The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Francois Frederick Maree - One of the best experts on this subject based on the ideXlab platform.
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pathogenesis biophysical stability and phenotypic variance of SAT2 foot and mouth disease virus
Veterinary Microbiology, 2020Co-Authors: Tovhowani Ramulongo, Francois Frederick Maree, Paidamwoyo Mutowembwa, Katherine Anne Scott, Pamela A Opperman, Jacques TheronAbstract:Foot-and-mouth disease (FMD) is a highly contagious vesicular disease of cloven-hoofed animals, which severely decreases livestock productivity. FMD virus (FMDV), the causative agent, initiates infection by interaction with integrin cellular receptors on pharyngeal epithelium cells, causing clinical signs one to four days after transmission to a susceptible host. However, some Southern African Territories (SAT) viruses have been reported to cause mild or subclinical infections that may go undiagnosed in field conditions and are likely to be more common than previously expected. The studies presented here demonstrate that not all SAT2 viruses are equally virulent in cattle. The two SAT2 viruses, ZIM/5/83 and ZIM/7/83, were both highly attenuated in cattle, as evidenced by the mild clinical signs observed after needle challenge, while two incongruent SAT2 viruses showed significantly different clinical signs in challenged cattle. We then explored the ability of the SAT2 viruses to infect different cell types with defined receptors that are utilised by FMDV and found differences in their ability to lyse cells in culture and to compete in a controlled cell culture environment. The population sequence variation between ZIM/5/83 and ZIM/7/83 revealed multiple sites of single nucleotide variants of low frequency between the predominant virus populations, as could be expected from the genome of an RNA virus. An assessment of the biophysical stability of SAT2 virions during acidification indicated that the SAT2 virus EGY/09/12 was more resilient to acidification than the ZIM/5/83 and ZIM/7/83 viruses; however, whether this difference relates to differences in virulence in vivo is unclear. This study is a consolidated view of the key findings of SAT2 viruses studied over a 14-year period involving many different experiments.
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inherent biophysical stability of foot and mouth disease sat1 SAT2 and sat3 viruses
Virus Research, 2019Co-Authors: Katherine Anne Scott, Lorens Maake, Elizabeth Botha, Jacques Theron, Francois Frederick MareeAbstract:Abstract Foot-and-mouth disease (FMD) virus (FMDV) isolates show variation in their ability to withstand an increase in temperature. The FMDV is surprisingly thermolabile, even though this virus is probably subjected to a strong extracellular selective pressure by heat in hot climate regions where FMD is prevalent. The three SAT serotypes, with their particularly low biophysical stability also only yield vaccines of low protective capacity, even with multiple booster vaccinations. The aim of the study was to determine the inherent biophysical stability of field SAT isolates. To characterise the biophysical stability of 20 SAT viruses from Southern Africa, the thermofluor assay was used to monitor capsid dissociation by the release of the RNA genome under a range of temperature, pH and ionic conditions. The SAT2 and SAT3 viruses had a similar range of thermostability of 48–54 °C. However, the SAT1 viruses had a wider range of thermostability with an 8 °C difference but with many viruses being unstable at 43–46 °C. The thermostable A-serotype A24 control virus had the highest thermostability of 55 °C with some SAT2 and SAT3 viruses of similar thermostability. There was a 10 °C difference between the most unstable SAT virus (SAT1/TAN/2/99) and the highly stable A24 control virus. SAT1 viruses were generally more stable compared to SAT2 and SAT3 viruses at the pH range of 6.7–9.1. The effect of ionic buffers on capsid stability showed that SAT1 and SAT2 viruses had an increased stability of 2–9 °C and 2–6 °C, respectively, with the addition of 1 M NaCl. This is in contrast to the SAT3 viruses, which did not show improved stabilisation after addition of 1 M or 0.5 M NaCl buffers. Some buffers showed differing results dependent on the virus tested, highlighting the need to test SAT viruses with different solutions to establish the most stabilising option for storage of each virus. This study confirms for the first time that more stable SAT field viruses are present in the southern Africa region. This could facilitate the selection of the most stable circulating field strains, for adaptation to cultured BHK-21 cells or manipulation by reverse genetics and targeted mutation to produce improved vaccine master seed viruses.
