Infection and Coinfection of Porcine-Selected Viruses (PPV1 to PPV8, PCV2 to PCV4, and PRRSV) in Gilts and Their Associations with Reproductive Performance.

Seven novel porcine parvoviruses (nPPVs) (PPV2 through PPV8) have been described, although their pathogenicity and possible effects on porcine reproductive failure (PRF) are undefined. In this study, these nPPVs were assessed in gilts from Colombia; their coinfections with PPV1, PCV2, PCV3, PCV4, and PRRSV and an association between the nPPVs and the reproductive performance parameters (RPPs) in sows were determined. For this, 234 serum samples were collected from healthy gilts from 40 herds in five Colombian regions, and the viruses were detected via real-time PCR. The results confirmed the circulation of PPV2 through PPV7 in Colombia, with PPV3 (40%), PPV5 (20%), and PPV6 (17%) being the most frequent. Additionally, no PCV4 or PPV8 was detected. PPV2 to PPV7 were detected in concurrence with each other and with the primary PRF viruses, and these coinfections varied from double to sextuple coinfections. Additionally, the association between nPPVs and PRF primary viruses was statistically significant for the presence of PPV6 in PCV3-positive (p < 0.01) and PPV5 in PPRSV-positive (p < 0.05) gilts; conversely, there was a significant presence of PPV3 in both PCV2-negative (p < 0.01) and PRRSV-negative (p < 0.05) gilts. Regarding the RPPs, the crude association between virus detection (positive or negative) and a high or low RPP was only statistically significant for PCV3 and the farrowing rate (FR), indicating that the crude odds of a low FR were 94% lower in herds with PCV3-positive gilts. This finding means that the detection of PCV3 in gilts (PCV3-positive by PCR) is associated with a higher FR in the farm or that these farms (with positive gilts) have lower odds (OR 0.06, p-value 0.0043) of a low FR. Additionally, a low FR tended to be associated with the detection of PPV4 and PPV5 (p-value < 0.20). This study is important for establishing the possible participation of nPPVs in PRF.

The Novel Porcine Parvoviruses: Current State of Knowledge and Their Possible Implications in Clinical Syndromes in Pigs.

Parvoviruses (PVs) affect various animal species causing different diseases. To date, eight different porcine parvoviruses (PPV1 through PPV8) are recognized in the swine population, all of which are distributed among subfamilies and genera of the Parvoviridae family. PPV1 is the oldest and is recognized as the primary agent of SMEDI, while the rest of the PPVs (PPV2 through PPV8) are called novel PPVs (nPPVs). The pathogenesis of nPPVs is still undefined, and whether these viruses are putative disease agents is unknown. Structurally, the PPVs are very similar; the differences occur mainly at the level of their genomes (ssDNA), where there is variation in the number and location of the coding genes. Additionally, it is considered that the genome of PVs has mutation rates similar to those of ssRNA viruses, that is, in the order of 10-5-10-4 nucleotide/substitution/year. These mutations manifest mainly in the VP protein, constituting the viral capsid, affecting virulence, tropism, and viral antigenicity. For nPPVs, mutation rates have already been established that are similar to those already described; however, within this group of viruses, the highest mutation rate has been reported for PPV7. In addition to the mutations, recombinations are also reported, mainly in PPV2, PPV3, and PPV7; these have been found between strains of domestic pigs and wild boars and in a more significant proportion in VP sequences. Regarding affinity for cell types, nPPVs have been detected with variable prevalence in different types of organs and tissues; this has led to the suggestion that they have a broad tropism, although proportionally more have been found in lung and lymphoid tissue such as spleen, tonsils, and lymph nodes. Regarding their epidemiology, nPPVs are present on all continents (except PPV8, only in Asia), and within pig farms, the highest prevalences detecting viral genomes have been seen in the fattener and finishing groups. The relationship between nPPVs and clinical manifestations has been complicated to establish. However, there is already some evidence that establishes associations. One of them is PPV2 with porcine respiratory disease complex (PRDC), where causality tests (PCR, ISH, and histopathology) lead to proposing the PPV2 virus as a possible agent involved in this syndrome. With the other nPPVs, there is still no clear association with any pathology. These have been detected in different systems (respiratory, reproductive, gastrointestinal, urinary, and nervous), and there is still insufficient evidence to classify them as disease-causing agents. In this regard, nPPVs (except PPV8) have been found to cause porcine reproductive failure (PRF), with the most prevalent being PPV4, PPV6, and PPV7. In the case of PRDC, nPPVs have also been detected, with PPV2 having the highest viral loads in the lungs of affected pigs. Regarding coinfections, nPPVs have been detected in concurrence in healthy and sick pigs, with primary PRDC and PRF viruses such as PCV2, PCV3, and PRRSV. The effect of these coinfections is not apparent; it is unknown whether they favor the replication of the primary agents, the severity of the clinical manifestations, or have no effect. The most significant limitation in the study of nPPVs is that their isolation has been impossible; therefore, there are no studies on their pathogenesis both in vitro and in vivo. For all of the above, it is necessary to propose basic and applied research on nPPVs to establish if they are putative disease agents, establish their effect on coinfections, and measure their impact on swine production.

