Newcastle Disease Vaccine Research Articles

Molasses, Antox® and EN-FLORAX® decreased antibody decay rate and enhanced response to a very virulent infectious bursal disease virus and Newcastle disease vaccine La Sota in ISA Brown chicks

ABSTRACT This study evaluated the effects of molasses, Antox® and EN-FLORAX® on antibody (Ab) decay and response to a very virulent IBD virus (vvIBDV) and ND vaccine La Sota (NDVLS) in ISA Brown chicks. Five groups, (A, B, C, D and E) of 50 chicks each were used for the study. Groups A, B and C were supplemented with molasses, Antox® and EN-FLORAX®, respectively, orally from 1 to 49 days, and inoculated with a vvIBDV at 28 days of age. Groups D, and E were positive, and negative controls, respectively. At 35 days of age, all groups were vaccinated with NDVLS. Antibody (Ab) titers to vvIBDV, and NDV, were determined by indirect enzyme linked immunosorbent assay (I-ELISA), and hemagglutination-inhibition (HI) tests, respectively. Results revealed significantly (P < .05) decreased Ab decay rates in supplemented groups (A, B, and C) compared to controls (D and E) up to day 28. There were significantly (P < .05) higher mean IBDV and ND HI Ab titers in supplemented groups compared to D with the highest in A up to day 49. Molasses, Antox®, and EN-FLORAX® decreased rate of Ab decay, elicited stronger Ab response against vvIBDV and production of protective NDVLS HI Ab titers.

Chicken ISG12(2) attenuates Newcastle disease virus and enhances the efficiency of Newcastle disease vaccine via activating immune pathways.

Low virulence and strong immunogenicity are quite important for Newcastle disease virus (NDV) producing Newcastle disease (ND) living-attenuated vaccine. However, immunogenicity of NDV positively correlates to its virulence. Usually, the velogenic NDV induces stronger immune responses of poultry than the lentogenic strain, but virulent NDV poses a risk for chicken. In this study, we identified the chicken interferon (IFN)-stimulated gene 12-2 (ISG12(2)) not only attenuated NDV, but also increased immunogenicity of ND vaccine strain. First, we found that NDV infection or IFNs stimulation induced expression of chicken ISG12(2) that reinforced expression of IFNs. Over-expression or knock-down proved that chicken ISG12(2) inhibited NDV replication. Then, recombinant NDV LaSota strains (rLaSota/Fmut/ISG12(2) and rLaSota/ISG12(2)), expressing ISG12(2), were rescued. Pathogenicity tests showed that ISG12(2) expression attenuated NDV. RNA-seq or RT-qPCR demonstrated that, comparing to rLaSota/Fmut and rLaSota, rLaSota/Fmut/ISG12(2) and rLaSota/ISG12(2) induced hosts to produce cytokines enriching in innate and adaptive immune pathways in vitro and in vivo. Finally, we showed that rLaSota/ISG12(2) vaccination improved immune condition of chicken to quickly respond NDV infection and then enhance protection. These results suggest that chicken ISG12(2) is a potential novel molecular adjuvant to regulate immune responses, which decrease virulence and increase immunogenicity of NDV. The chicken ISG12(2) may contribute to the development of high efficient poultry vaccine.

Modulation of the innate immune system by lipopolysaccharide in the proventriculus of chicks inoculated with or without Newcastle disease and infectious bronchitis vaccine

