South African Territories Research Articles

B and T Cell Epitopes of the Incursionary Foot-and-Mouth Disease Virus Serotype SAT2 for Vaccine Development.

Failure of cross-protection among interserotypes and intratypes of foot-and-mouth disease virus (FMDV) is a big threat to endemic countries and their prevention and control strategies. However, insights into practices relating to the development of a multi-epitope vaccine appear as a best alternative approach to alleviate the cross-protection-associated problems. In order to facilitate the development of such a vaccine design approach, identification and prediction of the antigenic B and T cell epitopes along with determining the level of immunogenicity are essential bioinformatics steps. These steps are well applied in Eurasian serotypes, but very rare in South African Territories (SAT) Types, particularly in serotype SAT2. For this reason, the available scattered immunogenic information on SAT2 epitopes needs to be organized and clearly understood. Therefore, in this review, we compiled relevant bioinformatic reports about B and T cell epitopes of the incursionary SAT2 FMDV and the promising experimental demonstrations of such designed and developed vaccines against this serotype.

Antigenicity and Immunogenicity Analysis of the E. coli Expressed FMDV Structural Proteins; VP1, VP0, VP3 of the South African Territories Type 2 Virus.

An alternative vaccine design approach and diagnostic kits are highly required against the anticipated pandemicity caused by the South African Territories type 2 (SAT2) Foot and Mouth Disease Virus (FMDV). However, the distinct antigenicity and immunogenicity of VP1, VP0, and VP3 of FMDV serotype SAT2 are poorly understood. Similarly, the particular roles of the three structural proteins in novel vaccine design and development remain unexplained. We therefore constructed VP1, VP0, and VP3 encoding gene (SAT2:JX014256 strain) separately fused with His-SUMO (histidine-small ubiquitin-related modifier) inserted into pET-32a cassette to express the three recombinant proteins and separately evaluated their antigenicity and immunogenicity in mice. The fusion protein was successfully expressed and purified by the Ni-NTA resin chromatography. The level of serum antibody, spleen lymphocyte proliferation, and cytokines against the three distinct recombinant proteins were analyzed. Results showed that the anti-FMDV humoral response was triggered by these proteins, and the fusion proteins did enhance the splenocyte immune response in the separately immunized mice. We observed low variations among the three fusion proteins in terms of the antibody and cytokine production in mice. Hence, in this study, results demonstrated that the structural proteins of SAT2 FMDV could be used for the development of immunodiagnostic kits and subunit vaccine designs.

REVIEW ON EPIDEMIOLOGY OF FOOT AND MOUTH DISEASE (FMD) IN ETHIOPIA

Foot and mouth disease (FMD) is a highly contagious transboundary disease that affects all cloven hoofed animals. It is caused by a virus that belongs to the genus Aphthovirus of the family Picornaviridae. Foot and mouth disease virus (FMDV) occurs in seven standard serotypes: A, O, C, and South African Territories (SAT) 1, SAT 2, SAT 3, and Asia1. The disease has a high morbidity although mortality is rare in adult animals. The impact posed by the disease is enormous. It affects animal’s performance directly through reduction of milk yield. Death of young animals and fertility impairment due to increased abortion rate are also the grave consequences of the disease. FMD has a great potential for causing severe economic loss. Greatest losses can result from refusal of FMD free countries to import livestock and livestock products from infected region. The disease has been present in almost every part of the world where livestock are kept. More than 100 countries are still affected by FMD worldwide and distribution of the disease roughly reflects economic development. Despite considerable information being available about the virus, the disease and vaccines, FMD remains a major threat to the livestock industry worldwide. FMD is endemic disease in Ethiopia with multiple serotypes in circulation at varying prevalence levels. Estimation of economic losses by FMD can provide a better overall view of the impact of the disease on national economy and can contribute in estimating the extent of the losses to be avoided and also understanding its transmission dynamics can contribute for suggesting appropriate control intervention mechanism. In Ethiopia there is limited research done on this aspect. Many resources have been and still are devoted to surveillance and molecular characterization of FMD, therefore the aims of this seminar paper are to review the major risk factors for transmission of disease, review the economic impact of FMD and suggest prevention and control measures.

FROM PORTUGAL TO THE COLONIES: CHARACTERISTICS OF PORTUGUESE EXILES AT THE END OF THE 18TH CENTURY.

