Foot‐and‐Mouth Disease Seroprevalence in Cattle in Eritrea

Information about seroprevalence of foot‐and‐mouth disease (FMD) and virus serotypes in Eritrea is unavailable, but is very important as it may guide the choice of intervention measures including vaccination to be implemented. We carried out a cross‐sectional study from February to June 2011 in Eritrea with a two‐stage cluster design, sampling cattle in 155 villages with the objective of determining the seroprevalence of FMD in four administrative regions of the country. We analysed cattle sera (n = 2429) for FMD virus antibodies using the non‐structural ELISA (NS ELISA) and virus neutralization test (VNT). The overall seroprevalence was 26% and 30% for the NS ELISA and VNT, respectively. FMD virus serotypes O (14%) and A (11%) were the most prevalent. Gash Barka showed the highest (39%) seroprevalence both in NS ELISA and VNT compared to the other three administrative regions. Strategic FMD virus vaccination with type O and A (matching circulating strains) in combination of zoo‐sanitary measures would be the best control option for Eritrea which could be started in areas where the disease is less endemic.     

Outbreak investigations and molecular characterization of foot‐and‐mouth disease viruses circulating in south‐west Niger

In Niger, the epidemiological situation regarding foot‐and‐mouth disease is unclear as many outbreaks are unreported. This study aimed (i) to identify Foot‐and‐mouth disease virus (FMDV ) strains currently circulating in cattle herds, and (ii) to identify risk factors associated with Foot‐and‐mouth disease (FMD )‐seropositive animals in clinical outbreaks. Epithelial tissues (n  = 25) and sera (n  = 227) were collected from cattle in eight districts of the south‐western part of Niger. Testing of clinical material revealed the presence of FMDV serotype O that was characterized within the O/WEST AFRICA topotype. The antigenic relationship between one of the FMDV isolates from Niger (O/NGR /4/2015) and three reference vaccine strains was determined by the two‐dimensional virus neutralization test (2dmVNT ), revealing a close antigenic match between the field isolate from Niger and three FMDV serotype O vaccine strains. Serological analyses using a non‐structural protein (NSP ) test provided evidence for previous FMDV infection in 70% (158/227) of the sera tested. Multivariate logistic regression analysis revealed that only the herd composition (presence of both cattle and small ruminants) was significantly associated with FMDV seropositivity as defined by NSP ‐positive results (p ‐value = .006). Of these positive sera, subsequent testing by liquid‐phase blocking ELISA (LPBE ) showed that 86% (136/158) were positive for one (or more) of four FMDV serotypes (A, O, Southern African Territories (SAT ) 1 and SAT 2). This study provides epidemiological information about FMD in the south‐western part of Niger and highlights the complex transboundary nature of FMD in Africa. These findings may help to develop effective control and preventive strategies for FMD in Niger as well, as other countries in West Africa.     

Heterogeneity in the Antibody Response to Foot‐and‐Mouth Disease Primo‐vaccinated Calves

Foot‐and‐mouth disease (FMD) vaccines are routinely used as effective control tools in large regions worldwide and to limit outbreaks during epidemics. Vaccine‐induced protection in cattle has been largely correlated with the FMD virus (FMDV)‐specific antibodies. Genetic control of cattle immune adaptive responses has been demonstrated only for peptide antigens derived from FMDV structural proteins. Here, we quantify the heterogeneity in the antibody response of cattle primo‐vaccinated against FMD and study its association with the genetic background in Holstein and Jersey sires. A total of 377 FMDV‐seronegative calves (122 and 255 calves from 16 and 15 Holstein and Jersey sires, respectively) were included in the study. Samples were taken the day prior to primo‐vaccination and 45 days post‐vaccination (dpv). Animals received commercial tetravalent FMD single emulsion oil vaccines formulated with inactivated FMDV. Total FMDV‐specific antibody responses were studied against three viral strains included in the vaccine, and antibody titres were determined by liquid‐phase blocking ELISA. Three linear hierarchical mixed regression models, one for each strain, were formulated to assess the heterogeneity in the immune responses to vaccination. The dependent variables were the antibody titres induced against each FMDV strain at 45 dpv, whereas sire's ‘breed’ was included as a fixed effect, ‘sire’ was included as a random effect, and ‘farm’ was considered as a hierarchical factor to account for lack of independence of within herd measurements. A significant association was found between anti‐FMDV antibody responses and sire's breed, with lower immune responses found in the Jersey sires’ offspring compared with those from Holstein sires. No significant intrabreed variation was detected. In addition, farm management practices were similar in this study, and results of the serological assays were shown to be repeatable. It therefore seems plausible that differences in the immune response may be expected in the event of a mass vaccination campaigns.     

