Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.(AU)

Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.(AU)

Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

ABSTRACT: Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.

Newcastle disease virus vaccine strains: immunogenicity is not influenced by ICPI

Intracerebral pathogenicity index (ICPI) and mean death time (MDT) were determined using commercial live vaccines against Newcastle disease available in Brazil. The ICPI profiles obtained for B1 vaccine strains were nonvirulent and varied from 0 to 0.19, and their MDT was 104-116 hours. The LaSota strains had an ICPI varying between 0.02 and 0.37 and MDT from 92 to 116 hours. ICPI and MDT for the Clone 30 were 0.11 and 104 hours, respectively. For Ulster vaccines, ICPI and MDT were 0 and >150 hours; for VG-GA was 0.03 and 140 hours; and for C2, 0.04 and >144 hours. Eye drop vaccination and IM challenge, at the 1st week and the 4th week, respectively, resulted in highest protection for B1 (95-100%) and LaSota (90-100%) strains. The variability in vaccine ICPI did not interfere with immune response and all vaccines provided similar protection. All vaccines were considered non virulent and were classified as lentogenic according to the immunobiological product standards.

Newcastle disease virus vaccine strains: immunogenicity is not influenced by ICPI

Intracerebral pathogenicity index (ICPI) and mean death time (MDT) were determined using commercial live vaccines against Newcastle disease available in Brazil. The ICPI profiles obtained for B1 vaccine strains were nonvirulent and varied from 0 to 0.19, and their MDT was 104-116 hours. The LaSota strains had an ICPI varying between 0.02 and 0.37 and MDT from 92 to 116 hours. ICPI and MDT for the Clone 30 were 0.11 and 104 hours, respectively. For Ulster vaccines, ICPI and MDT were 0 and >150 hours; for VG-GA was 0.03 and 140 hours; and for C2, 0.04 and >144 hours. Eye drop vaccination and IM challenge, at the 1st week and the 4th week, respectively, resulted in highest protection for B1 (95-100%) and LaSota (90-100%) strains. The variability in vaccine ICPI did not interfere with immune response and all vaccines provided similar protection. All vaccines were considered non virulent and were classified as lentogenic according to the immunobiological product standards.

Clinico-pathological assessment of virulent Newcastle Disease Virus in ducks

Abstract Newcastle disease (ND) is an infectious, highly contagious and lethal disease of avian species. It is considered that ducks are natural reservoir or carrier for Newcastle disease virus (NDV) and are resistant against different strains of NDV. Current study was designed to evaluate the pathogenesis of Newcastle disease in domestic ducks through histopathology, immunohistochemistry (IHC) and serum biochemical changes. For this purpose, eighty ducks were reared for 42 days and divided in two groups A and B. Ducks in group A were challenged with (NDV) at rate of 0.1 ml of ELD50 (virus titer 107.32/100µl) on second week of age, whereas Group B was control negative. Splenomegaly, atrophy of thymus and necrotic lesion in kidney were observed on 9th day of post infection. Hepatic degeneration and mononuclear cell infiltration were noticed in proventriculus and intestine in challenged ducks. Viral antigen detected in lungs, intestine, proventriculus and lymphoid organs of infected ducks through IHC. Albumin and total protein values were significantly low in infected groups A as compared to control group B. ALT, AST, and ALP values were significantly high in infected group A. On 5th and 7th day of post infection oropharyngeal swabs were negative for NDV and cloacal swabs were positive for NDV through Reverse transcriptase polymerase chain reaction. It is concluded that ducks are susceptible to NDV and virulent strain of NDV caused disease in ducks.

