Contagious Animal Diseases Research Articles

Web-GIS and livestock trace tools for epidemiological surveillance, control and management

Web-GIS and livestock trace tools for epidemiological surveillance, control and management

Outbreak investigation: how to prevent laboratory contamination during high-throughput testing.

This is particularly important for outbreaks of highly contagious animal diseases. Efficient and correct testing as well as the reduction of technical breakdowns should be addressed by a laboratory contingency plan specially designed for the use of polymerase chain reactions (PCRs), i.e. PCR or reverse transcription PCR ([RT]-PCR) or the high-throughput quantitative real-time form of these tests([RT]-qPCR). Problems with contamination during outbreak investigations can negatively impact reliable diagnostics, and ultimately the eradication of the disease in the field. Therefore, well-defined standard procedures for preventing contamination are highly recommended, particularly in emergencies when a steep increase in the number of samples necessitates the use of additional, less-experienced laboratory support staff. In the context of an outbreak, the possible implementation of preclinical testing is an important point of discussion. Very sensitive methods, which are prone to contamination, are used for this type of testing, increasing the risk of false-positive results. Potential approaches to minimising contamination include standard protocols adapted for high-throughput analyses, different procedures for samples with an expected high or low viral load, and the prioritisation and treatment of samples with respect to epidemiological aspects (e.g. epidemic vs endemic situations). Although there may be pressure to perform outbreak investigations as soon as possible, the authors do not recommend preclinical testing in every case due to the severe consequences of false-positive results. Contingency plans should be discussed with the responsible authorities and communicated to relevant personnel before an outbreak occurs. The specific aim of this paper is the detailed description of solutions to prevent the laboratory contamination of samples and to avoid the generation of false-positive results.

Immune Modulatory Potential of Anti-idiotype Antibodies as a Surrogate of Foot-and-Mouth Disease Virus Antigen.

The immunoprophylactic potential of anti-idiotype (anti-id) foot-and-mouth disease (FMD) antigen (Ag) was evaluated in the calves. The idiotype antibodies (Ab1) were produced in experimental goats by injecting inactivated FMD virus. The Fab (fragment antigen binding) of Ab1 was injected into the layer birds to raise anti-id antibodies (Ab2). The Ab2 was purified from egg yolks. The Fab component of Ab2 was emulsified in Montanide (1:1) and used as a surrogate of FMD virus. The immune response to Montanide adjuvanted monovalent and trivalent anti-id FMD virus antigen was determined in mice. The comparative immune potentiation potentials of Montanide adjuvanted trivalent anti-id FMD virus antigen and trivalent FMD vaccine were determined in mice and calves. Montanide adjuvanted monovalent anti-id FMD virus antigens produced mean Ab titers of 78.80%, 81.30%, and 81.20% for serotypes A, Asia 1, and O, respectively, at 45 days postimmunization (p.i.) in mice. Montanide adjuvanted trivalent anti-id FMD Ag in mice produced the highest Ab titer, 81.60%, at day 45 compared to the 77.50% titer measured for Montanide adjuvanted FMD vaccine at day 45 p.i. A slow decrease of 1% to 2% was recorded for the Ab titer of Montanide adjuvanted trivalent anti-id FMD virus antigen in mice at day 60. In calves, the titer corresponding to the immune response seen with Montanide adjuvanted trivalent anti-id FMD virus antigen (80%) was persistent whereas the titer of Montanide adjuvanted FMD vaccine decreased to 74% at day 60 p.i. Anti-id FMD virus antigen induced a strong and persistent immunogenic response in terms of Ab titer compared to the inactivated virus vaccine. Anti-id FMD virus antigen may serve as a surrogate of FMD virus vaccine.IMPORTANCE Foot-and-mouth disease (FMD) is a contagious viral disease of animals. Multiple serotypes and antigenic variation in the viral genome are probably the factors that reduce control of the disease. Currently, the vaccines employed against FMD use killed virus. The inactivation or killing of the virus makes it less immunogenic and reduces its immunoprophylactic potential. To cope with this situation, the present study was designed, anti-idiotype FMD virus antigen was prepared, and the immunogenic potential of the antigen was compared to that of commercial killed-virus vaccines. The overall results showed that a persistent and strong immune response occurred with anti-idiotype FMD virus antigen. Thus, anti-idiotype FMD virus antigen may serve as a potential surrogate of FMD virus vaccines.