Emergence of two novel sublineages Ind2001BD1 and Ind2001BD2 of foot‐and‐mouth disease virus serotype O in Bangladesh

Foot‐and‐mouth disease (FMD ) is endemic in Bangladesh, and the implementation of a control programme for this disease is at an early stage, according to the FAO ‐ and OIE ‐proposed Progressive Control Pathway for FMD (PCP ‐FMD ) Roadmap. To develop an effective control programme, understanding of foot‐and‐mouth disease virus (FMDV ) serotypes, even subtypes within the serotypes is essential. The present investigation aims at viral VP 1 coding region sequence‐based analysis of FMD samples collected from 34 FMD outbreaks during 2012–2016 in Bangladesh. Foot‐and‐mouth disease virus (FMDV ) serotype O was responsible for 82% of the outbreaks in Bangladesh, showing its dominance over serotype A and Asia1. The VP 1 phylogeny revealed the emergence of two novel sublineages of serotype O, named as Ind2001BD 1 and Ind2001BD 2, within the Ind2001 lineage along with the circulation of Ind2001d sublineage in Bangladesh, which was further supported by the multidimensional scaling with distinct clusters for each sublineage. The novel sublineages had evident genetic variability with other established sublineages within Ind2001 lineage. Ten mutations with three or more amino acid variations were detected within B‐C loop, G‐H loop and C‐terminal region of the VP 1 protein of FMDV serotype O viruses isolated exclusively from Bangladesh. Furthermore, two amino acid substitutions at positions 197 and 198 within the VP 1 C‐terminal region are unique to the novel sublineages. The existence of widespread genetic variations among circulatory FMDV serotype O viruses makes the FMD control programme complex in Bangladesh. Adequate epidemiological data, disease reporting, animal movement control, appropriate vaccination and above all stringent policies of the government are necessary to combat FMD in Bangladesh.     

Challenges for Serology‐Based Characterization of Foot‐and‐Mouth Disease Outbreaks in Endemic Areas; Identification of Two Separate Lineages of Serotype O FMDV in Uganda in 2011

Control of foot‐and‐mouth disease (FMD) in Uganda by ring vaccination largely depends on costly trivalent vaccines, and use of monovalent vaccines could improve the cost effectiveness. This, however, requires application of highly specific diagnostic tests. This study investigated outbreaks of FMD in seven Ugandan districts, during 2011, using the PrioCHECK^® FMDV NS ELISA, solid‐phase blocking ELISAs (SPBEs) and virus neutralization tests (VNTs), together with virological analyses for characterization of the responsible viruses. Two hundred and eighteen (218) cattle and 23 goat sera as well as 82 oropharyngeal fluid/epithelial tissue samples were collected. Some 50% of the cattle and 17% of the goat sera were positive by the PrioCHECK^® FMDV NS ELISA, while SPBEs identified titres ≥80 for antibodies against serotype O FMD virus (FMDV) in 51% of the anti‐NSP positive cattle sera. However, 35% of the anti‐NSP positive cattle sera had SPBE titres ≥80 against multiple serotypes, primarily against serotypes O, SAT 1 and SAT 3. Comparison of SPBEs and VNTs for the detection of antibodies against serotypes O, SAT 1 and SAT 3 in 72 NSP positive cattle sera showed comparable results against serotype O (P = 0.181), while VNTs detected significantly fewer samples positive for antibodies against SAT 1 and SAT 3 than the SPBEs (P < 0.001). Detection of antibodies against serotype O was consistent with the isolation of serotype O FMDVs from 13 samples. Four of these viruses were sequenced and belonged to two distinct lineages within the East Africa‐2 (EA‐2) topotype, each differing from the currently used vaccine strain (EA‐1 topotype). The relationships of these lineages to other serotype O viruses in the Eastern Africa region are discussed. To enhance the control of FMD in Uganda, there is need to improve the specificity of the SAT‐SPBEs, perform vaccine matching and implement improved regional FMD control.     