Resumo A doença de Newcastle (DN) é uma doença infecciosa, altamente contagiosa e letal de espécies aviárias. Considera-se que os patos são reservatórios ou portadores naturais do vírus da doença de Newcastle (VDN) e são resistentes a diferentes cepas de VDN. O presente estudo foi desenvolvido para avaliar a patogênese da DN em patos domésticos por meio de histopatologia, imuno-histoquímica (IHQ) e alterações bioquímicas séricas. Para este propósito, 80 patos foram criados por 42 dias e divididos em dois grupos A e B. Os patos do grupo A foram submetidos ao VDN a uma taxa de 0,1 ml de ELD50 (título viral de 107,32 / 100 µl) na segunda semana de idade, enquanto o Grupo B foi controle negativo. Esplenomegalia, atrofia do timo e lesão necrótica no rim foram observadas no 9º dia pós-infecção. Degeneração hepática e infiltração de células mononucleares foram observadas no proventrículo e intestino em patos infectados. Antígeno viral foi detectado em pulmões, intestino, proventrículo e órgãos linfoides de patos infectados por IHQ. Os valores de albumina e proteína total foram significativamente baixos no grupo A infectado em comparação com o grupo B. Os valores de ALT, AST e ALP foram significativamente altos no grupo A. No 5º e no 7º dia após a infecção, os esfregaços orofaríngeos foram negativos para VDN, enquanto os esfregaços cloacais foram positivos para VDN por meio da reação em cadeia da polimerase via transcriptase reversa. Conclui-se que os patos são suscetíveis ao VDN e à cepa virulenta de VDN que causou doenças em patos.

Clinico-pathological assessment of virulent Newcastle Disease Virus in ducks / Avaliação clínico-patológica do Vírus da Doença de Newcastle em patos

Abstract Newcastle disease (ND) is an infectious, highly contagious and lethal disease of avian species. It is considered that ducks are natural reservoir or carrier for Newcastle disease virus (NDV) and are resistant against different strains of NDV. Current study was designed to evaluate the pathogenesis of Newcastle disease in domestic ducks through histopathology, immunohistochemistry (IHC) and serum biochemical changes. For this purpose, eighty ducks were reared for 42 days and divided in two groups A and B. Ducks in group A were challenged with (NDV) at rate of 0.1 ml of ELD50 (virus titer 107.32/100µl) on second week of age, whereas Group B was control negative. Splenomegaly, atrophy of thymus and necrotic lesion in kidney were observed on 9th day of post infection. Hepatic degeneration and mononuclear cell infiltration were noticed in proventriculus and intestine in challenged ducks. Viral antigen detected in lungs, intestine, proventriculus and lymphoid organs of infected ducks through IHC. Albumin and total protein values were significantly low in infected groups A as compared to control group B. ALT, AST, and ALP values were significantly high in infected group A. On 5th and 7th day of post infection oropharyngeal swabs were negative for NDV and cloacal swabs were positive for NDV through Reverse transcriptase polymerase chain reaction. It is concluded that ducks are susceptible to NDV and virulent strain of NDV caused disease in ducks.

Resumo A doença de Newcastle (DN) é uma doença infecciosa, altamente contagiosa e letal de espécies aviárias. Considera-se que os patos são reservatórios ou portadores naturais do vírus da doença de Newcastle (VDN) e são resistentes a diferentes cepas de VDN. O presente estudo foi desenvolvido para avaliar a patogênese da DN em patos domésticos por meio de histopatologia, imuno-histoquímica (IHQ) e alterações bioquímicas séricas. Para este propósito, 80 patos foram criados por 42 dias e divididos em dois grupos A e B. Os patos do grupo A foram submetidos ao VDN a uma taxa de 0,1 ml de ELD50 (título viral de 107,32 / 100 µl) na segunda semana de idade, enquanto o Grupo B foi controle negativo. Esplenomegalia, atrofia do timo e lesão necrótica no rim foram observadas no 9º dia pós-infecção. Degeneração hepática e infiltração de células mononucleares foram observadas no proventrículo e intestino em patos infectados. Antígeno viral foi detectado em pulmões, intestino, proventrículo e órgãos linfoides de patos infectados por IHQ. Os valores de albumina e proteína total foram significativamente baixos no grupo A infectado em comparação com o grupo B. Os valores de ALT, AST e ALP foram significativamente altos no grupo A. No 5º e no 7º dia após a infecção, os esfregaços orofaríngeos foram negativos para VDN, enquanto os esfregaços cloacais foram positivos para VDN por meio da reação em cadeia da polimerase via transcriptase reversa. Conclui-se que os patos são suscetíveis ao VDN e à cepa virulenta de VDN que causou doenças em patos.