Surveillance of avian influenza and Newcastle disease viruses in backyard poultry raised near migratory bird sites in Mato Grosso state, Brazil.

The Pantanal and Cerrado biomes in the state of Mato Grosso contain migratory bird sites in the municipalities of Cáceres and Araguaiana, respectively. The levels of avian influenza (AI) and Newcastle disease (ND) viral activity in backyard poultry at these sites are unknown owing to a lack of studies. Considering the risk of introduction of AI and ND to Brazil from migratory birds, as well as the importance of active surveillance in the detection and prevention of diseases for official control, monitoring in these poultry populations is faster, more practical and cheaper for official service veterinarians. The objective of this study was to verify the presence of AI and ND viral activity in backyard poultry reared near these migratory bird sites in the years 2016 and 2019. Serum samples and cloacal and tracheal swab samples collected from chickens, turkeys, quails, ducks and geese were evaluated by indirect diagnostic methods including enzyme-linked immunosorbent assay and haemagglutination inhibition tests and direct detection of viral sequences using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). No positive samples were detected by qRT-PCR.The frequencies of birds seropositive for AI and ND were 0.7% and 19.6% in 2016 and 0.5% and 17.2% in 2019, respectively, in Araguaiana and 0.8% and 32.3% in 2016 and 7.0% and 38.1% in 2019, respectively, in Cáceres. Antibodies belonging to AI subtypes H1, H4, H6 and H14 were identified in Cáceres in 2019. Spatial analysis showed an agglomeration of farms with seropositive poultry within the urban area of Cáceres, suggesting AI and ND virus activity in this area. This study showed no circulation of the notifiable AI subtypes H5 and H7 or the ND virus in backyard poultry raised around migratory bird sites in the state of Mato Grosso. The results of the present study support evidence indicating that the circulation of strains with low pathogenicity in urban areas enables backyard poultry to serve as a source of infection for other birds; thus, increased surveillance is necessary in this population.

Les biomes du Pantanal et du Cerrado dans l'état du Mato Grosso contiennent deux sites accueillant des oiseaux migrateurs, situés respectivement dans les comtés de Cáceres et d'Araguaiana. Faute d'études de terrain, le niveau d'activité virale de l'influenza aviaire et de la maladie de Newcastle chez les volailles de basse-cour de ces deux sites était jusqu'à présent inconnu. Compte tenu du risque d'introduction au Brésil de l'influenza aviaire et de la maladie de Newcastle par les oiseaux migrateurs, et de l'importance de la surveillance active pour détecter et prévenir ces maladies dans le cadre des activités de lutte conduites par les Services vétérinaires, il est plus pratique, moins onéreux et plus rapide pour les vétérinaires des services officiels d'axer la surveillance sur les populations de volailles de basse-cour. Les auteurs présentent les résultats d'une étude conduite en 2016 et en 2019 pour déterminer le niveau de circulation des virus de l'influenza aviaire et de la maladie de Newcastle chez les volailles de basse-cour élevées à proximité des sites d'oiseaux migrateurs. Des échantillons sériques et des écouvillons cloacaux et trachéaux prélevés sur des poulets, des dindes, des cailles, des canards et des oies ont été soumis à des méthodes de diagnostic indirectes telles que les épreuves immuno-enzymatique et d'inhibition de l'hémagglutination, et à une méthode de détection directe des séquences virales par amplification en chaîne par polymérase quantitative en temps réel couplée à une transcription inverse (qRT-PCR). Aucun échantillon positif n'a été détecté par qRT-PCR. Les taux de séropositivité respectivement à l'influenza aviaire et à la maladie de Newcastle étaient, chez les volailles prélevées à Araguaiana, de 0,7 % et 19,6 % en 2016, et de 0,5 % et 17,2 % en 2019 ; chez les volailles prélevées à Cáceres, ils étaient de 0,8 % et 32,3 % en 2016, et de 7,0 % et 38,1 % en 2019. Les anticorps détectés à Cáceres en 2019 appartenaient aux sous-types H1, H4, H6 et H14 du virus de l'influenza aviaire. L'analyse spatiale a révélé une concentration importante d'élevages ayant des volailles séropositives dans la zone urbaine de Cáceres, indiquant une activité des virus de l'influenza aviaire et de la maladie de Newcastle dans cette région. Aucune circulation des sous-types H5 et H7 à déclaration obligatoire du virus de l'influenza aviaire ni du virus de la maladie de Newcastle n'a été mise en évidence chez les volailles de basse-cour élevées autour des sites d'oiseaux migrateurs dans l'état du Mato Grosso. Les résultats de cette étude étayent les données d'après lesquelles les volailles de basse-cour des zones urbaines deviennent des sources d'infection pour d'autres espèces d'oiseaux à la faveur d'une circulation de souches faiblement pathogènes ; il est donc nécessaire de renforcer la surveillance dans cette population.

