Live Newcastle Disease Vaccine Research Articles

Efficiency of Various Poultry Vaccination Methods in Industrial Poultry Farming

Introduction. Due to the growth of poultry stocking density in the allotted area in conditions of the industrial poultry farming, the issue of ensuring the epizootic welfare through vaccine-prophylaxis proves to be relevant. Another important aspect of poultry farming is reducing production costs, which could be achieved, among other things, through implementation of the cost-efficient methods of vaccination. A manual mode of spray vaccination method, which is currently used at the poultry farms, has a disadvantage because the dose of vaccine received by different birds may be unequal. However, under modern conditions, in order to increase the labour productivity and efficiency, the efforts are made to get the poultry vaccination process automated. The vaccination frame spray machines used in the industrial poultry farming have not been studied or evaluated before in a comparative aspect. Thus, the purpose of this research is to compare two methods of spray vaccination in chickens at the operating poultry farm with regard to the biological efficiency and economic profitability.Materials and Methods. The objects of the study were the young Brown Nick crossbreed chickens (n=46 heads). Vaccination was carried out in the young poultry at the age of 42-days. During the research, the dried live Newcastle disease and avian infectious bronchitis vaccines were used. To control the quality of vaccination, the amount of antibodies was estimated in the blood serum of poultry aged 56, 70 and 95 days old by ELISA method with TICAN equipment. Two groups of poultry were studied. In group 1 the “DESVAK” hand sprayer was used (“DESVAK” KIT– 2 model, produced by Ceva Santé Animale), in group 2 the automated frame spray machine was used (“SIMBIO ITERIS” model, produced by SIMBIO).Results. As a result of studies, in group 2 the higher intensity of immunity was obtained, showing on average the following figures: 56 days – antibody titre was 29 % higher (p≤0.05); 70 days – antibody titre was 18 % higher (p≤0.005); 95 days – antibody titre was 15 % higher (p≤0.05) compared to group 1. Economic efficiency was calculated based on the indicators of labour costs and labour intensity of the vaccination process: when using a frame spray machine, the costs turned out to be 2.3 times lower (1,131.4 person-rubbles) than with the DESVAK sprayer (2,590.4 person-rubbles). Additionally, the labour intensity of the vaccination process per head decreased by 5 times. In group 1 it was 0.0015 person-hour/head, in group 2 – 0.0003 person-hour/head.Discussion and Conclusion. Based on the results of the study, it was found that the spray vaccination method by means of the frame spray machine (the automated mode) is more efficient according to both biological and economic indicators compared to the manual mode. Taking into account all of the above, the frame spray machines could be recommended to the veterinary specialists for carrying out vaccine prophylaxis at the poultry farms by the spray method.

Immunological effect of Lactic acid bacteria adjuvant on in ovo injection of Newcastle disease vaccine

In ovo immunization of chicken embryos with live vaccines is an effective strategy to protect chickens against various viral pathogens. The immunogenic efficacies of in ovo administration of lactic acid bacteria (LAB) in combination with live Newcastle disease (ND) vaccine were investigated in this study. Four hundred healthy 1-day-old fertilized specific pathogen-free (SPF) eggs of similar weights were randomly assigned to one of four treatments, with five replicates of each treatment and a total of 20 for each replicate. On day 18.5 of incubation, in ovo injections were given. The treatment groups are as follows: (I) no injection, (II) 0.9% physiological saline injection, (III) ND vaccine injection, and (IV) LAB as an adjuvant for ND vaccine injection. The ND vaccine adjuvanted with LAB significantly increased the daily weight gain, immune organ index, and small intestine histomorphological development in layer chicks while decreasing the feed conversion ratio (FCR). The results suggested that the LAB-adjuvant group significantly affected the relative expression of mucosal mucin protein (mucin-1) and zoccluding small circle protein-1 (ZO-1) (P < 0.05), whereas the relative expression of occludin mRNA was not significantly affected (P > 0.05) compared with the non-injected group. Meanwhile, we indicated that intra-amniotic synbiotic injection significantly maintained the balance of flora (P < 0.05). Compared with the non-injected group, the ND vaccine adjuvanted with the LAB group exhibited significant promotion of the HI and SIgA antibody titers in serum on day 21 (P < 0.05), induction of higher production of cytokines (IL-2, IL-4, IL-6, IFN-γ) in serum. In summary, in ovo injection of ND vaccine adjuvanted with LAB has a positive impact on the growth performance, immune function, and microbiome of growing chicks.