The exile penalty has been widely used by the portuguese justice over the past centuries. The exiled were forced to cross the Atlantic in the direction of Brazil, Africa and Asia, where they fulfilled the punishment. The constant sending of large human contingents to colonial territories demonstrates the interests that the Crown had in removing the criminals from the metropolis. However, it can be an indicator of other objectives, such as the population and effective possession of the places where they were destined. This reality caused variations in the fate of the exiles according to the times and the needs that the Crown had in different periods. Thus, several authors agree that the sending of exiles to the colonies was aimed at occupation, defence, settlement and contribution to miscegenation in these territories. Through this research work, we seek to carry out a comparative study where we highlight the differences between the sending of exiles to the South American and African colonial territories. We also seek to get to know these individuals seeking to know their social status, profession, crime, age, marital status, place of birth, destination of exile and time of sentence. It was also our intention to analyze how the process of sending these individuals overseas was carried out, the time between the condemnation and their departure, how they were shipped, who was in charge of taking them to their destination and who guaranteed their survival during the trip.

Molecular matching of circulating foot and mouth disease viruses and vaccinal strains in Egypt, 2016-2019.

Regardless mass vaccination programs in Egypt with inactivated polyvalent vaccines of FMDvirus. FMD virus is still persistent with major economic burden. Serotypes of FMD namely, A, O, and South African Territories (SAT2) are endemic with repeated outbreaks of new linage. So selection of appropriate vaccine is very difficult. In this study; Phylogenetic analysis of VP1 genome for the existing serotype (A, O, SAT2) between 2016 to 2019 approved circulation of serotype O of East Africa 3 (EA-3) topoype, AIran05 lineage and A Africa G-IV lineage of serotype A and topotype VII of serotype SAT2 including Alx-12 and Lib-12 lineages. Significant amino acid changes in critical antigenic sites between field isolates and vaccine strains were observed. The present findings indicate the importance of an active routine surveillance system incorporating antigenic and genetic analysis designated to continually update information about field isolates of FMDV. Such as this protocols might be affected on FMD strategy control in Egypt and surrounding country.

Characterization of transboundary foot-and-mouth disease viruses in Nigeria and Cameroon during 2016.

Continuous surveillance for foot-and-mouth disease (FMD) in endemic settings such as West Africa is imperative to support improved local and regional control plans, with the long-term goal of regional eradication. This paper describes the genetic characterization of FMD viruses (FMDV) obtained from outbreaks in Nigeria (n=45) and Cameroon (n=15) during 2016 and from archival samples (n=3) retrieved from a 2014 outbreak in Nigeria. These viruses were analysed in the context of previously published FMDV sequences from the region. Four FMDV serotypes: O, A, SAT1 and SAT2, were detected. Phylogenetic analyses of the VP1 coding sequences indicate the continuity of FMDV serotype O East Africa-3 (O/EA-3), serotype A AFRICA genotype G-IV (A/AFRICA/G-IV) and serotype South African Territories (SAT) 2 lineage VII (SAT2/VII). The FMDV SAT1 topotype X (SAT1/X), which emerged in Nigeria in 2015, continued to be associated with outbreaks in the region during 2016, and SAT1 is reported for the first time from Cameroon. Additionally, a re-emergence or re-introduction of the serotype O West Africa (O/WA) topotype in Nigeria is described herein. Our findings indicate a consistent, pan-serotypic relationship between FMDV strains detected in Cameroon and Nigeria. Additionally, FMDV strains from West Africa obtained in this study were genetically related to those occurring in East and North Africa. These phylogenetic relationships suggest that animal movements (pastoralism and/or trade) are important factors for virus spread across the African continent. These data provide critical baselines which are a necessary component of Stages 0 and 1 of the Progressive Control Pathway of FMD (PCP-FMD). Specifically, characterizing the existing virus strains (risk) provides the basis for the comprehensive risk-based control plan which is the requisite criteria for Nigeria's transition to Stage 2 of PCP-FMD, and for coordinated regional control of FMD.

Development of Monoclonal Antibody Specific to Foot-and-Mouth Disease Virus Type A for Serodiagnosis.