Los biomas de Pantanal y Cerrado, situados en el estado de Mato Grosso, albergan espacios frecuentados por aves migratorias en los municipios de Cáceres y Araguaiana, respectivamente. Debido a la falta de estudios al respecto, se desconocen los niveles de actividad de los virus de la influenza aviar (IA) y de la enfermedad de Newcastle (EN) en las aves de corral caseras de estas zonas. Teniendo en cuenta el riesgo de introducción en el Brasil de la IA y la EN por conducto de aves migratorias, así como la importancia de una vigilancia activa para la detección y prevención de enfermedades con fines de control oficial, para los veterinarios de los servicios públicos resulta más rápido, práctico y barato vigilar esas poblaciones de aves de corral. Los autores describen un estudio encaminado a comprobar, en los años 2016 y 2019, la actividad de los virus de la IA y la EN en bandadas caseras de aves de corral criadas cerca de los antedichos espacios de aves migratorias. Tras obtener muestras séricas e hisopados cloacales y traqueales de pollos, pavos, codornices, patos y gansos, se analizaron las muestras con técnicas de diagnóstico indirecto (ensayo inmunoenzimático y prueba de inhibición de la hemaglutinación) y de detección directa de secuencias víricas (retrotranscripción acoplada a reacción en cadena de la polimerasa cuantitativa en tiempo real: qRT-PCR). No se detectó ninguna muestra positiva por qRT-PCR. En cuanto a las tasas de seropositividad para la IA y la EN, en Araguaiana resultaron positivas el 0,7% y el 19,6%, respectivamente, de las aves analizadas en 2016, por un 0,5% y un 17,2% en 2019, mientras que en Cáceres lo fueron el 0,8% y el 32,3% en 2016 y el 7,0% y el 38,1% en 2019. En 2019 se identificaron en Cáceres anticuerpos correspondientes a los subtipos H1, H4, H6 y H14 del virus de la influenza aviar. El análisis espacial puso de relieve una aglomeración de fincas con aves de corral seropositivas en la zona urbana de Cáceres, hecho indicativo de que en la zona hay actividad de los virus de la IA y la EN. El estudio no evidenció circulación alguna de los subtipos H5 y H7 del virus de la IA, que son de declaración obligatoria, ni del virus de la EN en las aves de corral caseras criadas en los alrededores de los espacios del estado de Mato Grosso que albergan aves migratorias. Los resultados del estudio parecen avalar los datos que indican que la circulación de cepas poco patógenas en zonas urbanas hace de las bandadas caseras una posible fuente de infección para otras aves, razón por cual es tanto más necesario redoblar la vigilancia de estas poblaciones de aves de corral.

