Newcastle Disease Outbreaks Research Articles

Genomic Diversity and Evolutionary Insights of Avian Paramyxovirus-1 in Avian Populations in Pakistan.

The virulent form of Avian paramyxovirus-1 (APMV-1), commonly known as Newcastle Disease Virus (NDV), is a pathogen with global implications for avian health, affecting both wild and domestic bird populations. In Pakistan, recurrent Newcastle Disease (caused by NDV) outbreaks have posed significant challenges to the poultry industry. Extensive surveillance in Pakistan over 20 years has demonstrated a dynamic genetic diversity among circulating APMV-1 strains, emphasizing the potential necessity for customized vaccination strategies and continuous surveillance. In this study, 13 APMV-1-positive isolates harboring four different APMV-1 genotypes circulating throughout Pakistan were identified. These included the highly virulent genotypes VII and XIII, genotype XXI, commonly associated with Columbiformes, and genotype II, hypothesized to have been detected following vaccination. These findings underscore the intricate interplay of mutational events and host-immune interactions shaping the evolving NDV landscape. This study advances our understanding of the evolutionary dynamics of APMV-1 in Pakistan, highlighting the need for tailored vaccination strategies and continuous surveillance to enable effective APMV-1 management in avian populations, further emphasizing the importance of globally coordinated strategies to tackle APMV-1, given its profound impact on wild and domestic birds.

Clinicopathological and Molecular Investigation of Newcastle Disease Outbreaks in Vaccinated and Non-Vaccinated Broiler Chicken Flocks in Nepal.

Newcastle disease (ND) is a highly contagious viral disease caused by the paramyxovirus, which is a single-stranded ribonucleic acid (RNA) virus. This study was conducted to investigate ND outbreaks in 10 vaccinated or non-vaccinated broiler farms, collectively housing 9840 birds of various ages in the Chitwan and Nawalpur districts of Nepal from July to December 2021. Clinically, the affected birds exhibited symptoms such as limb paralysis, greenish diarrhea (seven out of ten flocks), torticollis (two out of ten flocks), inappetence, and drowsiness (ten out of ten flocks). Birds that succumbed during the clinical course underwent a necropsy for gross pathology and samples were collected for the histopathology and molecular diagnosis. The gross and microscopic examination revealed hemorrhages in the proventriculus, erosions and ulcers in the small intestine, congestion, as well as sero-mucosal hemorrhages in the trachea of affected birds, which are typical of ND. Rapid test kits further confirmed the presence of the ND virus antigen while excluding the avian influenza virus. Furthermore, M gene-based real time polymerase chain reaction (RT-PCR) was performed in the pooled samples from the affected birds and the presence of a velogenic strain of the ND virus was identified. The phylogenetic analysis of the RT-PCR positive strain based on the partial F gene nucleotide sequence revealed these strains as genotype VII.2 (formerly VIIi). The findings highlight the occurrence of clinical ND outbreaks in farms despite adherence to recommended vaccination protocols in broiler flocks, underscoring the need for a regular comprehensive investigation involving in-depth examinations of available vaccines and genetic analyses.

Advancements in Newcastle Disease Vaccination: Evaluating Traditional and Thermostable Vaccines for Enhanced Control and Efficacy

Newcastle disease (ND) is a critical viral disease in poultry, affecting various avian species worldwide and causing substantial economic losses annually in commercial and backyard poultry operations. Despite its global prevalence, ND can be controlled through proper vaccination and biosecurity management. Over the past 60-65 years, both live attenuated and inactivated ND virus vaccines have been extensively used to mitigate the economic impact of ND. Although live vaccines demonstrate high efficacy against the disease, achieving comprehensive control of ND outbreaks and their financial consequences remains challenging. The primary limitation of most commercially available live vaccines is their heat sensitivity, necessitating a cold chain for quality maintenance, which poses difficulties in village conditions or remote areas of developing tropical countries. This review discusses various methods of ND vaccine administration, their efficacy, and immunogenicity, focusing on the efficacy and stability of thermostable ND vaccines. A thorough understanding of these factors is essential for the long-term control and eradication of ND.

Spillover of Newcastle disease virus to Himalayan Griffon vulture: a possible food-based transmission.