Quantitative characteristics of the foot‐and‐mouth disease carrier state under natural conditions in India

The goal of this study was to characterize the properties and duration of the foot‐and‐mouth disease (FMD ) carrier state and associated serological responses subsequent to vaccination and naturally occurring infection at two farms in northern India. Despite previous vaccination of cattle in these herds, clinical signs of FMD occurred in October 2013 within a subset of animals at the farms containing juvenile‐yearling heifers and steers (Farm A) and adult dairy cattle (Farm B). Subsequent to the outbreak, FMD virus (FMDV ) asymptomatic carriers were identified in both herds by seroreactivity to FMDV non‐structural proteins and detection of FMDV genomic RNA in oropharyngeal fluid. Carriers’ seroreactivity and FMDV genome detection status were subsequently monitored monthly for 23 months. The mean extinction time of the carrier state was 13.1 ± 0.2 months, with extinction having occurred significantly faster amongst adult dairy cattle at Farm B compared to younger animals at Farm A. The rate of decrease in the proportion of carrier animals was calculated to be 0.07 per month. Seroprevalence against FMDV non‐structural proteins decreased over the course of the study period, but was found to increase transiently following repeated vaccinations. These data provide novel insights into viral and host factors associated with the FMDV carrier state under natural conditions. The findings reported herein may be relevant to field veterinarians and governmental regulatory entities engaged in FMD response and control measures.     

Control of Bovine Brucellosis from Persistently Infected Holdings Using RB51 Vaccination with Test‐and‐Slaughter: A Comparative Case Report from a High Incidence Area in Portugal

Bovine brucellosis due to Brucella abortus infection causes significant reproductive and production losses in cattle and is a major zoonosis. Eradication of this disease has proved difficult to achieve in Portugal where it still occurs in some regions despite an ongoing national eradication programme. In 2004, the Alentejo region, a major cattle producing area, reported one of the highest levels of bovine brucellosis in the country, especially in one divisional area. In that area, bovine brucellosis was particularly problematic in a holding of ten herds, the largest extensive cattle unit in the country, which remained infected despite an extensive test‐and‐slaughter programme and depopulation of five herds. A 5‐year programme of RB51 vaccination with biannual test‐and‐slaughter was thus implemented in 2004. The apparent animal seroprevalence decreased from 19% (646/3,400) to 3% (88/2930) on the third herd‐level test and remained below 0.8% (27/3324) after the fourth test. After the tenth test, the holding had a prevalence of 0.1% (2/2332) and only one herd remained positive with a within‐herd prevalence of 1.1% (2/177). The results were compared to all other herds (n = 10) in the divisional area that were also persistently infected but were subject only to test‐and‐slaughter before being depopulated. In these herds, the strategy of test‐and‐slaughter did not reduce the prevalence, which remained significantly higher than the vaccinated group (median = 0.48% and 8.5% in vaccinated versus non‐vaccinated herds; Wilcoxon rank sum test; P < 0.01). The success of this pilot programme in continental Portugal provided a valuable case study to the official veterinary services by illustrating the value of RB51 vaccination with parallel testing and improved biosecurity as a comprehensive and sustainable strategy for bovine brucellosis control in persistently infected herds.     

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

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.     

Status of Foot‐and‐mouth Disease in India

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.     

A Review of OIE Country Status Recovery Using Vaccinate‐to‐Live Versus Vaccinate‐to‐Die Foot‐and‐Mouth Disease Response Policies II: Waiting Periods After Emergency Vaccination in FMD Free Countries