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evaluation of immune responses of stabilised SAT2 antigens of foot and mouth disease in cattle
Vaccine, 2017Co-Authors: Katherine Anne Scott, Alejandra Victoria Capozzo, N M Rathogwa, Francois Frederick MareeAbstract:Abstract Foot-and-mouth disease (FMD) vaccines with improved stability and less reliant on a cold-chain are needed to improve the longevity of immune responses elicited in animals. This is especially so for serotypes O and SAT2 which are unstable in mildly acidic pH conditions or at elevated temperatures leading to dissociation of the capsid (146S particle) and loss of immunogenicity. Previously, stabilised SAT2 viruses were generated by reverse genetic approaches and assessed in vitro and in vivo with a guinea pig trial. Here we investigated the efficacy and comparative immunological responses of two thermostable and wild-type SAT2 vaccines over 5 months followed by challenge. We assessed humoral immune responses elicited in cattle in terms of total and neutralizing antibodies and IgG1/2 isotyping; and cell-mediated responses of IFN-γ as in vitro markers of protection. Whilst there were significant differences in total and neutralizing antibodies for the vSAT2-93H group compared to other vaccinated groups after the first vaccination, there were no significant differences after the second immunization. Following intra-dermolingual challenge all vaccinated groups were fully protected as determined by the absence of generalized lesions. These results provide proof that two vaccine doses, consisting of SAT2 antigen combined with ISA206B adjuvant, administered 4–6 weeks apart were able to protect animals up to 5 months pv. Additionally, vSAT2-93Y had significantly higher levels of IFN-γ after challenge and had a lower clinical score indicative of better protection compared to other vaccinated groups and the importance of cell mediated responses and antigen stability in protection.
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SAT2 Foot-and-Mouth Disease Virus Structurally Modified for Increased Thermostability
Journal of Virology, 2017Co-Authors: Katherine A. Scott, Jingshan Ren, Elizabeth E. Fry, Abhay Kotecha, David I. Stuart, Bryan Charleston, Francois Frederick MareeAbstract:Foot-and-mouth disease virus (FMDV), particularly strains of the O and SAT serotypes, is notoriously unstable. Consequently, vaccines derived from heat-labile SAT viruses have been linked to the induction of immunity with a poor duration and hence require more frequent vaccinations to ensure protection. In silico calculations predicted residue substitutions that would increase interactions at the interpentamer interface, supporting increased stability. We assessed the stability of the 18 recombinant mutant viruses in regard to their growth kinetics, antigenicity, plaque morphology, genetic stability, and temperature, ionic, and pH stability by using Thermofluor and inactivation assays in order to evaluate potential SAT2 vaccine candidates with improved stability. The most stable mutant for temperature and pH stability was the S2093Y single mutant, while other promising mutants were the E3198A, L2094V, and S2093H single mutants and the F2062Y-H2087M-H3143V triple mutant. Although the S2093Y mutant had the greatest stability, it exhibited smaller plaques, a reduced growth rate, a change in monoclonal antibody footprint, and poor genetic stability properties compared to those of the wild-type virus. However, these factors affecting production can be overcome. The addition of 1 M NaCl was found to further increase the stability of the SAT2 panel of viruses. The S2093Y and S2093H mutants were selected for future use in stabilizing SAT2 vaccines. IMPORTANCE Foot-and-mouth disease virus (FMDV) causes a highly contagious acute vesicular disease in cloven-hoofed livestock and wildlife. The control of the disease by vaccination is essential, especially at livestock-wildlife interfaces. The instability of some serotypes, such as SAT2, affects the quality of vaccines and therefore the duration of immunity. We have shown that we can improve the stability of SAT2 viruses by mutating residues at the capsid interface through predictive modeling. This is an important finding for the potential use of such mutants in improving the stability of SAT2 vaccines in countries where FMD is endemic, which rely heavily on the maintenance of the cold chain, with potential improvement to the duration of immune responses.
