The African swine fever virus (ASFV) is currently causing a world-wide pandemic of a highly letha... more The African swine fever virus (ASFV) is currently causing a world-wide pandemic of a highly lethal disease in domestic swine and wild boar. Currently, recombinant ASF live-attenuated vaccines based on a genotype II virus strain are commercially available in Vietnam. With 25 reported ASFV genotypes in the literature, it is important to understand the molecular basis and usefulness of ASFV genotyping, as well as the true significance of genotypes in the epidemiology, transmission, evolution, control, and prevention of ASFV. Historically, genotyping of ASFV was used for the epidemiological tracking of the disease and was based on the analysis of small fragments that represent less than 1% of the viral genome. The predominant method for genotyping ASFV relies on the sequencing of a fragment within the gene encoding the structural p72 protein. Genotype assignment has been accomplished through automated phylogenetic trees or by comparing the target sequence to the most closely related gen...
Classical swine fever (CSF) remains one of the most economically significant viral diseases affec... more Classical swine fever (CSF) remains one of the most economically significant viral diseases affecting domestic pigs and wild boars worldwide. To develop a safe and effective vaccine against CSF, we have constructed a triple gene-deleted pseudorabies virus (PRVtmv)-vectored bivalent subunit vaccine against porcine circovirus type 2b (PCV2b) and CSFV (PRVtmv+). In this study, we determined the protective efficacy of the PRVtmv+ against virulent CSFV challenge in pigs. The results revealed that the sham-vaccinated control group pigs developed severe CSFV-specific clinical signs characterized by pyrexia and diarrhea, and became moribund on or before the seventh day post challenge (dpc). However, the PRVtmv+-vaccinated pigs survived until the day of euthanasia at 21 dpc. A few vaccinated pigs showed transient diarrhea but recovered within a day or two. One pig had a low-grade fever for a day but recovered. The sham-vaccinated control group pigs had a high level of viremia, severe lymphoc...
The immune response against foot-and-mouth disease virus (FMDV) was studied in a murine model. In... more The immune response against foot-and-mouth disease virus (FMDV) was studied in a murine model. In untreated control mice, the inoculation of 10,000 suckling mouse 50% lethal doses of Ol Campos FMDV i.p. was followed by a burst of viraemia that disappeared in less than 4 days, i.e. when the neutralizing antibodies (NAb) reached titres above one neutralizing unit. In mice treated with cyclophosphamide, the curves of viraemia and NAb were significantly delayed. Nu/nu mice injected with FMDV had curves of viraemia and NAb identical to those of their nu/t littermates. We then studied the secondary (memory) immune reaction in the same model. In order to investigate which preimmunized cells participate in the elimination of actively replicating FMDV, mice were irradiated, then infected with FMDV, and 24 hr later repopulated with cells obtained from either donor mice that had been previously immunized by infection with live virus, or non-infected controls. The transfer of control (non-immunized) lymphoid cells was unable to eliminate the viraemia in recipient animals at times significantly different from those observed with irradiated recipients receiving no cells, while repopulation of recipients with 10(8) immune lymphoid cells (obtained from pooled thymus, blood, peritoneal exudate, spleen and lymph nodes of preinfected donor mice) led to undetectable titres of viraemia at Day 5 post-infection (p.i.). High doses of thymus cells were totally inactive, while a few as 10(7) donor spleen cells were able to abort viraemia at 6 days p.i. When enriched preparations of B or T spleen cells were adoptively transferred, only B cells were able to abort viraemia in irradiated recipients. It is concluded that, in the murine model of FMDV infection, B cells are mainly responsible for primary response and short-term immunological memory. In both cases the protective immune reaction is T-independent.
Trono, Karina G.; Dus Santos, María José; Wigdorovitz, Andrés; Rodríguez, S.; Chiavenna, S.; Ardi... more Trono, Karina G.; Dus Santos, María José; Wigdorovitz, Andrés; Rodríguez, S.; Chiavenna, S.; Ardila, Fernando Jorge; Borca, MV; Carrillo, C. ... Asociación entre genotipo y evolución patógena en variantes naturales del virus de la Leucosis Bovina. ... Sociedad Argentina de ...