For countries with OIE status, FMD free country where vaccination is not practised, vaccinate‐to‐live policies have a significant economic disincentive as the trade restriction waiting period is double that of vaccinate‐to‐die policies. The disposal of healthy vaccinated animals strictly for the purpose of regaining markets with debatable scientific justification is a global concern. The feasibility of aligning the waiting periods to facilitate vaccinate‐to‐live is explored. The first article of this two‐part review (Barnett et al., 2015) explored the qualities of higher potency Foot‐and‐Mouth Disease (FMD) vaccines, performance of differentiating infected from vaccinated animals (DIVA) diagnostic assays particularly in vaccinates and carriers, as well as aspects of current limitations of post‐outbreak surveillance. Here, the history behind the OIE waiting periods for FMD free status is reviewed as well as whether the risk of vaccinated animals and their subsequent products differ appreciably at 3 versus 6 months. It is concluded that alignment is feasible for vaccinate‐to‐live using higher potency FMD vaccines within the current OIE waiting period framework of 3 and 6 months blocks of time. These waiting periods reflect precedence, historical practicalities and considered expert opinion rather than a specific scientific rationale. The future lies in updated epidemiological and diagnostic technology to establish an acceptable level of statistical certainty for surveillance or target probability of freedom of FMDV (infection or circulation) not time restricted waiting periods. The OIE Terrestrial Code limits trade from a FMD free country where vaccination is not practiced to animal products and live non‐vaccinated animals. The risk of FMDV in products derived from higher potency vaccinated animals is appreciably less than for countries with infected FMD status or even from a FMD free country where vaccination is practised for which the Code has Articles with guidelines for safe trade with time restrictions of 3 months or less. All these presume that key requirements in the implementation of emergency vaccination including appropriate vaccine match, vaccine application, susceptible population coverage, etc. are addressed.     

Benefit‐Cost Analysis of Foot and Mouth Disease Control in Large Ruminants in Cambodia

Foot and mouth disease (FMD) is endemic in Cambodia and throughout the Greater Mekong Subregion and causes significant losses to rural smallholders owning the majority of the national large ruminant population. However, due to underreporting, paucity of knowledge of FMD impacts, limited veterinary capacity and deficits of data available for analysis, the quantifiable benefits of a national FMD control programme are unknown. To address this deficit, existing literature and research data from the ‘Best practice health and husbandry of cattle, Cambodia' project conducted between 2007 and 2012, were used to develop a three‐phase analysis framework to: assess the impacts of the recent widespread FMD epizootic in Cambodia in 2010, conduct a value chain analysis of the large ruminant market and estimate the costs and benefits for a national large ruminant biannual FMD vaccination programme. A trader survey conducted in 2010–2011 provided cattle and buffalo value chain information and was matched to village herd structure data to calculate a total large ruminant farm‐gate value of USD 1.271 billion in 2010. Monte Carlo simulation modelling that implemented a 5‐year biannual vaccination programme at a cost of USD 6.3 an animal per year identified a benefit‐cost ratio of 1.40 (95% CI 0.96–2.20) when accounting for recent prices of cattle and buffalo in Cambodia and based on an expected annual incidence of 0.2 (assuming one major epizootic in the 5‐year vaccination programme). Given that the majority of the large ruminants are owned by rural smallholders, and mostly the poor are involved in agricultural employment, the successful implementation of an FMD control programme in Cambodia would be expected to avoid estimated losses of USD 135 million; equivalent to 10.6% of the 2010 farm‐gate value and contributing to important reductions in rural poverty and food insecurity.     

Serotype Specificity of Antibodies against Foot‐and‐Mouth Disease Virus in Cattle in Selected Districts in Uganda

Uganda had an unusually large number of foot‐and‐mouth disease (FMD) outbreaks in 2006, and all clinical reports were in cattle. A serological investigation was carried out to confirm circulating antibodies against foot‐and‐mouth disease virus (FMDV) by ELISA for antibodies against non‐structural proteins and structural proteins. Three hundred and forty‐nine cattle sera were collected from seven districts in Uganda, and 65% of these were found positive for antibodies against the non‐structural proteins of FMDV. A subset of these samples were analysed for serotype specificity of the identified antibodies. High prevalences of antibodies against non‐structural proteins and structural proteins of FMDV serotype O were demonstrated in herds with typical visible clinical signs of FMD, while prevalences were low in herds without clinical signs of FMD. Antibody titres were higher against serotype O than against serotypes SAT 1, SAT 2 and SAT 3 in the sera investigated for serotype‐specific antibodies. Only FMDV serotype O virus was isolated from one probang sample. This study shows that the majority of the FMD outbreaks in 2006 in the region studied were caused by FMDV serotype O; however, there was also evidence of antibodies to both SAT 1 and SAT 3 in one outbreak in a herd inside Queen Elizabeth national park area.     