Visual and equipment-free reverse transcription recombinase polymerase amplification method for rapid detection of foot-and-mouth disease virus

BackgroundFoot-and-mouth disease (FMD), which is caused by foot-and-mouth disease virus (FMDV), is a highly contagious tansboundary disease of cloven-hoofed animals and causes devastating economic damages. Accurate, rapid and simple detection of FMDV is critical to containing an FMD outbreak. Recombinase polymerase amplification (RPA) has been explored for detection of diverse pathogens because of its accuracy, rapidness and simplicity. A visible and equipment-free reverse-transcription recombinase polymerase amplification assay combined with lateral flow strip (LFS RT-RPA) was developed to detect the FMDV using primers and LF probe specific for the 3D gene.ResultsThe FMDV LFS RT-RPA assay was performed successfully in a closed fist using body heat for 15 min, and the products were visible on the LFS inspected by the naked eyes within 2 min. The assay could detect FMDV serotypes O, A and Asia1, and there were no cross-reactions with vesicular stomatitis virus (VSV), encephalomyocarditis virus (EMCV), classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus 2 (PCV2) and pseudorabies virus (PRV). The analytical sensitivity was 1.0 × 102 copies in vitro transcribed FMDV RNA per reaction, which was the same as a real-time RT-PCR. For the 55 samples, FMDV RNA positive rate was 45.5% (25/55) by LFS RT-RPA and 52.7% (29/55) by real-time RT-PCR. For the LFS RT-RPA assay, the positive and negative predicative values were 100% and 80%, respectively.ConclusionsThe performance of the LFS RT-RPA assay was comparable to real-time RT-PCR, while the LFS RT-RPA assay was much faster and easier to be performed. The developed FMDV LFS RT-RPA assay provides an attractive and promising tool for rapid and reliable detection of FMDV in under-equipped laboratory and at point-of-need facility, which is of great significance in FMD control in low resource settings.

Detection of foot-and-mouth disease virus in milk samples by real-time reverse transcription polymerase chain reaction: Optimisation and evaluation of a high-throughput screening method with potential for disease surveillance

This study aimed to evaluate the utility of milk as a non-invasive sample type for the surveillance of foot-and-mouth disease (FMD), a highly contagious viral disease of cloven-hooved animals. Four milking Jersey cows were infected via direct-contact with two non-milking Jersey cows that had been previously inoculated with FMD virus (FMDV: isolate O/UKG/34/2001). Milk and blood were collected throughout the course of infection to compare two high-throughput real-time reverse transcription polymerase chain reaction (rRT-PCR) protocols with different RT-PCR chemistries. Using both methods, FMDV was detected in milk by rRT-PCR one to two days before the presentation of characteristic foot lesions, similar to detection by virus isolation. Furthermore, rRT-PCR detection from milk was extended, up to 28 days post contact (dpc), compared to detection by virus isolation (up to 14 dpc). Additionally, the detection of FMDV in milk by rRT-PCR was possible for 18 days longer than detection by the same method in serum samples. FMDV was also detected with both rRT-PCR methods in milk samples collected during the UK 2007 outbreak. Dilution studies were undertaken using milk from the field and experimentally-infected animals, where for one sample it was possible to detect FMDV at 10−7. Based on the peak CT values detected in this study, these findings indicate that it could be possible to identify one acutely-infected milking cow in a typical-sized dairy herd (100–1000 individuals) using milk from bulk tanks or milk tankers. These results motivate further studies using milk in FMD-endemic countries for FMD surveillance.