The Newcastle disease virus (NDV) affects wild and domesticated bird species, including commercial poultry. Although the diversity of NDV in domestic chickens is well documented, limited information is available about Newcastle disease (ND) outbreaks in other bird species. We report an annotated sequence of NDV/Vulture/Borjuri/01/22, an avirulent strain of NDV reported from Borjuri, Northeast India, in Himalayan Griffon vulture. The complete genome is 15,186 bases long with a fusion protein (F) cleavage site 112GRQGR↓L117. The phylogenetic analysis based on the F protein gene and the whole genome sequence revealed that the isolate from the vulture belongs to genotype II, sharing significant homology with vaccine strain LaSota. The study highlights the possible spillover of the virus from domestic to wild species through the food chain.

Thermostability study of virulent Newcastle disease viruses isolated in Southern Angola.

Newcastle disease (ND) is endemic in Angola. Several outbreaks of ND occurred in small backyard flocks and village chickens with high mortality in the southern provinces of the country, Cunene, Namibe and Huíla, in 2016 and 2018. In those years, 15 virulent ND virus (NDV) strains were isolated and grouped within subgenotype 2 of genotype VII (subgenotype VII.2). We now present a study on the thermostability of the isolates, aiming at the selection of the most thermostable strains that, after being genetically modified to reduce their virulence, can be adapted to the production of vaccines less dependent on cold chain and more adequate to protect native chickens against ND. Heat-inactivation kinetics of haemagglutinin (Ha) activity and infectivity (I) of the isolates were determined by incubating aliquots of virus at 56 °C for different time intervals. The two isolates from Namibe province showed a decrease in infectivity of 2 log10in ≤ 10 min, therefore belonging to the I-phenotype, but while the NB1 isolate from 2016 maintained the Ha activity up to 30 min and was classified as thermostable virus (I-Ha+), the Ha activity of the 2018 NB2 isolate decreased by 2 log2in 30 min, being classified as a thermolabile virus (I-Ha-). Of the 13 NDV isolates from Huíla province, 10 isolates were classified as thermostable, eight with phenotype I+Ha+and 2 with phenotype I-Ha+. The other three isolates from this province were classified as thermolabile viruses (I-Ha-).Contribution:This study will contribute to the control and/or eradication of Newcastle disease virus in Angola. The thermostable viral strains isolated from chickens in the country can be genetically manipulated by reverse genetic technology in order to reduce their virulence and use them as a vaccine in the remote areas of Angola.

Immunological properties of inactivated vaccines against Newcastle disease based on virus antigens VII and II the genotype

Newcastle disease (ND) is now widely spread in many countries of Eurasia, Africa and the Americas and causes significant economic damage to poultry farming. New NDinfected localities are reported in the Russian Federation every year; besides, the number of farms with vaccinated poultry demonstrating high specific antibody titres, decreased performance and survivability while being asymptomatic has increased. This is attributed to the virus evolution leading to the emergence of new genotypes represented by highly virulent strains. Since 2019, subgenotype VII-L has been isolated from Newcastle disease outbreaks in Russia. The vaccines currently available on the market do not confer appropriate protection against it due to the lack of antigenic matching between vaccine strains and this subgenotype. The development of a vaccine based on subgenotype VII -L will allow to ensure protection of poultry flocks against Newcastle disease caused by new NDV isolates. The immunological properties of emulsion inactivated vaccine against Newcastle disease based on genotype VII NDV (ARRIAH G7 strain) antigen were studied in 30-day-old Hisex Brown chickens. A similar vaccine based on genotype II NDV LaSota strain antigen was used as control. Tests of different immunizing antigen doses were carried out. The vaccines were tested for induced humoral immunity level (HI antibody titres), as well as for protective effect (protective index) after challenge with a highly virulent genotype VII NDV strain. The tests revealed that the antigenic activity and protective effect of both vaccines depended on the antigen concentration in the inoculation volume. Antibody titres were always higher when homologous antigens were used in HI tests. The vaccine based on the antigen of ARRIAH G7 strain (homologous to the challenge strain) was more effective than the control vaccine. Less ARRIAH G7 strain antigen was required to protect 50% of vaccinated poultry, compared with LaSota strain antigen. The comparative assessment of the same doses of the antigens showed that the vaccine based on ARRIAH G7 strain antigen had better immunological properties. The tested antigens demonstrated 18.3% bilateral affinity.