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transmission of foot and mouth disease SAT2 viruses at the wildlife livestock interface of two major transfrontier conservation areas in southern africa
Frontiers in Microbiology, 2016Co-Authors: Francois Frederick Maree, Barbara Brito, Livio Heath, Ferran Jori, Rahana Dwarka, Andres M PerezAbstract:Over a decade ago, foot-and-mouth disease (FMD) re-emerged in Southern Africa specifically, in beef exporting countries that had successfully maintained disease-free areas in the past. FMD virus (FMDV) serotype SAT2 has been responsible for a majority of these outbreaks. Epidemiological studies have revealed the importance of the African buffalo as the major wildlife FMD reservoir in the region. We used phylogeographic analysis to study dynamics of FMD transmission between buffalo and domestic cattle at the interface of the major wildlife protected areas in the region currently encompassing two largest Transfrontier conservation areas (TFCA): Kavango-Zambezi (KAZA) and Great Limpopo (GL). Results of this study showed restricted local occurrence of each FMD virus SAT2 topotypes I, II and III, with occasional virus migration from KAZA to GLTP. Origins of outbreaks in livestock are frequently attributed to wild buffalo as the origin, but our results suggest that transmission from cattle to buffalo also occurs. This study contributes to understand the major dynamics of transmission and genetic variation of FMD virus SAT2 in southern Africa, which will ultimately support designing efficient strategies for the control of FMD at a local and regional level.
Andres M Perez - One of the best experts on this subject based on the ideXlab platform.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
Transboundary and Emerging Diseases, 2020Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:: Quantitative knowledge on the contribution of African buffalo to the epidemiology of foot-and-mouth disease virus (FMDV) in East Africa is lacking, and this information is essential for the design of control programs in the region. The objective of this study was to investigate the epidemiology of FMDV in buffalo, including the role of buffalo in the circulation of FMDV in livestock populations. We collected blood and oropharyngeal fluids from 92 wild buffalo and 98 sympatric cattle in central Kenya and sequenced the virus' VP1 coding region. We show that FMDV has a high seroprevalence in buffalo (~77%) and targeted cattle (~93%). In addition, we recovered 80 FMDV sequences from buffalo, all of which were serotype SAT1 and SAT2, and four serotype O and A sequences from sympatric cattle. Notably, six individual buffalo were co-infected with both SAT1 and SAT2. Amongst sympatric buffalo and cattle, the fact that no SAT1 or 2 sequences were found in cattle suggests that transmission of FMDV from buffalo to sympatric cattle is rare. Similarly, there was no evidence that serotype O and A sequences found in cattle were transmitted to buffalo. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were closely related to SAT1 and SAT2 viruses found in buffalo in this study, suggesting that FMDV in cattle and buffalo do not constitute independently evolving populations. We also show that fine-scale geographic features, such as rivers, influence the circulation of FMDV in buffalo and that social segregation amongst sympatric herds may limit between-herd transmission. These results significantly advance our understanding of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in East Africa and will help to inform the design of control and surveillance strategies for this disease in the region.