Direct detection and characterization of foot‐and‐mouth disease virus in East Africa using a field‐ready real‐time PCR platform

Effective control and monitoring of foot‐and‐mouth disease (FMD ) relies upon rapid and accurate disease confirmation. Currently, clinical samples are usually tested in reference laboratories using standardized assays recommended by The World Organisation for Animal Health (OIE ). However, the requirements for prompt and serotype‐specific diagnosis during FMD outbreaks, and the need to establish robust laboratory testing capacity in FMD ‐endemic countries have motivated the development of simple diagnostic platforms to support local decision‐making. Using a portable thermocycler, the T‐COR ™ 8, this study describes the laboratory and field evaluation of a commercially available, lyophilized pan‐serotype‐specific real‐time RT ‐PCR (rRT ‐PCR ) assay and a newly available FMD virus (FMDV) typing assay (East Africa‐specific for serotypes: O, A, Southern African Territories [SAT ] 1 and 2). Analytical sensitivity, diagnostic sensitivity and specificity of the pan‐serotype‐specific lyophilized assay were comparable to that of an OIE ‐recommended laboratory‐based rRT ‐PCR (determined using a panel of 57 FMDV ‐positive samples and six non‐FMDV vesicular disease samples for differential diagnosis). The FMDV ‐typing assay was able to correctly identify the serotype of 33/36 FMDV ‐positive samples (no cross‐reactivity between serotypes was evident). Furthermore, the assays were able to accurately detect and type FMDV RNA in multiple sample types, including epithelial tissue suspensions, serum, oesophageal–pharyngeal (OP ) fluid and oral swabs, both with and without the use of nucleic acid extraction. When deployed in laboratory and field settings in Tanzania, Kenya and Ethiopia, both assays reliably detected and serotyped FMDV RNA in samples (n  = 144) collected from pre‐clinical, clinical and clinically recovered cattle. These data support the use of field‐ready rRT ‐PCR platforms in endemic settings for simple, highly sensitive and rapid detection and/or characterization of FMDV.     

Epidemiological Patterns of Foot‐and‐Mouth Disease Worldwide

Foot‐and‐Mouth Disease (FMD) is a clinical syndrome in animals due to FMD virus that exists in seven serotypes, whereby recovery from one sero‐type does not confer immunity against the other six. So when considering intervention strategies in endemic settings, it is important to take account of the characteristics of the different serotypes in different ecological systems. FMD serotypes are not uniformly distributed in the regions of the world where the disease still occurs. For example, the cumulative incidence of FMD serotypes show that six of the seven serotypes of FMD (O, A, C, SAT‐1, SAT‐2, SAT‐3) have occurred in Africa, while Asia contends with four sero‐types (O, A, C, Asia‐1), and South America with only three (O, A, C). Periodically there have been incursions of Types SAT‐1 and SAT‐2 from Africa into the Middle East. This paper describes the global dynamics for the seven sero‐types and attempts to define FMD epidemiological clusters in the different regions of the world. These have been described on a continent by continent basis. The review has reaffirmed that the movement of infected animals is the most important factor in the spread of FMD within the endemically infected regions. It also shows that the eco‐system based approach for defining the epidemiological patterns of FMD in endemic, which was originally described in South America, can apply readily to other parts of the world. It is proposed that any coordinated regional or global strategy for FMD control should be based on a sound epidemiological assessment of the incidence and distribution of FMD, identifying risk sources as either primary or secondary endemic eco‐systems.     