Canine circovirus genomic characterization in dogs with and without diarrheal syndrome in Medellín, Colombia.

Canine circovirus (CanineCV) is an emerging agent described for the first time in 2011, it infects domestic and wild canids, mainly associated with gastrointestinal signs; however, it has also been reported in samples obtained from animals without clinical signs, so its pathogenesis and epidemiology are still poorly understood. In Colombia, the CanineCV was first reported in 2020 from CPV-2 positive dogs. In the present work, CanineCV was detected in 30% of fecal samples obtained from dogs with or without diarrhea, in the city of Medellín, Colombia. No coinfection with CPV-2 was found. The highest number of positive samples was found in the subgroup of animals with diarrhea. Phylogenetic and evolutionary analyses confirmed the separation of the CanineCV genomes into five different clades with a European origin of the Colombian viruses and at least two different introductions of the CanineCV into the country. Our results highlight the importance of the CanineCV in Colombian dog populations and the need for continue surveillance of emerging pathogens in canine populations.

Recovery of complete genomes of canine parvovirus from clinical samples.

Canine parvovirus (CPV) is a highly pathogenic virus that affects dogs, especially puppies. CPV is believed to have evolved from feline panleukopenia virus (FPV), eventually giving rise to three antigenic types, CPV-2a, 2b, and 2c. CPV-2 is recognized for its resilience in contaminated environments, ease of transmission among dogs, and pathogenicity for puppies. Despite the relevance of the virus, complete genome sequences of CPV available at GenBank, to date, are scarce. In the current study, we have developed a methodology to allow the recovery of complete CPV-2 genomes directly from clinical samples. For this, seven fecal samples from Gurupi, Tocantins, North Brazil, were collected from puppies with clinical signals of viral enteritis, and submitted to viral DNA isolation and amplification. Two multiplex PCR strategies were designed including primers targeting fragments of 400 base pairs (bp) and 1,000 bp along the complete genome. Sequencing was performed with the Nanopore® technology and results obtained with the two approaches were compared. Genome assembly revealed that the 400 bp amplicons generated larger numbers of reads, allowing a more reliable coverage of the whole genome than those attained with primers targeting the larger (1000 bp) amplicons. Nevertheless, both enrichment methodologies were efficient in amplification and sequencing. Viral genome sequences were of high quality and allowed more precise typing and subtyping of viral genomes compared to the commonly employed strategy relying solely on the analysis of the VP2 region, which is limited in scope. The CPV-2 genomes recovered in this study belong to the CPV2a and CPV-2c subtypes, closely related to isolates from the neighboring Amazonian region. In conclusion, the technique reported here may contribute to increase the number of full CPV genomes available, which is essential for understanding the genetic mechanisms underlying the evolution and spread of CPV-2.

Canine circovirus: An emerging or an endemic undiagnosed enteritis virus?

Canine Circovirus (CanineCV) belongs to the family Circoviridae. It is an emerging virus described for the first time in 2011; since then, it has been detected in different countries and can be defined as worldwide distribution virus. CanineCV infects domestic and wild canids and is mainly related to hemorrhagic enteritis in canines. However, it has been identified in fecal samples from apparently healthy animals, where in most cases it is found in coinfection with other viral agents such as the canine parvovirus type-2 (CPV). The estimated prevalence/frequency of CanineCV has been variable in the populations and countries where it has been evaluated, reaching from 1 to 30%, and there are still many concepts to define the epidemiological characteristics of the virus. The molecular characterization and phylo-evolutive analyses that allow to postulate the wild origin and intercontinental distribution of the virus. This review focuses on the importance on continuing research and establish surveillance systems for this emerging virus.

The Prevalence and Genetic Diversity of PCV3 and PCV2 in Colombia and PCV4 Survey during 2015-2016 and 2018-2019.