Effects of Escherichia coli strain Nissle 1917 on immune responses of Japanese quails (Coturnix japonica) to Newcastle disease vaccines.

The development of proper immune responses to Newcastle disease (ND) vaccines is important in controlling the disease. Escherichia coli strain Nissle 1917 (EcN) is involved in regulating the immune system. The current study evaluated the effects of EcN on immune responses to ND live vaccines in Japanese quails. A total of 150 one-day-old quails were divided into three equal groups. Groups A and B received 107 and 106 CFU/ml/day of EcN, respectively, sprayed on their diets, while group C received 1 ml/day of PBS. All birds were vaccinated with B1 and Lasota vaccines at 10 and 20 days of age, respectively. Serum samples were collected in order to assay the levels of IgA and certain cytokines, including IL4, IFN-α, and IFN-γ, as well as antibody titers to NDV by HI and ELISA methods. No significant difference (P>0.05) was observed in serum IgA and IFN-α levels among the groups. However, concentrations of IFN-γ and IL-4 in 42-day-old chicks in group A were significantly (P<0.05) higher than in both other groups. After 15 days of the second vaccination, the mean HI titer following NDV was significantly higher in group A than group C. Groups B and C showed significantly lower HI titer than group A after 22 days of the second vaccination. Mean ELISA titer to NDV was significantly (P<0.05) higher in group A than in groups B and C after 22 days of the second vaccination. It seems that the spraying of 107 CFU/ml/day of EcN on quail diets enhances the immune response to NDV vaccines by increasing serum levels of IFN-γ and IL-4.

The co-administration of live fowlpox and Newcastle disease vaccines by non-invasive routes to chickens reared by smallholders in Tanzania and Nepal

The co-administration of commercial live fowlpox (FP) and Newcastle disease (ND) vaccines when given by non-invasive (needle-free) routes was demonstrated to be safe and to elicit immunity in two field studies, one in Tanzania the other in Nepal. Both studies were of a cluster-randomised controlled design in which birds were randomly assigned to one of five treatment groups: (i) administration with FP vaccine alone (feather follicle), (ii) administration with ND vaccine alone (eye-drop), (iii) concurrent administration of FP (feather follicle) and ND (eye-drop) vaccines, (iv) concurrent administration of FP (wing-web) and ND (eye-drop) vaccines, and (v) unvaccinated, acting as environmental sentinels. Data from a total of 1167 birds from seven villages in Hanang District of Tanzania together with 1037 birds from eleven villages in Dhading District of Nepal were collected over a period of 21 and 28 days, respectively. Immune responses to FP vaccination were evaluated by local take reactions, while those to ND vaccination were evaluated serologically by haemagglutination inhibition test. The two studies demonstrated that the concurrent vaccination of free-range, indigenous breeds of chicken with live FP and ND vaccines, both administered by non-invasive routes, was safe and induced immunity against FP and ND that were non-inferior to the administration of FP and ND vaccines alone. These findings are important to appropriately trained small-scale backyard poultry farmers as well as to paraprofessionals and community health workers helping to increase vaccine uptake and the control of both FP and ND in low- to middle-income countries.

Novel Recombinant Newcastle Disease Virus-Based In Ovo Vaccines Bypass Maternal Immunity to Provide Full Protection from Early Virulent Challenge.