Foot-and-mouth disease (FMD) is a highly contagious and economically devastating disease affecting cloven-hoofed livestock worldwide. FMD virus (FMDV) type A is one of the most common causes of FMD outbreaks among the seven FMDV serotypes, and its serological diagnosis is therefore important to confirm FMDV type A infection and to determine FMD vaccine efficacy. Here, we generated monoclonal antibodies (mAbs) specific to FMDV type A via hybridoma systems using an inactivated FMDV type A (A22/Iraq/1964) and found 4 monoclones (#29, #106, #108, and #109) with high binding reactivity to FMDV type A among 594 primary clones. In particular, the #106 mAb had a higher binding reactivity to the inactivated FMDV type A than the other mAbs and a commercial mAb. Moreover, the #106 mAb showed no cross-reactivity to inactivated FMDV type South African territories 1, 2, and 3, and low reactivity to inactivated FMDV type O (O1 Manisa). Importantly, the solid-phase competitive ELISA (SPCE) using horseradish peroxidase (HRP)-conjugated #106 mAb detected FMDV type A-specific Abs in sera from FMD type A-vaccinated cattle more effectively than a commercial SPCE. These results suggest that the newly developed FMDV type A-specific mAb might be useful for diagnostic approaches for detecting Abs against FMDV type A.

Evaluation of novel inactivated vaccines for the SAT 1, SAT 2 and SAT 3 serotypes of foot-and-mouth disease in pigs

BackgroundThe foot-and-mouth disease (FMD) virus is classified into seven serotypes, of which the South African types have South African Territories (SAT)1, SAT2, and SAT3 that are prevalent in Africa. Especially SAT2 have spread to Arabian Peninsula and the Palestinian Autonomous Territories. Of these viruses, the incidence of SAT2 is the highest. It is important to prepare for the spread of the virus to other continents, even though most FMD viruses are bovine-derived. In particular, due to the high breeding density of pigs in Asia, more attention is usually paid to the immunity and protection of pigs than cattle. For this reason, this study investigated the immunity and protection of pigs against the SAT viruses.MethodsSpecific vaccines were developed for SAT1, SAT2, and SAT3 serotypes. These vaccine viruses were designed to be distinguished from the wild-type strain. An immunogenicity test was conducted using these vaccines in both cattle (n = 5/group) and pigs (n = 20/group).ResultsHigh virus-neutralizing titer of antibodies (> 1:100) was induced in only 2 weeks after the immunization of cattle with the individual vaccine for SAT1, SAT2 or SAT3, and a clear immune response was induced after the second immunization in pigs. When the vaccinated pigs (n = 4–5/group) were challenged by the homologous wild-type virus strain 4 weeks after immunization, all the pigs were protected from the challenge.ConclusionsThis study confirmed that these vaccines can be used against SAT1, SAT2, and SAT3 viruses in cattle and pigs. The vaccine strains developed in this study are expected to be used as vaccines that can protect against FMD in the event of a future FMD outbreak in pigs in consideration of the situation in Asia.

Foot-and-mouth disease outbreaks in Egypt during 2013-2014: Molecular characterization of serotypes A, O, and SAT2.

Background and Aim:Foot-and-mouth disease virus (FMDV) serotypes A, O and South African Territories (SAT2) are endemic in Egypt; each is presented by a number of partially related topotypes and lineages, depending on their geographical origin. Continuous mutations and the emergence of new topotypes that lead to occasional vaccination failures were frequently recorded, so this study aimed to genetically characterize the circulating FMD virus strains in Egypt during 2013 and 2014 outbreaks, focusing on amino acids variations in VP1 region.Materials and Methods:A total of 51 oral tissue samples were collected from cattle and buffaloes in 13 farms, and 38 individual cases showed clinical signs suspected to be FMD in six Egyptian Governorates (Cairo, Giza, Qaliubia, Fayoum, Sharquia, and Assiut). FMDV in collected samples was characterized by reverse transcription-polymerase chain reaction (RT-PCR) amplification of full VP1 region, sequencing, and phylogenetic analysis.Results:Out of 51 samples, 44 (86.27%) were positive by RT-PCR using universal primers. Serotype O was predominant and detected in 31 samples (70.45%), serotype A was detected in 9 samples (20.45%), and then serotype SAT2 was identified in 4 samples (9.10%). Sequencing and phylogenetic analysis of VP1 demonstrated clustering of serotype O, A, and SAT2 in EA-3 topotype, ASIA topotype, and topotype VII, respectively. Serotype O is closely related to O/SUD/8/2008 with 94.6% identity but showed 14.6% differences from vaccine strain (O/PanAsia-2) of ME-SA topotype. Furthermore, Serotype A and SAT2 were closely related to recent circulating Egyptian isolates and vaccine strains type A/EGY/1/2012 (Asia topotype, lineage Iran-05) with identity 96.4% and vaccine strain of SAT2/EGY/A/2012 (topotype VII, lineage SAT2/VII/ALX-12) with identity 95.3%, respectively.Conclusion:The present study recommended further studies of serotype O to determine the immunogenic relationship between the vaccine strain and the new strains to attain maximum protection against circulating viruses.

