Correlation of Marek's disease herpesvirus vaccine virus genome load in feather tips with protection, using an experimental challenge model

Baigent, Susan J.; Smith, Lorraine P.; Currie, Richard J. W.; Nair, Venugopal

doi:10.1080/03079450701639319

Cited by 34 publications

(16 citation statements)

References 31 publications

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“…Our results indicated that virulence of the challenge MDV did not affect the ability of the vaccine HVT to replicate. It has been proposed that strong replication of MDV vaccine is necessary to acquire adequate protection (3,8,17). Results in this study suggest that adequate replication of HVT is not enough to warrant the protection against challenge with very virulent or very virulent plus challenge.…”

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confidence: 71%

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Load of Challenge Marek's Disease Virus DNA in Blood as a Criterion for Early Diagnosis of Marek's Disease Tumors

Gimeno

Cortes²,

Silva

2008

Avian Diseases

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Outbreaks of Marek's disease (MD) in vaccinated flocks still occur sporadically and lead to economic losses. Unfortunately, adequate methods to predict MD outbreaks are lacking. In the present study, we have evaluated whether high load of challenge MD virus (MDV) DNA in peripheral blood could aid in the early diagnosis of MD and in monitoring efficacy of vaccines against MD. One experiment was conducted to simulate field conditions by combining various vaccines (turkey herpesvirus [HVT] and HVT + MDV serotype 2 [SB1]) and challenge viruses (GA, Md5, and 648A). Vaccine efficacy among our experimental groups ranged from 13.3% to 94.2%. Each chicken was sampled three times during the length of the experiment (3, 5, and 15 wk postchallenge [wpc]), and gross lesions were evaluated in chickens that died and at termination of the experiment. DNA was extracted from whole blood and buffy coats from each sample, and the load of challenge MDV DNA and HVT DNA were quantified by real-time polymerase chain reaction. Chickens that developed MD by the end of the experiment had higher load of challenge MDV DNA (threshold cycle [Ct] glyceraldehyde-3-phosphate dehydrogenase [GAPDH]/Ct glycoprotein B [gB] ratios of 1.0, 1.04, and 1.05 at 3, 5, and 15 wpc, respectively) than those that did not develop MD (Ct GAPDH/Ct gB ratios of 0.7, 0.69, and 0.46 at 3, 5, and 15 wpc, respectively). However, load of HVT DNA in blood was not correlated with the development of tumors (Ct GAPDH/Ct HVT ratios from 0.04 to 0.10 in both groups). Vaccinated groups with >75% protection had statistically significant less challenge DNA virus (Ct GAPDH/Ct gB ratios of 0.76, 0.70, and 0.45 at 3, 5, and 15 wpc, respectively) than less protected groups (Ct GAPDH/Ct gB ratios of 0.92, 0.97, and 0.85 at 3, 5, and 15 wpc, respectively). No differences in the load of HVT DNA could be found between protected and nonprotected groups at any time point of the study (Ct GAPDH/Ct HVT from 0.05 to 0.09 in both groups). Our results showed that load of challenge MDV DNA but not load of HVT DNA in blood can be used as criterion for early diagnosis of MD.

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confidence: 71%

“…Data are presented as the mean and the 0.95 confidence interval. Differences between chickens without lesions (N) and with lesions (Y) at each time point (3,5, and 15 wpc) were statistically studied (Student t-test, P , 0.05). Within each time point, the same letter placed above the bars means that the differences were not significant.…”

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confidence: 99%

Load of Challenge Marek's Disease Virus DNA in Blood as a Criterion for Early Diagnosis of Marek's Disease Tumors

Gimeno

Cortes²,

Silva

2008

Avian Diseases

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“…The number of copies of the Rispens genome at 21 days post-vaccination is highly variable between birds [93]. Whether quantitation of the genome of vaccinating strains in feathers by qPCR allows to evaluate the level of protection of the flock in poultry farms remains to be determined [93,94]. …”

Section: Excretion Of Vaccinating Strains and Pathogenic Strains mentioning

confidence: 99%

Marek’s disease virus and skin interactions

Couteaudier¹,

Denesvre²

2014

Vet Res

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Marek’s disease virus (MDV) is a highly contagious herpesvirus which induces T-cell lymphoma in the chicken. This virus is still spreading in flocks despite forty years of vaccination, with important economical losses worldwide. The feather follicles, which anchor feathers into the skin and allow their morphogenesis, are considered as the unique source of MDV excretion, causing environmental contamination and disease transmission. Epithelial cells from the feather follicles are the only known cells in which high levels of infectious mature virions have been observed by transmission electron microscopy and from which cell-free infectious virions have been purified. Finally, feathers harvested on animals and dust are today considered excellent materials to monitor vaccination, spread of pathogenic viruses, and environmental contamination. This article reviews the current knowledge on MDV-skin interactions and discusses new approaches that could solve important issues in the future.

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“…The causative agent of MD is MDV, which is ubiquitous, globally distributed and very common in commercial poultry flocks with an estimated cost to the industry more than US$ 1-2 billion (Baigent et al, 2007;Morrow and Fehler 2004). Domestic fowls are the natural host of the MDV, but quail, geese and turkey are also affected.…”

Section: Discussionmentioning

confidence: 99%

Pathological investigation of Marek’s disease in a pullet farm of Bangladesh and detection of Marek’s disease virus by pcr

et al. 2018

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Marek's disease (MD) is a lymph proliferative disease of chickens, characterized by progressive emaciation, morbidity and mortality. The causative agent is a cell associated oncogenic alpha-herpes virus. This study investigated an outbreak of MD in a pullet farm (N=2200) of Ramu Upazilla, Cox's bazaar during May 2016 vaccinated against MD. The infectivity was reported on day 45 of age. Birds (N=10) submitted to diagnose disease at necropsy in the Department of Pathology, Bangladesh Agricultural University showed prominent keel bone, asymmetric progressive paralysis of one or both of the legs and wings. At necropsy, the skeletal muscle appeared thinner and there was enlargement of liver, spleen, kidney and sciatic nerve. Impression smears prepared from the liver showed huge infiltration of lymphocytes. Sections of heart, lungs, liver, kidney, nerve, skin and spleen were stained with hematoxylin and eosin showed wide spread infiltrations and accumulation of lymphocytes. Lymphocytic infiltration was seen in the skin, nerves and all visceral organs and showed combined infectivity due to visceral and classical forms. The etiology of MD was confirmed by using polymerase chain reaction (PCR) targeting fragment of Meq gene of very virulent plus or very virulent MDV1. Results of PCR showed amplification of 317bp fragment of Meq gene suggestive for infectivity due to MDV1GA (Md/5) strain. It requires isolating viruses in culture to test further for its virulence and pathotype in vivo. Sequencing and phylogenetic analysis of Meq gene may unveil the pathotype of the virus involved.

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Correlation of Marek's disease herpesvirus vaccine virus genome load in feather tips with protection, using an experimental challenge model

Cited by 34 publications

References 31 publications

Load of Challenge Marek's Disease Virus DNA in Blood as a Criterion for Early Diagnosis of Marek's Disease Tumors

Load of Challenge Marek's Disease Virus DNA in Blood as a Criterion for Early Diagnosis of Marek's Disease Tumors

Marek’s disease virus and skin interactions

Pathological investigation of Marek’s disease in a pullet farm of Bangladesh and detection of Marek’s disease virus by pcr

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