Four genotypes of circovirus have been recognized in swine, with PCV2 and PCV3 being the most associated with clinical manifestations, while PCV4 does not have a defined disease. In addition, PCV2 is associated with different syndromes grouped as diseases associated with porcine circovirus (PCVAD), while PCV3 causes systemic and reproductive diseases. In the present study, we retrospectively detected PCV2, PCV3, and PCV4 in Colombia during two periods: A (2015-2016) and B (2018-2019). During period A, we evaluated stool pools from the 32 Colombian provinces, finding a higher prevalence of PCV3 compared to PCV2 as well as PCV2/PCV3 co-infection. Furthermore, we determined that PCV3 had been circulating since 2015 in Colombia. Regarding period B, we evaluated sera pools and tissues from abortions and stillborn piglets from the five provinces with the highest pig production. The highest prevalence found was for PCV3 in tissues followed by sera pools, while PCV2 was lower and only in sera pools. In addition, PCV2/PCV3 co-infection in sera pools was also found for this period. The complete genome sequences of PCV3 and PCV3-ORF2 placed the Colombian isolates within clade 1 as the majority in the world. For PCV2, the predominant genotype currently in Colombia is PCV2d. Likewise, in some PCV3-ORF2 sequences, a mutation (A24V) was found at the level of the Cap protein, which could be involved in PCV3 immunogenic recognition. Regarding PCV4, retrospective surveillance showed that there is no evidence of the presence of this virus in Colombia.

Evidence of bovine leukemia virus circulating in sheep and buffaloes in Colombia: insights into multispecies infection.

Bovine leukemia virus (BLV) is the causative agent of leukemia/lymphoma in cattle. However, previous evidence has shown its presence in other species of livestock as well as in humans, suggesting that other species can be accidental hosts of the virus. In viral infections, receptors that are common to different animal species are proposed to be involved in cross-species infections. For BLV, AP3D1 has been proposed to be its receptor, and this protein is conserved in most mammalian species. In Colombia, BLV has been reported in cattle with high prevalence rates, but there has been no evidence of BLV infections in other animal species. In this study, we tested for the virus in sheep (n = 44) and buffaloes (n = 61) from different regions of Colombia by nested PCR, using peripheral blood samples collected from the animals. BLV was found in 25.7% of the animals tested (12 buffaloes and 15 sheep), and the results were confirmed by Sanger sequencing. In addition, to gain more information about the capacity of the virus to infect these species, the predicted interactions of AP3D1 of sheep and buffaloes with the BLV-gp51 protein were analyzed in silico. Conserved amino acids in the binding domains of the proteins were identified. The detection of BLV in sheep and buffaloes suggests circulation of the virus in multiple species, which could be involved in dissemination of the virus in mixed livestock production settings. Due to the presence of the virus in multiple species and the high prevalence rates observed, integrated prevention and control strategies in the livestock industry should be considered to decrease the spread of BLV.

The first report of porcine parvovirus 7 (PPV7) in Colombia demonstrates the presence of variants associated with modifications at the level of the VP2-capsid protein.

There are a wide variety of porcine parvoviruses (PPVs) referred to as PPV1 to PPV7. The latter was discovered in 2016 and later reported in some countries in America, Asia, and Europe. PPV7 as a pathogenic agent or coinfection with other pathogens causing disease has not yet been determined. In the present study, we report the identification of PPV7 for the first time in Colombia, where it was found retrospectively since 2015 in 40% of the provinces that make up the country (13/32), and the virus was ratified for 2018 in 4/5 provinces evaluated. Additionally, partial sequencing (nucleotides 380 to 4000) was performed of four Colombian strains completely covering the VP2 and NS1 viral genes. A sequence identity greater than 99% was found when comparing them with reference strains from the USA and China. In three of the four Colombian strains, an insertion of 15 nucleotides (five amino acids) was found in the PPV7-VP2 capsid protein (540-5554 nt; 180-184 aa). Based on this insertion, the VP2 phylogenetic analysis exhibited two well-differentiated evolutionarily related groups. To evaluate the impact of this insertion on the structure of the PPV7-VP2 capsid protein, the secondary structure of two different Colombian strains was predicted, and it was determined that the insertion is located in the coil region and not involved in significant changes in the structure of the protein. The 3D structure of the PPV7-VP2 capsid protein was determined by threading and homology modeling, and it was shown that the insertion did not imply a change in the shape of the protein. Additionally, it was determined that the insertion is not involved in suppressing a potential B cell epitope, although the increase in length of the epitope could affect the interaction with molecules that allow a specific immune response.

Field infection of a gilt and its litter demonstrates vertical transmission and effect on reproductive failure caused by porcine circovirus type 3 (PCV3).