Comparison among three different serological methods for the detection of equine influenza virus infection

The equine influenza virus (EIV) H3N8 subtype is responsible for all EIV outbreaks worldwide while the H7N7 subtype is less pathogenic and is considered extinct as it has not been confirmed in outbreaks since 1980. Although EIV is enzootic in Brazil, few reports describe the actual EIV antibody status in the country. The aims of this study were: ­ to evaluate the efficiency of different serum treatments described by the World Organisation for Animal Health (OIE) and the World Health Organization (WHO) to remove non-specific haemagglutination inhibitors for the haemagglutination inhibition (HI) assay for EIV ­ to evaluate the presence of EIV antibodies by HI, enzyme-linked immunosorbent assay and agar gel immunodiffusion in 83 non-vaccinated equines from São Paulo State ­ to evaluate a strategy to better analyse equine sera for EIV antibodies. Although there was no statistical difference among treatments, receptor-destroying enzyme treatment followed by chicken erythrocyte adsorption showed more consistent results, which corroborate the OIE and WHO recommendation to use this treatment preferentially. The HI results suggest equine H3N8 virus circulation among the animals tested from São Paulo State. The algorithm suggested here could be used to guide antibody detection against equine influenza virus in equines, improving the test specificity by aiming to avoid false positive results.(AU) i

Comparison among three different serological methods for the detection of equine influenza virus infection.

The equine influenza virus (EIV) H3N8 subtype is responsible for all EIV outbreaks worldwide while the H7N7 subtype is less pathogenic and is considered extinct as it has not been confirmed in outbreaks since 1980. Although EIV is enzootic in Brazil, few reports describe the actual EIV antibody status in the country. The aims of this study were: - to evaluate the efficiency of different serum treatments described by the World Organisation for Animal Health (OIE) and the World Health Organization (WHO) to remove non-specific haemagglutination inhibitors for the haemagglutination inhibition (HI) assay for EIV - to evaluate the presence of EIV antibodies by HI, enzyme-linked immunosorbent assay and agar gel immunodiffusion in 83 non-vaccinated equines from São Paulo State - to evaluate a strategy to better analyse equine sera for EIV antibodies. Although there was no statistical difference among treatments, receptor-destroying enzyme treatment followed by chicken erythrocyte adsorption showed more consistent results, which corroborate the OIE and WHO recommendation to use this treatment preferentially. The HI results suggest equine H3N8 virus circulation among the animals tested from São Paulo State. The algorithm suggested here could be used to guide antibody detection against equine influenza virus in equines, improving the test specificity by aiming to avoid false positive results.

Tous les foyers de grippe équine dans le monde sont dus au sous-type H3N8 du virus. Le sous-type H7N7, moins pathogène, est considéré comme éteint, sa présence n'ayant été confirmée dans aucun des foyers enregistrés depuis 1980. Au Brésil, la grippe équine est enzootique mais la prévalence d'anticorps dans le pays est peu documentée. La présente étude avait trois objectifs : ­ évaluer l'efficacité de plusieurs traitements de sérums décrits par l'Organisation mondiale de la santé animale (OIE) et l'Organisation mondiale de la santé (OMS) sur la suppression des inhibiteurs d'hémagglutination non spécifiques, afin de pouvoir utiliser l'épreuve d'inhibition de l'hémagglutination pour la détection de la grippe équine, ­ évaluer la présence d'anticorps dirigés contre la grippe équine chez 83 chevaux non vaccinés de l'état de São Paulo en utilisant l'inhibition de l'hémagglutination, l'épreuve immuno-enzymatique (ELISA) et l'épreuve d'immunodiffusion en gélose (IDG) ; ­ évaluer une stratégie visant à améliorer les techniques sérologiques de détection des anticorps dirigés contre la grippe équine. S'il n'y a pas eu de différence statistique significative entre les traitements, celui faisant appel à l'enzyme de destruction du récepteur suivi d'une adsorption sur érythrocytes de poule a permis d'obtenir les résultats les plus cohérents, ce qui corrobore les recommandations de l'OIE et de l'OMS en faveur de ce traitement. Les résultats obtenus au moyen de l'inhibition de l'hémagglutination indiquent que le virus H3N8 est présent parmi les animaux testés de l'état de São Paulo. L'algorithme présenté par les auteurs pourrait servir de modèle pour détecter la présence d'anticorps dirigés contre le virus de la grippe équine chez les chevaux : en effet, il permet d'éviter les résultats faussement positifs, ce qui améliore la spécificité du test utilisé.