Generation of monoclonal antibodies against foot-and-mouth disease virus SAT 2 and the development of a lateral flow strip test for virus detection.

Foot-and-mouth disease (FMD) remains a major economic concern for the livestock productivity in many developing countries and a continued threat to countries that are disease free because of its potential devastating impact on agricultural, food chain and tourism sectors. FMD virus (FMDV) is recognized as having seven serotypes: O, A, C, Asia 1, South African Territories (SAT) 1, 2, 3 and multiple subtypes within each serotype. FMD outbreaks due to SAT 2 have been reported in many African countries. The development of a rapid and easily performed test for FMD detection is critical for controlling FMD outbreaks and containing its spread. The present project developed a lateral flow immunochromatographic (LFI) strip test for the rapid detection of FMDV SAT 2. A panel of monoclonal antibodies (mAbs) against FMDV serotype SAT 2 was produced and characterized. One mAb (#10) was selected as the capture mAb because it reacted to all 23 SAT 2 isolates archived at the National Center for Foreign Animal Disease. The LFI strip test was developed using biotin-conjugated mAb #10, and the colloid gold-conjugated FMDV serotype-independent mAb as the detection mAb. A generic Rapid Assay Device (gRAD) with one test line and a control line was used for the test. The LFI strip test detected all 23 tested SAT 2 isolates and recent outbreak strains. The results indicated that the diagnostic specificity and sensitivity of the LFI strip test were greater than the double antibody sandwich (DAS) DAS ELISA. The ability of the LFI strip test to produce rapid diagnostic results will be useful for early on-site diagnosis during FMD outbreaks.

Serological responses of cattle inoculated with inactivated trivalent foot-and-mouth disease vaccine at the wildlife-livestock interface of the Kruger National Park, South Africa

Foot-and-mouth disease (FMD) virus is economically one of the world’s most important animal pathogens, which can be responsible for losses in livestock trade, as well as frequent and highly disruptive large-scale epidemics. The control of FMD in southern Africa typically includes vaccination of cattle with a trivalent or bivalent vaccine preparation. The objective of this study was to determine the level and duration of the antibody responses conferred by the current FMD vaccination programme in cattle at the western boundary of the Kruger National Park (KNP) in South Africa. Two hundred and eighty-three cattle from four communal dip tanks were longitudinally sampled after vaccination using an inactivated trivalent FMD vaccine (South African Territories (SAT) 1, SAT 2 and SAT 3). Blood samples were collected fortnightly over four months and antibodies were measured using a liquid-phase blocking ELISA. Only 5%, 43%, and 16% of enrolled cattle had evidence of pre-existing antibody responses to the three SAT viruses at the beginning of the study (≥1.6 log10 titre for SAT 1–3 respectively), which was 7–12 months after the last vaccination campaign. However, 14 days after vaccination this proportion increased to between 66% and 93%, with SAT 2 having the highest proportion. Young animals (<1 year old) tended to have higher predicted baseline antibody levels that peaked by 14 days. Positive serological responses were transient and by 56 days post-vaccination antibody levels begun to decline below the threshold of 1.6 log10 titre. Predicted peak antibody levels only consistently reached 2.0 log10 for SAT 2. Serological responses for SAT 2 tended to be longer, but in most cases the duration of antibody levels was short-lived. More research is necessary to determine the reasons for the limited duration of antibody responses, especially among younger cattle, in order to achieve more effective prophylactic vaccination.