Emergence and Distribution of Foot‐and‐Mouth Disease Virus Serotype A and O in Bangladesh

Foot‐and‐mouth disease (FMD) is endemic in Bangladesh and is predominantly due to FMDV serotype O. In 2012, FMD outbreaks were identified in five different districts of Bangladesh. Of 56 symptomatic cattle epithelial tissue samples, diagnostic PCR assay based on 5′‐URT detected 38 FMDV infections. Viral genotyping targeting VP1‐encoding region confirmed emergence of two distinct serotypes, A and O with an abundance of serotype A in Chittagong and Gazipur districts and serotype O in Pabna and Faridpur. Only single lineage of both A and O was retrieved from samples of five different regions. Sequencing and phylogenetic analysis of VP1 sequences revealed that serotype O sequences were closely related to the Ind 2001 sublineage of Middle East–South Asia (ME‐SA) topotype that was previously circulating in Bangladesh, and serotype A sequences belonging to the genotype VII that was dominant in India during the last decade. The results suggest that extensive cross‐border animal movement from neighbouring countries is the most likely source of FMDV serotypes in Bangladesh.     

The Epidemiological Characteristics of the 2007 Foot‐and‐Mouth Disease Epidemic in Sarpang and Zhemgang Districts of Bhutan

This study was undertaken to compare the epidemiological characteristics of the 2007 foot‐and‐mouth disease outbreak in two districts of Sarpang and Zhemgang in Bhutan. Zhemgang district recorded a significantly higher cumulative incidence in all species (26.9%) as well as for cattle (29.3%) compared to Sarpang (6.5% and 7.4%, respectively). The case fatality for cattle in Zhemgang (14.1%) was significantly higher than in Sarpang (3.3%). A total of 404 cattle and 73 pigs died of FMD in Zhemgang, whereas only 21 cattle died in Sarpang. Although all four species were affected in Sarpang, no sheep or goats were affected in Zhemgang. Spatiotemporal analyses showed the existence of four significant clusters, a primary one in Sarpang and three secondary clusters in Zhemgang. The virus belonged to the PanAsia strain of the Middle‐East South‐Asia topotype (O serotype), and the strain was closely related to the PanAsia strain that circulated in Bhutan during the 2003/2004 outbreaks. The severity of FMD infection in Zhemgang district could be attributed to low vaccination coverage (36.5% in 2006 when compared to 87.6% in Sarpang), inadequate biosecurity, poor nursing care of the sick animals and delayed reporting to the livestock centre. This study highlights the ability of the PanAsia strain of the O serotype to cause unprecedented morbidity and mortality, especially in a naïve population. The study also highlights the benefits of maintaining good herd immunity in the susceptible population, through adequate vaccination coverage, to minimize the severity of infection and limit the spread of disease from infected to non‐infected herds.     

Serological Evidence Indicates that Foot‐and‐Mouth Disease Virus Serotype O,C and SAT1 are most Dominant in Eritrea

Foot‐and‐mouth disease (FMD) is endemic in Eritrea and in most parts of Africa. To be able to control FMD using vaccination, information on the occurrence of various foot‐and‐mouth disease serotypes in Eritrea is needed. In this cross‐sectional study, 212 sera samples were collected from FMD infected and recovered animals in Eritrea. These samples were tested for the presence of antibodies against FMD non‐structural proteins (NSP) and neutralizing antibodies against six of the seven (all but SAT 3) serotypes of FMD virus (FMDV). Of these, 67.0% tested positive to non‐structural protein antibodies in the FMD NS ELISA. By virus neutralization, FMDV serotype O antibodies were shown to be the most dominant (approximately 50%). Virus neutralization test results indicate that infection with serotype C and SAT 1 might have occurred, although there are no reports of isolation of these two serotypes. Because the samples were not randomly selected, further random serological surveillance in all age group animals is necessary both to estimate the prevalence of FMD in the country and to confirm the serological results with serotype C and SAT 1.     

A Survey on the Frequency of Foot‐and‐Mouth Disease Virus Carriers in Cattle in North–East of Iran by RT‐PCR: Implications for Revising Disease Control Strategy