Molecular Characterization of Class II Newcastle Disease Virus from Field Outbreaks in Mizoram, India

Background: Newcastle disease (ND) is a highly contagious and economically important disease affecting poultry of all ages. The causative agent, class II NDV strains are frequently virulent and are classified into at least 21 distinct genotypes with several sub-genotypes. The circulating strains of NDV from mainland India are identified as genotype XIII, whereas emergence of a new genotype XXII has been reported recently from North East Region of India. Methods: A total of 25 poultry farms comprising a total population of 2165 birds were studied for field outbreaks of ND. Detailed post-mortem examination was conducted on a total of 121 dead birds and field outbreaks were confirmed by the detection of the F gene in tissue samples by reverse transcription PCR. Deduced amino acid sequence analysis of fusion proteins and phylogenetic analysis based on complete F gene were carried out to understand the molecular epidemiology of the circulating NDV strains. Result: This study has confirmed severe NDV outbreaks in the vaccinated flock, from Mizoram state of India. The three isolates from the outbreaks revealed the presence of the multi-basic amino acid residues at the fusion protein cleavage site (112RRQKRF117) identified as characteristic of velogenic strain. The phylogenetic analysis based on the complete F gene has characterized the isolates belonging to newly identified genotype XXII and subgroup XXII.2. The evolutionary evidence of this new genotype of NDV in the unique ecosystem of NER, India, warrants detailed studies for better understanding of the variant.

Newcastle Disease Outbreak in Backyard Poultry: Herbal Remediation Using Phyllanthus Polygonoides and Carica Papaya Leaves

Newcastle disease (ND) is a devastating disease of backyard poultry and causes great economic losses to rural poor. The study was undertaken to assess the effectiveness of herbal extracts of Phyllanthus polygonoides and Carica papaya leaves for control of Newcastle outbreak in backyard poultry. A total of 60 representative desi fowl (chicken 50, turkey 7 and duck 3) from 40 flocks were presented to VCC hospital, VC&RI, Orathanadu for treatment. The samples like oropharyngeal fluid/ clocal swab was collected from 40 birds (flocks) and performed haemagglutination test. Out of 40 birds screened, 18 birds (Chicken-13, turkey- 4 and Duck- 1) were positive for haemagglutination test and showed the presence of Newcastle disease virus and confirmed by PCR. The infected birds were treated with aqueous extract of Carica papaya and Phyllanthus polygonoides leaves @ 0.5ml/ kg b.wt orally for 3 days. Most of the birds recovered in single dose, the moderately infected birds recovered after 3 days of treatment. The herbal extract was also used prophylactically other than the infected birds in their respective flocks to prevent the infection. None of the adult birds in their flocks become infected and protected from infection. The plant juice of Phyllanthus polygonoides and Carica papaya leaves were highly effective for control of ND in backyard poultry, it could be used prophylactically every 30 days to prevent Newcastle disease outbreak in backyard poultry to minimize economic losses to the farmers.

Assessment of implementation of biosecurity measures and its impacts on Newcastle disease in some poultry farms and live bird markets in Sokoto State, Nigeria

There is considerable global concern over the outbreaks of Newcastle disease (ND) affecting domestic poultry flocks around the world including Nigeria. There have been little investigations on the biosecurity measures taken by poultry stakeholders in relation to the rate of ND in Sokoto State, Nigeria. Thus, this study evaluated the biosecurity practices in commercial poultry farms and live bird markets in Sokoto State, Nigeria. Data were collected through questionnaire administered to commercial farmers, flock owners at live bird markets as well as other poultry value chain intermediaries. A traffic light system model was used to test for relative risks based on the biosecurity measures put in place at the farm and live bird markets. The result indicates that both commercial farms and live bird markets were at high risk (56.9% and 77.3% respectively) of ND virus infection. The high risk practices identified include unsafe disposal of poultry carcasses (50%), locating farms on high ways (75%), absence of high pressure sprayer at gate (100%), presence of water body (37.5%), raising different species of birds (25% for farms and 100% for live bird markets), presence of multi age groups (100%), feed spillage (100%), fly and rodent infestation (100%), lack of personal protective equipment (50% for farms and 100% for live bird markets), absence of changing room (87.5%), poor handling of sick birds (75% for farms and 100% for live bird markets), inadequate washing and disinfection of hands and equipment (100%). Using chi square, presence of fence, washing and disinfection of pen, washing and disinfection of equipment, always allowing visitors to enter farm, borrowing of equipment, sale of runt and sick birds, isolation of sick/new birds, culling of diseased birds, safe and clean store for feed, observing signs of ND in the last 3 months showed significant statistical difference (P<0.05) between live bird markets and poultry houses. Thus, that may contribute to the risk of environmental contamination and disease transmission. Outreach and biosecurity awareness raising initiatives should be specifically developed for all the poultry value chain stakeholders with the objective of improving general poultry management and thus preventing ND and other poultry diseases.

