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The present paper describes the investigation of foot-and-mouth disease (FMD) outbreak in a private pig farm at Kotty in Kollam district of Kerala during October 2013. During the clinical phase, severe vesicular lesions on snout and skin around the coronary bands were observed in pigs. A total of 48 serum samples and 12 clinical samples (ruptured snout epithelia) were collected. All serum samples were subjected to indirect 3AB nonstructural protein (NSP) ELISA and liquid phase blocking (LPB) ELISA. In 3AB NSP ELISA, all serum samples were found positive for NSP antibodies indicating infection. In LPB ELISA, 42 of 48 (87.5%) pigs were found to have protective log10 antibody titre of ≥1.8 against FMD virus serotypes O, A and Asia 1. All the clinical materials were found positive for serotype O in antigen detection ELISA as well as in multiplex reverse transcription-polymerase chain reaction (mRT-PCR). In VP1 region-based phylogenetic analysis, the serotype O isolates causing the outbreak were found to conglomerate within Ind2001 lineage. Pigs infected with FMD may pose rigorous threat to other susceptible domestic livestock as they exhale enormous quantity of virus. As a consequence, they should be included under prophylactic vaccination and surveillance programmes ongoing in the country. [ABSTRACT FROM AUTHOR]

Summary: Foot‐and‐mouth disease (FMD) is an important transboundary disease with substantial economic impacts. Although between‐herd transmission of the disease has been well studied, studies focusing on within‐herd transmission using farm‐level outbreak data are rare. The aim of this study was to estimate parameters associated with within‐herd transmission, host physiological factors and FMD virus (FMDV) persistence using data collected from an outbreak that occurred at a large, organized dairy farm in India. Of 1,836 regularly vaccinated, adult dairy cattle, 222 had clinical signs of FMD over a 39‐day period. Assuming homogenous mixing, a frequency‐dependent compartmental model of disease transmission was built. The transmission coefficient and basic reproductive number were estimated to be between 16.2–18.4 and 67–88, respectively. Non‐pregnant animals were more likely to manifest clinical signs of FMD as compared to pregnant cattle. Based on oropharyngeal fluid (probang) sampling and FMDV‐specific RT‐PCR, four of 36 longitudinally sampled animals (14%) were persistently infected carriers 10.5 months post‐outbreak. There was no statistical difference between subclinical and clinically infected animals in the duration of the carrier state. However, prevalence of NSP‐ELISA antibodies differed significantly between subclinical and clinically infected animals 12 months after the outbreak with 83% seroprevalence amongst clinically infected cattle compared to 69% of subclinical animals. This study further elucidates within‐herd FMD transmission dynamics during the acute‐phase and characterizes duration of FMDV persistence and seroprevalence of FMD under natural conditions in an endemic setting. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is a highly contagious and globally significant viral disease principally of cloven-hoofed livestock species. The present study describes the results of molecular epidemiologic investigation of FMD in pigs across various states of India between 2008 and 2014. During this period, a total of 37 clinical epithelial samples (vesicle/foot/snout epithelium) of FMD-suspected pigs were tested in a serotype differentiating antigen detection ELISA and samples found negative were further subjected to multiplex reverse transcription-polymerase chain reaction (mRT-PCR). A total of 29 (78.37%) samples were found positive for serotype O in antigen detection ELISA and 8 ELISA-negative samples were subsequently found positive for serotype O in mRT-PCR. The VP1 region-based phylogenetic analysis demonstrated the involvement of O/ME-SA/Ind2001 lineage in the outbreaks. The pig isolates clustered with the contemporary virus isolates collected from bovine indicating a close genetic relationship and therefore signifying inter-species transmission during the outbreaks. [ABSTRACT FROM AUTHOR]

The yak and mithun husbandry in India is confronted with several challenges including the prevalence of foot-and-mouth disease (FMD). The present study was initiated to investigate FMD outbreaks in semi-domesticated mithun and yak population in various parts of India. A total of 64 clinical samples (vesicle/tongue/foot epithelium/fluid) from mithun and 6 from yak were collected from suspected FMD outbreaks during 2008-2013. Supernatants of the homogenized clinical samples were tested in a serotype discriminating antigen detection ELISA and ELISA-negative samples were further subjected to multiplex reverse transcription-polymerase chain reaction (mRT-PCR). A total of 45 mithun samples and only 1 yak sample were found positive for serotype O in antigen detection ELISA. A total of 12 ELISA-negative samples from mithun and 4 from yak were later on found positive for serotype O in mRT-PCR. The phylogenetic analysis based on VP1 genome indicated the involvement of both O/ME-SA/PanAsia and O/ME-SA/Ind2001 lineages of serotype O in those outbreaks. These viruses were genetically similar to those contemporary virus isolates responsible for FMD in domestic livestock indicating a situation of virus sharing among different species of domestic and semi-domestic animals. Thus, mithuns and yaks should be synchronously considered and targeted along with cattle for the effective control of the disease in the country. [ABSTRACT FROM AUTHOR]