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phylogeographical and cross species transmission dynamics of sat1 and SAT2 foot and mouth disease virus in eastern africa
Molecular Ecology, 2019Co-Authors: George Omondi, Francis Gakuya, Abraham Sangula, Steven J Pauszek, Andres M Perez, Vincent Obanda, Moh A Alkhamis, Stephen Ngulu, Richard Van AardtAbstract:Understanding the dynamics of foot-and-mouth disease virus (FMDV), an endemic and economically constraining disease, is critical in designing control programmes in Africa. This study investigates the evolutionary epidemiology of SAT1 and SAT2 FMDV in Eastern Africa, as well as between cattle and wild African buffalo. Bayesian phylodynamic models were used to analyse SAT1 and SAT2 VP1 gene segments collected between 1975 and 2016, focusing on the SAT1 and SAT2 viruses currently circulating in Eastern Africa. The root state posterior probabilities inferred from our analyses suggest Zimbabwe as the ancestral location for SAT1 currently circulating in Eastern Africa (p = 0.67). For the SAT2 clade, Kenya is inferred to be the ancestral location for introduction of the virus into other countries in Eastern Africa (p = 0.72). Salient (Bayes factor >10) viral dispersal routes were inferred from Tanzania to Kenya, and from Kenya to Uganda for SAT1 and SAT2, respectively. Results suggest that cattle are the source of the SAT1 and SAT2 clades currently circulating in Eastern Africa. In addition, our results suggest that the majority of SAT1 and SAT2 in livestock come from other livestock rather than wildlife, with limited evidence that buffalo serve as reservoirs for cattle. Insights from the present study highlight the role of cattle movements and anthropogenic activities in shaping the evolutionary history of SAT1 and SAT2 in Eastern Africa. While the results may be affected by inherent limitations of imperfect surveillance, our analysis elucidates the dynamics between host species in this region, which is key to guiding disease intervention activities.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
bioRxiv, 2018Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:Transmission of pathogens at wildlife-livestock interfaces poses a substantial challenge to the control of infectious diseases, including for foot-and-mouth disease virus (FMDV) in African buffalo and cattle. The extent to which buffalo play a role in the epidemiology of this virus in livestock populations remains unresolved in East Africa. Here, we show that FMDV occurs at high seroprevalence (~77%) in Kenyan buffalo. In addition, we recovered 80 FMDV VP1 sequences from buffalo, all of which were serotype SAT1 and SAT2, and seventeen FMDV VP1 sequences from cattle, which included serotypes A, O, SAT1 and SAT2. Notably, six individual buffalo were co-infected with both SAT1 and SAT2 serotypes. Our results suggest that transmission of FMDV between sympatric cattle and buffalo is rare. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were caused by viruses closely related to SAT1 and SAT2 viruses found in buffalo. We also show that the circulation of FMDV in buffalo is influenced by fine-scale geographic features, such as rivers, and that social segregation amongst sympatric herds may limit between-herd transmission. Our results significantly advance knowledge of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in Eastern Africa, and will help to inform the design of control and surveillance strategies for this disease in the region.
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transmission of foot and mouth disease SAT2 viruses at the wildlife livestock interface of two major transfrontier conservation areas in southern africa
Frontiers in Microbiology, 2016Co-Authors: Francois Frederick Maree, Barbara Brito, Livio Heath, Ferran Jori, Rahana Dwarka, Andres M PerezAbstract:Over a decade ago, foot-and-mouth disease (FMD) re-emerged in Southern Africa specifically, in beef exporting countries that had successfully maintained disease-free areas in the past. FMD virus (FMDV) serotype SAT2 has been responsible for a majority of these outbreaks. Epidemiological studies have revealed the importance of the African buffalo as the major wildlife FMD reservoir in the region. We used phylogeographic analysis to study dynamics of FMD transmission between buffalo and domestic cattle at the interface of the major wildlife protected areas in the region currently encompassing two largest Transfrontier conservation areas (TFCA): Kavango-Zambezi (KAZA) and Great Limpopo (GL). Results of this study showed restricted local occurrence of each FMD virus SAT2 topotypes I, II and III, with occasional virus migration from KAZA to GLTP. Origins of outbreaks in livestock are frequently attributed to wild buffalo as the origin, but our results suggest that transmission from cattle to buffalo also occurs. This study contributes to understand the major dynamics of transmission and genetic variation of FMD virus SAT2 in southern Africa, which will ultimately support designing efficient strategies for the control of FMD at a local and regional level.