Rapid detection of foot-and-mouth disease virus using reverse transcription recombinase polymerase amplification combined with a lateral flow dipstick

Foot-and-mouth disease caused by foot-and-mouth disease virus (FMDV) is one of the most highly contagious diseases of domestic animals, and leads to enormous economic loss. Currently there are two main prevention and control strategies for the disease: eradication of the infected animals in FMDV free countries, and vaccination of the susceptible animals in countries with endemic FMDV infection. Early discovery and diagnosis of the source of infection is therefore integral to the containment of FMDV. In this study, a two-step reverse transcription recombinase polymerase amplification assay combined with lateral flow detection (RPA-LFD) was developed to detect FMDV. With incubation at 38 °C, a region of the 2B gene on the FMDV genome was successfully amplified within 20 min using specific primers and a probe. The amplified RPA product can be visualized on a lateral flow dipstick. The RPA-LFD assay was highly sensitive, detecting down to 10 copies of plasmid DNA. There was no cross-reactivity with other pathogens causing vesicular lesions. In addition, 143 clinical samples were used to compare RPA-LFD with real-time PCR, with 98.6% concordance between the assays. Therefore, the developed RPA-LFD assay provides a rapid, simple, highly promising approach to be used as point-of-care diagnostics in the field.

Development of a droplet digital RT-PCR for the quantification of foot-and-mouth virus RNA

Foot-and-mouth-disease (FMD) is a highly contagious disease of domestic animals which can result in substantial economic losses, caused by the FMD virus (FMDV). The aim of this study was to develop and standardize a novel reverse transcriptase droplet digital PCR (RT-ddPCR) assay for the quantification of FMDV RNA. This assay was based upon an OIE-recognized real-time RT-PCR that detects the 3D-encoding region of FMDV. The limit of detection at 101.4 TCID50/mL and 26.5 copies was determined using FMDV-A24-Cruzeiro-virus and a plasmid containing the 3D-FMDV sequences, respectively. FMDV O, A and C serotypes and 11 species of non-FMDV were used to confirm the sensitivity and specificity of the assay. The RT-ddPCR was standardized using 60 bovine samples (representing negative and positive samples of epithelium and/or oesophageal-pharyngeal [OP] fluid) from animals suspected of vesicular diseases and previously tested by RT-qPCR. The RT-ddPCR showed robustness, sensitivity, specificity and accuracy, with similar results to the RT-qPCR. Moreover, the new RT-ddPCR diagnostic tool allowed the absolute quantification of FMDV RNA from epithelium and OP-fluid samples, as well as having the advantages of direct quantification by endpoint, eliminating the need for a calibration standard curve required in quantitative real-time RT-PCR.

Dealing with highly contagious animal diseases under neoliberal governmentality in Mongolia

In Mongolia, since the collapse of communism in 1990, the government has implemented a centralized system of veterinary care inherited from the Communist period that suffers from inadequate infrastructures. Highly contagious diseases chronically re-emerge, undermining the country, its economy, and the way of life of its affected inhabitants. Since the early 2000s, the government has put in place a new surveillance system that relies on nomadic herders as ‘sentinels’. These herders combine popular perceptions and treatments of animal diseases with some veterinary practices and international standards of surveillance and control. But they sometimes refuse to cooperate with private veterinarians or report symptoms, out of a lack of trust in the system of financial compensation for culled herds, compensation that – if sufficient – would enable them to maintain a substantial herd and a nomadic way of life. This article argues that Mongolia constitutes a sort of laboratory to study a neoliberal governmentality toward animal diseases, where the capacities to manage diseases that spread across species (wild/domestic, animal/human) and political borders (regional, national, continental) are delegated to local actors (nomadic herders) who resort to compromises in order to address tensions with political leaders regarding how to control highly contagious animal diseases.

The protective capacity of high payload FMDV A22 IRQ vaccine in sheep against direct-contact challenge with a heterologous, contemporary FMDV A strain from South East Asia.