Foraging behaviour and habitat use by Indian Yellow-nosed Albatrosses (Thalassarche carteri) breeding at Prince Edward Island

ABSTRACTDemographic parameters of wild animals are often closely associated with their foraging distribution and behaviour, and understanding these attributes can assist in identifying causes of population changes. The Indian Yellow-nosed Albatross (Thalassarche carteri) is endangered but little information is available on its at-sea distribution and behaviour. It breeds only in French (Iles Amsterdam, St Paul, Kerguelen and Crozet) and South African (Prince Edward Island, PEI) territories in the south-west Indian Ocean, with PEI supporting about 20% of the global population. This study aimed to investigate the at-sea distributions of adult Indian Yellow-nosed Albatrosses provisioning chicks at PEI and to compare them with distributions of Yellow-nosed Albatrosses breeding at other localities. Using satellite transmitters, we identified two areas that were particularly favoured for foraging. Parents whose partners were brooding small chicks frequently moved north-east of PEI to shallow, productive waters where cold, nutrient-rich water upwells and results in enhanced levels of chlorophyll-a. By contrast, parents with older chicks that could be left unattended often foraged along the Agulhas Bank where eddies and shear forces promote vertical mixing. The at-sea distribution of birds breeding at PEI was located between those reported for Indian Yellow-nosed Albatrosses breeding at Ile Amsterdam and Atlantic Yellow-nosed Albatrosses (T. chlororhynchos) breeding at Gough Island, so that birds from these localities may face different threats at sea. Our study is the first to highlight key feeding areas for Indian Yellow-nosed Albatrosses from PEI and to demonstrate partitioning of foraging grounds by Yellow-nosed Albatrosses from different localities.

Complete Genome Sequences of Four Foot-and-Mouth Disease Viruses of Serotype South African Territories 1 (SAT 1), Topotype X, Isolated from Cattle in Nigeria in 2015.

ABSTRACTThe complete genome sequences of four foot-and-mouth disease viruses of South African territories 1 (SAT 1) serotype are reported. These viruses originate from an outbreak in Nigeria in 2015 and belong to the novel SAT 1 topotype X from the west and central African virus pool.

Foot-and-mouth disease virus serotype SAT1 in cattle, Nigeria.

The knowledge of foot-and-mouth disease virus (FMDV) dynamics and epidemiology in Nigeria and the West Africa subregion is important to support local and regional control plans and international risk assessment. Foot-and-mouth disease virus serotype South African territories (SAT)1 was isolated, identified and characterized from an FMD outbreak in cattle in Nigeria in 2015, 35years after the last report of FMDV SAT1 in West Africa. The VP1 coding sequence of the Nigerian 2015 SAT1 isolates diverges from reported SAT1 topotypes resulting in a separate topotype. The reporting of a novel FMDV SAT1 strain in the virus pool 5 (West and Central Africa) highlights the dynamic and complex nature of FMDV in this region of Africa. Sustained surveillance is needed to understand the origin, the extent and distribution of this novel SAT1 topotype in the region as well as to detect and monitor the occurrence of (re-)emerging FMDV strains.

A thiazepino[4,5-a]benzimidazole derivative hampers the RNA replication of Eurasian serotypes of foot-and-mouth disease virus

The stamping-out policy for the control of foot-and-mouth disease virus (FMDV) in countries that are free from FMD without vaccination has a dramatic socio-economic impact, huge animal welfare issues and may result in the loss of farm animal genetic resources. As an alternative to pre-emptive culling or emergency vaccination we further explore the possibility to use antiviral drugs in the event of an FMD outbreak. In the present study, we tested the in vitro cytotoxicity and anti-FMDV activity of 1,2,4,5-tetrahydro-[1,4]thiazepino[4,5-a]benzimidazole. The molecule was shown to inhibit the replication of reference strains of the Eurasian FMDV serotypes O, A, C and Asia but not the FMDV serotypes from the South African Territories (SAT) neither a related picornavirus, i.e. swine vesicular disease virus. The molecule can be added until 2h post inoculation in a ‘single replication cycle experiment’ without losing its antiviral activity. The genetic characterization of progressively selected resistant FMD viruses shows that the molecule presumably interacts with the non-structural 2C protein of FMDV. Further studies are required on the use of this molecule in vivo.

Characteristics of Foot-and-Mouth Disease Viral Strains Circulating at the Wildlife/livestock Interface of the Great Limpopo Transfrontier Conservation Area.