Barbara Brito - One of the best experts on this subject based on the ideXlab platform.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
Transboundary and Emerging Diseases, 2020Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:: Quantitative knowledge on the contribution of African buffalo to the epidemiology of foot-and-mouth disease virus (FMDV) in East Africa is lacking, and this information is essential for the design of control programs in the region. The objective of this study was to investigate the epidemiology of FMDV in buffalo, including the role of buffalo in the circulation of FMDV in livestock populations. We collected blood and oropharyngeal fluids from 92 wild buffalo and 98 sympatric cattle in central Kenya and sequenced the virus' VP1 coding region. We show that FMDV has a high seroprevalence in buffalo (~77%) and targeted cattle (~93%). In addition, we recovered 80 FMDV sequences from buffalo, all of which were serotype SAT1 and SAT2, and four serotype O and A sequences from sympatric cattle. Notably, six individual buffalo were co-infected with both SAT1 and SAT2. Amongst sympatric buffalo and cattle, the fact that no SAT1 or 2 sequences were found in cattle suggests that transmission of FMDV from buffalo to sympatric cattle is rare. Similarly, there was no evidence that serotype O and A sequences found in cattle were transmitted to buffalo. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were closely related to SAT1 and SAT2 viruses found in buffalo in this study, suggesting that FMDV in cattle and buffalo do not constitute independently evolving populations. We also show that fine-scale geographic features, such as rivers, influence the circulation of FMDV in buffalo and that social segregation amongst sympatric herds may limit between-herd transmission. These results significantly advance our understanding of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in East Africa and will help to inform the design of control and surveillance strategies for this disease in the region.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
bioRxiv, 2018Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres Perez, Vincent ObandaAbstract:Transmission of pathogens at wildlife-livestock interfaces poses a substantial challenge to the control of infectious diseases, including for foot-and-mouth disease virus (FMDV) in African buffalo and cattle. The extent to which buffalo play a role in the epidemiology of this virus in livestock populations remains unresolved in East Africa. Here, we show that FMDV occurs at high seroprevalence (~77%) in Kenyan buffalo. In addition, we recovered 80 FMDV VP1 sequences from buffalo, all of which were serotype SAT1 and SAT2, and seventeen FMDV VP1 sequences from cattle, which included serotypes A, O, SAT1 and SAT2. Notably, six individual buffalo were co-infected with both SAT1 and SAT2 serotypes. Our results suggest that transmission of FMDV between sympatric cattle and buffalo is rare. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were caused by viruses closely related to SAT1 and SAT2 viruses found in buffalo. We also show that the circulation of FMDV in buffalo is influenced by fine-scale geographic features, such as rivers, and that social segregation amongst sympatric herds may limit between-herd transmission. Our results significantly advance knowledge of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in Eastern Africa, and will help to inform the design of control and surveillance strategies for this disease in the region.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
bioRxiv, 2018Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:Transmission of pathogens at wildlife-livestock interfaces poses a substantial challenge to the control of infectious diseases, including for foot-and-mouth disease virus (FMDV) in African buffalo and cattle. The extent to which buffalo play a role in the epidemiology of this virus in livestock populations remains unresolved in East Africa. Here, we show that FMDV occurs at high seroprevalence (~77%) in Kenyan buffalo. In addition, we recovered 80 FMDV VP1 sequences from buffalo, all of which were serotype SAT1 and SAT2, and seventeen FMDV VP1 sequences from cattle, which included serotypes A, O, SAT1 and SAT2. Notably, six individual buffalo were co-infected with both SAT1 and SAT2 serotypes. Our results suggest that transmission of FMDV between sympatric cattle and buffalo is rare. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were caused by viruses closely related to SAT1 and SAT2 viruses found in buffalo. We also show that the circulation of FMDV in buffalo is influenced by fine-scale geographic features, such as rivers, and that social segregation amongst sympatric herds may limit between-herd transmission. Our results significantly advance knowledge of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in Eastern Africa, and will help to inform the design of control and surveillance strategies for this disease in the region.