This study aimed to determine whether the innate immune system in the proventriculus of broiler chicks responds to lipopolysaccharide (LPS) and whether this response is affected by Newcastle disease and infectious bronchitis (ND/IB) vaccination. Chicks were divided into 4 groups: nonvaccinated and injected with PBS or LPS (V-L- and V-L+), and vaccinated and injected with PBS or LPS (V+L- and V+L+). Vaccination was performed on d 1, and LPS was intraperitoneally injected on d 11 of age. The gene expression and protein levels of immune molecules, including toll-like receptors (TLRs), antimicrobial peptides, interleukin-1β (IL-1B), and immunoglobulin A (IgA) in the proventriculus and serum were analyzed. The results showed that the expression levels of TLR21 were higher in vaccinated (V+L-) group than in nonvaccinated (V-L-) group. Gene expression levels of avian β-defensin (AvBDs) and cathelicidin1 (Cath1) were not different among the 4 groups. However, the results of LC/MS analysis showed that the levels of AvBD2, 6, and 7 significantly increased after the LPS challenge in nonvaccinated and vaccinated chicks; the levels were higher in V-L+ and V+L+ than in V-L- and V+L-, respectively. Immunohistochemistry analysis revealed the localization of AvBD1 protein in the epithelial cells of the surface glands and AvBD2 and CATH1 in the heterophil-like cells in the lamina propria of surface glands. Although IL-1B gene expression and protein concentration in the proventriculus tissues were not different among the 4 groups, serum IL-1B levels were upregulated by LPS in both the nonvaccinated and vaccinated groups (V-L- vs. V-L+, V+L- vs. V+L+). Moreover, IgA levels in the proventriculus and serum were not affected by vaccination or LPS challenge. Taken together, we conclude that LPS derived from gram-negative bacteria upregulates the innate immune system, including antimicrobial peptide synthesis in the proventriculus. ND/IB vaccination may not significantly affect antimicrobial peptide synthesis in response to LPS; however, TLR21 expression is upregulated by that vaccination. The antimicrobial peptides synthesized in the proventriculus probably prevent pathogenic microbes from entering the intestine.

Participatory control of Newcastle disease in village poultry using thermo-stable Newcastle disease vaccines in Bulle district of Gedio Zone, Southern Ethiopia

Newcastle Disease (ND) is regarded as one of the major diseases of poultry because of the devastating losses that the virulent form of the virus can impose on both commercial and village chicken. However, the disease can be controlled through the administration of effective vaccines. Almost all the commercially available vaccines require refrigeration and begin to deteriorate rapidly after 1-2 hours if left at room temperature (around 25°C). Subsequently, because maintaining an adequate supply of refrigerated facilities may be a difficult task in many developing countries with unreliable electrical supplies, the development and large scale production and utilization of an effective thermo-stable Newcastle disease vaccine seems imperative to support rural poultry industry. Participatory/action research on vaccination of village poultry against Newcastle disease (ND) was carried out in two selected villages of Bullie district of Gedio zone, southern Ethiopia; with an objective to demonstrate community based thermo-stable ND vaccination scheme and thereby; to increase the population of chicken in backyard production system. We have selected four community vaccinators, two per each village and trained on diagnosis of major poultry diseases, with the major emphasis on Newcastle disease, on preparation, handling and administration of thermo-sable ND vaccine. From the two villages, we have vaccinated 362 chicken of all age ranges of 54 households, in the two rounds. For the vaccination we have selected a site which is suitable for household members to bring their chicken for vaccine administration. We used eye drop technique to administer a vaccine, by preparing one eye drop in one dose base for all age groups. We administered a vaccine before a pick prevalence of Newcastle disease in the study area, for the remaining three months, data was collected on the mortality rate of the chicken. The result shows that, of the total vaccinated chicken (362) from the two villages on the two rounds, 51 chicken were dead due to diseases, of the cases with a clinical sign not related with Newcastle disease. The total mortality rate of 14%, in this study shows that, thermo-stable Newcastle disease vaccine applied via eye drop is the most effective method for control Newcastle disease in village chicken. Therefore; with proper use of vaccine and vaccination programs using well trained community vaccinators, we can reduce village chicken mortality highly to enhance productivity of rural community at large.

Effects of Spirulina (Arthrospira platensis) as a drinking water supplement during cyclical chronic heat stress on broiler chickens: Assessing algal composition, production, stress, health and immune-biochemical indices.

Spirulina, the blue green algae is considered to exhibit multifaceted benefits on both human health and animal production. Three hundred sixty day old unsexed broiler chicks of CARIBROVISHAL strain were assigned to five treatment groups each comprising nine replicates of 8 chicks. The experiment was carried out during the hot humid summer season (Mid-April to May) under deep litter rearing system with uniform managemental conditions. Birds were administered orally with Spirulina through drinking water in the morning (06:00-12:00 PM) on daily basis throughout the experimental period at 5, 10, 15 and 20gL-1 concentration. Spirulina supplementation neither improved nor compromised production performance of broilers reared during hot climatic condition. Results based on one way analysis of variance indicated a significant effect on haemoglobin and total red blood cell count. Serum lipid content and transaminases were reduced, while serum protein concentration was higher (P<0.01) in the groups administered with 15 and 20gL-1 of Spirulina. The extent of imparting shank pigmentation was improved in all the supplemented groups. Cell mediated and humoral immunity against Phytoheamagglutunin-P and Newcastle disease vaccination respectively were maximized (P<0.05) at 20gL-1. These findings provide direct evidence of dose-related modulation of production, physiological and immunological attributes by Spirulina engendering its further investigation as a potential source of drinking water supplement for stress alleviation in broilers. From the results, it may concluded that Spirulina can be incorporated at 15 or 20gL-1 for achieving optimal improvement of health and welfare attributes in broilers reared during hot summer without compromising production.

