Evaluation of histopathological changes, viral load and immune function of domestic geese infected with Newcastle disease virus

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.

Pathologic Mechanisms of the Newcastle Disease Virus

Newcastle disease (ND) has been a consistent risk factor to the poultry industry worldwide. Its pathogen, Newcastle disease virus (NDV), is also a promising antitumor treatment candidate. The pathogenic mechanism has intrigued the great curiosity of researchers, and advances in the last two decades have been summarized in this paper. The NDV’s pathogenic ability is highly related to the basic protein structure of the virus, which is described in the Introduction of this review. The overall clinical signs and recent findings pertaining to NDV-related lymph tissue damage are then described. Given the involvement of cytokines in the overall virulence of NDV, cytokines, particularly IL6 and IFN expressed during infection, are reviewed. On the other hand, the host also has its way of antagonizing the virus, which starts with the detection of the pathogen. Thus, advances in NDV’s physiological cell mechanism and the subsequent IFN response, autophagy, and apoptosis are summarized to provide a whole picture of the NDV infection process.

Evaluation of the safety and protection efficacy of an attenuated genotype vii newcastle disease virus strain as a candidate vaccine

Newcastle disease (ND) is a serious avian infectious disease, causing severe economic loss worldwide. Its prevention depends on comprehensive vaccination scheme against Newcastle disease virus (NDV). However, current vaccine strains are of different genotypes with prevalent circulating strains (genotype VII), with significant genetic distance. Our team previously generated a genotype matched attenuated NDV strain (rmNA-1). In this study, its safety and immunization efficacy were evaluated. Its lentogenic characteristic was stable for 25 generations in embryonated chicken eggs and for six generations in SPF chickens. Overdosed administration did not cause any clinical signs or pathogenic changes in chickens. As to its immunization effect, rmNA-1 stimulated a comparable serum NDV specific antibody level to a LaSota (genotype II) strain based commercial vaccine, and provided full protection against virulent genotype VII strain challenge, with significantly reduced virus shedding period.

Phosphorylated abacavir analogue (ABC-1) has ameliorative action against Newcastle disease virus induced pathogenesis in chicken

Newcastle disease virus (NDV) causes huge economic loss to the poultry industry due to high mortality and morbidity. The present study aimed to assess the protective role of novel phosphorylated analogue ABC-1 in vivo in NDV-infected chickens through the inhibition of fusion protein. Both NDV-induced oxidative damage and protective role of novel phosphorylated ABC-1 were evaluated in vital organs such as the liver and lung of chickens. Enzyme linked immunosorbent assay (ELISA) results showed that protein oxidation and nitration levels were significantly raised in NDV-infected tissues compared to healthy controls, whereas these levels were reduced significantly (P < 0.05) in birds treated with phosphorylated compounds compared to the NDV-infected group alone. Additional investigation with double immunofluorescence showed that the large amount of immuno colocalization and Western blot analysis also confirmed this observation through its band pattern in NDV-infected birds compared to healthy birds, whereas these alterations were reduced in treatment with novel phosphorylated ABC-1. The expression of fusion glycoprotein was studied by immuno colocalization, PCR, and flow cytometry, and results demonstrated that the novel phosphorylated analogues reduced the expression of fusion glycoprotein. These results put forth that novel phosphorylated ABC-1 protects chickens from NDV-induced pathogenesis, protein oxidation/nitration, and exerts potent antiviral activity.