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transmission of foot and mouth disease SAT2 viruses at the wildlife livestock interface of two major transfrontier conservation areas in southern africa
Frontiers in Microbiology, 2016Co-Authors: Francois Frederick Maree, Barbara Brito, Livio Heath, Ferran Jori, Rahana Dwarka, Andres M PerezAbstract:Over a decade ago, foot-and-mouth disease (FMD) re-emerged in Southern Africa specifically, in beef exporting countries that had successfully maintained disease-free areas in the past. FMD virus (FMDV) serotype SAT2 has been responsible for a majority of these outbreaks. Epidemiological studies have revealed the importance of the African buffalo as the major wildlife FMD reservoir in the region. We used phylogeographic analysis to study dynamics of FMD transmission between buffalo and domestic cattle at the interface of the major wildlife protected areas in the region currently encompassing two largest Transfrontier conservation areas (TFCA): Kavango-Zambezi (KAZA) and Great Limpopo (GL). Results of this study showed restricted local occurrence of each FMD virus SAT2 topotypes I, II and III, with occasional virus migration from KAZA to GLTP. Origins of outbreaks in livestock are frequently attributed to wild buffalo as the origin, but our results suggest that transmission from cattle to buffalo also occurs. This study contributes to understand the major dynamics of transmission and genetic variation of FMD virus SAT2 in southern Africa, which will ultimately support designing efficient strategies for the control of FMD at a local and regional level.
Vincent Obanda - One of the best experts on this subject based on the ideXlab platform.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
Transboundary and Emerging Diseases, 2020Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:: Quantitative knowledge on the contribution of African buffalo to the epidemiology of foot-and-mouth disease virus (FMDV) in East Africa is lacking, and this information is essential for the design of control programs in the region. The objective of this study was to investigate the epidemiology of FMDV in buffalo, including the role of buffalo in the circulation of FMDV in livestock populations. We collected blood and oropharyngeal fluids from 92 wild buffalo and 98 sympatric cattle in central Kenya and sequenced the virus' VP1 coding region. We show that FMDV has a high seroprevalence in buffalo (~77%) and targeted cattle (~93%). In addition, we recovered 80 FMDV sequences from buffalo, all of which were serotype SAT1 and SAT2, and four serotype O and A sequences from sympatric cattle. Notably, six individual buffalo were co-infected with both SAT1 and SAT2. Amongst sympatric buffalo and cattle, the fact that no SAT1 or 2 sequences were found in cattle suggests that transmission of FMDV from buffalo to sympatric cattle is rare. Similarly, there was no evidence that serotype O and A sequences found in cattle were transmitted to buffalo. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were closely related to SAT1 and SAT2 viruses found in buffalo in this study, suggesting that FMDV in cattle and buffalo do not constitute independently evolving populations. We also show that fine-scale geographic features, such as rivers, influence the circulation of FMDV in buffalo and that social segregation amongst sympatric herds may limit between-herd transmission. These results significantly advance our understanding of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in East Africa and will help to inform the design of control and surveillance strategies for this disease in the region.
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genome sequences of foot and mouth disease virus sat1 and SAT2 strains from kenya in 2014 to 2016
Microbiology Resource Announcements, 2019Co-Authors: Rachel Palinski, Francis Gakuya, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Vincent Obanda, Miranda R Bertram, George OmondiAbstract:Here, we report the near-complete genomes of three Southern African Territories 1 (SAT1) serotype strains and one SAT2 serotype strain of foot-and-mouth disease virus (FMDV) recently isolated from Kenya. Viral isolates were obtained from bovine epithelial tissues collected in 2014 and 2016 following outbreaks of foot-and-mouth disease (FMD). These near-complete genome sequences provide a critical update of Kenyan FMDV molecular epidemiology.