A systematic vaccination programme is ongoing in India to control the three prevailing serotypes (A, O, Asia1) of foot-and-mouth disease ( FMD) virus. Under the programme, more than 120 million bovine (term bovine applicable to both cattle and buffalo in this study) population of 221 of the 666 districts in the country are being bi-annually vaccinated with trivalent vaccine since 2010. Although clinical disease has reduced in these districts because of the systematic vaccinations, an abrupt increase in the number of FMD cases was recorded in 2013. Hence, a longitudinal field study was conducted in the year 2014 to estimate the serological herd immunity level in bovines, the impact of systematic vaccinations and field efficacy of the vaccines used. Serum samples ( n = 115 963) collected from 295 districts of the 18 states of the country were analysed to estimate antibody titres against structural proteins of the three serotypes. The efficacy of the vaccine was demonstrated in the control group (group-D) where animals of the group were identified by ear tags for the purpose of repeated sampling after vaccination. Progressive building of the herd immunity in the field after systematic vaccination was demonstrated. The mean antibody titre against the serotypes O, A and Asia1 was estimated as log10 1.93 (95% CI 1.92-1.93), 2.02 (2.02-2.02) and 2.02 (2.02-2.02), respectively, in the states covered under the control programme. However, in other states herd immunity was significantly low [mean titre log10 1.68 (95% CI 1.67-1.69), 1.77 (1.76-1.78) and 1.85 (1.84-1.86) against the three serotypes]. Inverse relationship between the herd immunity and FMD incidences was observed the states following different vaccination practices. The study helped in demarcation of FMD risk zones in the country with low herd immunity. Estimation of herd immunity kinetics in the field helped in refining the vaccination schedule under the control programme. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the impact of Foot-and-mouth Disease ( FMD) outbreak in cattle and buffaloes on farming community in Kolar district, Karnataka state, India. Primary data were collected using pre-tested schedule from 178 sample farms using multistage random cluster sample technique. The results revealed that 78% of surveyed villages were affected with FMD. The FMD incidence risk was high across the herd sizes, whereas the mortality risk was high in small herds. In indigenous cattle, the highest loss due to FMD was distress sale (208 USD) followed by other losses, whereas, in Crossbred cattle, the highest loss was mortality loss (515 USD) followed by distress sale (490 USD), milk yield loss (327 USD), treatment cost (38 USD) and extra labour engagement expenses for nursing of FMD-affected bovines (30 USD). In local and upgraded buffaloes, the mean total loss per affected animal was 440 USD and 513 USD, respectively. A very high variability in the loss per animal was observed across the type of losses in the Crossbred cattle, and it may be due to differences in age of the FMD-infected animal, value of the animal, milking stage, lactation levels, herd sizes and labour engagement levels, etc. In local and upgraded buffaloes, the mean total loss per animal was 639 USD and 1008 USD, respectively. The sensitivity analysis for 5% change in price revealed that the mean total loss per animal was positively correlated with price. Further, the social impact elicitation revealed that majority of the livestock owners perceived FMD had caused permanent asset loss, which in turn increased psychological stress of the family. The estimated losses and social impact due to FMD signify the importance of the intervention to control the disease and thus socio-economic gain to the farmer and society at large. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease viruses are often restricted to specific geographical regions and spread to new areas may lead to significant epidemics. Phylogenetic analysis of sequences of the VP1 genome region of recent outbreak viruses from Libya and Saudi Arabia has revealed a lineage, O-Ind-2001, normally found in the Indian subcontinent. This paper describes the characterization of field viruses collected from these cases and provides information about a new real-time RT- PCR assay that can be used to detect viruses from this lineage and discriminate them from other endemic FMD viruses that are co-circulating in North Africa and western Eurasia. [ABSTRACT FROM AUTHOR]

A total of 41 clinical samples (vesicle/tongue/foot/nasal epithelium) from Indian gaur, deer, spotted deer, nilgai, chowsinga, bison, black buck, elephant, sambar deer were collected in 50% phosphate buffered saline/glycerol medium (pH-7.5) during suspected FMD outbreaks. Supernatants of homogenized clinical samples were used in a serotype differentiating antigen detection ELISA and samples found negative were further subjected to multiplex PCR (mPCR). A total of 3/11 (27.2%) samples from Indian gaur, 2/7 (28.5%) chital deer, 5/5 (100%) nilgai, 2/2 (100%) black buck were found positive for serotype O in antigen detection ELISA. A total of 3 ELISA-negative samples from spotted deer, 2 from bison and 2 from sambar deer were found positive for serotype O in mPCR. The VP1 region-based phylogenetic analysis indicated the involvement of both O/ME-SA/Ind2001 and PanAsia lineage of serotype O in the outbreaks. The wildlife species infected with FMD may pose further threat to the surrounding domestic livestock. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is endemic in India and causes severe economic loss. Status of FMD in the country for five fiscal years is presented. Outbreaks were more in number in 2007-2008 than 2010-2011. Three serotypes of FMD virus (O, A and Asia1) are prevalent. Serotype O was responsible for 80% of the confirmed outbreaks/cases, whereas Asia1 and A caused 12% and 8%, respectively. Geographical region-wise assessment indicated varying prevalence rate in different regions viz; 43% in Eastern region, 31.5% in Southern region, 11.6% in North-eastern region, 5% Central region, 4.4% Western region and 4% in Northern region. Highest number of outbreaks/cases was recorded in the month of September and lowest in June. Emergence and re-emergence of different genotypes/lineages within the serotypes were evident in real-time investigation carried out from time to time. Continues antigenic divergence in serotype A resulted in change in the vaccine strain in 2009. As on date, all genetic diversity within the serotypes is well tolerated by the vaccine strains. Unrestricted animal movements in the country play a major role in the spread of FMD. [ABSTRACT FROM AUTHOR]