Immunostimulating potentials of methanolic extract of <i>Plectranthus parviflorus</i> in chickens vaccinated against Newcastle disease and Infectious bursal disease

Outbreaks of Newcastle disease (ND) and Infectious Bursal disease (IBD) have been reported in vaccinated poultry flocks in many countries highlighting the need for the administration of immunostimulants to improve immunity in such birds. The immunomodulatory effects of methanol leaf extract of plectranthus parviflorus on ND and IBD antibody titre was investigated. One hundred day-old cockerels were randomly assigned into five groups each, A-E and A1-E1 for Newcastle disease and Infectious bursal disease studies respectively. Groups A and A1 were control groups and received water only while groups B and B1 received LaSota and IBD intermediate plus ® vaccine respectively. Groups C and C1, D and D1 were administered 100mg/kg and 200mg/kg of Plectranthus parviflorus orally for three days before vaccination respectively, while groups E and E1were given 100mg/kg of the extract orally three days post vaccination. Blood samples were obtained via jugular vein at day-old and 14 days as well as on days 7, 14 and 21 post vaccination. Haemagglutination- inhibition (HI) test and enzyme linked immunosorbent assay (ELISA) were used to assay the antibody titre against ND and IBD respectively. A decline in maternal antibody over 14 days was observed for antibody titre against Newcastle disease and infectious bursal disease from 6.1 to 1.8 geometric mean (log2) and (1043.37±2.1) to (524.48±2.7) respectively. Group D was observed to have a significant titre value of 2.3 and 3.7 geometric mean (log2) 14 and 21 days post ND vaccination while group D1 also had a significant increase (1037.90±3.6) titre 14 days post-vaccination. This study showed that plectranthus parviflorus extract had a significant effect on Newcastle disease and Infectious bursal disease humoral response when administered orally at 200mg/kg before vaccination with ND and IBD vaccines respectively.

Possible Outbreak of Newcastle Virus Infection in the Face of Increasing Trend of Backyard Poultry Farm Management Interface in Nigeria: A Public Health and Food Security Threat

Introduction: Newcastle disease is a highly contagious illness and one of the "notifiable illnesses" on the World Health Organization list for Animal Health (OIE) Outcome. There are constantly new cases being reported as new NDV isolates from around the world. Newcastle disease poses a significant global economic threat to the poultry sector, causing highly contagious and transmissible diseases in birds with huge food security threat among the weak and vulnerable developing and underdeveloped countries Aim: The aim of this article borders on bringing to light the risk of possible Newcastle disease outbreak in Nigeria due to increasing poor management of poultry farms and poultry waste product. Furthermore, it will also underscore and outline various ways which can be adopted to prevent this poultry disease which is of great public health, economic and food security protection importance. Method/Methodology: This is a systematic review of published research articles focusing on Newcastle disease, epidemiology, pathogenicity, transmission and factors that can play important roles in the possible outbreak of the disease in poultries. Studies reviewed comprise of cross-sectional, prospective, longitudinal and observational studies. The study approach follows the systematic review of peer-reviewed published articles as well as online publications and articles derived from various databases with search keywords relevant to the topic of discourse. Findings and Results: The findings in this study highlight the endemicity of Newcastle virus disease in various part of the country, and how the severity of the disease is influenced by host characteristics, viral properties, and environmental factors. The study pointed out critical evidence-based possible reasons that could promote a new round of Newcastle disease epidemic outbreak as a result of poor poultry management practices such as high bird densities, poor poultry infrastructure, lack of quarantine of sick birds, mixed species rearing, free range system of poultry, poor waste disposal, lack of expertise, and insufficient biosecurity outcomes. However, the lack of education and awareness among farmers exacerbates the problem, hindering preventive measures. The complexity is increased by difficulties with vaccination, unrestrained bird movement through trading with neighboring countries and interstate, and a lack of diagnostic facilities. The consequences of an outbreak extends beyond financial losses to potential disruptions in the poultry supply chain, food security risks, and public health concerns. Conclusion and Recommendation: The growing difficulties in poultry management methods increases the serious public health concern posed by a possible Newcastle Virus epidemic outbreak in Nigeria. A paradigm shift in poultry farming practices is necessary to address this problem. A comprehensive strategy that incorporates infrastructural development, regulatory frameworks, and education in order to strengthen the poultry industry is needed, so as to address and prevent the looming public health and food security crises that may break out from the above scenario