BACKGROUND: PCV3 is a member of the Circovirus family, associated with disease and mortality in pigs. It is not clear whether PCV3 putatively causes clinical symptoms and disease. In the present case, we reported a gilt infected with PCV3 associated with reproductive failures, vertical transmission, tissue lesions, viral replication by in situ hybridization, and the hypothesis that some strains of PCV3 clade one are associated with reproductive failures at the field level. CASE PRESENTATION: In May 2019, a pig farm in Colombia reported increased reproductive failures, and the presence of PCV3 in gilts and sows was established in a single form or coinfections, mainly with PCV2 and PPV7. Ten sows with a single infection with PCV3 were found, and one gilt with a pre-farrowing serum viral load above 103 was studied. This gilt was followed up during the pre-farrowing, farrowing period and on her litter for 6 weeks. During dystocic farrowing, a mummy and ten piglets were released, including two weak-born piglets. The highest viral loads for PCV3 were found in the mummy and the placenta. In the weak-born piglets, there were viral loads both in serum and in tissues, mainly in the mesenteric ganglia and lung. Replication of PCV3 in these tissues was demonstrated by in situ hybridizations. PCV3 was also found in the precolostrum sera of piglets and colostrum, showing vertical transmission. The viral load in piglets decreased gradually until week six of life. The viral genome's complete sequencing was made from the mummy, and its analysis classified it as PCV3 clade one. CONCLUSIONS: This report confirms that PCV3 can cause disease at the field level, and putatively, in this case, we find the generation of reproductive failures. The ability of PCV3 to cause disease as a putative pathogen may be associated with the viral load present in the pig and the strain that is affecting the farm. For this case, we found that viral loads above 103 (4.93 log genomic copies / mL) in the gilt were associated with clinical manifestation and that some PCV3 strains belonging to clade one are more associated with the reproductive presentation.

First detection and full genomic analysis of Canine Circovirus in CPV-2 infected dogs in Colombia, South America.

Canine Circovirus (CanineCV) is an emerging virus which since its first report in USA in 2012, it has been described worldwide. It was the second mammalian circovirus species identified in dogs and its role in canine enteritis is still being uncertain as much as its association in disease with the Canine Parvovirus-2 (CPV-2). Here, we aim to confirm for the first time the presence of CanineCV in Colombia and to develop phylogenetic evolutive analyses of CanineCV in CPV-2 positive animals. DNA from samples were extracted and PCR, full genome sequencing and phylogenetic analysis was performed to detect and characterize CanineCV. From a total of 30 CPV-2 positive samples, 16.6% (n = 5) were positives for CanineCV. Sequencing analysis of Colombian CanineCV wild-type strains displayed high identity to each other (99.5-99.7% nt; 99.7% aa). The full genome phylogenetic analysis confirmed that worldwide reported CanineCV strains were separated into four distinct genotypes in addition to a European origin of the South American CanineCV strains. This study demonstrated the importance of continue surveillance of emerging viruses in canine populations and confirm for the first time the circulation and origin of CanineCV in Colombia.

First detection of porcine circovirus type 3 in Colombia and the complete genome sequence demonstrates the circulation of PCV3a1 and PCV3a2.

Porcine circovirus 3 (PCV3) was recently discovered and is a new species of the genus circovirus. Clinically, it is associated with absence of symptoms or with different clinical syndromes. It has been reported in different countries of America, Europe and Asia. Last year, in Colombia, some farms have reported symptoms similar to those caused by PCV2. Samples were taken from two farms located in the centre of the country, and the presence of PCV3 was determined by PCR in two samples, one from a pool of sera and another from mesenteric lymph node. The strains were fully sequenced (GenBank accession numbers MH327784 and MH327785) and classified into subgroups a1 and a2. According to this classification and its analysis, strain a2 is located within the group called "Linker" that may be evolving towards group "b". In addition to the above, the two Colombian strains were compared with 104 strains reported in the GenBank database. The phylogenetic tree obtained grouped according to the classification of subgroups a1, a2, b1 and b2. It was found that subgroups a1 and a2 were well grouped when comparing whole genomes, but the same was not observed with the strains of group "b". In the latter, no subgroups were evidenced when comparing complete genomes. It is suggested that a new classification of PCV3 subgroups should be proposed, based on whole genome sequences. This is the first report of PCV3 in Colombia and its complete genome sequence.

Longitudinal comparison of the humoral immune response and viral load of Porcine Circovirus Type 2 in pigs with different vaccination schemes under field conditions.

Background: Porcine Circovirus type 2 (PCV2) infections are distributed worldwide and cause Porcine Circovirus Associated Disease (PCVAD). To minimize the impact of PCV2 infection on swine health and production, different vaccination schemes have been used since 2006. However, the association between vaccination schemes, virus load and disease under field conditions are not completely understood. Therefore, the objective of this study was to compare the effect of two different PCV2 vaccination schemes on the humoral response and PCV2 load in pigs after weaning under field conditions. Methods: Two commercial pig farms (Farm A and B), endemically infected with PCV2, which were using two different PCV2 subunit vaccinations schemes for sow, gilts and piglets, were selected. We designed a longitudinal study and measured IgG levels by ELISA and virus load by quantitative PCR in pigs after weaning. Forty 3-week old piglets were randomly selected at weaning and followed for 20 weeks. IgG levels and virus loads were compared within and between farms and considered statistically different if the non-parametric Kruskal Wallis test p value was lower than 0.05. Results: We found that low virus loads were maintained in pigs from both farms regardless of the vaccination scheme used (p>0.05). However, there was significant difference in the mean IgG levels observed over time (p<0.05), suggesting that different humoral immune response are not necessarily associated with different virus loads observed over time. Conclusions: These results are important because they can help to prevent PCV2 infections using different vaccination schemes to minimize the effect of PCVAD on swine health and production.

