Host responses in the bursa of Fabricius of chickens infected with virulent Marek's disease virus

Abstract The aim of the study was to determine the effect of field strain, serotype 7 (FAdV-7 JN-5/10), of fowl adenovirus infection on the replication of Rispens/CVI988 strain of Marek’s disease virus. Ninety one-day-old SPF chickens were divided into six groups. The chickens from group I were vaccinated against Marek’s disease (MD) and 24 h later infected with the adenovirus; chickens from group II were vaccinated and infected simultaneously; chickens from group III were infected with the adenovirus and 24 h after the infection vaccinated against MD. The chickens from groups IV-VI were: control of infection (IV), control of vaccination (V), and neither vaccinated nor infected (VI). After 3, 7, 14, 21, and 28 d post infection, the number of copies of pp38 gene of Rispens strain and hexon gene of FAdV strain was determined in the bursa of Fabricius and liver using real-time PCR. The results indicated that in all cases the replication of Rispens strain was reduced to about 1.0 log10 - 3.5 log10 in chickens infected with the adenovirus and vaccinated against MD compared with the chickens only vaccinated. Sixty-three one-day-old SPF chickens infected with adenovirus and vaccinated against MD were challenged with vv MD virus field strain. The protection index in this experiment was 55.6%-77.8%.

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Isolation and identification of Marek’s disease virus (MDV) from feather follicle epithelium and internal organs of diseased chickens in Dakahlia Governorate, Egypt

Mansoura Veterinary Medical Journal ◽

10.35943/mvmj.2019.22.102 ◽

2019 ◽

Vol 20 (2) ◽

pp. 6-11

Author(s):

Aly El-Kenawy ◽

Mohamed El-Tholoth ◽

Emad A

Keyword(s):

Real Time ◽

Disease Virus ◽

Real Time Pcr ◽

Marek's Disease Virus ◽

Marek's Disease ◽

Marek’S Disease Virus ◽

Marek’S Disease ◽

Field Samples ◽

Feather Follicle ◽

Positive Results

In the present study, a total of 16 samples including feather follicle epithelium, ovary, spleen and kidney (4 samples for each organ) were collected from diseased chicken flocks suspected to be infected with Marek’s disease virus (MDV) at Dakahlia Governorate, Egypt during the period from October 2016 to October 2017. Each sample was pooled randomly from three to five birds (90 to 360 days old). The isolation of the suspected virus from the collected samples was carried out via chorioallantoic membranes (CAMs) of 12 days old embryonated chicken eggs (ECEs). Three egg passages were carried out for each sample. Hyperimmune serum was prepared against standard MDV. MDV in both field and egg passaged samples (after 3rd passage) was identified by agar gel precipitation test (AGPT) and indirect fluorescence antibody test (IFAT). Molecular identification of virus was carried out by conventional polymerase chain reaction (PCR) and real- time PCR in four selected samples. The results revealed that 14 samples (87.5%) including 4 (100%) samples from feather follicle epithelium, ovary and kidney and 2 (50%) samples from spleen, showed positive results in virus isolation after 3rd passage. The positive results percentage by AGPT for field samples were 50% (8 out of 16 samples), while after the 3rd passage in ECEs were 37.5% (6 out of 16 samples) and the positive results percentage by IFAT for field samples were 62.5% (10 out of 16 samples), while after the 3rd passage in ECEs were 81.25 % (13 out of 16 samples). Viral nucleic acid was detected in all selected samples by conventional and real- time PCR. The results indicate that feather follicle epithelium is the best organ for MDV detection. IFAT is superior over AGPT in virus detection. Conventional and real - time PCR could be efficiently used for molecular detection of the virus.

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