Effectiveness of a community-centered Newcastle disease vaccine delivery model under paid and free vaccination frameworks in southeastern Kenya.

In the absence of effective drugs, vaccines constitute the cornerstone for the prevention of Newcastle disease (ND). Different strategies have been implemented to increase vaccination, but uptake remains low, underscoring the need for novel vaccine delivery methods. We designed and assessed the effectiveness of a community-centered ND vaccine delivery model in southeastern Kenya. Under the model, we sensitized smallholder chicken farmers (SCFs) through structured training on chicken husbandry, biosecurity, ND, and its vaccination, among other aspects. We subsequently engaged trained community vaccinators (CVs) to deliver vaccines and/or provide vaccination services to SCFs at a cost on one hand and, at no cost on the other, in selected sites to address challenges of inadequate service providers, vaccine unavailability, and inaccessibility. We tested this model under paid and free vaccination frameworks over one year and assessed the model's effect on vaccine uptake, ND-related deaths, and vaccine accessibility, among other aspects. Overall, we vaccinated more chickens at free sites compared to paid sites. However, we vaccinated a significantly higher mean number of chickens per household at paid (49.4±38.5) compared to free (28.4±25.9) sites (t = 8.4, p<0.0001). We recorded a significant increase in the proportion of SCFs who vaccinated their chickens from 31.3% to 68.4% (χ2(1, N = 399) = 58.3, p<0.0001) in paid and from 19.9% to 74.9% (χ2(1, N = 403) = 115.7, p<0.0001) in free sites pre- and post-intervention, respectively. The mean number of ND-related deaths reported per household decreased from 18.1±31.6 pre-intervention to 7.5±22.3 post-intervention (t = 5.4, p = 0.000), with higher reductions recorded in paid sites (20.9±37.7 to 4.5±11.2) compared to free sites (15.0±22.6 to 10.7±29.7) pre- and post-intervention, respectively. Farmers with access to vaccines increased significantly from 61.1% to 85.4% (χ2(1, N = 399) = 31.7, p<0.0001) in paid and 43.6% to 74.9% (χ2(1, N = 403) = 38.4, p = 0.0001) in free sites pre- and post-intervention, respectively. We established that type of intervention framework, gender of household head, if the household head attended training on chicken production in the last 12 months, access to information on ND vaccination, and the number of chickens lost to the previous ND outbreak were significant predictors of ND vaccine uptake. Our findings indicate the model has a broader reach and benefits for SCFs. However, policies should be enacted to regulate the integration of CVs into the formal animal health sector.

Molecular Identification and Phylogenetic Study Based on the Fusion Gene of Newcastle Disease Virus Isolated from Broiler Poultry Farms in Markazi Province, Iran.