Comportamiento del virus de la bronquitis infecciosa aviar en aves con sintomatología respiratoria provenientes de granjas de producción del Departamento de Cundinamarca / Avian Infectious Bronchitis virus behavior in birds from commercial farms with a history of respiratory disease, located in the department of Cundinamarca

Objetivo. Evaluar la dinámica serológica contra el virus de bronquitis infecciosa aviar y su relación con la presentación y/o antecedentes de signos clínicos y hallazgos patológicos, bajo condiciones de campo. Materiales y métodos. Se realizó un muestreo al azar en dos fases, en pollo de engorde y reproductoras de granjas del Departamento de Cundinamarca. En la primera fase se tomó muestra de sangre a un total de 224 aves, distribuidas en 7 granjas. En la segunda fase, realizada 20 días posteriores al primer muestreo, se tomó una segunda muestra al mismo número de aves empleadas inicialmente. Las muestras de los sueros obtenidos se emplearon para la realización del inmunoensayo ligado a enzima (ELISA), diseñado para detectar anticuerpos frente al virus de la bronquitis infecciosa aviar en suero sanguíneo. Resultados. Se obtuvo que del total de las granjas analizadas el 85.72% mostró reactividad serológica al virus de la Bronquitis Infecciosa aviar (VBIA), con correlación ante la presencia de los signos clínicos o antecedentes respiratorios en granja.

Objective. Evaluate the serological dynamics against avian infectious bronchitis virus and its relationship with the presentation and / or a history of clinical signs and pathological findings, under field conditions. Materials and methods. A random sampling was conducted in two phases, in broiler and breeder farms located in the Department of Cundinamarca. In the first phase blood sample were taken from a total of 224 birds, distributed over the 7 farms. In the second phase, carried out 20 days after the first, a second sample was collected from the same number of birds used in the first phase. The serum samples were used to carry out the enzyme linked immunoassay (ELISA) intended to detect antibodies against avian infectious bronchitis virus in blood serum. Results. As a result it was found that from the total farms analyzed the 85.72% showed serologic reactivity against Avian Infectious Bronchitis Virus (AIBV) that correlated to the presence of clinical signs or previous history of respiratory disease in the farm.

An inactivated vaccine from a field strain of bovine herpesvirus-1 (BoHV-1) has high antigenic mass and induces strong efficacy in a rabbit model.

Bovine Herpesvirus-1 (BoHV-1) is a DNA virus belonging to the family Herpesviridae, subfamily Alfaherpesvirinae; it is a worldwide pathogen, causing serious economic losses in livestock. In Colombia there have been multiple isolates of BoHV-1 that have been subjected to molecular characterization, classifying most of the country isolates as BoHV-1.1. In the present study we developed and evaluated an ethyleneimine binary inactivated isolate from the native BoHV-1 strain (Córdoba-2) in a rabbit model of vaccination and infection. The vaccine was evaluated in two phases, one of immunogenicity with vaccination and a booster after 21 days, and an evaluation phase of protection against challenge with a highly virulent reference strain. The results demonstrate optimum serum-conversion, with protective neutralizing antibody titers 28 days post vaccination and optimal protection against challenge with the reference strain with decreased clinical signs of infection, protection against the onset of fever and decrease of virus excretion post challenge. In conclusion, our results show the enormous potential that an immunogenic inactivated vaccine has produced from the native BoHV-1.1 strain, which produces a high antigen mass to the vaccine to induce optimal immunity and protection, and it is a strong candidate for evaluation and possible future use in different cattle populations.

Molecular and in vitro characterization of field isolates of bovine herpesvirus-1.

Bovine Herpesvirus-1 (BoHV-1) is distributed worldwide and is a major pathogen in cattle, being the causal agent of a variety of clinical syndromes. The aim of this study was to isolate and to characterize (molecular and biological characterization) BoHV-1 from 29 immunosuppressed animals. It was possible to obtain 18 isolates, each from a different animal, such as from the respiratory and reproductive tracts. In some cases the cytopathic effect was visible 12 hours post-inoculation, and became characteristic after 36-48 hours. Biological characteristics were evaluated and compared with Iowa and Colorado-1 reference strains, and differences were found in plaque size, virus titer measured by TCID50 and PFU/mL, and one step virus curves. These results showed that some isolates had a highly virulent-like behavior in vitro, compared to the reference strains, with shorter eclipse periods, faster release of virus into the supernatants, and higher burst size and viral titer. There were no differences in glycoprotein expression of BoHV-1 isolates, measured by Western blot on monolayers. Moreover, using restriction endonucleases analysis, most of the viruses were confirmed as BoHV-1.1 and just one of them was confirmed as BoHV-1.2a subtype. These findings suggest that some wild-type BoHV-1 isolates could be useful as seeds to develop new monovalent vaccines.