Foot‐and‐mouth disease (FMD) is endemic in Iran. It is essential to timely evaluate the current disease control programme in Iran. Here, we report the frequency of FMD virus (FMDV) carrier state in cattle slaughtered in Mashhad abattoir, Mashhad, Khorasan Razavi, north–east of Iran, which contains long common borders with Afghanistan and Turkmenistan. Soft palate samples were collected immediately after slaughter for the detection of FMDV by RT‐PCR. The results show that 37.7% of cattle (96 of 255) were carriers of the virus. Among positive samples (96), 58 (60.4%) belonged to serotype O. No evidence was detected for the presence of Asia 1 and A serotypes. Nucleotide sequencing and phylogenic dendogram showed close similarity and common lineage between our samples and viruses isolated in Pakistan. With an approximate more than 80% of cattle population vaccination coverage such a high rate of carrier state may show an extensive FMDV exposure. Therefore, limiting control programmes to timely prophylactic vaccination may be insufficient. This is also true when meat market instabilities act as a temptation to import livestock, legally or illegally, through the eastern frontiers. It is recommended to change the current prophylactic vaccination strategy to a well‐developed regional control programme, with close monitoring of animal movement through eastern frontiers, supported by government commitment and educational programmes. Timely estimation of the frequency of carrier state both in cattle and small ruminants is also advocated as a gauge to monitor the virus status in the region.     

A Review of OIE Country Status Recovery Using Vaccinate‐to‐Live Versus Vaccinate‐to‐Die Foot‐and‐Mouth Disease Response Policies I: Benefits of Higher Potency Vaccines and Associated NSP DIVA Test Systems in Post‐Outbreak Surveillance

To rapidly return to trade, countries with OIE status, FMD‐free country where vaccination is not practised, have destroyed emergency vaccinated animals, raising ethical concerns with respect to social values, the environment, animal welfare and global food security. This two‐part review explores whether science could support eligibility to return to previous OIE status in 3 months irrespective of vaccinate‐to‐live or vaccinate‐to‐die policies. Here, we examine the benefits of higher potency (≥ 6 PD₅₀), high‐purity vaccines formulated from antigen banks for emergency use, their efficacy and performance in differentiating infected from vaccinated animals (DIVA) assays for post‐outbreak surveillance. From an intensive programme of research, we conclude that high‐quality, higher potency vaccines are proven to reduce FMD virus (FMDV) subclinical circulation and the risk of carriers. Broader coverage than predicted by serology suggests the potential to hold a few ‘key’ vaccine strains improving logistics and reducing the financial burden of antigen banks. The OIE should adopt formal definitions for emergency vaccination and emergency vaccines. In terms of supportive tools, we consider that the lack of OIE recognition of DIVA tests other than those of PANAFTOSA in cattle is a shortcoming. There is need for research on maternal antibody interference with DIVA tests and on the use of such tests to establish whether greater purification of vaccines improves performance. We consider that alignment of waiting periods for vaccinate‐to‐live and vaccinate‐to‐die in OIE Code Article 8.5.9 1 b. and c. is feasible until an acceptable level of statistical certainty for surveillance or target probability of freedom is established to substantiate the absence of FMDV infection or circulation. It is surveillance intensity rather than waiting periods that establishes the risk of residual FMDV. EU Directive 2003/85/EC implicitly recognizes this, permitting derogation of the OIE waiting periods.     

Molecular Characterization of Foot‐and‐Mouth Disease Virus: Implications for Disease Control in Bangladesh

Foot‐and‐mouth disease (FMD) is endemic in Bangladesh, and to implement an effective FMD control programme, it is essential to understand the complex epidemiology of the disease. Here, we report on the characterization of FMD virus (FMDV) recovered from FMD outbreaks in Bangladesh in late 2009. All isolated viruses belonged to the FMDV serotype O. The phylogenetic reconstruction showed that all isolates belonged to the Middle East–South Asia (ME–SA) topotype, but fell into two distinct sublineages, one named Ind‐2001 (the other has not been named). Within both sublineages, the 2009 Bangladesh isolates were most closely related to viruses from Nepal collected during 2008 and 2009. Additionally, both sublineages contained older viruses from India collected in 2000 and 2001. In South Asia, there is extensive cross‐border cattle movement from Nepal and India to Bangladesh. Both these findings have implications for the control of FMD in Bangladesh. Because of the porous borders, a regional FMD control strategy should be developed. Further, animal identification and monitoring animal movements are necessary to identify the cross‐border movements and market chain interactions of ruminants, leading to improved border and movement controls. Additionally, a vaccination strategy should be developed with the initial objective of protecting small‐scale dairy herds from disease. For any successful FMD control programme, long‐term Government commitment and adequate resources are necessary. A sustainable programme will also need farmer education, commitment and financial contributions.