Newcastle disease (ND) is an economically significant and extremely spreadable viral illness affecting a wide variety of avian species. ND can rapidly spread within poultry farms and result in considerable economic losses for the global poultry industry. This disease is endemic in Iran, and despite intensive vaccination efforts in the poultry industry, outbreaks of ND occur unexpectedly. This study aimed to isolate the Newcastle disease virus (NDV) from poultry farms with breathing problems in Markazi province, Iran, and investigate the evolutionary relationship and molecular characteristics of the isolates during 2017-2019. To this end, tissue samples (lung, brain, and trachea) were taken from 42 broiler farms exhibiting respiratory symptoms. The samples were inoculated into 9-11-day-old embryonated eggs, and the virus was isolated from 20 (47.6%) of the 42 farms. Subsequently, RT-PCR was used to amplify partial fusion gene sequences from the new isolates. The amplified products were sequenced and compared phylogenetically to the standard pilot dataset (125 selected sequences) generated by the NDV consortium. As determined by phylogenetic analysis, all nine isolates belonged to subgenotype VII.1.1 of genotype VII and were highly similar to isolates from other parts of Iran and China. Moreover, all isolates possessed a polybasic cleavage site motif (112RRQKRF117), characteristic of virulent strains. Furthermore, the present isolates shared a high nucleotide identity (96%) with viruses previously isolated from other provinces of Iran, as determined by BLAST searches and multiple alignments. In addition, they shared a high degree of sequence similarity but were distinct from the existing NDV vaccines. Therefore, the genetic dissimilarity between current vaccine strains and circulating NDVs must be considered in vaccination programs.

NEWCASTLE DISEASE IS A PARTICULARLY DANGEROUS PSEUDOCUMA OF BIRDS

Newcastle disease is a serious infectious disease affecting the internal organs, nervous and respiratory systems. It is caused by paramyxovirus PMV-1 and has a large number of different strains that can cause various forms of the disease. These forms can sometimes "masquerade" as other diseases such as cholera, bronchitis, avian flu or laryngotracheitis. Newcastle disease can only be detected by an accurate diagnosis. Poultry of all ages and breeds are susceptible to the disease, but most often Newcastle disease is diagnosed in domestic chickens. Outbreaks of Newcastle disease are reported worldwide and can cause problems for large poultry farms. Although Newcastle disease does not directly affect humans, a flu-like condition can develop after contact with an infected person. Characteristic signs of Newcastle disease in birds include encephalitis, pneumonia and hemorrhage into internal organs due to their damage.The last outbreak of Newcastle disease in birds in the Republic of Kazakhstan was detected in the village of Akhmet in the Nurinsky district of the Karaganda region on October 4, 2023. On October 6, the Karaganda Regional Territorial Inspection of the Veterinary Control and Supervision Committee of the Ministry of Agriculture declared quarantine in rural areas.The study conducted in the Karaganda region of the Republic of Kazakhstan was aimed at studying the outbreak of Newcastle disease in poultry in the village of Akhmet in the Nurinsky district. During the study, veterinary and sanitary measures were carried out, including sampling for laboratory diagnostics, vaccination of livestock and the introduction of quarantine restrictions. The results of the study showed the high effectiveness of the measures taken to localize and eliminate the source of infection. The virus has been identified, which underlines the need for constant monitoring of the epizootic situation. The data obtained make it possible to recommend the expansion of vaccination programs and the strengthening of veterinary control at poultry farms to prevent the further spread of Newcastle disease.Despite the fact that Newcastle disease has been known to veterinarians for several years, no treatment method has yet been developed. However, the control of Newcastle disease in poultry can be achieved through isolation and quarantine of infected animals, vaccination programs, biosafety measures at livestock facilities, monitoring of animal movements and surveillance

The Development of Novel Reverse Transcription Loop-Mediated Isothermal Amplification Assays for the Detection and Differentiation of Virulent Newcastle Disease Virus.

Newcastle disease (ND) is a highly pathogenic viral infection of poultry with significant economic impacts worldwide. Despite the widespread use of vaccines, ND outbreaks continue to occur even within vaccinated poultry farms. Furthermore, novel Newcastle disease virus (NDV) genotypes are emerging in poultry, increasing the need for the development of rapid, accurate, and simple diagnostic methods. We therefore developed two novel sets of visual reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays based on highly conserved regions of the HN and F genes. The limits of detection of the NDV-Common-LAMP assay, for all the NDV strains, were 103.0 EID50/0.1 mL for Kr005 and 102.0 EID50/0.1 mL for Lasota within 35 min. The sensitivity of the NDV-Patho-LAMP assay, used for the strain differentiation of virulent NDV, was 102.0 EID50/0.1 mL for Kr005. No amplification was detected for the non-NDV templates. Next, we probed 95 clinical strains and 7 reference strains with the RT-LAMP assays to assess the feasibility of their use in diagnostics. We observed no cross-reactivity across the 102 strains. Furthermore, there was 100% congruence between the RT-LAMP assays and full-length sequencing of the target genes, indicating the potential for visual RT-LAMP in the identification and differentiation of NDV. These novel RT-LAMP assays are ideally suited for the field or resource-limited environments to facilitate the faster detection and differentiation of NDV, which can reduce or avoid further spread.