Prevalencia serológica y aislamiento del Herpesvirus Bovino-1 (BHV-1) en hatos ganaderos de Antioquia y del Valle del Cauca / Serological prevalence and isolation of Bovine herpesvirus-1 (BHV-1) in cattle herds from Antioquia and Valle del Cauca provinces / Prevalência sorológica e isolamento do Herpesvirus Bovino-1 (BHV-1) em rebanhos bovinos de Antioquia e Valle del Cauca

El BHV-1 es un agente causante de graves pérdidas económicas. En nuestro país, ha sido reportado desde comienzos de los años 70 y aunque existe un plan de vacunación y prevención de la enfermedad, se sospecha que es uno de los principales limitantes de las explotaciones ganaderas del país. El objetivo de la presente investigación fue desarrollar un estudio serológico de la presencia del BHV-1 en dos sistemas de producción ganadera de leche y carne con antecedentes de no vacunación y posterior intento de aislamiento viral. Se realizó un estudio serológico transversal en el cual se muestrearon 316 individuos pertenecientes a 6 diferentes haciendas ganaderas, ubicadas en los departamentos de Antioquia y del Valle del Cauca. Utilizando la prueba de seroneutralización en cultivo celular, se encontró un 100% de prevalencia serológica por hato para el BHV-1 y una prevalencia general por individuos del 75.63%. La prevalencia para los hatos pertenecientes a los departamentos de Antioquia y del Valle fue del 85.51% y 69.84% respectivamente. Posteriormente, mediante inmunosupresión farmacológica, se realizó aislamiento viral en individuos que presentaron los títulos seroneutralizantes más altos, lográndose aislamientos del virus tanto de toros como de vacas y de diferentes muestras, indicando un estado de enzootia de la infección y demostrando que el BHV-1 sigue siendo uno de los agentes de mayor difusión en diferentes ámbitos ganaderos del país.

Bovine herpesvirus 1 (BHV-1) causes severe economic losses. This virus has been reported in Colombia since the early 70s, and although vaccination and prevention plans have been established, it is considered one of the major constraints for the cattle industry. Our objective was to conduct a serological survey for the presence of BHV-1 in non-vaccinated beef cattle and dairy farms. A cross-sectional serological survey, sampling 316 unvaccinated individuals from six farms located in Antioquia and Valle del Cauca provinces was conducted. The serum neutralization test showed 100% sero-prevalence of BHV-1 in each herd and 75.63% overall prevalence for individuals. The prevalence for herds in Antioquia and Valle provinces was 85.51% and 69.84% respectively. By immunosuppressive therapy, viral isolations were attempted from samples of individuals with the highest neutralizing titers, obtaining isolates from both bulls and cows, indicating an enzootic state of infection and demonstrating that BHV-1 remains one of the most widely dispersed agents in the country.

O BHV-1 é um agente que causa grandes perdas econômicas. Em nosso país, tem sido reportado desde começos dos anos 70 e embora exista um plano de vacinação e prevenção da doença, suspeita-se que é um dos principais limitantes da produção em no pais. O objetivo do presente trabalho foi desenvolver um estudo sorológico da presença do BHV-1 em dois sistemas de produção de leite e de corte com antecedentes de não vacinação e posterior intento de isolamento viral. Foi realizado um estudo sorológico transversal no qual foram mostrados 316 indivíduos pertencentes a seis fazendas localizadas nos departamentos de Antioquia e Valle del Cauca. Foi utilizada um teste de soro neutralização em cultivo celular, foi encontrado um 100% de prevalência sorológica por fazenda BHV-1 e uma prevalência geral por indivíduos do 75.63%. A prevalência para as fazenda dos departamentos de Antioquia e Valle del Cauca foi do 85.51% e 69.84%, respectivamente. Posteriormente, mediante imuno supressão farmacológica, foi realizado um isolamento viral em indivíduos que apresentaram que títulos soroneutralizantes mais altos, logrando-se isolamentos do vírus em touros e vacas e de diferentes amostras, indicando um estado de enzootia da infecção e demonstrando que o BHV-1 segue sendo um dos agentes de maior difusão em diferentes âmbitos gerados no país.