Foot-and-mouth disease (FMD) inflicts severe economic losses within infected countries and is arguably the most important trade-restricting livestock disease in the world. In southern Africa, infected African buffaloes (Syncerus caffer) are the major reservoir of the South African Territories (SAT) types of the virus. With the progressive expansion of transfrontier conservation areas (TFCAs), the risk of FMD outbreaks is expected to increase due to a higher probability of buffalo/livestock contacts. To investigate the dynamics of FMD within and around the Great Limpopo TFCA (GLTFCA), 5 herds of buffaloes were sampled in June 2010 to characterize circulating viruses in South Africa and Zimbabwe. Three SAT-2 and three SAT-3 viral strains were isolated in both countries, including one that was genetically linked with a recent SAT-2 outbreak in Mozambique in 2011. In addition, two groups of unvaccinated cattle (n = 192) were serologically monitored for 1 year at the wildlife/livestock interface of Gonarezhou National Park (GNP) in Zimbabwe between April 2009 and January 2010, using the liquid-phase blocking ELISA (LPBE) and a test for antibodies directed against non-structural proteins (NSP). Neither clinical signs nor vaccination of cattle were reported during the study, yet a high proportion of the monitored cattle showed antibody responses against SAT-3 and SAT-1. Antibodies against NSP were also detected in 10% of the monitored cattle. The results of this study suggest that cattle grazing in areas adjacent to the GLTFCA can be infected by buffalo or other infected livestock and that cattle trade movements can act as efficient disseminators of FMD viruses to areas several hundred kilometres from the virus source. Current methods of surveillance of FMD at the GLTFCA interface seem insufficient to control for FMD emergence and dissemination and require urgent reassessment and regional coordination.

The effects of the codon usage and translation speed on protein folding of 3Dpol of foot-and-mouth disease virus

Foot-and-mouth disease virus (FMDV) can cause a highly infectious disease of cloven-hoofed livestock including sheep, domestic pig and cattle. As for the sever economic and social effects of a foot-and-mouth disease (FMD) outbreak, FMD has been recognized as the most important constraint to international trade in animals and animal products by the World Organization for Animal Heath (OIE) (Leforban 1999). FMDV is one of the members in the Aphthovirus genus which is classified into the Picornaviridae family. This virus exists in the form of seven different serotypes: Asia 1, O, C, A and South African Territories 1 (SAT 1), SAT 2 and SAT 3, but a many subtypes have evolved within each serotype. The genome of FMDV consists of a single open reading frame (ORF) flanked by a 5′ untranslated region and a 3′untranslated region. The ORF encodes 12 viral proteins, from 5′ termination to 3′ termination, including the leader protease (L), four capsid proteins (VP4, VP2, VP3 and VP1) and the nonstructural proteins 2A, 2B, 2C, 3A, 3B, 3C and 3D (Cooke and Westover 2008; Klein 2009). In Picornaviridae family, the 3D, namely RNAdependent RNA polymerase, is responsible for synthesis of RNA virus genomes. Under physiological conditions, 3D catalyze the formation of phosphodiester bonds between ribonucleotides in an RNA template-dependent fashion. However, because of the limited template copying fidelity of 3D, FMDV genome replication reflects the error-prone nature(Pariente et al. 2003). Given the important function of 3D for virus multiplication, the FMDV 3D has been the subject of intensive study for a long time. The 3D was first described in polymerase complex in the infected cells by FMDV. This complex was originally called the virus infection-associated antigen (VIAA), since it could be recognized by positive serum against FMDV (Cowan and Graves 1966). Subsequently, this VIAA was identified to contain the 3D (Lowe and Brown 1981; Newman et al. 1979; Robertson et al. 1983). Among the different FMDV serotypes or subtypes, the amino acid sequence for 3D of FMDV are conserved to some degree (Martinez-Salas et al. 1985; Villaverde et al. 1988), furthermore, some variable residues, invariable residues and peptide motifs were thought to play important roles in sustaining the functional integrity of the 3D (Carrillo et al. 2005; Doherty et al. 1999; George et al. 2001; Kaku et al. 1999; Xiang et al. 1998). However, these observations fail to indicate the overall structure of FMDV 3D. Fortunately, at this time, crystallization structure of FMDV 3D has been identified and the structure-function relationships were analyzed. The two studies help researchers to understand FMDV genome synthesis at the molecular level, account for the error-prone properties of the replication machinery (Ferrer-Orta et al. 2004, 2009). The primary sequence was regarded as the determinant of the protein secondary structure, hence, some studies of various protein structures were carried out based on this theory (Chou and Fasman 1974, 1978; Lim 1974; Qian and Sejnowski 1988; Xiao-xia Ma and Yu-ping Feng contributed equally to this work.