African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks fo... more African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks for over a century in Africa ever since its first discovery in 1921. Since 1957, there have been sporadic outbreaks outside of Africa; however, no outbreak has been as devastating and as far-reaching as the current pandemic that originated from a 2007 outbreak in the Republic of Georgia. Derivatives with a high degree of similarity to the progenitor strain, ASFV-Georgia/2007, have been sequenced from various countries in Europe and Asia. However, the current strains circulating in Africa are largely unknown, and 24 different genotypes have been implicated in different outbreaks. In this study, ASF isolates were collected from samples from swine suspected of dying from ASF on farms in Ghana in early 2022. While previous studies determined that the circulating strains in Ghana were p72 Genotype I, we demonstrate here that the strains circulating in 2022 were derivatives of the p72 Genotype I...
Here, we announce the predicted structures of the 193 proteins encoded by African swine fever vir... more Here, we announce the predicted structures of the 193 proteins encoded by African swine fever virus (ASFV) strain Georgia 2007 (ASFV-G). Previously, only the structures of 16 ASFV proteins were elucidated.
Currently, there are no African swine fever (ASF) commercial vaccines that can be used to prevent... more Currently, there are no African swine fever (ASF) commercial vaccines that can be used to prevent or control the spread of ASF. The only effective experimental vaccines against ASF are live-attenuated vaccines.
No commercial vaccine is available to prevent African swine fever. The ASF pandemic caused by ASF... more No commercial vaccine is available to prevent African swine fever. The ASF pandemic caused by ASFV Georgia2007 strain (ASFV-G) is seriously affecting pork production in a contiguous area from Central Europe to East Asia.
In this study, we analyzed full-length SARS-CoV-2 genomes from multiple countries to determine ea... more In this study, we analyzed full-length SARS-CoV-2 genomes from multiple countries to determine early trends in the evolutionary dynamics of the novel COVID-19 pandemic. Results indicated SARS-CoV-2 evolved early into at least three phylogenetic groups, characterized by positive selection at specific residues of the accessory proteins ORF3a and ORF8. Also, we are reporting potential relevant sites under positive selection at specific sites of non-structural proteins nsp6 and helicase. Our analysis of co-evolution showed evidence of epistatic interactions among sites in the genome that may be important in the generation of variants adapted to humans. These observations might impact not only public health but also suggest that more studies are needed to understand the genetic mechanisms that may affect the development of therapeutic and preventive tools, like antivirals and vaccines. Collectively, our results highlight the identification of ongoing selection even in a scenario of conse...
The African swine fever virus (ASFV) is currently causing a world-wide pandemic of a highly letha... more The African swine fever virus (ASFV) is currently causing a world-wide pandemic of a highly lethal disease in domestic swine and wild boar. Currently, recombinant ASF live-attenuated vaccines based on a genotype II virus strain are commercially available in Vietnam. With 25 reported ASFV genotypes in the literature, it is important to understand the molecular basis and usefulness of ASFV genotyping, as well as the true significance of genotypes in the epidemiology, transmission, evolution, control, and prevention of ASFV. Historically, genotyping of ASFV was used for the epidemiological tracking of the disease and was based on the analysis of small fragments that represent less than 1% of the viral genome. The predominant method for genotyping ASFV relies on the sequencing of a fragment within the gene encoding the structural p72 protein. Genotype assignment has been accomplished through automated phylogenetic trees or by comparing the target sequence to the most closely related gen...
Classical swine fever (CSF) remains one of the most economically significant viral diseases affec... more Classical swine fever (CSF) remains one of the most economically significant viral diseases affecting domestic pigs and wild boars worldwide. To develop a safe and effective vaccine against CSF, we have constructed a triple gene-deleted pseudorabies virus (PRVtmv)-vectored bivalent subunit vaccine against porcine circovirus type 2b (PCV2b) and CSFV (PRVtmv+). In this study, we determined the protective efficacy of the PRVtmv+ against virulent CSFV challenge in pigs. The results revealed that the sham-vaccinated control group pigs developed severe CSFV-specific clinical signs characterized by pyrexia and diarrhea, and became moribund on or before the seventh day post challenge (dpc). However, the PRVtmv+-vaccinated pigs survived until the day of euthanasia at 21 dpc. A few vaccinated pigs showed transient diarrhea but recovered within a day or two. One pig had a low-grade fever for a day but recovered. The sham-vaccinated control group pigs had a high level of viremia, severe lymphoc...