Foot-and-mouth disease (FMD) is an acute, highly contagious viral disease of domestic and wild cloven-hoofed animals, caused by FMD virus (FMDV). An FMD outbreak can cause major production losses and have significant implications for trade. Vaccination can assist in controlling the disease, and emergency vaccination using high antigen payload vaccines (>6 PD50/dose) is considered an important control approach in the event of an outbreak. In recent years there has been a divergence of serotype A viruses in South East Asia (SEA) into several distinct genetic and antigenic clusters. Numerous variants were found to poorly match serotype A vaccines commonly included in international antigen banks. This study examined the ability of single vaccination with high-potency monovalent A22 IRQ vaccine to protect sheep following challenge with the A/VIT/15/2012 strain, just four days following vaccination. The vaccine proved effective at limiting clinical disease but did not prevent infection.

Immunogenicity evaluation of MS2 phage-mediated chimeric nanoparticle displaying an immunodominant B cell epitope of foot-and-mouth disease virus.

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals that has caused tremendous economic losses worldwide. In this study, we designed a chimeric nanoparticles (CNPs) vaccine that displays the predominant epitope of the serotype O foot-and-mouth disease virus (FMDV) VP1 131-160 on the surface of MS2 phage. The recombinant protein was expressed in Escherichia Coli and can self-assemble into CNPs with diameter at 25–30 nm in vitro. A tandem repeat peptide epitopes (TRE) was prepared as control. Mice were immunized with CNPs, TRE and commercialized synthetic peptide vaccines (PepVac), respectively. The ELISA results showed that CNPs stimulated a little higher specific antibody levels to PepVac, but was significantly higher than the TRE groups. Moreover, the results from specific IFN-γ responses and lymphocyte proliferation test indicated that CNP immunized mice exhibited significantly enhanced cellular immune response compared to TRE. These results suggested that the CNPs constructed in current study could be a potential alternative vaccine in future FMDV control.

Full Genome Sequencing Reveals New Southern African Territories Genotypes Bringing Us Closer to Understanding True Variability of Foot-and-Mouth Disease Virus in Africa.

Foot-and-mouth disease virus (FMDV) causes a highly contagious disease of cloven-hooved animals that poses a constant burden on farmers in endemic regions and threatens the livestock industries in disease-free countries. Despite the increased number of publicly available whole genome sequences, FMDV data are biased by the opportunistic nature of sampling. Since whole genomic sequences of Southern African Territories (SAT) are particularly underrepresented, this study sequenced 34 isolates from eastern and southern Africa. Phylogenetic analyses revealed two novel genotypes (that comprised 8/34 of these SAT isolates) which contained unusual 5′ untranslated and non-structural encoding regions. While recombination has occurred between these sequences, phylogeny violation analyses indicated that the high degree of sequence diversity for the novel SAT genotypes has not solely arisen from recombination events. Based on estimates of the timing of ancestral divergence, these data are interpreted as being representative of un-sampled FMDV isolates that have been subjected to geographical isolation within Africa by the effects of the Great African Rinderpest Pandemic (1887–1897), which caused a mass die-out of FMDV-susceptible hosts. These findings demonstrate that further sequencing of African FMDV isolates is likely to reveal more unusual genotypes and will allow for better understanding of natural variability and evolution of FMDV.

Factors Associated with a Low Veterinary Regulatory Compliance in Uganda, Their Impact and Quality Management Approaches to Improve Performance

Organized veterinary services in Uganda were established in year 1908 and successfully controlled animal diseases nationally through a centralized chain of veterinary command. Such services were of public good, mandatory by regulations and also referred to as the “veterinary regulatory services”. However, from 1993; policy reforms were introduced coincidentally at the same time with a national animal health passive surveillance system. Despite reforms, continued losses in livestock were observed necessitating a longitudinal survey based on the above surveillance system. Study findings were to serve as an indicator of performance for the reforms as regards animal disease control. Overall aim of the study was to: Confirm the assumed increase of disease after reforms; identify predisposing factors; gauge their impact and make recommendations to improve service delivery. Results confirmed that: Local government veterinary personnel reduced by 90.61% after the first year of decentralization; national animal health report submissions reduced from average of 81% to only 47.06% with a correlation or association of negative (-) 27.3% albeit at p-value > 0.05. Further, correlation at p-value < 0.05 confirmed that: Contagious and other major animal disease cases increased by 46.1%; roundworm infestation in pigs increased by 69.4%; field animal vaccine availability decreased by (-) 64.3% with time and a positive correlation of 65.3% was confirmed between human deaths and the number of bites by suspected rabid animals. Regression confirmed that with other factors held constant; on average: 69.5% of all Foot and Mouth Disease outbreaks in other areas of the country originated or depended on the same disease found in the cattle corridor while 42.7% human deaths from rabies was attributed to bites from suspected rabid animals. Conclusion was that: Increased animal disease prevalence was primarily attributed to the reform policies but confounded by other veterinary institution internal and external/shock factors. This requires further policy reforms and a review of the national animal health passive surveillance system by all stakeholders to be done through and implemented by an efficient quality management system which is: staff-management-client focused.

