1a. Objectives (from AD-416):
1. Determine the impact of variant and emerging viruses on the development and control of Newcastle disease by developing means to detect and survey variant and emerging Newcastle disease viruses and by determining the presence of variant and emerging Newcastle disease viruses in wild birds and live poultry markets. 1.A. Determine the impact of variant and emerging viruses on the evolution and control of Newcastle disease by determining the presence of variant and emerging Newcastle disease viruses in wild birds and live poultry markets. 1.B. Develop means to detect and survey variant and emerging Newcastle disease viruses. 2. Elucidate the host-pathogen interactions of Newcastle disease virus infections that impact vaccine efficacy by defining host pathways modulated by Newcastle disease viral infections and by identifying genetic and biological viral determinants that affect the safety and efficacy of Newcastle disease vaccine virus strains. 2.A. Define host response pathways modulated by Newcastle disease viral infections. 2.B. Identify viral determinants that affect the safety and efficacy of Newcastle disease vaccine virus strains. 3. Develop vaccine strategies to effectively control Newcastle disease and stop disease outbreaks by developing vaccine platforms specifically designed to control low virulent and virulent Newcastle disease outbreaks.
1b. Approach (from AD-416):
Field samples of Newcastle disease virus (NDV) collected from poultry, cormorants, pigeons, wild birds, and live bird markets from the U.S. and abroad will be characterized by genomic nucleotide sequencing and by performing virulence testing. Sequence variants or genetically diverse isolates will be biologically evaluated by determining the mean death time in eggs (MDT) and the intra-cerebral pathogenicity index (ICPI) in one day old chicks. Viruses of novel lineages that display evidence of increased virulence will be further characterized in specific pathogen free chickens by conducting standard pathogenesis experiments. Field samples from exotic viruses and viruses circulating in U.S. wild bids, and live bird market will be evaluated using available real time rapid detection assays (fusion, matrix and polymerases gene based) and those samples that fail detection with any of the U.S. Department of Agriculture (USDA) real time polymerase chain reaction rapid tests will be further analyzed using classical virological techniques or random sequencing. We will construct chimeric vaccine viruses by replacing the surface fusion and hemagglutinin-neuraminidase proteins from current circulating virulent field strains onto a tested vaccine backbone (LaSota). The effect of replacing these genes on virulence, clinical signs, tissue tropism, viral shedding, and induction of antigenic and protective response will be evaluated in animals experiments using immunologically mature chickens. Vaccination-challenge experiments will be performed to evaluate how well new circulating Asian, African and South American virulent viruses perform during current commercial vaccination schemes. Current vaccines such as LaSota or B1 will be used to vaccinate birds and clinical signs, pathological outcomes, viral replication and shedding will be compared after challenges with emerging strains of NDV. Live vaccines viruses expressing genes of NDV from viruses of recent outbreaks will be evaluated with the expectation that improved protection will result. This increased protection after virulent challenge should effectively reduce transmission from vaccinated animals and provide better clinical protection. Additionally, utilizing recombinant technology live vaccines expressing chicken cytokines will be developed.
3. Progress Report:
The Newcastle Disease Virus project has remained active nationally and internationally to meet the objectives and milestones of Project No. 6612-32000-064-00D, entitled, “INTERVENTION STRATEGIES TO CONTROL NEWCASTLE DISEASE as part of the National Program 103 (Animal Health). SEPRL has continued to evaluate and sequence viral isolates (Milestone 1a) aSequence and evaluation of 20 viral isolates and continue the evaluation of different rapid diagnostic RT_PCR tests (Milestone 1B. In order to elucidate host pathogen interaction the role of host cytokines has been studied (milestone 2a) and the complete pathogenesis and gene expression evaluation of new isolates has been conducted (milestone 2B). The evaluation of classical and experimental vaccines against viruses of new genotypes (milestones 3a and b) has continued and new recombinant viruses expressing cytokines have been made and are being evaluated (Milestone 3c). For objectives 1 milestone 1.1 the group evaluated the sequence of 67 new isolates from the US and exotic virulent Newcastle Disease Viruses. This work has led to the discovery of additional genetic diversity with one additional genotype identified since last year. For objective 1.b: Develop means to detect and survey variant and emerging Newcastle Disease viruses we have characterized new isolates from historical Samples from the US, Nigeria and Pakistan, and studied the evolution of Newcastle disease viruses. The research lead to three publications and one other that will be published in a manuscript entitled:” Genetic diversity of avian paramyxovirus type 1 from Pakistan. For sub-objective 2a “To study the host response pathways modulated by Newcastle Disease Virus we have continued the study the role of the gene interferon gamma, interleukin 2, 4 and 10 on the immune response and determined that high levels of interferon expressed early during infection effectively attenuate Newcastle disease virus. The research led to one publication. The milestones of sub objective 2b: construction of recombinant viruses with F and HN replacements were fully met and four different vaccine viruses containing the surface proteins F and HN from viruses of different genotypes were constructed and these viruses have been transferred to a company in Mexico. One publication was produced. The evaluation of the virulence of those recombinant viruses has been completed and a manuscript is in preparation. The milestone of sub-objective 3a, “Evaluation of classical vaccines against genotypes were fully met with the publication of three manuscripts. Collaborative work continues with a number of national and international partners and additional funding has been obtained from the Gates Foundation to develop chickens resistant to Newcastle Disease Resistant Viruses, and with the Biosecurity Engagement program from The Department of State to support collaborations with Indonesia, Pakistan, Ukraine and Russia. Isolates from most of the above countries have been incorporated in our repositories and are being characterized.
1. Determined the impact of emerging viruses on the control of Newcastle disease has been accomplished leading to 4 publications. Studied the genetic diversity and mutation of avian paramyxovirus serotype 1 in wild birds, conducted molecular epidemiology of Newcastle disease in Mexico, evaluated progress and gaps in the development of vaccines and diagnostic tools, and characterized the genome sequences of emerging Newcastle disease virus strains isolated from China and the Dominican Republic.
2. Developed vaccine strategies to effectively control Newcastle Disease Virus (NDV) which led to three publications. One of these studied the effect of humoral antibodies on shedding and transmission, other characterized the study of immune response to NDV, and the third characterized the protection of the LaSota vaccine to Asian viruses upon early challenges.
Li, J., Hu, H., Yu, Q., Diel, D.G., Li, D., Miller, P.J. 2012. Generation and characterization of a recombinant Newcastle disease virus expressing the red fluorescent protein for use in co-infection studies. Virology Journal. 9:227. DOI 10.1186/1743-422X-9-227.