Small ruminants (sheep and goats) are susceptible to foot-and-mouth disease (FMD), while studies with due emphasis on their role in the disease epidemiology have been meagre. The present study summarizes the results of clinico-molecular investigation of FMD in sheep and goats across several states of India during 2008–2014, where a total of 51 clinical epithelial tissue samples (vesicle/tongue/gum/foot epithelium) from sheep and 78 from goats were found positive for FMD virus (FMDV) serotype O in serotyping ELISA and multiplex reverse transcription-PCR. The VP1 region-based phylogenetic analysis demonstrated the involvement of O/ME-SA/Ind2001 lineage of serotype O virus in the outbreaks. The field viruses recovered from both small and large ruminant population during the same time period showed a close genetic relationship suggesting frequent inter-species transmission of virus. Since the disease often remains clinically camouflaged in small ruminants, the animals silently infected with FMD may pose potential threats to the in-contact livestock. Regular vaccination combined with surveillance and monitoring of protective antibody status in these species is therefore crucial to the effective control of FMD in the country. [ABSTRACT FROM AUTHOR]

Polymorphism of bovine leukocyte antigen (BoLA) DRB3 gene is being intensively investigated for potential association with economically important diseases of cattle. Accordingly, we investigated the association of DRB3 Exon 2 polymorphism as evidenced by the variation in the binding pockets with variability in immune response to inactivated trivalent (O, A and Asia1) foot and mouth disease virus (FMDV) vaccine in a closed population of crossbred cattle. Antibody titer of ⩾1.8 was set as the cut off value to distinguish the protected (P1.8) and unprotected (⩾1.8) animals. Eleven different alleles of over 3% frequency were detected in the population. We found that DRB3 alleles 8 0201, 8 0801 and 8 1501 always ranked high for protective immune response whereas alleles 8 0701, 8 1103 and 8 1101 consistently ranked low for unprotected immune response for all the three serotypes. Rank correlation of DRB3 alleles among the three serotypes was positive, high in magnitude and statistically significant (P < 0.05). Logistic regression analysis revealed that odds of protection from the vaccine were highest for all the three serotypes if allele 8 1501 was present and strengthened the results of allele ranking. Predicted amino acid substitution in the peptide binding pockets revealed that all the important sites had high Wu-Kabat index. Similarly, specific residues in pockets were crucial for immune response to FMD vaccine. There were specific substitutions in un-protected alleles such as absence of acidic amino acids substituted by basic amino acid at β71, presence of non-polar cysteine or basic histidine at b30 and presence of polar tyrosine at β37. From the observations, we hypothesize that the substitutions lead to unique conformational changes in the protein products of the studied alleles that would associate with the protective or unprotective antibody response to FMDV vaccine. The knowledge has potential implications in future selection programs if integrated with the complete BoLA haplotype details and production traits of the herd. [ABSTRACT FROM AUTHOR]

Complete 1D gene sequences of 13 Indian foot-and-mouth disease virus (FMDV) type C field isolates and a vaccine strain (C-Bombay/64) were determined. All the field isolates showed a greater genetic homogeneity (95–100%) among themselves and were 19.7–21.2% divergent from the vaccine strain. In the phylogenetic analysis, the Indian field isolates formed a separate lineage (lineage VII) different from the previously identified six lineages (lineage I–VI) in type C FMDV [J. Virol. 66 (1992) 3557]. The vaccine strain was grouped with European lineage (lineage II). Comparison of the deduced amino acid sequences of antigenic sites A and C of field isolates showed no significant variation from the vaccine strain. One-way serological relationship determined in ELISA showed antigenic closeness of the field isolates with C-Bombay/64. [Copyright &y& Elsevier]

Abstract: In India, systematic genotype replacement has been observed for serotype A foot-and-mouth disease virus. After a decade of co-circulation of genotypes VI and VII, genotype VII emerged as the single dominant genotype since 2001. To derive possible explanations for such epochal evolution dynamics, in vitro intergenotype growth competition experiments involving both co- and superinfection regimes were conducted. Coinfection of BHK-21 cells demonstrated abrupt loss in the genotype VI viral load with commensurate increase in the load of genotype VII as measured by the genotype differentiating ELISA, RT-PCR and real-time RT-PCR. The superinfection dynamics was shaped by temporal spacing of infection, where the invading genotype VII took more number of passages than coinfection to eventually overtake the resident genotype VI. It was speculated that such superior replicative fitness of genotype VII could have been a possible factor for the ultimate dominance of genotype VII in nature. [Copyright &y& Elsevier]