Wpływ barier sanitarnych w handlu produktami zwierzęcymi na gospodarkę narodową Wielkiej Brytanii

Głównym celem artykułu jest przedstawienie źródeł sankcji stosowanych w przeszłości na import produktów zwierzęcych z terytorium Wielkiej Brytanii, a także ich wielowymiarowych skutków (ekonomicznych, politycznych, społecznych, zdrowotnych, ekologicznych, regulacyjnych) dla tego państwa. Dokonano zestawienia chronologii zdarzeń związanych z wybuchem epidemii BSE i FMD oraz ukazano szeroki zakres ich konsekwencji. Z przeglądu literatury, analizy oficjalnych dokumentów i danych z bazy Eurostat wynika, że wprowadzenie zakazu handlu wewnętrznego i zagranicznego zwierzętami oraz produktami zwierzęcymi z powodu występowania zakaźnych chorób zwierzęcych odbiło się bardzo niekorzystnie nie tylko na sektorze rolnym, ale pośrednio również na całej brytyjskiej gospodarce oraz jakości życia obywateli. Całkowite straty wywołane BSE i FMD były znaczne, mogły nawet sięgnąć odpowiednio 5,5 mld i 4 mld GBP.

Spatial pattern of foot-and-mouth disease in animals in China, 2010-2016.

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. An outbreak of FMD can produce devastating economic losses for a considerable length of time. In order to investigate the distribution characteristics of FMD in China, data from 2010 to 2016 were collected, including information on 65 outbreaks of FMD (25 by serotype A and 40 by serotype O), and 5,937 diseased animals (1,691 serotype A and 4,284 serotype O cases). Spatial autocorrelation, including global spatial autocorrelation and local spatial autocorrelation, as well as directional distribution analysis, were performed. Global spatial autocorrelation analysis of FMD cases from 2010 to 2016 did not show clustering (P > 0.05). In 2013 and 2014, the FMD serotype A hotspots areas were Tibet (Z = 3.3236, P < 0.001 in 2013; Z = 3.2001, P < 0.001 in 2014) and Xinjiang provinces (Z = 4.2113, P < 0.001 in 2013; Z = 3.9888, P < 0.001 in 2014). The FMD serotype O hotspots areas were: Xinjiang (Z = 2.5832, P = 0.0098) province in 2010; Tibet (Z = 3.8814, P < 0.001) and Xinjiang (Z = 4.9128, P < 0.001) provinces in 2011; and Tibet (Z = 3.0838, P = 0.0020), Xinjiang (Z = 3.8705, P < 0.001) and Qinghai (Z = 2.8875, P = 0.0039) provinces in 2013. The distribution of FMD cases from 2010 to 2016 showed a significant directional trend (northwest-southeast). In conclusion, our findings revealed the spatial patterns of FMD cases, which may provide beneficial information for the prevention and control of FMD.