El subtipo H3N8 del virus de la gripe equina (VGE) es el agente etiológico de todos los brotes que se producen en el mundo, mientras que el subtipo H7N7, menos patogénico, se da por extinto, en la medida en que desde 1980 no se ha confirmado su intervención en brote alguno. Aunque en el Brasil el VGE es enzoótico, existen pocos trabajos que den cuenta de la situación real del país en cuanto a la presencia de anticuerpos contra el virus. Los autores describen un estudio que perseguía los siguientes objetivos: ­ evaluar la eficacia de distintos tratamientos séricos descritos por la Organización Mundial de Sanidad Animal (OIE) y la Organización Mundial de la Salud (OMS) para eliminar los inhibidores inespecíficos de la hemaglutinación con objeto de aplicar la técnica de inhibición de la hemaglutinación a la detección del VGE; ­ evaluar la presencia de anticuerpos contra el VGE por inhibición de la hemaglutinación, ensayo inmunoenzimático (ELISA) e inmunodifusión en gel de agar en 83 ejemplares equinos no vacunados del estado de São Paulo; ­ evaluar una estrategia encaminada a analizar más eficazmente sueros equinos para detectar en ellos anticuerpos anti-VGE. Aunque no se observaron diferencias estadísticamente significativas entre los tratamientos, el uso de enzimas destructores de receptores seguido de la técnica de adsorción de eritrocitos de pollo arrojó resultados más coherentes, cosa que avala la recomendación de la OIE y la OMS de privilegiar este tratamiento. Los resultados obtenidos por inhibición de la hemaglutinación parecen indicar que el virus H3N8 equino circula entre los animales analizados del estado de São Paulo. El algoritmo aquí propuesto podría servir de guía para detectar en equinos la presencia de anticuerpos contra el VGE. Puesto que apunta a evitar falsos positivos, su aplicación mejoraría la especificidad de la prueba.

Prevalence of newcastle disease virus in broiler chickens (gallus gallus) in Brazil

This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1 percent, and the isolation percentage by flock varied from 1.0 to 7.6 percent, and by region from 6.5 to 58.4 percent. Higher isolation rates (74.3-83.3 percent) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.

A survey for maintenance of virulent newcastle disease virus-free area in poultry production in Brazil

In 2003, Brazil was recognized as a pathogenic Newcastle Disease Virus (NDV) strain-free country for commercial poultry. This research was conducted in Brazil between December 2003 and March 2005 to verify the maintenance of this virulent NDV-free status. Serum samples from 5,455 flocks for commercial poultry farms were collected, comprising 81,825 broiler chickens. The farms were located in nine states of the country, grouped in three geographic regions. Serological evidence of NDV infection was detected in 28.8 percent of the surveyed farms. However, all fifteen viruses isolated and identified as Newcastle Disease Virus (NDV) were characterized as nonpathogenic strains, based on the Intracerebral Pathogenicity Index. These results showed that Brazil preserves the virulent NDV-free status for commercial flocks.

Prevalence of newcastle disease virus in broiler chickens (Gallus gallus) in Brazil.

This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1%, and the isolation percentage by flock varied from 1.0 to 7.6%, and by region from 6.5 to 58.4%. Higher isolation rates (74.3-83.3%) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.

A survey for maintenance of virulent newcastle disease virus-free area in poultry production in Brazil.