Newcastle disease (ND) is one of the most economically important poultry diseases. Despite intensive efforts with current vaccination programs, this disease still occurs worldwide, causing significant mortality even in vaccinated flocks. This has been partially attributed to a gap in immunity during the post-hatch period due to the presence of maternal antibodies that negatively impact the replication of the commonly used live vaccines. In ovo vaccines have multiple advantages and present an opportunity to address this problem. Currently employed in ovo ND vaccines are recombinant herpesvirus of turkeys (HVT)-vectored vaccines expressing Newcastle disease virus (NDV) antigens. Although proven efficient, these vaccines have some limitations, such as delayed immunogenicity and the inability to administer a second HVT vaccine post-hatch. The use of live ND vaccines for in ovo vaccination is currently not applicable, as these are associated with high embryo mortality. In this study, recombinant NDV-vectored experimental vaccines containing an antisense sequence of avian interleukin 4 (IL4R) and their backbones were administered in ovo at different doses in 18-day-old commercial eggs possessing high maternal antibodies titers. The hatched birds were challenged with virulent NDV at 2 weeks-of-age. Post-hatch vaccine shedding, post-challenge survival, challenge virus shedding, and humoral immune responses were evaluated at multiple timepoints. Recombinant NDV (rNDV) vaccinated birds had significantly reduced post-hatch mortality compared with the wild-type LaSota vaccine. All rNDV vaccines were able to penetrate maternal immunity and induce a strong early humoral immune response. Further, the rNDV vaccines provided protection from clinical disease and significantly decreased virus shedding after early virulent NDV challenge at two weeks post-hatch. The post-challenge hemagglutination-inhibition antibody titers in the vaccinated groups remained comparable with the pre-challenge titers, suggesting the capacity of the studied vaccines to prevent efficient replication of the challenge virus. Post-hatch survival after vaccination with the rNDV-IL4R vaccines was dose-dependent, with an increase in survival as the dose decreased. This improved survival and the dose-dependency data suggest that novel attenuated in ovo rNDV-based vaccines that are able to penetrate maternal immunity to elicit a strong immune response as early as 14 days post-hatch, resulting in high or full protection from virulent challenge, show promise as a contributor to the control of Newcastle disease.

Production of Newcastle Disease Polyclonal Antibody as the Alternative of Immunohistochemistry Primary Antibody against Newcastle Disease in Poultry

Newcastle disease (ND) is the most pathogenic viral infection in poultry. Furthermore, the availability of laboratories that support the molecular diagnosis of ND is still limited in Indonesia. The present study aimed to produce ND polyclonal antibody as the alternative of immunohistochemistry primary antibody against ND in poultry. Two adult male New Zealand White rabbits weighed 2.5 kg were vaccinated seven days after the adaptation using intraperitoneal injection of the ND live vaccine at multilevel doses weekly. The serum was collected inactivated, and purified in the sixth week. A total number of 31 chicken samples were collected and their samples of brain, lung, spleen, and intestine were tested using immunohistochemistry and Reverse Transcription Polymerase Chain reaction (RT-PCR). The result showed that 19/31 (61%) were positive against immunohistochemistry and RT-PCR and a total of 12/31 (39%) were negative. Based on the obtained results, immunohistochemistry using ND polyclonal antibody had a similar accuracy with RT-PCR. It can be concluded that ND polyclonal antibody produced by vaccination in the rabbit could be used as the alternative immunohistochemistry primary antibody for diagnosing ND in poultry.

Vaccine Quality Is a Key Factor to Determine Thermal Stability of Commercial Newcastle Disease (ND)Vaccines.

Vaccination against Newcastle disease (ND), a devastating viral disease of chickens, is often hampered by thermal inactivation of the live vaccines, in particular in tropical and hot climate conditions. In the past, “thermostable” vaccine strains (I-2) were proposed to overcome this problem but previous comparative studies did not include formulation-specific factors of commercial vaccines. In the current study, we aimed to verify the superior thermal stability of commercially formulated I-2 strains by comparing six commercially available ND vaccines. Subjected to 37 °C as lyophilized preparations, two vaccines containing I-2 strains were more sensitive to inactivation than a third I-2 vaccine or compared to three other vaccines based on different ND strains. However, reconstitution strains proved to have a comparable tenacity. Interestingly, all vaccines still retained a sufficient virus dose for protection (106 EID50) after 1 day at 37 °C. These results suggest that there are specific factors that influence thermal stability beyond the strain-specific characteristics. Exposing ND vaccines to elevated temperatures of 51 and 61 °C demonstrated that inactivation of all dissolved vaccines including I-2 vaccine strains occurred within 2 to 4 h. The results revealed important differences among the vaccines and emphasize the importance of the quality of a certain vaccine preparation rather than the strain it contains. These data highlight that regardless of the ND strain used for vaccine preparation, the appropriate cold chain is mandatory for keeping live ND vaccines efficiency in hot climates.