Perspectivas para el control del Virus de la Diarrea Viral Bovina (BVDV) / Perspectivas para o controle do vírus da diarréia viral Bovina (BVDV) / Perspectives to control Bovine Viral Diarrhea Virus (BVDV)

El virus de la diarrea viral bovina (VDVB) es uno de los agentes infecciosos más importantes del ganadobovino. Este patógeno tiene una distribución mundial y es endémico en la mayoría de las poblacionesbovinas donde alcanza un nivel de seropositividad del 40 al 80%. Así mismo, ocasiona pérdidas económicasprincipalmente de origen reproductivo. Una de las características más importantes de este virus es sualta frecuencia de mutación y la tendencia a la recombinación, lo que ha llevado a que tenga una grandiversidad genética y antigénica; problema que se ve reflejado en las múltiples manifestaciones clínicasobservadas en los animales afectados y en el difícil control de la enfermedad. Los programas de controlutilizados por algunos países se fundamentan en gran medida en la eliminación de la principal fuentede infección: los animales persistentemente infectados (PI), así como en mejorar la respuesta inmunemediante el empleo de vacunas. La inmunización con vacunas inactivadas y virus vivo modificado contraVDVB se ha empleado por décadas sin evidencia de una reducción significativa de la prevalencia de laenfermedad o un control de la infección, por lo cual se han empezado a desarrollar otras estrategiasexperimentales como las vacunas recombinantes, donde se seleccionan genes específicos del BVDV con elfin de inmunizar al ganado buscando superar los inconvenientes de las vacunas convencionales.

Bovine Viral Diarrhea Virus (BVDV) is one of the most important infectious agents in cattlepopulation. BVDV is widespread throughout the world and it is endemic disease in most of the cattle population where 40 to 80% are seropositive. It causes economic losses mainly in breeding cattle. BVDVgenetic and antigenic diversity is due to the virus high mutation and recombination frequency, which isreflected in many clinical manifestations and the difficult control of the disease. Control and preventionmeasures implemented by some countries are based on the elimination of the main source of infection: thepersistently infected animals (PI animals), as well as the improvement of the immune response throughthe use of vaccines. Immunization with inactivated and modified-live vaccines has been used for decadeswithout any significant improvement. New experimental strategies are being developed: recombinantvaccines where BVDV specific genes are selected in order to immunize cattle and thus overcome theshortcomings of conventional vaccines.

O vírus da diarréia viral bovina (VDVB) é um dos agentes mais importantes do gado bovino. Estepatogénio tem uma distribuição mundial e é endêmico na maioria das populações bovinas onde alcançaum nível de seropositividade do 40 ao 80%. Também ocasiona perdas econômicas, principalmente deorigem reprodutivo. Uma das características mais importantes do vírus é sua alta freqüência de mutação etendência à recombinação, o que tem ocasionado uma grande diversidade genética e antigênica; problemaque ocasiona múltiples manifestações clinicas observadas nos animais afetados e no difícil controle dadoença. Os programas de controle utilizados por alguns países que fundamentam em grande medidaa eliminação da principal fonte de infecção: os animais persistentemente infectados (PI). Assim comomelhorar a resposta imune mediante o uso de vacinas. A imunização com vacinas inativas e vírus vivomodificado contra o VDVB tem-se utilizado por décadas sim evidencia de uma redução significativa daprevalência da doença o um controle da infecção, pelo qual se utilizam estratégias experimentais comovacinas recombinantes, onde se selecionam genes específicos do BVDV com o propósito de imunizar ogado buscando superar os inconvenientes das vacinas convencionais.

Vacunas contra ll herpesvirus bovino-1: una mirda desde el pasado hacia el futturo de la inmunización / Bovine Herpesvirus-1 Vaccine’s: A Look From The Past To The Immunization Future

El herpesvirus Bovino-1 (BHV-1) es uno de los principales patógenos que afecta el ganado; la infección primaria se acompaña de varias manifestaciones clínicas tales como la rinotraqueitis, aborto, vulvovaginitis/balanopostitis pustular y en algunos casos, enfermedad neurológica. Luego de la recuperación, la infección persiste durante toda la vida del individuo en un estado de latencia en ganglios nervioso trigémino o sacro. La Organización Mundial de Sanidad Animal (OIE) reporta que la vacunación contra el BHV-1 puede ser efectiva en reducir las manifestaciones clínicas y en consecuencia las pérdidas económicas, pero no logra proteger completamente de la infección. Es por esto que durante los últimos años se han desarrollado gran cantidad de agentes vacunales que van desde las vacunas clásicas inactivadas hasta aquellas que usan tecnología de DNA recombinante. El presente artículo se enfoca en presentar una actualización acerca de las vacunas más usadas desde hace ya varios años y resumir los avances más importantes en la generación de nuevas vacunas contra el BHV-1; tratando así de abrir un nuevo panorama para la generación de vacunas en Colombia.

