Morphological and Immunohistochemical Examination of Lymphoproliferative Lesions Caused by Marek’s Disease Virus in Breeder Chickens

Abstract

Marek’s disease is widely controlled by vaccination programs; however, chickens are not totally protected, especially immediately after the vaccination when a strong challenge could interfere with the effectiveness of vaccination in the absence of proper biosecurity practice. This case report describes the occurrence of Marek’s disease (MD) observed in a breeder chicken flock reared southeast of Sicily. MD outbreak occurred from 32 to 47 weeks with an increase in weekly mortality rate (+0.4–0.6%). Overall, mortality rate related to Marek’s disease was about 6% at the end of the cycle. Carcasses of chickens found during the occurrence of disease underwent necropsy, and tissues were collected to confirm the infection. Gizzard, cecal tonsil, intestine, spleen and tumor mass were collected and analyzed from a carcass of one hen, 32 weeks old and apparently asymptomatic. Multiplex real-time PCR performed on spleen tissues detected the presence of MD virus pathogenic strain. Macroscopic and microscopic evaluation of the rest of the samples confirmed the neoplastic disease. Moreover, the immunophenotype of the tumor cells was identified as CD3 positive by immunohistochemical (IHC) staining. The vaccinated flock had become rapidly infected with the MD virus, which proves that the challenge of the MD virus was too strong in the rearing house at the beginning of the cycle, causing the outbreak.

Molecular characterization of Marek's Disease virus reveals reticuloendotheliosis virus-long terminal repeat integration in the genome of the field isolates in Egypt

“…As depicted by our findings, the examined chickens suspected of being diseased displayed the enlargement of peripheral nerves, an ovary with a cauliflower-like appearance, as well as enlarged liver and kidneys with focal nodular lesions. These observations align with those documented in prior research ( Hassanin et al, 2013 ; Zhuang et al, 2015 ; Boodhoo et al, 2016 ; El-Kenawy et al, 2019 ; Stamilla et al, 2020 ; Ewies et al, 2021 ; Birhan et al, 2023 ). Notably, 31 of 36 (86%) clinical samples inoculated on CAM of 11-day-old SPF ECEs (REV-free), showed pock lesions, embryo dwarfism, a swollen greenish pale liver, and a pale appearance of the heart.…”

Economic and value chain analysis to support an investigation and risk mitigation efforts on Marek's disease in layers in the southern part of Thailand

“…Clinical signs of infected birds are most commonly seen between 12 and 30 weeks of age [30], and MD outbreaks usually occur from 32 to 47 weeks of the production cycle [31], which matches the median age of sick birds of 31 weeks recorded in this study.…”

Subclinical Clostridium Perfringens Infection and Marek’s Disease in Jordanian Broiler Chickens

“…1) which were mainly elongated and small to medium-sized lymphoblasts and lymphocytes. Tumor compositions are similar between organs, but sometimes the involvement may vary (Stamilla et al 2020;Khan et al 2021). Wen et al (2018) reported the existence of Marek's disease virus in the nucleus of lymphoid tumor cells in the liver with the presence of Meg Protein.…”

“…Marek's disease is a common avian infection in chicken flocks worldwide (Birhan et al 2021). The Herpes virus is an etiological agent which has three serotypes (Stamilla et al 2020). In chicken, Marek's disease virus (MDV) causes a variety of pathological signs and symptoms in poultry (Lopez et al 2019;Khan et al 2021).…”