Development, Biological Characterization, and Immunological Evaluation of Virosome Vaccine against Newcastle Disease in Pakistan.

Newcastle disease (ND) is a highly fatal, infectious, viral disease, and despite immunization with live and inactivated vaccines, the disease is still endemic, causing heavy morbidity and mortality leading to huge economic losses to the poultry industry in Pakistan. Therefore, the present study was aimed for the first time in the country at using novel virosomal technology to develop the ND vaccine using an indigenous highly virulent strain of the virus. ND virosome was prepared using Triton X-100, and SM2 Bio-Beads were used to remove the detergent and reconstitute the viral membrane into virosome. Confirmation was done by transmission electron microscopy and protein analysis by SDS-PAGE. In vitro cell adhesion property was observed by incorporating green fluorescent protein (GFP), producing plasmid into virosome and in vitro cell culture assay. Sterility, safety, and stability of the vaccine were tested before in vivo evaluation of immunogenicity and challenge protection study in commercial broiler. The virosome vaccine was administered (30 μg/bird) at days 7 and 14 through the intranasal route in comparison with commercially available live and inactivated ND vaccines. Results revealed significantly high (p < 0.05) and clinically protective hemagglutination inhibition (HI) antibody titers at 7, 14, 21, and 28 days postimmunization with the virosome vaccine in comparison to the negative control. The GMTs were comparable to live and inactivated vaccines with nonsignificant (p > 0.05) differences throughout the experiment. Antibody levels increased in all vaccinated groups gradually from the 7th day and were maximum at 28th-day postvaccination. In the virosome-administered group, GMT was 83.18 and 77.62 at 21st and 28th-days postvaccination, respectively. Challenge revealed 100%, 90%, and 80% protection in virosome, live, and inactivated vaccinated groups, respectively. Under given experimental conditions, we can conclude that ND virosome vaccine prepared from the indigenous virus was found to be safe and immunogenic.

Effect of infectious bronchitis and Newcastle disease vaccines on experimental avian influenza infection (H9N2) in broiler chickens

Despite the fact that H9N2 avian influenza virus (AIV) is considered a low-pathogenic agent, frequent outbreaks of this subtype have caused high mortality and economic losses in poultry farms around the world including Iran. Coinfection with a respiratory pathogen or environmental factors may explain the exacerbation of H9N2 AIV infection. In this study, the role of infectious bronchitis (IB) vaccines (H120 and 4/91) and Newcastle disease (ND) vaccines (B1 and LaSota) on experimental H9N2 AIV infection was investigated in 180 broiler chickens allotted into 6 groups (n=30). At the age of 18 days, groups 3 and 4 received H120 and 4/91 infectious bronchitis live vaccines (IBLVs) and groups 5 and 6 received B1 and LaSota Newcastle disease live vaccines (NDLVs), respectively. At the age of 20 days, all birds in the experimental groups except the negative control group (group 1), were inoculated intra-nasally with H9N2 AIV. After the inoculation, clinical signs, gross and microscopic lesions, and viral detection were examined. The results of this study revealed that clinical signs, gross and microscopic lesions were more severe in the AIV challenged groups which had been previously vaccinated with IB vaccines. In addition, AI viral RNA from tracheal and faecal samples in IB vaccinated birds were recovered at a higher rate. Moreover, in the 4/91 IB vaccinated group, the AI virus shedding period was longer than the other challenged groups. In conclusion, infectious bronchitis live vaccines (IBLVs) exacerbated the H9N2 AIV infection; also, 4/91 IBLV extended AI virus shedding period and increased the recovery rate of AI virus from feaces. However, the coinfection of Newcastle disease live vaccines (NDLVs) had no considerable adverse effects on AIV infection in broiler chickens.