Bovine herpesvirus-1 is one of the most important pathogens of cattle; the primary infection is characterized by clinical manifestations such as infectious bovine rhinotracheitis, abortion, infectious pustular vulvovaginitis and in some cases, neurological signs. After recovering, the virus establishes viral latency in sensory neurons of trigeminal or sacral ganglia. The World Organization for Animal Health (OIE) reports that vaccination against BHV-1 could be useful to reduce the clinical manifestations and in consequence the economic looses, but it can not protect against the infection. Therefore, a huge amount of vaccines have been developed that includes from classic inactivation to recombinant DNA technologies. This paper makes an updated review about the most used vaccines since many years and try to resume the most important advances in BHV-1 vaccine’;s generation; trying to open a window for new vaccine’;s generation in Colombia.

Virus de Fiebre Aftosa: una aproximación al estado del arte / Vírus da Febre Aftosa: uma aproximação ao estado da arte / Foot and Mouth Disease virus: an Approach to the state of the art

La fiebre aftosa es una enfermedad viral causada por uno de los miembros prototipo de la familiaPicornaviridae, y aunque dicha enfermedad ha sido descrita hace más de 5 siglos, sigue siendo una de lasprincipales barreras económicas y sanitarias tanto para importación como para exportación de ganadobovino y porcino y sus derivados. Dado que el 75% del hato bovino nacional se encuentra libre de laenfermedad con vacunación, es necesario que nos actualicemos en el estado del arte de la enfermedadpara poder así estar preparados para el anhelado momento en el que el país sea declarado libre sinvacunación y apartir del cual, un completo conocimiento de la enfermedad, sus factores de riesgo, sucorrecto reconocimiento y diagnóstico, van a ser clave para mantener este importante estatus zoosanitarioque beneficia tanto a la comunidad ganadera como al país.

Foot-and-Mouth disease (FMD) is a viral disease caused by a prototype member of the Picornaviridaefamily. Although the disease has been described for more than 5 centuries, it remains one of the majorhealth and economic barriers for cattle and swine import and export. Since 75% of the national cattle herdis FMD free, it is necessary to provide an updated literature review of the disease. Updated informationof FMD will assist in the decision making of the need and use of vaccines, especially at the time when thecountry is declared free of FMD.

A febre aftosa é uma doença viral causada por dos membros protótipo da família Picornaviridae.Embora que esta doença tem sido descrita a mais cinco séculos, tem sido a principal barreira econômicae sanitária pra a importação e exportação de gado bovino e suíno e seus derivados. Dado que o 75% dorebanho bovino nacional encontra-se livre da doença com vacinação, é necessária a atualização do estadoda arte da doença para poder assim estar preparados para o esperado momento em que o país seja declaradolivre de vacinação. Momento pelo qual, um completo conhecimento da doença, seus fatores de risco, seucorreto reconhecimento e diagnóstico, serão chaves para manter este importante status zoosanitario quebeneficia tanto aos criadores com ao país.

Latencia del heppesvirus bovino-1: el papel de los transcritos relacionados con latencia (rl) / Bovine Herpesvirus-1: The Role of Latency-Related Genes

El herpesvirus bovino-1 es un virus de distribución mundial causante de graves pérdidas económicas debidas principalmente a la disminución de la eficiencia y en los indicadores de salud y productividad de cualquier hato ganadero infectado. Luego de la infección inicial del tracto respiratorio de los animales, el virus establece un estado de latencia viral en las neuronas sensoriales del ganglio trigémino y en los centros germinales de las tonsilas faríngeas. Periódicamente, el virus es reactivado y excretado en secreciones a través de las cuales puede infectar a otros animales susceptibles. Durante dicho estado de latencia hay disminución dramática de la expresión de genes virales, llevando solo a la expresión de dos transcritos: El RNA codificado por el gen relacionado con latencia (RL) y el ORF-E viral. Múltiples estudios demuestran como el RL y el ORF-E están involucrados en la regulación del complejo ciclo de latencia y reactivación de la infección. La presente revisión de literatura se enfocará en describir y analizar los distintos estudios que han llevado a dilucidar el papel jugado por el gen RL y el ORF-E, sus transcritos y sus productos proteicos en el establecimiento, mantenimiento y reactivación de la latencia del HVB-1.

Bovine herpesvirus-1 is a world wide spread virus that causes significant economic losses due mainly to a decrease in the efficiency and in the health and productivity indicators in all the infected herds. After a primary infection of the respiratory tract of the animals, the virus establishes viral latency state in sensory neurons of trigeminal ganglia and germinal centers of pharyngeal tonsils. Periodically, the virus reactivates from latency, is shed through secretions, and can infect other susceptible animals. During latency there is a dramatic reduction of viral gen expression; only two transcripts are abundantly expressed: the latency related (LR) RNA and the viral ORF-E. Multiple studies have shown LR and ORF-E role in the regulation of BHV-1 latencyreactivation cycle. This review focuses on the description and analysis of the litherature that had lead to incriminate LR gene and viral ORF-E, their transcripts and protein products in the establishment, maintenance and reactivation of BHV-1 latency state.