ABSTRACT
High Pathogenicity Avian Influenza (HPAI) poses a significant threat to public and animal health. Clade 2.3.4.4b recently emerged from the Eastern hemisphere and disseminated globally, reaching the Latin American (LATAM) region in late 2022 for the first time. HPAI in LATAM has resulted in massive mortalities and culling of poultry and wild birds, causing infection in mammals and humans. Despite its meaningful impact in the region, only occasional evidence about the genetic and epitope characteristics of the introduced HPAI is reported. Hence, this study seeks to phylogenetically characterize the molecular features and the source of HPAI in LATAM by evaluating potential antigenic variations. For such a purpose, we analyzed 302 whole genome sequences. All Latin American viruses are descendants of the 2.3.4.4b clade of the European H5N1 subtype. According to genomic constellations deriving from European and American reassortments, the identification of three major subtypes and eight sub-genotypes was achievable. Based on the variation of antigenic motifs at the HA protein in LATAM, we detected three potential antigenic variants, indicating the HA-C group as the dominant variant. This study decidedly contributes to unraveling the origin of the 2.3.4.4b clade in LATAM, its geographic dissemination, and evolutionary dynamics within Latin American countries. These findings offer useful information for public health interventions and surveillance initiatives planned to prevent and manage the transmission of avian influenza viruses.
ABSTRACT
RESUMEN Objetivo. identificar el virus de la anemia infecciosa aviar (chicken anemia virus, CAV) en granjas avícolas y aves de traspatio en Antioquia, Colombia. Materiales y métodos. Se tomaron muestras de sangre y plumas de gallinas ponedoras; en cada granja se eligieron tres aves de seis edades diferentes (1, 15, 30, 60, 90 y 120 días de edad). También se obtuvieron muestras de aves de traspatio ubicadas cerca de las granjas estudiadas. Se realizó ELISA y PCR para el análisis de las muestras. Resultados. Mediante PCR, el 84% de las aves resultaron positivas al CAV en sangre total y el 66% en muestras de plumas. El 60% de las aves de traspatio dieron positivo en sangre y el 40% en folículo de pluma. Mediante ELISA, el 22% de las aves de las granjas avícolas presentó títulos de anticuerpos altos y el 19% moderados. En las aves de traspatio, el 43% presentó títulos de anticuerpos altos y 29% moderados. Además, los resultados de la prueba de RFLP y la secuenciación mostraron que el virus circulante encontrado en este estudio era diferente del de la cepa vacunal Cux-1 utilizada en el país. Conclusiones. El CAV está presente en Colombia en aves comerciales como de traspatio. Según los hallazgos, un alto porcentaje de las aves dieron positivo para la detección viral, aunque el número de aves positivas por anticuerpos fue bajo. Se requiere determinar las características del virus circulante para explicar la respuesta de anticuerpos obtenida.
ABSTRACT Objective. identify the presence of chicken anemia virus (CAV) in poultry farms and backyard chickens from Antioquia, Colombia. Materials and Methods. Blood and feather samples were taken from laying chickens; in each farm, three birds of six different ages (1, 15, 30, 60, 90, and 120 days old) were chosen randomly. Backyard chicken samples were also obtained near the research farms. We used serology and molecular techniques to analyze the samples. Results. By PCR, the 84% of the birds were positive in whole blood and 66% were positive in feather samples. The 60% of backyard chickens tested were positive in blood and 40% in feather follicle. By serology, the 22% of the poultry farm birds presented high antibody titers and 19% moderate antibody titers. In the backyard chickens, 43% of them presented high antibody titers and 29% moderate antibody titers. In addition, results from the RFLP test and sequencing showed that the circulating virus found in this study was different from the Cux-1 vaccine strain used in Colombia. Conclusions. CAV is present in Colombia in both commercial and backyard chickens. According to the findings, a high percentage of the birds tested positive for viral detection, whereas the number of birds that tested positive for antibodies was low. Thus, the characteristics of the circulating virus need to be determined to explain the antibody response observed in this study.