The ability to resist Newcastle disease through inherited immunity in different strains of broilers in Nineveh governorate.

Newcastle disease (ND) is a viral disease that affects numerous bird species and is still present in many places, including Iraq. The purpose of this study was to compare maternal derived antibodies against against ND vaccination in 1-day-old imported Cobb 500 and Ross 308 chicks. From April to October 2020, four locations in Mosul governorate were chosen to compute the maternal derived antibodies from 1-day-old broiler chicks. Seven hundred and seven blood samples (451) from imported 28 Ross 308 flocks and 256 from 17 Cobb 500 flocks were obtained and tested for antibody levels using an indirect enzyme-linked immunosorbent assay assay (BioChek commercial kit, UK). The Cobb 500 broiler chicks outperformed the Ross 308 broiler chicks in that all of the Cobb 500 broiler chicks had maternal antibody titers (100% positivity) versus 97.78% of the Ross 308 chicks, had a mean Maternal antibody titer of 9,871.47 versus 8,647.76, and had a mean CV percentage of 12.41% versus 15.18%, respectively. The mean vaccination index of Cobb 500 broiler chicks was 966.59 versus 821.60 for Ross 308 broiler chicks. Although both broiler types produced chicks with high and uniform maternal antibody titers, Cobb 500 produced chicks with higher protective titers than Ross 308.

Efficacy of genotype-matched Newcastle disease virus vaccine formulated in carboxymethyl sago starch acid hydrogel in chickens vaccinated via different routes.

BackgroundThe commercially available Newcastle disease (ND) vaccines were developed based on Newcastle disease virus (NDV) isolates genetically divergent from field strains that can only prevent clinical disease, not shedding of virulent heterologous virus, highlighting the need to develop genotype-matched vaccinesObjectivesThis study examined the efficacy of the NDV genotype-matched vaccine, mIBS025 strain formulated in standard vaccine stabilizer, and in carboxymethyl sago starch-acid hydrogel (CMSS-AH) following vaccination via an eye drop (ED) and drinking water (DW).MethodsA challenge virus was prepared from a recent NDV isolated from ND vaccinated flock. Groups of specific-pathogen-free chickens were vaccinated with mIBS025 vaccine strain prepared in a standard vaccine stabilizer and CMSS-AH via ED and DW and then challenged with the UPM/NDV/IBS362/2016 strain.ResultsChickens vaccinated with CMSS-AH mIBS025 ED (group 2) developed the earliest and highest Hemagglutination Inhibition (HI) NDV antibody titer (8log2) followed by standard mIBS025 ED (group 3) (7log2) both conferred complete protection and drastically reduced virus shedding. By contrast, chickens vaccinated with standard mIBS025 DW (group 5) and CMSS-AH mIBS025 DW (group 4) developed low HI NDV antibody titers of 4log2 and 3log2, respectively, which correspondingly conferred only 50% and 60% protection and continuously shed the virulent virus via the oropharyngeal and cloacal routes until the end of the study at 14 dpc.ConclusionsThe efficacy of mIBS025 vaccines prepared in a standard vaccine stabilizer or CMSS-AH was affected by the vaccination routes. The groups vaccinated via ED had better protective immunity than those vaccinated via DW.

Моніторинг вакцинопрофілактики ньюкаслської хвороби в Україні

Моніторинг вакцинопрофілактики ньюкаслської хвороби в Україні

Evaluation of Newcastle disease virus vaccine effectiveness in dogs with neurological signs of canine distemper.