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phylogeographical and cross species transmission dynamics of sat1 and SAT2 foot and mouth disease virus in eastern africa
Molecular Ecology, 2019Co-Authors: George Omondi, Francis Gakuya, Abraham Sangula, Steven J Pauszek, Andres M Perez, Vincent Obanda, Moh A Alkhamis, Stephen Ngulu, Richard Van AardtAbstract:Understanding the dynamics of foot-and-mouth disease virus (FMDV), an endemic and economically constraining disease, is critical in designing control programmes in Africa. This study investigates the evolutionary epidemiology of SAT1 and SAT2 FMDV in Eastern Africa, as well as between cattle and wild African buffalo. Bayesian phylodynamic models were used to analyse SAT1 and SAT2 VP1 gene segments collected between 1975 and 2016, focusing on the SAT1 and SAT2 viruses currently circulating in Eastern Africa. The root state posterior probabilities inferred from our analyses suggest Zimbabwe as the ancestral location for SAT1 currently circulating in Eastern Africa (p = 0.67). For the SAT2 clade, Kenya is inferred to be the ancestral location for introduction of the virus into other countries in Eastern Africa (p = 0.72). Salient (Bayes factor >10) viral dispersal routes were inferred from Tanzania to Kenya, and from Kenya to Uganda for SAT1 and SAT2, respectively. Results suggest that cattle are the source of the SAT1 and SAT2 clades currently circulating in Eastern Africa. In addition, our results suggest that the majority of SAT1 and SAT2 in livestock come from other livestock rather than wildlife, with limited evidence that buffalo serve as reservoirs for cattle. Insights from the present study highlight the role of cattle movements and anthropogenic activities in shaping the evolutionary history of SAT1 and SAT2 in Eastern Africa. While the results may be affected by inherent limitations of imperfect surveillance, our analysis elucidates the dynamics between host species in this region, which is key to guiding disease intervention activities.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
bioRxiv, 2018Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres Perez, Vincent ObandaAbstract:Transmission of pathogens at wildlife-livestock interfaces poses a substantial challenge to the control of infectious diseases, including for foot-and-mouth disease virus (FMDV) in African buffalo and cattle. The extent to which buffalo play a role in the epidemiology of this virus in livestock populations remains unresolved in East Africa. Here, we show that FMDV occurs at high seroprevalence (~77%) in Kenyan buffalo. In addition, we recovered 80 FMDV VP1 sequences from buffalo, all of which were serotype SAT1 and SAT2, and seventeen FMDV VP1 sequences from cattle, which included serotypes A, O, SAT1 and SAT2. Notably, six individual buffalo were co-infected with both SAT1 and SAT2 serotypes. Our results suggest that transmission of FMDV between sympatric cattle and buffalo is rare. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were caused by viruses closely related to SAT1 and SAT2 viruses found in buffalo. We also show that the circulation of FMDV in buffalo is influenced by fine-scale geographic features, such as rivers, and that social segregation amongst sympatric herds may limit between-herd transmission. Our results significantly advance knowledge of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in Eastern Africa, and will help to inform the design of control and surveillance strategies for this disease in the region.