Application of the Ceditest® FMDV type O and FMDV-NS enzyme-linked immunosorbent assays for detection of antibodies against Foot-and-mouth disease virus in selected livestock and wildlife species in Uganda

Diagnosis and control of Foot-and-mouth disease virus (FMDV) requires rapid and sensitive diagnostic tests. Two antibody enzyme-linked immunosorbent assay (ELISA) kits, Ceditest® FMDV-NS for the detection of antibodies against the nonstructural proteins of all FMDV serotypes and Ceditest® FMDV type O for the detection of antibodies against serotype O, were evaluated under African endemic conditions where the presence of multiple serotypes and the use of nonpurified vaccines complicate serological diagnosis. Serum samples from 218 African buffalo, 758 cattle, 304 goats, and 88 sheep were tested using both kits, and selected samples were tested not only in serotype-specific ELISAs for antibodies against primarily FMDV serotype O, but also against other serotypes. The FMDV-NS assay detected far more positive samples (93%) than the FMDV type O assay (30%) in buffalo (P < 0.05), with predominant antibodies against the South African Territories (SAT) serotypes, while the seroprevalence was generally comparable in cattle with antibodies against serotype O elicited by infection and/or vaccination. However, some districts had higher seroprevalence using the FMDV type O assay indicating vaccination without infection, while 1 cattle herd with antibodies against the SAT serotypes had far more positive samples (85%) using the FMDV-NS versus the FMDV type O (10%), consistent with the latter test's lower sensitivity for antibodies against SAT serotypes. Based on the current investigation, the FMDV type O ELISA may be limited by the presence of SAT serotypes. The FMD NS assay worked well as a screening test for antibodies against all FMDV serotypes present in Uganda; however, as long as nonpurified vaccines are applied in the region, this test cannot be used to differentiate between vaccinated and infected animals.

Predicting antigenic sites on the foot-and-mouth disease virus capsid of the South African Territories types using virus neutralization data

Foot-and-mouth disease virus (FMDV) outer capsid proteins 1B, 1C and 1D contribute to the virus serotype distribution and antigenic variants that exist within each of the seven serotypes. This study presents phylogenetic, genetic and antigenic analyses of South African Territories (SAT) serotypes prevalent in sub-Saharan Africa. Here, we show that the high levels of genetic diversity in the P1-coding region within the SAT serotypes are reflected in the antigenic properties of these viruses and therefore have implications for the selection of vaccine strains that would provide the best vaccine match against emerging viruses. Interestingly, although SAT1 and SAT2 viruses displayed similar genetic variation within each serotype (32 % variable amino acids), antigenic disparity, as measured by r(1)-values, was less pronounced for SAT1 viruses compared with SAT2 viruses within our dataset, emphasizing the high antigenic variation within the SAT2 serotype. Furthermore, we combined amino acid variation and the r(1)-values with crystallographic structural data and were able to predict areas on the surface of the FMD virion as antigenically relevant. These sites were mostly consistent with antigenic sites previously determined for types A, O and C using mAbs and escape mutant studies. Our methodology offers a quick alternative to determine antigenic relevant sites for FMDV field strains.

The importance of FMDV localisation in lymphoid tissue

Foot-and-mouth disease virus, a highly contagious pathogen that can cause lameness, low weight and decreased milk production, is a scourge of agricultural livestock around the world. Although the acute phase of infection is rarely fatal, infection may persist in animals that have apparently recovered, creating a viral reservoir that some fear could contribute to the spread of disease. We have used an array of molecular techniques to search for traces of virus in tissues from the mouths and throats of infected cattle. In a carefully controlled study, we have found evidence of intact, non-replicating virus particles trapped by follicular dendritic cells within the germinal centres of lymph nodes. Strikingly, virus was present for up to 38 days post infection, even though it was undetectable in surrounding tissues. The retention of intact virus within germinal centres is likely to have a role in stimulating the long lasting immune response that is characteristic of viral infections. Our data suggests that this capture may also be responsible for preserving intact viruses capable of infecting susceptible cells as they come into contact with germinal centres.African buffalo (Syncerus caffer) are typically infected with all three South African Territories types of FMDV by 2 years of age and these viruses can be transmitted to farmed livestock. Buffalo harbour persistent virus in greater amounts and for longer periods than cattle and thus provided us with further opportunities to define the sites of viral localisation.