ABSTRACT
Influenza is one of the most critical viral agents involved in the respiratory disease complex affecting swine production systems worldwide. Despite the absence of vaccination against swine influenza virus in Colombia, the serologic reactivity to classic H1N1 and H3N2 subtypes reported since 1971 indicates the virus has been circulating in the country's swine population for several decades. However, successful isolation and sequencing of field virus from pigs was nonexistent until 2008, when H1N1 classical influenza virus was identified. One year later, due to the emergence of the influenza A (H1N1) pdm09 virus, responsible for the first global flu pandemic of the 21st century, it was introduced in the country. Therefore, to understand the impact of the introduction of the H1N1pdm09 virus in Colombia on the complexity and dynamics of influenza viruses previously present in the swine population, we carried out a study aiming to characterize circulating viruses genetically and establish possible reassortment events that might have happened between endemic influenza viruses before and after the introduction of the pandemic virus. A phylogenetic analysis of ten swine influenza virus isolates from porcine samples obtained between 2008 and 2015 was conducted. As a result, a displacement of the classical swine influenza virus with the pdmH1N1 virus in the swine population was confirmed. Once established, the pandemic subtype exhibited phylogenetic segregation based on a geographic pattern in all the evaluated segments. The evidence presents reassortment events with classic viruses in one of the first H1N1pdm09 isolates. Thus, this study demonstrates complex competition dynamics and variations in Colombian swine viruses through Drift and Shift.
ABSTRACT
The Orthomyxoviridae family includes the genera Influenzavirus, Isavirus, Quaranjavirus, and Thogotovirus. In turn, Influenzavirus can be classified into four types: α, ß, γ, and δ (Formerly A, B, C, and D), from which Alphainfluenzavirus (AIV) has the broadest host range, including birds, mammals, reptiles, and amphibians. Additionally, AIV has shown global epidemiological relevance owing to its pandemic potential. The epidemiological relevance of Chiropteran due to its multiple functional characteristics makes them ideal reservoirs for many viral agents. Recently, new influenza-like subtypes have been reported in Neotropical bats, but little is known about the relevance of bats as natural reservoirs of influenza viruses. Therefore, the current study aimed to determine the presence of AIV and new influenza-like subtypes in South American bats. For a better understanding of the drivers and interactions between AIV and bats, we used molecular assays with different gene targets (i.e., M, NP, and PB1) to identify AIV in New World bats. A housekeeping gene (CytB) PCR was used to check for nucleic acid preservation and to demonstrate the bat-origin of the samples. A total of 87 free-living bats belonging to 25 different species of the families Phyllostomidae and Vespertilionidae were collected in Casanare, Colombia. As a result, this study found seven AIV-positive bat species, three of them reported for the first time as AIV prone hosts. Neither of the AIV-like analyzed samples were positive for H17N10/H18/N11 subtypes. Although additional information is needed, the presence of a completely new or divergent AIV subtype in neotropical bats cannot be discarded. Collectively, the results presented here expand the epidemiological knowledge and distribution of AIV in neotropical free-ranging bats and emphasize the need to continue studying these viruses to establish the role they could play as a threat to animal and public health.
ABSTRACT
Marek's disease (MD) is a lymphoproliferative disease caused by an Alphaherpesvirus, genus Mardivirus, serotype 1 (Gallid Herpesvirus 2, GaHV-2) that includes all known pathogenic strains. In addition to Marek's disease virus (MDV) serotype 1, the genus includes 2 distinct nonpathogenic serotypes: serotype 2 (GaHV-3) and serotype 3 (Meleagridis Herpesvirus 1, MeHV-1) which are used in commercially available vaccines against MD. As a result of vaccination, clinical signs are not commonly observed, and new cases are usually associated with emerging variant strains against which the vaccines are less effective. In this study, a commercial layer farm showing clinical signs compatible with MDV infection was evaluated. Histological lesions and positive immunohistochemistry in the sciatic nerve and thymus were compatible with cytolytic phase of MD. GaHV-2, GaHV-3 and MeHV-1 were identified by PCR and qPCR in blood samples from 17 birds with suspected MD. Analysis of the Meq gene of the Colombian GaHV-2 isolate revealed a 99% sequence identity with Asian strains, and in the phylogenetic analysis clustered with vv+ MDV. The analysis of amino acid alignments demonstrated an interruption of the proline rich region in P176A, P217A and P233L positions, which are generally associated with vv+ strains. Some of these changes, such as P233L and L258S positions have not been reported previously. In addition, primary cell cultures inoculated with lymphocytes isolated from the spleen showed typical cytopathic effect of GaHV-2 at 5 d post infection. Based on the molecular analysis, the results from this study indicate the presence of vv+ MDV infection in commercial birds for the first time in Colombia. It is recommended to perform further assays in order to demonstrate the pathotype characteristics in vivo.