Pathobiology of Avian avulavirus 1: special focus on waterfowl

Avian avulaviruses serotype 1 (abbreviated as APMV-1 for the historical name avian paramyxovirus 1) are capable of infecting a wide spectrum of avian species with variable clinical symptoms and outcomes. Ease of transmission has allowed the virus to spread worldwide with varying degrees of virulence depending upon the virus strain and host species. The emergence of new virulent genotypes from global epizootics, and the year-to-year genomic changes in low and high virulence APMV-1 imply that distinct genotypes of APMV-1 are simultaneously evolving at different geographic locations across the globe. This vast genomic diversity may be favoured by large variety of avian species susceptibility to APMV-1 infection, and by the availability of highly mobile wild birds. It has long been considered that waterfowls are not sensitive to APMV-1 and are unable to show any clinical signs, however, outbreaks from the 90's contradict these concepts. The APMV-1 isolates are increasingly reported from the waterfowl. Waterfowl have strong innate immune responses, which minimize the impact of virus infection, however, are unable to prevent the viral shedding. Numerous APMV-1 are carried by domestic waterfowl intermingling with terrestrial poultry. Therefore, commercial ducks and geese should be vaccinated against APMV-1 to minimize the virus shedding and for the prevention the transmission. Genetic diversity within APMV-1 demonstrates the need for continual monitoring of viral evolution and periodic updates of vaccine seed-strains to achieve efficient control and eradication of APMV-1 in waterfowls.

Newcastle disease virus-like particles induce dendritic cell maturation and enhance viral-specific immune response

Circulating of genotype VII Newcastle disease virus (NDV) is a great threat to the poultry industry worldwide. Virus-like particles (VLPs) are increasingly being considered as potential viral vaccines due to their safety and efficacy. In this study, we analyzed in vitro the stimulatory effects of VLPs containing the matrix and hemagglutinin-neuraminidase of genotype VII NDV on dendritic cells (DCs) and evaluated their immunogenicity in mice. The results showed that immature bone marrow-derived dendritic cells (BMDCs) responded to stimulation with VLPs by up-regulating expressions of MHC II, CD40, CD80, and CD86 molecules and by increasing the cytokine secretions of TNF-α, IFN-γ, IL-6, and IL-12p70. Besides, VLPs enhanced the immunostimulatory capacity of DCs to stimulate autologous T cell proliferation. Furthermore, VLPs can induce efficient humoral and cellular immune responses, and recruit mature DCs to the spleen in C57BL/6 mice, as shown by an obvious increase in double-positive proliferation of splenic CD11c+CD86+ cells. These data indicate that NDV VLPs can be a valuable candidate for NDV vaccine development.

Pathogenesis of Pancreatitis in Chickens after Experimental Infection with 9a5b Newcastle Disease Virus Mutant Isolate

The aim of this study was to investigate the effect of Newcastle disease virus (NDV) on the chicken pancreas. A virulent 9a5b mutant NDV isolate was inoculated intranasally into 32-day-old specific pathogen-free white Leghorn chickens. The pancreas was examined grossly and fixed for histopathological, immunohistochemical and electron microscopical investigations. Inflammatory changes were observed in the peripancreatic tissue at the early stage of infection (12 h post infection) and became more prevalent towards the end of the experiment. Multifocal areas of necrotizing inflammation were detected in the exocrine portion of the pancreas by 5 days post infection (dpi) and became more severe at 10 dpi. The endocrine islets were generally preserved, but slight degenerative changes were observed at 10 dpi. Immunohistochemically, NDV-nucleoprotein (NDV-NP) signals were detected in the peripancreatic tissues (associated with macrophages and other lymphoid cells) by 1 dpi. In the exocrine portion of the pancreas, NDV-NP signals were detected at 5 dpi and increased in intensity and distribution by 10 dpi. NDV particles were confirmed in the cytoplasm of exocrine acinar cells by transmission electron microscopy. CD3-positive cells were observed in the peripancreatic tissues earlier than in the pancreatic tissue. Moreover, in comparison with control chickens, insulin immunoexpression was unchanged, except on the last day of the experiment, when it was slightly reduced. The 9a5b NDV infection induced an inflammatory reaction and viral replication in the peripancreatic tissues earlier than in the pancreatic tissue. Furthermore, necrosis affected mainly the exocrine portion of the pancreas, while the endocrine portion was generally unaffected.