Genetic Diversity of Newcastle Disease Virus Involved in the 2021 Outbreaks in Backyard Poultry Farms in Tanzania.

Newcastle disease virus is a significant avian pathogen with the potential to decimate poultry populations all over the world and cause enormous economic losses. Distinct NDV genotypes are currently causing outbreaks worldwide. Due to the high genetic diversity of NDV, virulent strains that may result in a lack of vaccine protection are more likely to emerge and ultimately cause larger epidemics with massive economic losses. Thus, a more comprehensive understanding of the circulating NDV genotypes is critical to reduce Newcastle disease (ND) burden. In this study, NDV strains were isolated and characterized from backyard poultry farms from Tanzania, East Africa in 2021. Reverse-transcription polymerase chain reaction (RT-PCR) based on fusion (F) gene amplification was conducted on 79 cloacal or tracheal swabs collected from chickens during a suspected ND outbreak. Our results revealed that 50 samples out 79 (50/79; 63.3%) were NDV-positive. Sequencing and phylogenetic analyses of the selected NDV isolates showed that 39 isolates belonged to subgenotype VII.2 and only one isolate belonged to subgenotype XIII.1.1. Nucleotide sequences of the NDV F genes from Tanzania were closely related to recent NDV isolates circulating in southern Africa, suggesting that subgenotype VII.2 is the predominant subgenotype throughout Tanzania and southern Africa. Our data confirm the circulation of two NDV subgenotypes in Tanzania, providing important information to design genotype-matched vaccines and to aid ND surveillance. Furthermore, these results highlight the possibility of the spread and emergence of new NDV subgenotypes with the potential of causing future ND epizootics.

Economic losses due to Newcastle disease in layers in subtropical India

Newcastle disease (ND) is a highly contagious viral disease of birds causing immense direct and indirect losses to the poultry industry. Various studies conducted across the world suggested that ND has been creating havoc in the poultry industry. Over the past decade, India has been reporting cases of ND outbreaks every year. Therefore, a retrospective study was conducted to estimate the losses due to ND and identify the factors influencing those losses. The primary data was obtained directly from farmers employing multistage purposive random sampling. A modified methodology was employed to provide an aggregate figure accounting for the approximate losses due to ND over the period of 72 weeks of the commercial layers’ life cycle. The results of the study indicated that the losses due to morbidity were much higher compared to those due to mortality in ND-infected birds. The major factors influencing ND losses on the farms were drop in egg production, mortality of birds due to ND, duration of ND infection, reduction in feed intake, age at which birds get infected with ND, and experience of poultry farmers in the poultry business.

Immunomodulatory effects of aqueous extracts of Azadirachta indica and Piper Guineense on Newcastle disease vaccination in cockrels

The increased incidence of Newcastle disease (ND) outbreaks in the country even amongst vaccinated flocks, has given rise to the search for other means of boosting the immune system besides vaccination alone. A lot of plants have been shown to possess antimicrobial, antipyretic and anticoccidial effects. This study was designed to evaluate the immunomodulatory effect of the aqueous extracts of the leaves of Piper guineense and Azadirachta indica (Neem) on immune response to Newcastle vaccination in birds. A total of 110 cockrels were used in this study (30 for acute toxicity test and 80 for immuonomodulatory effects of extracts). The 80 cockerels were divided into four groups (A, B, C and D), each consisting 20 birds. Group A and B were treated with 100mg/kg of the aqueous extracts of Azadirachta indica and Piper guineense respectively for the first three weeks. All the birds in groups A to C were vaccinated with Newcastle disease vaccine Lasota (NDV-L) at day 21, while Group D was given distilled water only. Blood samples were taken from all groups on day 1, 7, 14 and 21 post-vaccination. Serum antibody level against ND virus were measured by HI test and antibody titre was found to be significantly (p≤0.05) higher in the group treated with Azadirachta indica but low in those treated with Piper guineense. There was no significant (p≥0.05) difference in the immune response seen in Group A compared to the positive control (Group C), but significantly (p≤0.05) higher compared to the negative control (Group D). It was therefore concluded that the aqueous extract of Azadirachta indica may enhance immunomodulatory effects against Newcastle disease virus, unlike that of Piper guineense.