Development of TaqMan Real-Time Polymerase Chain Reaction Assay for Detection of Chicken Anemia Virus in Newcastle Disease Vaccines.

Exogenous chicken anemia virus (CAV) has been detected in commercial poultry vaccines in various countries of the world. The presence of unwanted CAV in vaccines not only influences the epidemiology of chicken infectious anemia disease, but may also lead to vaccine failure and confusing results when vaccine responses are monitored. To detect CAV in contaminated vaccines, nucleic acid testing (unlike conventional testing) has a shorter processing time and does not require cell culture or live animals. The aim of the current study was to develop a TaqMan real-time polymerase chain reaction (PCR) assay to detect and quantify CAV in poultry vaccines and investigate CAV contamination in Razi live Newcastle disease vaccines. The TaqMan real-time PCR assay was set up, optimized, and validated in successive experiments. A standard plasmid pUC-VP2 containing viral protein 2 of CAV was constructed and used in the assay to generate a standard curve to quantify CAV genomes. A clear linear correlation was observed between threshold cycle (Ct) values and plasmid copy numbers in the amplification plots of 10-fold serial dilution of the plasmid. Total DNA of three samples of each of four different Razi live Newcastle disease vaccines, namely LaSota, B1, clone.12IR, and thermo-resistant strains, were extracted and subjected to real-time PCR assay. No CAV contamination was detected in the Razi Live Newcastle vaccines. The developed TaqMan real-time PCR assay provides a quick, specific, and sensitive method for use in detecting CAV in quality control vaccine testing and viral load studies.

Effects of ND vaccination combined LPS on growth performance, antioxidant performance and lipid metabolism of broiler

Newcastle Disease Virus (NDV) is the important pathogen of Newcastle Disease (ND) attacking chicken, turkey and other birds. Therefore, the purpose of this study was to assess the effects of immune stress induced by ND vaccination and lipopolysaccharide (LPS) on growth performance, antioxidant ability, and lipid metabolism of broilers. In total, 128 one-day-old broilers were randomly assigned to the following four groups and were treated as indicated: normal control (NC); vaccinated with live LaSota ND vaccine (CV); administered ND vaccine and 0.25 mg/kg body weight (BW) LPS (L-LPS); and administered ND vaccine and 0.5 mg/kg BW LPS (H-LPS). The results demonstrated that broiler feed conversion ratio (FCR) was increased in the groups CV, L-LPS and H-LPS from d 0 to 42 days compared with the group NC. The antioxidant function of broilers was decreased as indicated by the malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) levels in the serum of the treated groups. ND vaccination combined LPS increased the concentration of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), but decreased the concentration of high-density lipoprotein cholesterol (HDLC) compared with the group NC. The reverse transcription (RT)-PCR results revealed that the mRNA expression of acetyl-CoA carboxylase gene (ACC) and 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMGR) in the liver were downregulated, whereas the mRNA expression of carnitine palmitoyltransferase-1 (CPT-1) and peroxisome proliferator-activated receptor (PPAR)-α were upregulated compared with the group NC. These results suggest that ND vaccination combined LPS reduced broiler growth performance and antioxidant ability, whereas it activated AMPK-mediated lipid metabolism.

