Presence of Virulent Newcastle Disease Virus in Vaccinated Chickens in Farms in Pakistan

Rehmani, Shafqat Fatima; Wajid, Abdul; Bibi, Tasra; Nazir, Bushra; Mukhtar, Nadia; Hussain, Abid; Lone, Nazir A.; Yaqub, Tahir; Afonso, Claudio L.

doi:10.1128/jcm.02818-14

Cited by 69 publications

(52 citation statements)

References 9 publications

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“…The sequence data described here provide evidence that vNDV strains were circulating among vaccinated flocks in three different provinces of Indonesia during 2013 to 2014. Vaccination can prevent or reduce clinical disease, but NDV can still circulate in vaccinated flocks (15)(16)(17), as also demonstrated here. Thеsе facts highlight the need for continuous vaccine evaluation and development of improved vaccines for disease control (18,19).…”

supporting

confidence: 72%

Complete Genome Sequences of 11 Newcastle Disease Virus Isolates of Subgenotype VII.2 from Indonesia

Goraichuk

Williams-Coplin

Wibowo

et al. 2020

Microbiol Resour Announc

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supporting

confidence: 72%

Complete Genome Sequences of 11 Newcastle Disease Virus Isolates of Subgenotype VII.2 from Indonesia

Goraichuk

Williams-Coplin

Wibowo

et al. 2020

Microbiol Resour Announc

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“…Even though birds vaccinated with inactivated vaccines tend to have higher humoral antibody levels, they do not develop a strong cell mediated response (Schijns et al, 2013), and shed larger amounts of virulent challenge virus compared to birds vaccinated with live ND vaccines (Miller et al, , 2009. Although live and inactivated vaccines protect against clinical disease in SPF chickens, there are continuous reports of vaccine failures under field conditions (Perozo et al, 2012;Rehmani et al, 2015). One of the possible reasons for these failures may be poor vaccination response that is also dependent on field-associated factors unrelated to the vaccines, such as immunosuppression (Meulemans, 1988) from infections prior to ND vaccination.…”

Section: Traditional Vaccinesmentioning

confidence: 99%

Newcastle disease vaccines—A solved problem or a continuous challenge?

Dimitrov

Afonso

et al. 2017

Veterinary Microbiology

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293

230

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Newcastle disease (ND) has been defined by the World Organisation for Animal Health as infection of poultry with virulent strains of Newcastle disease virus (NDV). Lesions affecting the neurological, gastrointestinal, respiratory, and reproductive systems are most often observed. The control of ND must include strict biosecurity that prevents virulent NDV from contacting poultry, and also proper administration of efficacious vaccines. When administered correctly to healthy birds, ND vaccines formulated with NDV of low virulence or viral-vectored vaccines that express the NDV fusion protein are able to prevent clinical disease and mortality in chickens upon infection with virulent NDV. Live and inactivated vaccines have been widely used since the 1950's. Recombinant and antigenically matched vaccines have been adopted recently in some countries, and many other vaccine approaches have been only evaluated experimentally. Despite decades of research and development towards formulation of an optimal ND vaccine, improvements are still needed. Impediments to prevent outbreaks include uneven vaccine application when using mass administration techniques in larger commercial settings, the difficulties associated with vaccinating free-roaming, multi-age birds of village flocks, and difficulties maintaining the cold chain to preserve the thermo-labile antigens in the vaccines. Incomplete or improper immunization often results in the disease and death of poultry after infection with virulent NDV. Another cause of decreased vaccine efficacy is the existence of antibodies (including maternal) in birds, which can neutralize the vaccine and thereby reduce the effectiveness of ND vaccines. In this review, a historical perspective, summary of the current situation for ND and NDV strains, and a review of traditional and experimental ND vaccines are presented.

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“…Currently, ND is still a serious threat to the poultry industry, even though intensive vaccination programs have been applied. Recently, some studies have reported ND outbreaks among vaccinated commercial flocks, causing up to 76.8-84.4% mortality in India [19], 70-80% mortality in Indonesia [45], 60-70% mortality in Japan [40], and 5-50% mortality in Pakistan [29]. In Egypt, ND was first reported in 1948 [6], and it was classified as an endemic disease by the beginning of the 1960s [10].…”

Section: Discussionmentioning

confidence: 99%

Molecular characterization of full genome sequences of Newcastle disease viruses circulating among vaccinated chickens in Egypt during 2011–2013

Tran

Sultan

Osman

et al. 2020

The Journal of Veterinary Medical Science

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Although intensive vaccination programs have been implemented, Newcastle disease (ND) outbreaks, accompanied by severe economic losses, are still reported in Egypt. The genetic characterization of ND virus (NDV) strains isolated from ND-vaccinated chicken flocks provides essential information for improving ND control strategies. Therefore, here, 38 NDV strains were isolated and identified from outbreaks among vaccinated flocks of broiler chickens located in the provinces of Qena, Luxor, and Aswan of Upper Egypt during 2011-2013. The investigated broiler chicken flocks (aged 28 to 40 days) had high mortality rates of up to 80%. All NDV isolates were genetically analyzed using next-generation DNA sequencing. From these isolates, 10 representative NDV strains were selected for further genetic analyses. Phylogenetic analysis of full-length coding genes revealed that the Egyptian NDV isolates belonged to a single sub-genotype, VII.1.1. These isolates were phylogenetically distant from the vaccine strains, including La Sota or Clone 30 (genotype II), which have been commonly used to vaccinate chicken flocks. Amino acid substitution K78R was observed in the neutralizing epitopes of the F proteins; whereas several mutations were found in the neutralizing epitopes of the hemagglutinin-neuraminidase proteins, notably, E347K. Overall, our results suggested that the occurrence of neutralizing epitope variants may be one of potential reasons for ND outbreaks. Further studies are needed to determine the protective effect of current vaccines against circulating virulent NDV strains.

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Presence of Virulent Newcastle Disease Virus in Vaccinated Chickens in Farms in Pakistan

Cited by 69 publications

References 9 publications

Complete Genome Sequences of 11 Newcastle Disease Virus Isolates of Subgenotype VII.2 from Indonesia

Complete Genome Sequences of 11 Newcastle Disease Virus Isolates of Subgenotype VII.2 from Indonesia

Newcastle disease vaccines—A solved problem or a continuous challenge?

Molecular characterization of full genome sequences of Newcastle disease viruses circulating among vaccinated chickens in Egypt during 2011–2013

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