title: Severe necrotic dermatitis in the combs of line 63 chickens infected with Marek's disease virus.
abstract: Marek's disease virus (MDV), the aetiological agent of Mareks' disease (MD), is a highly cell-associated oncogenic α-herpesvirus that replicates in chicken lymphocytes and establishes a latent infection within CD4(+) T cells. We investigated the possible effect of MDV infection on the exacerbation of necrotic dermatitis in the combs of MD-susceptible (72) and MD-resistant (63) chicken lines at 21 days post infection. MDV-infected birds of line 63 are relatively resistant to tumour development but exhibit an unusual necrosis of combs, wattles, and footpads that is intensified when infected with MDV. Chickens from line 72, on the other hand, are highly susceptible to MDV infection and tumour development. Real-Time PCR analysis revealed that IL-6, IL-8, IL-12, IL-18, iNOS, and IFNγ were all up regulated in the comb tissues of MDV-infected susceptible line 72 with no visible necrotic damage. With the exception of IL-8 and iNOS, the expression of all the other tested genes was barely detected in the necrotic combs of the resistant line 63. Real-Time PCR analysis revealed the MDV meq oncogene transcripts in the spleen tissues of both infected lines but in the comb tissues of only the susceptible line 72. A significant infiltration of macrophages and lymphocytes was detected in the comb tissues of both resistant and susceptible lines. Histopathological analysis also showed thinning and erosion of epidermis and inflammation, lympho-plasmocytic infiltration, heterophilic, and histocytic cellulitis within the connective tissues of the necrotic combs. Gram stain of the sectioned frozen comb samples exposed the presence of Gram-positive micrococcus.
authors.affiliation: a United States Department of Agriculture , Agriculture Research Service, Avian Disease and Oncology Laboratory , East Lansing , MI , USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Heidari
authors.affiliation: b College of Animal Science and Veterinary Medicine , Shandong Agricultural University , Tai'an , People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.affiliation: c Pathobiology and Diagnostic Investigation, College of Veterinary Medicine , Michigan State University , East Lansing , MI , USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Fitzgerald
authors.affiliation: b College of Animal Science and Veterinary Medicine , Shandong Agricultural University , Tai'an , People's Republic of China.
authors.forename: Shuhong
authors.initials: S
authors.lastname: Sun
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002645:Chickens / Q000235:genetics / Q000276:immunology / Q000821:virology*; D005533:Foot Dermatoses / Q000276:immunology / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D020869:Gene Expression Profiling / Q000662:veterinary; D008381:Herpesvirus 2, Gallid / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007249:Inflammation / Q000662:veterinary; D008380:Marek Disease / Q000276:immunology / Q000473:pathology / Q000821:virology*; D009336:Necrosis / Q000662:veterinary; D011201:Poultry Diseases / Q000276:immunology / Q000473:pathology / Q000821:virology*; D013154:Spleen / Q000473:pathology / Q000821:virology
chemical_list: D015415:Biomarkers
keywords: Marek’s disease; Real-Time PCR; histocytic cellulitis; lympho-plasmocytic infilteration; necrotic dermatitis