, Bangladesh. The lineage subsequent to its first appearance in 2019 seems to have displaced all other prevalent strains, in support of the phenomenon of 'genotype/lineage turnover'. It has diversified into two distinct sub-clusters, reflecting a phase of active evolution. The rate of evolution of the VP1 region for the Indian serotype A dataset was estimated to be 6.747 × 10−3 substitutions/site/year. India is implementing a vaccination centric FMD control programme. The novel lineage showed good antigenic match with the proposed vaccine candidate A IND 27/2011 when tested in virus neutralization test, while the existing vaccine strain A IND 40/2000 showed homology with only 31% of the isolates. Therefore, in order to combat this challenge of antigenic divergence, A IND 27/2011 could be the preferred strain in the Indian vaccine formulations. [ABSTRACT FROM AUTHOR]

The present study was undertaken to see the excretion of FMD virus in milk during and after the subset of FMD outbreak. Fore-milk (50 ml) was sampled from 12 clinically infected and 3 asymptomatic cows in the morning. Analytical sensitivity of NAR methods was estimated using uninfected negative milk sample spiked with 105.7 TCID50/ml FMD serotype O virus (IND R2/1975) in 10 fold serial dilution. Detection limit of mPCR and RT- LAMP assay was 102.7 and 101.7 TCID50/ml, respectively. 15 individual and pooled cows’ milk samples infected with FMD virus were processed for virus isolation (VI) and detection till 37 days post clinical manifestation (dpm). Virus isolation from individual and pooled milk from infected cow was positive till 6 and 4 dpm, respectively. Individual milk and pooled milk samples were found positive by m-PCR till 37 and 14 dpm, respectively, but by RT-LAMP till 37 and 21 dpm, respectively. In case of asymptomatic cows, viral genome was detected 2–5 days before appearance of disease in other animals. Milk virus isolate had 100% nucleotide identity at VP1 coding region. mPCR and RT LAMP assays has potential to detect FMD virus in milk and help to prevent the spread of FMD virus from one place to another place.

Effect of physical factors (temperature, pH and UV light) on replicating ability of “O” type of Foot and Mouth Disease (FMD) virus on Baby Hamster Kidney (BHK) cell line was determined. The freshly grown FMD virus containing 106 units of tissue culture infective dose (TCID50) was divided into aliquots. Each of the 9 virus aliquots was exposed to 37, 57 or 77C for 15, 30 or 45 minutes, respectively. Each of the 5 virus aliquots was mixed with MEM-199 maintenance medium having pH 3, 5, 7, 9, or 11. Similarly, each of the 3 aliquots having 1 mm depth of the medium was exposed to ultraviolet light (252.7 nm wavelength: one foot distance) for 15, 30 or 45 minutes. Each of the virus aliquot exposed to either of the temperature, pH or ultraviolet light (UV) for either of the interaction time was inoculated to 8 wells of the 96-well cell culture plate containing complete monolayer of BHK cell line. One row of 8 wells served as virus control and other row of 8 wells served as control for monolayer of the BHK-21 cell line. The plates were incubated at 37°C for 48 hours. It was observed that temperature of 57 and 77C inactivated the virus within 15 minutes. The virus when admixed in the MEM-199 maintenance medium having pH 3, 5, 9 or 11, of the medium inactivated the virus while pH 7 did not show any detrimental effect on its survival. The ultraviolet light for 15, 30 or 45 minutes showed undetectable effect on survival of the virus as either of the virus aliquot exposed to the UV light for either of the interaction time showed cytopathogenic effects (CPE). It was concluded that the temperature of 57°C or higher for 15 minutes, acidic pH (below 5) or basic pH (more than 9) may inactivate the FMD virus.

Foot-and-mouth disease (FMD) is endemic to sub-Saharan Africa. To further understand its complex epidemiology, which involves multiple virus serotypes and host species, we characterized the viruses recovered from FMD outbreaks in Ethiopia during 1981–2007. We detected 5 of the 7 FMDV serotypes (O, A, C, Southern African Territories [SAT] 1, and SAT 2). Serotype O predominated, followed by serotype A; type C was not recognized after 1983. Phylogenetic analysis of virus protein 1 sequences indicated emergence of a new topotype within serotype O, East Africa 4. In 2007, serotype SAT 1 was detected in Ethiopia and formed a new distinct topotype (IX), and serotype SAT 2 reappeared after an apparent gap of 16 years. The diversity of viruses highlights the role of this region as a reservoir for FMD virus, and their continuing emergence in Ethiopia will greatly affect spread and consequent control strategy of the disease on this continent.

