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.

Identification of Newcastle Disease Virus sub-genotype VII 1.1 isolated from chickens in Sabah, Malaysia

@#Newcastle disease (ND) is an extremely contagious and fatal viral disease causing huge economic losses to the poultry industry. Following recent ND outbreaks in Sabah in commercial poultry and backyard farms, it was speculated that this could be due to a new introduction of Newcastle Disease Virus (NDV) genotype/sub-genotype. Here we report the genetic characterization of NDVs isolated from Sabah during early 2021. All isolates were amplified and sequenced with primers specific to the viral fusion (F) gene using reverse transcription-polymerase chain reaction (RT-PCR). Nucleotide sequence analysis of the F gene showed that all isolates shared similar homology of 99.4% with NDV strain from Iran isolated in 2018. Amino acid sequences of the F protein cleavage site revealed the motif of 112RRQKRF117 indicating all isolates were of virulent strain. Phylogenetic analysis demonstrated that all isolates were clustered under sub-genotype VII 1.1 and clustered together with isolates from Iran (previously known as subgenotype VIIl). The present findings suggested that there is an emerging of a new sub-genotype into the poultry population in Sabah and this sub-genotype has never been reported before in Malaysia. Therefore, transboundary monitoring and continuous surveillance should be implemented for proper control and prevention of the disease. A further molecular epidemiological analysis of NDV is needed to well understand the circulatory patterns of virulent strains of NDV in the country to prevent future outbreaks.

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)

Preliminary observation on the interference effect of Helicobacter hepaticus infection on the immune response in BALB/c mice / 中国实验动物学报

Objective To determine the interference effect of H. hepaticus infection on the functional characteris-tics of dendritic cell ( DC) surface molecules and immune response in mice. Methods Male BALB/c mice were inocula-ted with H. hepaticus (ATCC 51450). Murine bone marrow-derived dendritic cells (DC) were isolated and co-cultured which were stimulated by GM-CSF and IL-4 at the fifth month after the last inoculation. Then the DCs were subjected to FACS analysis for surface markers (CD11c, CD40, CD80 and MHCII) detection. On this basis, virus suspension of New-castle disease virus( NDV) ZJ1 strain was inoculated into the mice. Serum was collected for detection of the NDV antibody titer in serum weekly to explore the difference of antibody titer between the two groups. Results The expression rates of CD40 and MHCII on the mouse DCs in experimental group were higher than that in the control group. The NDV antibody ti-ter of experimental group was slightly lower than that in the control group in the first week. During the 2nd to 5th weeks, the titer was higher than that in the control group, with a very significant difference. In the 6th week, the titer of both the two groups tended to fall. Conclusions H. hepaticus infection can promote bone marrow DC maturation in mice, stimulate the expression rates of MHC II and CD40, and enhance the NDV antibody levels.

Rescue and Preliminary Application of a Recombinant Newcastle Disease Virus Expressing Green Fluorescent Protein Gene / 中国病毒学

Based on the complete genome sequence of Newcastle disease virus (NDV) ZJI strain,seven pairs of primers were designed to amplify a cDNA fragment for constructing the plasmid pNDV/ZJI,which contained the full-length cDNA of the NDV ZJI strain.The pNDV/ZJI,with three helper plasmids,pCIneoNP,pCIneoP and pCIneoL,were then cotransfected into BSR-T7/5 cells expressing T7 RNA polymerase.After inoculation of the transfected cell culture supernatant into embryonated chicken eggs from specific-pathogen-free (SPF) flock,an infectious NDV ZJI strain was successfully rescued.Green fluorescent protein (GFP) gene was amplified and inserted into the NDV full-length cDNA to generate a GFP-tagged recombinant plasmid pNDV/ZJIGFP.After cotransfection of the resultant plasmid and the three support plasmids into BSR-T7/5 cells,the recombinant NDV,NDV/ZJIGFP,was rescued.Specific green fluorescence was observed in BSR-T7/5 and chicken embryo fibroblast (CEF) cells 48h post-infection,indicating that the GFP gene was expressed at a relatively high level.NDV/ZJIGFP was inoculated into 10-day-old SPF chickens by oculonasal route.Four days post-infection,strong green fluorescence could be detected in the kidneys and tracheae,indicating that the recombinant GFP-tagged NDV could be a very useful tool for analysis of NDV dissemination and pathogenesis.