Canine Distemper Virus (CDV) is the cause of a highly lethal infectious disease affecting a broad range of carnivores. Despite using various treatments, there is still no effective treatment, especially in the neurological form of distemper. The aim of this study was to evaluate the therapeutic effect of injecting Newcastle disease vaccine into the subarachnoid space of dogs with neurological form of distemper. The dogs that had symptoms of nervous distemper, particularly myoclonus, were included in the plan. After anesthetizing of dogs, 0.10 to 1.00 mL of cerebrospinal fluid (CSF) were removed and, 0.10 to 0.50 mL of the prepared Newcastle solution were injected into their subarachnoid space. Another 0.50 to 1.00 mL of normal saline was then injected to remove the needle from the vaccine. The live attenuated LaSota or B1 vaccine was used in this study. Rapid kit tests and reverse transcription polymerase chain reaction (RT-PCR) assays were used to diagnose of the disease. Dogs were monitored for up to 3 to 24 months during that time they were evaluated for improvement or worsening of clinical symptoms. Out of nine dogs in which distemper were diagnosed with different tests, one dog recovered completely and another dog recovered greatly. Therefore, the overall recovery rate was 22.20%. It is concluded that administration of Newcastle vaccine into the subarachnoid space of dogs with nervous distemper causes at least 22.20% improvement and does not cause specific side effects and can be used to treat affected dogs.

Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage in vivo.

Background This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five in vivo passages through SPF chickens. Methods Study design was to international requirements including European Pharmacopoeia, Ph. Eur., v9.0 04/2013:0450, 2013. I-2 Working Seed (WS) was compared with five-times-passaged I-2 WS (5XP WS) in intracerebral pathogenicity index (ICPI), F o cleavage site sequencing and Safety tests. Results The first passage series used a 50% brain: 50% tracheal tissue challenge homogenate and was unsuccessful as I-2 was not detected after the fourth passage. A second passage series used 10% brain: 90% tracheal tissue homogenates. I-2 was isolated from tracheal tissue in each passage. However harvested titres were below the minimum challenge level (10 7 EID 50) specified for the ICPI and Safety tests, possibly reflecting I-2's inherently low pathogenicity (interestingly caecal tonsils yielded significant titres). Given this the WS and 5XP WS comparisons proceeded. ICPI values were 0.104 and 0.073 for the WS group and the 5XP WS group respectively confirming that I-2, whether passaged or not, expressed low pathogenicity. F 0 amino-acid sequences for both WS and 5XP WS were identified as 112R-K-Q-G-R-↓-L-I-G 119 and so compatible with those of avirulent ND viruses. In safety, no abnormal clinical signs were observed in both groups except for two chicks in the 5XP WS group, where one bird was withdrawn due to a vent prolapse, and another bird died with inconclusive necropsy results. Conclusions: These data, the issue of low passage titres with little or no virus isolation from brain tissues and the genomic copy approach suggest a need to amend Ph. Eur. v9.0 04/2013:0450, 2013 for naturally attenuated, low pathogenicity vaccine viruses such as I-2.From an international regulatory perspective, the study provides further definitive data demonstrating that Newcastle disease vaccine virus I-2 is safe for use.

CAvant® WO-60 as an Effective Immunological Adjuvant for Avian Influenza and Newcastle Disease Vaccine.

Despite the immunogenicity of vaccines currently used in poultry, several pathogens, including avian influenza virus (AIV) and Newcastle disease virus (NDV), cause enormous economic losses to the global poultry industry. The efficacy of vaccines can be improved by the introduction of effective adjuvants. This study evaluated a novel water-in-oil emulsion adjuvant, CAvant® WO-60, which effectively enhanced both the immunogenicity of conserved influenza antigen sM2HA2 and inactivated whole H9N2 antigen (iH9N2). CAvant® WO-60 induced both humoral and cell-mediated immunity in mice and provided 100% protection from challenge with 10 LD50 of A/Aquatic bird/Korea/W81/2005 (H5N2) and A/Chicken/Korea/116/2004 (H9N2) AIV. Importantly, immunization of chickens with iH9N2 plus inactivated NDV LaSota (iNDV) bivalent inactivated vaccine emulsified in CAvant® WO-60 induced seroprotective levels of antigen-specific antibody responses. Taken together, these results suggested that CAvant® WO-60 is a promising adjuvant for poultry vaccines.