Large scale Production of I-2 thermostable Newcastle Disease Vaccine in Sudan

In the present study, a live attenuated Newcastle Disease (ND) vaccine of I-2strain was produced locally. the master seed I-2 virus was first supplied by the Department of Veterinary Pathology of the University of Queensland, Australia, which then handed over by the Department of Veterinary Virology of the Central Veterinary Research Laboratory (CVRL) Sudan. A 11 days old embryonated chicken eggs with a minimal risk of vertical transmission were used for the virus propagation. The ND I-2 Master Seed Lot ( MSL) was prepared in aliquots and stored in a liquid form at -20⁰C. The Working Seed Lot (WSL) was prepared from the MSL and stored in a freeze dried form. The WSL then complied with the main quality tests of identity,safety, immunogenicity, efficacy, microbial contamination, thermostability and the infectivity titer tests.The virulence of the WSL was estimated via intracerepral pathogenicity index test (ICPI), the ICPI was 0.125 and the vaccine was proved to be safe in day old chicks.The immunogenicity measured by mean of ELISA. The GMT titer for the post vaccination serum was statistically significant than the pre vaccinated serum(P=0.001) paired sample t.test.The efficacy against a vvND virus, (ICPI 1.97) was 89% and the WSL was proved to be free from any detectable contaminant microorganisms. The temperature sensitivity for vaccine potency had been determined at different temperature levels and at Fluctuating Room Temperature (FRT). The titer decreased only by 0.2, 4.5 and 4.6 logs at temperatures -20⁰C, 37⁰C and 56⁰C respectively, while in the FRT decreased by 7.53 logs. The virus titer of WSL on the embryonated chickens, eggs was 9.1 EID50/ml.

The immune adjuvant effect of Astragalus polysaccharide on in ovo injection of Newcastle disease vaccine.

In this study, immunogenic efficacies of in ovo administration of Astragalus polysaccharide (APS) along with live Newcastle disease vaccine (live ND vaccine) (live VG/GA strain) were evaluated. Four hundred fertilized eggs were randomly divided into four groups (n=100/group), and vaccinated in ovo, respectively, with solutions of APS, live ND vaccine, live ND vaccine combined with APS, and 0.9% physiological saline into their amniotic fluid on d 18.5 of incubation. Significant improvement of chicks' development was displayed in those vaccinated with live ND vaccine adjuvanted with APS in ovo, manifested as enhanced hatchability and gaining weight. Moreover, in ovo administration of live NDV vaccine plus APS could significantly enhance the serum anti-NDV antibody titres and interferon gamma (IFN-γ), interleukin (IL)-2, IL-4 and IL-6 concentrations, promote lymphocyte proliferative capability as well as improve the frequencies of CD4+ and CD8+ T cells in peripheral blood. Overall results indicated in ovo administration of live ND vaccine adjuvanted with APS could stimulate stronger humoral and cellular responses in newly hatched chicks.

Effect of Newcastle disease and infectious bronchitis live vaccines on the immune system and production parameters of experimentally infected broiler chickens with H9N2 avian influenza

H9N2 Avian influenza (AI) is an infectious disease which considered to have low pathogenic virulence, but in the case of coinfection with other pathogens it has the potential to become a major threat to the poultry industry. Infectious bronchitis (IB) and Newcastle diseases (ND) are other common problems to the poultry industry, which there are an extensive vaccination program against these viral pathogens. To investigate the effects of administration of infectious bronchitis and Newcastle disease live vaccines (IBLVs and NDLVs) in the presence of H9N2 AI infection on the immune system and some production parameters, 180 one-day-old broiler chicks were randomly allocated into six groups with different vaccination programs including H120 IBLV, 4/91 IBLV, B1 NDLV and LaSota NDLV. At the age of 20 days, all birds of the experimental groups except the negative control group, were inoculated intra-nasally (at dose of 106 EID50) with H9N2 AIV. After the inoculation, gross and microscopic lesions of the immune organs, serological changes and some production parameters were examined. The findings of this study showed that coinfection of H9N2 AI with NDLVs exacerbated the gross and microscopic injuries in the immune organs; especially the bursa of Fabricius. LaSota + AIV group had the most severe lesion in the bursa of Fabricius, spleen and thymus. Furthermore, the birds of LaSota + AIV group consumed the least amount of feed and water and their final body weight were significantly (P ≤ 0.05) lower in comparison with the other groups. Interestingly, in the context of this experiment both 4/91 and H120 IB live vaccines enhanced the HI antibody titers against H9N2 AIV, but the 4/91 showed the most significant (P ≤ 0.05) increase compared to the other experimental groups.