Pig mange in Ossha Umuahia Southern Nigeiria – A case report

The increased incidence of Newcastle disease (ND) outbreaks in the country even amongst vaccinated flocks, has given rise to the search for other means of boosting the immune system besides vaccination alone. A lot of plants have been shown to possess antimicrobial, antipyretic and anticoccidial effects. This study was designed to evaluate the immunomodulatory effect of the aqueous extracts of the leaves of Piper guineense and Azadirachta indica (Neem) on immune response to Newcastle vaccination in birds. A total of 110 cockrels were used in this study (30 for acute toxicity test and 80 for immuonomodulatory effects of extracts). The 80 cockerels were divided into four groups (A, B, C and D), each consisting 20 birds. Group A and B were treated with 100mg/kg of the aqueous extracts of Azadirachta indica and Piper guineense respectively for the first three weeks. All the birds in groups A to C were vaccinated with Newcastle disease vaccine Lasota (NDV-L) at day 21, while Group D was given distilled water only. Blood samples were taken from all groups on day 1, 7, 14 and 21 post-vaccination. Serum antibody level against ND virus were measured by HI test and antibody titre was found to be significantly (p≤0.05) higher in the group treated with Azadirachta indica but low in those treated with Piper guineense. There was no significant (p≥0.05) difference in the immune response seen in Group A compared to the positive control (Group C), but significantly (p≤0.05) higher compared to the negative control (Group D). It was therefore concluded that the aqueous extract of Azadirachta indica may enhance immunomodulatory effects against Newcastle disease virus, unlike that of Piper guineense.

A Booster with a Genotype-Matched Inactivated Newcastle Disease Virus (NDV) Vaccine Candidate Provides Better Protection against a Virulent Genotype XIII.2 Virus.

Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle disease virus (NDV) vaccines based on lentogenic virus strains, locally produced live vaccines of the mesogenic Mukteswar strain, as well as imported inactivated vaccines of lentogenic strains, are being used in Bangladesh under different vaccination regimens. Despite these vaccinations, frequent outbreaks of ND are being reported in Bangladesh. Here we compared the efficacy of booster immunization with three different vaccines in chickens that had been primed with two doses of live LaSota vaccine. A total of 30 birds (Group A) were primed with two doses of live LaSota virus (genotype II) vaccine at days 7 and 28, while 20 birds (Group B) remained unvaccinated. At day 60, birds of Group A were divided into three sub-groups, which received booster immunizations with three different vaccines; A1: live LaSota vaccine, A2: inactivated LaSota vaccine, and A3: inactivated genotype XIII.2 vaccine (BD-C161/2010 strain from Bangladesh). Two weeks after booster vaccination (at day 74), all vaccinated birds (A1-A3) and half of the unvaccinated birds (B1) were challenged with a genotype XIII.2 virulent NDV (BD-C161/2010). A moderate antibody response was observed after the primary vaccination, which substantially increased after the booster vaccination in all groups. The mean HI titers induced by the inactivated LaSota vaccine (8.0 log2/5.0 log2 with LaSota/BD-C161/2010 HI antigen) and the inactivated BD-C161/2010 vaccine (6.7 log2/6.2 log2 with LaSota/BD-C161/2010 HI antigen) were significantly higher than those induced by the LaSota live booster vaccine (3.6 log2/2.6 log2 with LaSota/BD-C161/2010 HI antigen). Despite the differences in the antibody titers, all chickens (A1-A3) survived the virulent NDV challenge, while all the unvaccinated challenged birds died. Among the vaccinated groups, however, 50% of the chickens in Group A1 (live LaSota booster immunization) shed virus at 5- and 7-days post challenge (dpc), while 20% and 10% of the chickens in Group A2 (inactivated LaSota booster immunization) shed virus at 3 and 5 dpc, respectively, and only one chicken (10%) in Group A3 shed virus at 5 dpc. In conclusion, the genotype-matched inactivated NDV booster vaccine offers complete clinical protection and a significant reduction in virus shedding.