Molecular Characterization and Pathology of Virulent Newcastle Disease Virus Isolated from Broiler Chickens in District Lahore, Pakistan

Background: This study elucidated the molecular detection and pathological alterations in broiler chickens naturally infected with field circulating NDV strains along with their phylogenomic dynamics. Methods: Morbid tissue samples of diseased/dead chickens were collected from 100 poultry flocks presented to poultry disease diagnostic laboratories from September 2018 to August 2019. Samples were subjected to molecular detection of NDV along with phylogenetic analysis and subsequent gross and histopathological examination. Result: Based on RT-PCR results, the positivity of NDV was 04/100 (4%). Genetic analysis of the NDV Fusion (F) gene revealed 98.92% and 98.74% similarity with Iranian and Pakistani isolates, respectively. The evolutionary tree showed that present study isolates were placed in a clade belongs to genotype Vll sub-genotype i and l. Necropsy examinations revealed the petechial haemorrhages associated with multifocal necrosis in gastrointestinal and respiratory organs. Besides these pathological findings, amino acid sequence of F gene revealed that study isolates are having pathogenic potential similar to the velogenic strains of NDV. Based on all essential analyses, the present study concluded that the evolution and distribution of the Newcastle disease virus of various genotypes VIIi and VIIl in Pakistan are having significant pathogenic potential. Therefore, it emphasizes developing ND vaccine from indigenous strains for better protection of commercial poultry in Pakistan.

Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage in vivo.

Background This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five in vivo passages through SPF chickens. Methods Study design was to international requirements including European Pharmacopoeia, Ph. Eur., v9.0 04/2013:0450, 2013. I-2 Working Seed (WS) was compared with five-times-passaged I-2 WS (5XP WS) in intracerebral pathogenicity index (ICPI), F o cleavage site sequencing and Safety tests. Results The first passage series used a 50% brain: 50% tracheal tissue challenge homogenate and was unsuccessful as I-2 was not detected after the fourth passage. A second passage series used 10% brain: 90% tracheal tissue homogenates. I-2 was isolated from tracheal tissue in each passage. However harvested titres were below the minimum challenge level (10 7 EID 50) specified for the ICPI and Safety tests, possibly reflecting I-2's inherently low pathogenicity (interestingly caecal tonsils yielded significant titres). Given this the WS and 5XP WS comparisons proceeded. ICPI values were 0.104 and 0.073 for the WS group and the 5XP WS group respectively confirming that I-2, whether passaged or not, expressed low pathogenicity. F 0 amino-acid sequences for both WS and 5XP WS were identified as 112R-K-Q-G-R-↓-L-I-G 119 and so compatible with those of avirulent ND viruses. In safety, no abnormal clinical signs were observed in both groups except for two chicks in the 5XP WS group, where one bird was withdrawn due to a vent prolapse, and another bird died with inconclusive necropsy results. Conclusions: These data, the issue of low passage titres with little or no virus isolation from brain tissues and the genomic copy approach suggest a need to amend Ph. Eur. v9.0 04/2013:0450, 2013 for naturally attenuated, low pathogenicity vaccine viruses such as I-2.From an international regulatory perspective, the study provides further definitive data demonstrating that Newcastle disease vaccine virus I-2 is safe for use.

Paulownia tomentosa flower polysaccharide as an effective immunopotentiator to enhance immune responses for Newcastle disease vaccine in mice

To investigate the immunomodulatory activity and explore the mechanism of Paulownia tomentosa flower polysaccharides (PTFP). PTFP was orally administrated to mice for seven successive days before and after Newcastle disease vaccination. The results demonstrated that compared with the vaccine control (VC) group, PTFP enhanced the inhibition of hemagglutination assay antibody titers, promoted the antigen-specific immunoglobulin (Ig)G, IgG1, IgG2a, and IgG2b antibodies responses, enhanced proliferation of spleen T and B lymphocytes, increased the secretions of interferon-γ and interleukin-10 cytokines of spleen lymphocytes, and promoted the activation of natural killer cells. Therefore, PTFP, as an effective immunopotentiator, could induce a mixed T-helper (Th)1 and Th2 immune responses and an innate immune response.