Novel expression of immunogenic foot-and-mouth disease virus-like particles in Nicotiana benthamiana

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals and is endemic in Africa, parts of South America and southern Asia. The causative agent, FMD virus (FMDV) is a member of the genus Aphthovirus, family Picornaviridae. Vaccines currently used against FMDV are chemically inactivated virus strains which are produced under high-level biocontainment facilities, thus raising their cost. The development of recombinant FMDV vaccines has focused predominantly on FMDV virus-like particle (VLP) subunit vaccines for which promising results have been achieved. These VLPs are attractive candidates because they avoid the use of live virus in production facilities, but conserve the complete repertoire of conformational epitopes of the virus. Recombinant FMDV VLPs are formed by the expression and assembly of the three structural proteins VP0, VP1 and VP3. This can be attained by co-expression of the three individual structural capsid proteins or by co-expression of the viral capsid precursor P1-2A together with the viral protease 3C. The latter proteolytically cleaves P1-2A into the respective structural proteins. These VLPS are produced in mammalian or insect cell culture systems, which are expensive and can be easily contaminated. Plants, such as Nicotiana benthamiana, potentially provide a more cost-effective and very highly scalable platform for recombinant protein and VLP production. In this study, P1-2A was transiently expressed in N. benthamiana alone, without the 3C protease. Surprisingly, there was efficient processing of the P1-2A polyprotein into its component structural proteins, and subsequent assembly into VLPs. The yield was ∼0.030μg per gram of fresh leaf material. Partially purified VLPs were preliminarily tested for immunogenicity in mice and shown to stimulate the production of FMDV-specific antibodies. This study, has important implications for simplifying the production and expression of potential vaccine candidates against FMDV in plants, in the absence of 3C expression.

Вплив інокуляції та морфорегулятора на особливості росту рослин сої в умовах Лісостепу

The purpose. To study possible role of the fixed and temporary parasites as mechanical and transmissive transmitting agents of causal organisms of contagious and invasion diseases of animals and auk, to develop up-to-date domestic means against them. Methods. Immunologic (RIF), ecological-and-entomological, laboratory. Results. Role of ectoparasites as transmitting agents of causal organisms of contagions of animals and auk is specified. In view of urgency of the problem series of domestic means against such ectoparasites is developed and offered to practical veterinary medicine. Conclusions. Basic characteristics are brought of the following preparations: Akarinotsid — against red chicken mite; Diptotsid — bait against flies; Ektotsid-plus — against Ixodidae mites on pastures.

Rapid and simple detection of foot-and-mouth disease virus: Evaluation of a cartridge-based molecular detection system for use in basic laboratories.

SummaryHighly contagious transboundary animal diseases such as foot‐and‐mouth disease (FMD) are major threats to the productivity of farm animals. To limit the impact of outbreaks and to take efficient steps towards a timely control and eradication of the disease, rapid and reliable diagnostic systems are of utmost importance. Confirmatory diagnostic assays are typically performed by experienced operators in specialized laboratories, and access to this capability is often limited in the developing countries with the highest disease burden. Advances in molecular technologies allow implementation of modern and reliable techniques for quick and simple pathogen detection either in basic laboratories or even at the pen‐side. Here, we report on a study to evaluate a fully automated cartridge‐based real‐time RT‐PCR diagnostic system (Enigma MiniLab®) for the detection of FMD virus (FMDV). The modular system integrates both nucleic acid extraction and downstream real‐time RT‐PCR (rRT‐PCR). The analytical sensitivity of this assay was determined using serially diluted culture grown FMDV, and the performance of the assay was evaluated using a selected range of FMDV positive and negative clinical samples of bovine, porcine and ovine origin. The robustness of the assay was evaluated in an international inter‐laboratory proficiency test and by deployment into an African laboratory. It was demonstrated that the system is easy to use and can detect FMDV with high sensitivity and specificity, roughly on par with standard laboratory methods. This cartridge‐based automated real‐time RT‐PCR system for the detection of FMDV represents a reliable and easy to use diagnostic tool for the early and rapid disease detection of acutely infected animals even in remote areas. This type of system could be easily deployed for routine surveillance within endemic regions such as Africa or could alternatively be used in the developed world.

CSFV Infection Up-Regulates the Unfolded Protein Response to Promote Its Replication.