Effects of polysaccharide from Ophiopogon japonicus on immune response to Newcastle disease vaccine in chicken

In order to investigate the immune enhancement effects of Ophiopogon japonicus polysaccharide Ophiopogon japonicus (OJPS) on Newcastle disease (ND) live vaccine, chickens vaccinated against ND live vaccine was orally administered with the OJPS at high, medium and low concentrations respectively. In negative control group, chickens were given orally equal volume of physiological saline. On day 14, 21 and 28, the serum antibody titer, erythrocyte-C3b receptor rosette rate (E-C3bRR), erythrocyte-C3b immune complex rosette rate (E-ICRR) and peripheral lymphocyte proliferation were measured. The results showed that at most time points, the antibody titer, peripheral lymphocyte proliferation, E-C3bRR and elimination rate of immune complex of three OJPS administrating groups were significantly higher (P<0.05) than those in negative control group. It indicated that OJPS could significantly improve the immune efficacy of Newcastle disease live vaccine, Ophiopogon japonicus polysaccharide possessed synergistical immunoenhancement.

COMPARATIVE EVALUATION OF THE PROTECTIVE EFFICACY OF DIFFERENT VACCINATION PROGRAMS AGAINST A VIRULENT FIELD STRAIN OF THE NEWCASTLE DISEASE VIRUS IN BROILERS

Despite the intensive vaccination programs used for controlling Newcastle disease (ND) in the Iranian poultry industry, outbreaks of ND have been reported in poultry farms. This study was conducted to evaluate the effectiveness of vaccines for the protection against ND infection and virus-shedding period of velogenic Newcastle disease virus (vNDV) field strain after different immunization schemes. Eight groups of commercial broiler chickens were used. Six groups were vaccinated with different vaccination programs using commercial live and inactivated ND vaccines. All groups, except for group 8, were challenged with a virulent field isolate (104EID50/bird) at 28 days of age. Clinical signs, mortality rate and gross lesions were investigated. Antibody titers were assayed by hemagglutination inhibition test and fecal virus shedding was determined for 14 days post challenge (dpc) with 3-day intervals by the RT-PCR method. All unvaccinated-challenged control birds died. Vaccination with these ND vaccines protected chickens from clinical disease. The mortality rate in the vaccinated groups was significantly lower than in the positive control group. However, vaccinated chickens shed the challenge virus in fecal samples. Although the different vaccination regimens displayed close degrees of protection against the disease, the best protection was observed in broilers primed with the live B1 vaccine via eye drop simultaneously with inactivated vaccine at 8 days of age and boosted with B1 or LaSota via drinking water on day 18. In conclusion, the currently used vaccines with different vaccination schemes can protect chickens against the disease in areas where ND is endemic, while the spread of the field virus to other flocks cannot be prevented.

Biological evaluation of N-2-hydroxypropyl trimethyl ammonium chloride chitosan as a carrier for the delivery of live Newcastle disease vaccine

Mucosal immune system plays a very important role in antiviral immune response. We prepared Newcastle disease viruses (NDV) encapsulated in N-2-hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) nanoparticles (NDV/La Sota-N-2-HACC-NPs) by an ionic cross linking method, and assessed the potential of N-2-HACC-NPs as a mucosal immune delivery carrier. The properties of the nanoparticles were determined by transmission electron microscopy, Zeta potential and particle size analysis, encapsulation efficiency and loading capacity. NDV/La Sota-N-2-HACC-NPs have regular spherical morphologies and high stability; with 303.88±49.8nm mean diameter, 45.77±0.75mV Zeta potential, 94.26±0.42% encapsulation efficiency and 54.06±0.21% loading capacity. In vitro release assay indicated that the release of NDV from NDV/La Sota-N-2-HACC-NPs is slow. The NDV/La Sota-N-2-HACC-NPs have good biological characteristics, very low toxicity and high level of safety. Additionally, specific pathogen-free chickens immunized with NDV/La Sota-N-2-HACC-NPs showed much stronger cellular, humoral and mucosal immune responses than commercial attenuated live Newcastle disease vaccine, and NDV/La Sota-N-2-HACC-NPs reached the sustainable release effect. Our study here provides a foundation for the further development of mucosal vaccines and drugs, and the N-2-HACC-NPs should be a potential drug delivery carrier with immense potential in medical applications.