Quercetin ameliorates ochratoxin A-Induced immunotoxicity in broiler chickens by modulation of PI3K/AKT pathway

Ochratoxin A (OTA) is a fungal secondary metabolite produced by certain species of Aspergillus and Penicillium, and exerts immunosuppressive effect on humans and animals. Quercetin (QUE) is one of the flavonoids produced as a plant-secondary metabolite. The present study was designed to evaluate the efficacy of QUE against the immunotoxic hazard of OTA in broiler chickens. Forty one-day-old broiler chicks were randomly and equally allocated into four groups; control, OTA (0.5 mg/kg feed), QUE (0.5 g/kg feed) and OTA + QUE (0.5 mg/kg OTA + 0.5 g/kg QUE). The results revealed that dietary OTA induced a significant decrease in the antibody response to Newcastle Disease (ND), Infectious Bronchitis (IB) and Avian Influenza (AI) vaccination and in the lymphoproliferative response to Phytohemagglutinin-P (PHA-P). Ochratoxin A also induced oxidative stress and lipid peroxidation in the bursa of Fabricius, spleen and thymus tissues of chickens as demonstrated by decreased CAT and GSH levels and increased TBARS content. In addition, administration of OTA resulted in apoptosis, which was evident by the increased expression level of PTEN, Bax and Caspase-3 genes and decreased expression level of PI3K, AKT and Bcl-2 genes. Furthermore, exposure to OTA resulted in various pathological lesions in the bursa of Fabricius, spleen and thymus of chickens. On the other hand, administration of QUE ameliorated most of the immunotoxic effects of OTAby its immunomodulatory, antioxidant and anti-apoptotic activities. Taken together, the results suggested that QUE potentially alleviated the OTA-induced immunotoxicity in broiler chickens, probably through amelioration of oxidative stress and activation of the PI3K/AKT signaling pathway.

Retrospective study of livestock vaccine coverage and trend in Lemu and Bilbilo Woreda, Arsi Zone, Ethiopia

Vaccination is one of the most efficient tools for protection against clinical disease of livestock and reduces the rate of spread of infection. The study was conducted using secondary data that recorded at Lemu and Bilbilo Woreda veterinary clinic with the objective to assess the vaccination coverage in the study area from March to September 2021. Results revealed the most commonly practiced vaccine were bacterial and viral diseases from secondary data recorded were Lumpy skin disease, Black leg, Pasteurellosis, New castle, Gumboro disease, chicken pox, Fowl pox, and Fowl Cholera. The percentage of vaccine coverage for lumpy skin disease decreases from a year 2017 (51.1%) to 2021(24%). The majority of Goat (96.7%) was vaccinated against goat pox during 2017 and the 0% Anthrax vaccine for Goat in 2021. Only 7.3% sheep in 2017 and near 37.4% in 2021 were vaccinated with sheep pox from total population. About 87.4% of equines were vaccinated from total population in 2017. The proportion of Newcastle disease and Gumboro disease vaccine coverage were 35% and 15.4%, respectively. Dog vaccination against rabies is increases from a year 2017 (4.8%) to 2020 (11%) in except 0.5% in 2021. The vaccine trends were fluctuating and/or decreasing from year to year. However, vaccine trend for Anthrax of cattle was increasing from year to year. It is therefore, suggested that implementation of planed and regularly vaccination of animal was very important for diseases control and prevention are recommended in order to decrease disease reoccurrence in the area.

What drives small-scale farmers to vaccinate their multiple livestock species animals against common infectious diseases in Myanmar?

Livestock rearing is an important income source for small-scale farmers in Myanmar, but Foot and Mouth Disease (FMD) and Newcastle disease (ND) are major constraints to livestock production. A study was conducted to identify perceptions of farmers about FMD and ND disease risks and perceptions about vaccination practices by using the modified health belief model. The majority of livestock farmers (>70%) reported that they were aware of the risk and impact of FMD and ND and were willing to vaccinate their livestock (>60%). Focusing on three main livestock farmer groups, about 17.0% of cattle, 15.4% of village chicken, but only 2.3% of small ruminant owners, indicated that the non-availability of vaccinations in the villages was the major constraint to vaccinations (p<0.001), while in contrast twice as many small ruminant farmers compared to cattle and village chicken farmers indicated they had no knowledge about vaccinations and no funds to conduct vaccinations. Limited accessibility to vaccines and vaccinators was related to size of villages (p = 0.001 for cattle; p = 0.027 for small ruminants; p = 0.005 for village chicken). Willingness to vaccinate small ruminants against FMD was associated with the perceived impact of the disease on sales and accessibility of information about vaccination. Accessibility to information about ND vaccination influenced the willingness of village chicken farmers to conduct vaccinations. In addition, beliefs in the effectiveness of vaccinations played a major role in the willingness to carry out vaccinations on both, cattle (β = 0.3, p = 0.018) and village chicken farms (β = 0.5, p<0.001). Our study highlights that policies that increase the accessibility of vaccines and the dissemination of information about disease prevention and vaccination practices in villages of all sizes, have the potential to increase FMD and ND vaccination rates and thereby reduce outbreak occurrence in Myanmar. On the other hand, indirect factors, such as village size strongly influenced the availability of vaccinations.