The present study was undertaken to see the excretion of FMD virus in milk during and after the subset of FMD outbreak. Fore-milk (50 ml) was sampled from 12 clinically infected and 3 asymptomatic cows in the morning. Analytical sensitivity of NAR methods was estimated using uninfected negative milk sample spiked with 105.7 TCID50/ml FMD serotype O virus (IND R2/1975) in 10 fold serial dilution. Detection limit of mPCR and RT-LAMP assay was 102.7 and 101.7 TCID50/ml, respectively. 15 individual and pooled cows' milk samples infected with FMD virus were processed for virus isolation (VI) and detection till 37 days post clinical manifestation (dpm). Virus isolation from individual and pooled milk from infected cow was positive till 6 and 4 dpm, respectively. Individual milk and pooled milk samples were found positive by m-PCR till 37 and 14 dpm, respectively, but by RT-LAMP till 37 and 21 dpm, respectively. In case of asymptomatic cows, viral genome was detected 2-5 days before appearance of disease in other animals. Milk virus isolate had 100% nucleotide identity at VP I coding region. mPCR and RT LAMP assays has potential to detect FMD virus in milk and help to prevent the spread of FMD virus from one place to another place. [ABSTRACT FROM AUTHOR]

Three decades-long (1977–2013) evolutionary trend of the capsid coding (P1) region of foot-and-mouth disease virus (FMDV) serotype A isolated in India was analysed. The exclusive presence of genotype 18 since 2001 and the dominance of the VP3 59 -deletion group of genotype 18 was evident in the recent years. Clade 18c was found to be currently the only active one among the three clades (18a, 18b and 18c) identified in the deletion group. The rate of evolution of the Indian isolates at the capsid region was found to be 4.96 × 10 − 3 substitutions/site/year. The timescale analysis predicted the most recent common ancestor to have existed during 1962 for Indian FMDV serotype A and around 1998 for the deletion group. The evolutionary pattern of serotype A in India appears to be homogeneous as no spatial or temporal structure was observed. Bayesian skyline plots indicate a sharp decline in the effective number of infections after 2008, which might be a result of mass vaccination or inherent loss of virus fitness. Analyses of variability at 38 known antigenically critical positions in a countrywide longitudinal data set suggested that the substitutions neither followed any specific trend nor remained fixed for a long period since frequent reversions and convergence was noticed. A maximum of 6 different amino acid residues was seen in the gene pool at any antigenically critical site over the decades, suggesting a limited combination of residues being responsible for the observed antigenic variation. Evidence of positive selection at some of the antigenically critical residues and the structurally proximal positions suggest a possible role of pre-existing immunity in the host population in driving evolution. The VP1 C-terminus neither revealed variability nor positive selection, suggesting the possibility that this stretch does not contribute to the antigenic variation and adaptation under immune selection. [ABSTRACT FROM AUTHOR]

A new immunologically distinct strain (A-Iran-05) of foot-and-mouth disease virus serotype A emerged in the Middle East in 2003 that replaced the previously circulating strains (A-Iran-96 and A-Iran-99) in the region. This resulted in introduction of a new vaccine of this strain (A/TUR/2006) in 2006. Though this vaccine strain has been predominantly used to control FMD in the region, recent viruses isolated in 2012 and 2013 have shown antigenic drift and a poor match with it. In this study, we report the antigenic matching results and capsid sequence data of currently circulating viruses belonging to the SIS-10 and SIS-12 sub-lineages of A-Iran-05 (isolated in 2012 and 2013), highlighting the inadequacy of the currently used serotype A vaccines. Implications of these results in the context of FMD control in the Middle East are discussed. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease virus (FMDV) particles lose infectivity due to their dissociation into pentamers at pH value below 6.5. After the uptake of FMDV by receptor-mediated endocytosis, the acid-dependent dissociation process is required for the release of FMDV genome inside endosomes. Nevertheless, dissociation of FMDV particles in mildly acidic conditions renders the inactivated FMD vaccine less effective. To improve the acid stability of inactivated FMD vaccine during the manufacturing process, a serotype A IND 40/2000 (in-use vaccine strain) mutant with increased resistance to acid inactivation was generated through reverse genetics approach. Based upon the earlier reports, the crucial amino acid residue, H142 of VP3 capsid protein was substituted separately to various amino acid residues Arg (R), Phe (F), Ala (A), and Asp (D) on the full-genome length cDNA clone. While the H142 → R or H142 → F or H142 → A substitutions resulted in non-infectious FMDV, H142 → D mutation on VP3 protein (H3142D) resulted in the generation of mutant virus with enhanced resistance to acid-induced inactivation. In addition, H3142D substitution did not alter the replication ability and antigenicity of mutant as compared to the parental virus. However, the virus competition experiments revealed that the H3142D substitution conferred a loss of fitness for the mutant virus. Results from this study demonstrate that the H3142D substitution is the molecular determinant of acid-resistant phenotype in FMDV serotype A. [ABSTRACT FROM AUTHOR]

For expression of FMDV empty capsids, high protease activity associated with 3C co-expressed with P1 polyprotein has been reported to adversely affect the yields of capsids. Limiting the levels of 3Cpro relative to P1-2A polypeptide is thus critical to enhance the yields. In this study, FMDV internal ribosome entry site (IRES) sequence which serves as an alternative to the CAP-dependent translation initiation mechanism, was used for controlled translation of 3C protease. Baculovirus expressing bicistronic cDNA cassette containing two open reading frames-FMDV capsid gene (P1-2A) and 3Cpro intervened by IRES was prepared. Analysis of the expression in insect cells infected with baculovirus showed increased accumulation of processed capsids. Recombinant capsids showed higher immunoreactivity similar to the whole virus antigen, when reacted with polyclonal antibodies against the purified whole virus 146S particles. Thus, inclusion of the IRES upstream of 3Cpro facilitated reduced expression of the protease in baculovirus expression system, without causing significant proteolysis, thereby contributing to improved yields of the processed capsid antigens. [ABSTRACT FROM AUTHOR]