The immune response against foot-and-mouth disease virus (FMDV) was studied in a murine model. In... more The immune response against foot-and-mouth disease virus (FMDV) was studied in a murine model. In untreated control mice, the inoculation of 10,000 suckling mouse 50% lethal doses of Ol Campos FMDV i.p. was followed by a burst of viraemia that disappeared in less than 4 days, i.e. when the neutralizing antibodies (NAb) reached titres above one neutralizing unit. In mice treated with cyclophosphamide, the curves of viraemia and NAb were significantly delayed. Nu/nu mice injected with FMDV had curves of viraemia and NAb identical to those of their nu/t littermates. We then studied the secondary (memory) immune reaction in the same model. In order to investigate which preimmunized cells participate in the elimination of actively replicating FMDV, mice were irradiated, then infected with FMDV, and 24 hr later repopulated with cells obtained from either donor mice that had been previously immunized by infection with live virus, or non-infected controls. The transfer of control (non-immunized) lymphoid cells was unable to eliminate the viraemia in recipient animals at times significantly different from those observed with irradiated recipients receiving no cells, while repopulation of recipients with 10(8) immune lymphoid cells (obtained from pooled thymus, blood, peritoneal exudate, spleen and lymph nodes of preinfected donor mice) led to undetectable titres of viraemia at Day 5 post-infection (p.i.). High doses of thymus cells were totally inactive, while a few as 10(7) donor spleen cells were able to abort viraemia at 6 days p.i. When enriched preparations of B or T spleen cells were adoptively transferred, only B cells were able to abort viraemia in irradiated recipients. It is concluded that, in the murine model of FMDV infection, B cells are mainly responsible for primary response and short-term immunological memory. In both cases the protective immune reaction is T-independent.
Trono, Karina G.; Dus Santos, María José; Wigdorovitz, Andrés; Rodríguez, S.; Chiavenna, S.; Ardi... more Trono, Karina G.; Dus Santos, María José; Wigdorovitz, Andrés; Rodríguez, S.; Chiavenna, S.; Ardila, Fernando Jorge; Borca, MV; Carrillo, C. ... Asociación entre genotipo y evolución patógena en variantes naturales del virus de la Leucosis Bovina. ... Sociedad Argentina de ...
African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks fo... more African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks for over a century in Africa ever since its first discovery in 1921. Since 1957, there have been sporadic outbreaks outside of Africa; however, no outbreak has been as devastating and as far-reaching as the current pandemic that originated from a 2007 outbreak in the Republic of Georgia. Derivatives with a high degree of similarity to the progenitor strain, ASFV-Georgia/2007, have been sequenced from various countries in Europe and Asia. However, the current strains circulating in Africa are largely unknown, and 24 different genotypes have been implicated in different outbreaks. In this study, ASF isolates were collected from samples from swine suspected of dying from ASF on farms in Ghana in early 2022. While previous studies determined that the circulating strains in Ghana were p72 Genotype I, we demonstrate here that the strains circulating in 2022 were derivatives of the p72 Genotype I...
Here, we announce the predicted structures of the 193 proteins encoded by African swine fever vir... more Here, we announce the predicted structures of the 193 proteins encoded by African swine fever virus (ASFV) strain Georgia 2007 (ASFV-G). Previously, only the structures of 16 ASFV proteins were elucidated.
Currently, there are no African swine fever (ASF) commercial vaccines that can be used to prevent... more Currently, there are no African swine fever (ASF) commercial vaccines that can be used to prevent or control the spread of ASF. The only effective experimental vaccines against ASF are live-attenuated vaccines.
No commercial vaccine is available to prevent African swine fever. The ASF pandemic caused by ASF... more No commercial vaccine is available to prevent African swine fever. The ASF pandemic caused by ASFV Georgia2007 strain (ASFV-G) is seriously affecting pork production in a contiguous area from Central Europe to East Asia.
In this study, we analyzed full-length SARS-CoV-2 genomes from multiple countries to determine ea... more In this study, we analyzed full-length SARS-CoV-2 genomes from multiple countries to determine early trends in the evolutionary dynamics of the novel COVID-19 pandemic. Results indicated SARS-CoV-2 evolved early into at least three phylogenetic groups, characterized by positive selection at specific residues of the accessory proteins ORF3a and ORF8. Also, we are reporting potential relevant sites under positive selection at specific sites of non-structural proteins nsp6 and helicase. Our analysis of co-evolution showed evidence of epistatic interactions among sites in the genome that may be important in the generation of variants adapted to humans. These observations might impact not only public health but also suggest that more studies are needed to understand the genetic mechanisms that may affect the development of therapeutic and preventive tools, like antivirals and vaccines. Collectively, our results highlight the identification of ongoing selection even in a scenario of conse...
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Papers by Manuel V Borca