Glycyrrhiza polysaccharides can improve and prolong the response of chickens to the Newcastle disease vaccine

Licorice is a medicinal and food plant widely used to treat diseases and produce food additives, because of its unique chemical constituents like polysaccharides, flavones, and saponins. Glycyrrhiza Polysaccharides (GPS-1) are water-soluble neutral polysaccharides extracted from licorice. Currently, GPS-1 is administrated to chickens by gavage every d for 14 d to observe the impact of GPS-1 on the Newcastle disease vaccine. To determine the immunity of these chickens to NDV, blood serum levels of hemagglutinin-inhibition (HI) antibody, and immunoglobulins IgA and IgG were measured. Meanwhile, the expression levels of cytokines IL-2, IL-4, IL-17, and IFN-γ were measured to evaluate the degree of immune booster activity. The chickens’ spleen and peripheral blood lymphocytes displayed a significant increase in the proportion of CD4+ and CD8+ T cells after booster treatments with GPS-1. The results indicated that GPS-1 had a significant, dose-dependent, immune-boosting effect which could enhance NDV vaccine immunity in chickens.

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.

PSX-B-24 Influence of the immunomodulatory drug Azoxivet on the post-vaccination immune response in laying hens

Abstract Vaccination is a primary way to prevent infectious disease in poultry. The quality of immune response depends on the immune status of the body which, in turn, depends on many endogenous and exogenous factors. This study analyzed the effect of the immunomodulatory drug Azoxivet on the immune response in laying hens after vaccination against Newcastle Disease and Infectious Bursal Disease. There were 4 groups of Loman White cross laying hens (n=20). At age 120 days, all hens habitated in individual cages with an area of 0,15 m2. The conditions of keeping and feeding matched breed requirements. All groups were vaccinated against Newcastle Disease (NDV) (LaSota strain) and Infectious Bursal Disease (IBD) (Winterfield 2512 strain). All groups received Azoxivet (Az) at a dose of 0,3 mg/kg in water three times daily. Blood sera were collected weekly for serological studies using BioChek IBD and NDV test systems. The antibody level of all hens before and after vaccination: 1378 (IBD+Az) vs. 1674,93 (IBD) (P &amp;lt; 0,05), 5194,75 (NDV+Az) vs. 5612,87 (NDV) (P &amp;lt; 0,05). After one week of vaccination: 5931,25 (IBD+Az) vs. 5006,14 (IBD) (P &amp;lt; 0,05), 6207,58 (NDV+Az) vs. 5765,21 (NDV) (P &amp;lt; 0,05). Two weeks: 11086,00 (IBD+Az) vs. 10485,83 (IBD) (P &amp;lt; 0,05), 11255,25 (NDV+Az) vs. 8478,75 (NDV) (P &amp;lt; 0,05). Three weeks: 11478 (IBD+Az) vs. 8286 (IBD) (P &amp;lt; 0,05), 14725 (NDV+Az) vs. 12677 (NDV) (P &amp;lt; 0,05). Four weeks: 12999 (IBD+Az) vs. 1009,67 (IBD) (P &amp;lt; 0,05), 17399 (NDV+Az) vs. 16373,17 (NDV) (P &amp;lt; 0,05). Five weeks: 13601,15 (IBD+Az) vs. 9021,30 (IBD) (P &amp;lt; 0,05), 19671 (NDV+Az) vs. 16309 (NDV) (P &amp;lt; 0,05). Thus, Azaxul had a positive influence on the post-vaccination immune response in laying hens when used after Newcastle Disease and Infectious Bursal Disease vaccines. The results of the study can be used to improve disease prevention in poultry farming.