Aerosol Disinfection Capacity of Slightly Acidic Hypochlorous Acid Water Towards Newcastle Disease Virus in the Air: An In Vivo Experiment.

Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we selected slightly acidic hypochlorous acid water (SAHW) as a candidate and evaluated its virucidal efficacy toward a virus in the air. Three-day-old conventional chicks were challenged with 25 doses of Newcastle disease live vaccine (B1 strain) by spray with nebulizer (particle size <3 μm in diameter), while at the same time reverse osmosis water as the control and SAHW containing 50 or 100 parts per million (ppm) free available chlorine in pH 6 were sprayed on the treated chicks with other nebulizers. Exposed chicks were kept in separated cages in an isolator and observed for clinical signs. Oropharyngeal swab samples were collected from 2 to 5 days postexposure from each chick, and then the samples were titrated with primary chicken kidney cells to detect the virus. Cytopathic effects were observed, and a hemagglutination test was performed to confirm the result at 5 days postinoculation. Clinical signs (sneezing) were recorded, and the virus was isolated from the control and 50 ppm treatment groups, while no clinical signs were observed in and no virus was isolated from the 100 ppm treatment group. The virulent Newcastle disease virus (NDV) strain Sato, too, was immediately inactivated by SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms.

O-2′-Hydroxypropyltrimethyl ammonium chloride chitosan nanoparticles for the delivery of live Newcastle disease vaccine

A novel complex chitosan derivative, O-2′-hydroxypropyltrimethyl ammonium chloride chitosan (O-2′-HACC), was synthesized and used to make nanoparticles as a delivery vehicle for live attenuated Newcastle disease vaccine. We found that O-2′-HACC had high antimicrobial activity, low toxicity, and a high safety level. Newcastle disease virus (NDV) was then encapsulated in the O-2′-HACC nanoparticles (NDV/La Sota-O-2′-HACC-NPs) by the ionic crosslinking method, and the properties of the resulting nanoparticles were determined by transmission electron microscopy, Zeta potential analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray diffraction. NDV/La Sota-O-2′-HACC-NPs had regular spherical morphologies and high stability, with an encapsulation efficiency of 95.68±2.2% and a loading capacity of 58.75±4.03%. An in vitro release assay indicated that release of NDV from NDV/La Sota-O-2′-HACC-NPs occurred slowly. Specific pathogen-free chickens immunized with NDV/La Sota-O-2′-HACC-NPs intranasally had much stronger cellular, humoral and mucosal immune responses than did those immunized intramuscularly or with live attenuated Newcastle disease vaccine. NDV/La Sota-O-2′-HACC-NPs are a novel drug delivery carrier with immense potential in medical applications.

Immune responses and interactions following simultaneous application of live Newcastle disease, infectious bronchitis and avian metapneumovirus vaccines in specific-pathogen-free chicks

Interactions between live Newcastle disease virus (NDV), avian metapneumovirus (aMPV) and infectious bronchitis virus (IBV) vaccines following simultaneous vaccination of day old specific pathogen free (SPF) chicks were evaluated. The chicks were divided into eight groups: seven vaccinated against NDV, aMPV and IBV (single, dual or triple) and one unvaccinated as control. Haemagglutination inhibition (HI) NDV antibody titres were similar across all groups but were above protective titres. aMPV vaccine when given with other live vaccines suppressed levels of aMPV enzyme-linked immunosorbent assay (ELISA) antibodies. Cellular and local immunity induced by administration of NDV, aMPV or IBV vaccines (individually or together) showed significant increase in CD4+, CD8+ and IgA bearing B-cells in the trachea compared to the unvaccinated group. Differences between the vaccinated groups were insignificant. Simultaneous vaccination with live NDV, aMPV and IBV did not affect the protection conferred against aMPV or IBV.