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the role of african buffalo in the epidemiology of foot and mouth disease in sympatric cattle and buffalo populations in kenya
bioRxiv, 2018Co-Authors: George Omondi, Francis Gakuya, Jonathan Arzt, Abraham Sangula, Ethan J Hartwig, Steven J Pauszek, George R Smoliga, Barbara Brito, Andres M Perez, Vincent ObandaAbstract:Transmission of pathogens at wildlife-livestock interfaces poses a substantial challenge to the control of infectious diseases, including for foot-and-mouth disease virus (FMDV) in African buffalo and cattle. The extent to which buffalo play a role in the epidemiology of this virus in livestock populations remains unresolved in East Africa. Here, we show that FMDV occurs at high seroprevalence (~77%) in Kenyan buffalo. In addition, we recovered 80 FMDV VP1 sequences from buffalo, all of which were serotype SAT1 and SAT2, and seventeen FMDV VP1 sequences from cattle, which included serotypes A, O, SAT1 and SAT2. Notably, six individual buffalo were co-infected with both SAT1 and SAT2 serotypes. Our results suggest that transmission of FMDV between sympatric cattle and buffalo is rare. However, viruses from FMDV outbreaks in cattle elsewhere in Kenya were caused by viruses closely related to SAT1 and SAT2 viruses found in buffalo. We also show that the circulation of FMDV in buffalo is influenced by fine-scale geographic features, such as rivers, and that social segregation amongst sympatric herds may limit between-herd transmission. Our results significantly advance knowledge of the ecology and molecular epidemiology of FMDV at wildlife-livestock interfaces in Eastern Africa, and will help to inform the design of control and surveillance strategies for this disease in the region.
Harinder S Hundal - One of the best experts on this subject based on the ideXlab platform.
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insulin promotes the cell surface recruitment of the SAT2 ata2 system a amino acid transporter from an endosomal compartment in skeletal muscle cells
Journal of Biological Chemistry, 2002Co-Authors: Russell Hyde, Karine Peyrollier, Harinder S HundalAbstract:SAT1-3 comprise members of the recently cloned family of System A transporters that mediate the sodium-coupled uptake of short chain neutral amino acids, and their activity is regulated extensively by stimuli such as insulin, growth factors, and amino acid availability. In skeletal muscle, insulin stimulates System A activity rapidly by a presently ill-defined mechanism. Here we demonstrate that insulin induces an increase in the plasma membrane abundance of SAT2 in a phosphatidylinositol 3-kinase-dependent manner and that this increase is derived from an endosomal compartment that is required for the hormonal activation of System A. Chloroquine, an acidotropic weak base that impairs endosomal recycling of membrane proteins, induced a complete inhibition in the insulin-mediated stimulation of System A, which was associated with a loss in SAT2 recruitment to the plasma membrane. The failure to stimulate System A and recruit SAT2 to the cell surface could not be attributed to a block in insulin signaling, as chloroquine had no effect on the insulin-mediated phosphorylation of protein kinase B or glycogen synthase kinase 3 or upon insulin-stimulated GLUT4 translocation and glucose transport. Our data indicate strongly that insulin increases System A transport in L6 cells by stimulating the exocytosis of SAT2 carriers from a chloroquine-sensitive endosomal compartment.
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subcellular localization and adaptive up regulation of the system a SAT2 amino acid transporter in skeletal muscle cells and adipocytes
Biochemical Journal, 2001Co-Authors: Russell Hyde, Graham R Christie, Gary J Litherland, Eric Hajduch, Peter M Taylor, Harinder S HundalAbstract:The recently cloned amino acid transporter SAT2 is ubiquitously expressed and confers Na(+)-dependent transport of short-chain neutral amino acids, characteristics of the functionally defined System A transporter. Here we report the presence of SAT2 mRNA and protein in both skeletal muscle and adipocytes, and the characterization of polyclonal antibodies directed against this transporter. SAT2 protein was present in both plasma-membrane and internal-membrane fractions derived from rat skeletal muscle and adipose tissue, L6 myotubes and 3T3-L1 adipocytes, having a localization similar to that of the glucose transporter GLUT4. Moreover, consistent with the adaptive up-regulation of System A activity following chronic amino acid deprivation, a time-dependent increase in SAT2 protein abundance was observed in amino-acid-deprived L6 myotubes and 3T3-L1 adipocytes. These studies provide the first evidence regarding the subcellular distribution and adaptive up-regulation of SAT2 protein and the characterization of molecular probes for this physiologically important transporter, the function of which is altered in several disease states.