Classical swine fever (CSF) is an OIE-listed, highly contagious animal disease caused by classical swine fever virus (CSFV). The endoplasmic reticulum (ER) is an organelle in which the replication of many RNA viruses takes place. During viral infection, a series of events elicited in cells can destroy the ER homeostasis that cause ER stress and induce an unfolded protein response (UPR). In this study, we demonstrate that ER stress was induced during CSFV infection as several UPR-responsive elements such as XBP1(s), GRP78 and CHOP were up-regulated. Specifically, CSFV transiently activated IRE1 pathway at the initial stage of infection but rapidly switched off, likely due to the reduction in cytoplasm Ca2+ after viral incubation. Additionally, our data show that the ER stress induced by CSFV can promote CSFV production, which the IRE1 pathway play an important role in it. Evidence of ER stress in vivo was also confirmed by the marked elevation of GRP78 in CSFV-infected pig PBMC and tissues. Collectively, these data indicate that the ER stress was induced upon CSFV infection and that the activation of the IRE1 pathway benefits CSFV replication.

Clinicopathological Investigation of Foot and Mouth Disease and Serotype Identification of the Viruses in Cattle of Bangladesh

Foot and Mouth Disease (FMD) is a highly contagious viral disease of farm animals. This study was aimed to identify symptoms, characteristics pathology and viral serotypes involved in infected cattle of Bangladesh. Dominant signs observed were salivation, vesicular eruption, lameness and maggot infestations in 66%, 80%, 36% and 14% cattle respectively. Out of 202 infected cattle investigated, 35 were below six months of age. A total of 18 young calves and 8 adult cattle were died due to FMD. Seven young calves and two adult cattle were examined at necropsy, 'Tiger heart disease' was commonly seen both in the young and adult cattle. The 'currant jelly clot' was common in the atrium, ventricles, aorta and veins of the heart of adult cattle. Congested and consolidated lungs, atrophied spleen, and fibrosed udder were grossly seen in the infected and dead cattle. Microscopically, hyalinization of cardiac muscle in young calf and degeneration, necrosis and multifocal lymphocytic infiltration in heart muscle were suggestive for infectivity due to FMD viruses. There were bronchiolitis, pulmonary emphysema, interstitial pneumonia and thickening of interlobular septa of lungs. Cattle survived from the acute infection developed respiratory distress in 15% cattle. Out of 202 samples tested in reverse transcriptase polymerase chain reaction (RT-PCR), 187 samples found to generate positive amplicons. Single infectivity due to FMD viral Serotypes O, A and Asia 1 were seen in 115 (62%), 26 (14%) and 34 (18%) cases, respectively. Seven cattle were co-infected with FMD viral Serotypes O and Asia 1 and four with FMD viral Serotypes O and A. FMD viral serotype O was dominating in cattle all over the country and was related to death of infected young and adult cattle. Cardiac myonecrosis and respiratory failure were the dominant lesions may be related to death of infected animals.

Evaluation of genetic and non-genetic factors on foot and mouth disease (FMD) virus vaccine-elicited immune response in Hardhenu (Bos taurus x Bos indicus) cattle.

Foot and mouth disease (FMD) is the most contagious disease of mammals and a major threat to animal husbandry sector. In India, vaccination with the inactivated trivalent (O, A and Asia1) vaccine is one proven way for protecting the livestock from FMD. However, many outbreaks have been reported in different parts of the country. Therefore, present study was aimed at elucidating the effects of genetic and non-genetic factors on FMD viral vaccine-elicited immune response in Hardhenu cattle. The effect of season of vaccination was not consistent. The effect of status of animal was significant for all the pre and post AB titres except for pre AB titre of serotype O and post AB titre of Asia1.The estimates of heritability for response to vaccination were low to high ranging from 0.11 to 0.45. The highest heritability estimate was obtained for serotype O and the lowest for Asia1. The heritability estimates for pre and post AB titres ranged from 0.15 to 0.33. All the pre and post AB titres and responses to vaccination had genetic correlations ranged from high negative to high positive among them. Results of this study highlight the variation in vaccine response which needs to be further exploited on large-scale animal data for better immunization and protection against highly contagious viral vesicular disease of cloven-hoofed animals.