In 2003, Brazil was recognized as a pathogenic Newcastle Disease Virus (NDV) strain-free country for commercial poultry. This research was conducted in Brazil between December 2003 and March 2005 to verify the maintenance of this virulent NDV-free status. Serum samples from 5,455 flocks for commercial poultry farms were collected, comprising 81,825 broiler chickens. The farms were located in nine states of the country, grouped in three geographic regions. Serological evidence of NDV infection was detected in 28.8% of the surveyed farms. However, all fifteen viruses isolated and identified as Newcastle Disease Virus (NDV) were characterized as nonpathogenic strains, based on the Intracerebral Pathogenicity Index. These results showed that Brazil preserves the virulent NDV-free status for commercial flocks.

Establishment and partial characterization of an ovine synovial membrane cell line obtained by transformation with Simian Virus 40 T antigen.

The small ruminant lentiviruses, namely caprine arthritis encephalitis virus (CAEV) and Maedi Visna virus (MVV) are grown currently in secondary synovial membrane cells. Primary and secondary cell cultures are sometimes difficult to obtain and support a low number of passages and, therefore, permissive cell lines are needed. A transformed cell line was obtained by transfection of ovine synovial membrane secondary cell culture with a plasmid containing the SV40 large T antigen gene. The transformed cell culture described in this paper showed a higher growth rate and a more homogenous population of fibroblast-like cells when compared to the original ovine synovial membrane secondary cell cultures. Karyotype analysis has indicated the induction of many random chromosome changes, leading to a decrease in chromosome number. The SV40 DNA was detected in the nucleus and in the cytoplasm of transformed cells. The putative expression of large T antigen was presumed by the detection of the corresponding mRNA by PCR. Finally, the transformed ovine synovial membrane cells were shown to be permissive to small ruminant lentiviruses, and these are suggested as a cell line for in vitro isolation and propagation of these viruses.

Deteccao da infecçäo pelo virus da artrite - encefalite caprina: imunodifusao em agar e reacao em cadeia da polimerase com primers degenerados / Detection of caprine arthritis-encephalitis virus infection: agar gel immunodiffusion and polymerase chain reaction with degenerated primers

O objetivo deste trabalho foi analisar amostras de soro e de células sangüíneas de caprinos para detecçäo de anticorpos e DNA proviral do vírus da artrite-encefalite caprina (CAEV), respectivamente. Utilizou-se a técnica de imunodifusäo em ágar (AGID) e a reaçäo em cadeia da polimerase (PCR) com "primers" degenerados. Foram analisadas amostras de diferentes procedências: 39 de Mato Grosso do Sul (MS), 19 de Säo Paulo (SP) e 22 do Ceará (CE), dessas últimas, 12 oriundas de animais importados do Canadá. Os resultados de AGID e PCR foram discordantes, pois o primeiro permitiu a detecçäo de 25 animais soropositivos, enquanto a PCR detectou DNA proviral de CAEV em 16 amostras. Pela PCR foi possível identificar animais infectados cujos testes sorológicos foram negativos pela AGID: oito amostras do MS e um do CE. Säo discutidos diferentes aspectos que poderiam estar envolvidos na discordância dos resultados

Phylogenetic analysis of small ruminant lentiviruses from Southern Brazil.

The first lentivirus isolated from sheep in Brazil was analysed phylogenetically. Evolutionary trees of the proviral 597 nucleotide gag and 432 nucleotide pol sequences obtained by the maximum likelihood method demonstrated that the sheep isolate clustered with prototype Maedi Visna virus whereas three lentiviruses isolated from goats in the same geographic region were close to caprine arthritis encephalitis prototypes. A subsequent comparison of sequence data of these viruses with those contained in the EMBL sequence database revealed that, in contrast to caprine prototypic viruses, all prototypic Maedi Visna viruses contain a deletion of six nucleotides in the gag gene resulting in the deletion of two residues in the central region of capsid protein. This deletion may be a useful marker in the analysis of small ruminant lentiviruses, especially when considering possible transmission of lentiviruses between sheep and goats.